Volvo Service Manual TP 15052/1

Group 72 Spring Assembly

Design and Function

Leaf Springs (BLF)

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B10M buses with the leaf-type suspension may be fitted either with the conventional semi-elliptical leaf springs or parabel springs. The suspension consists of leaf springs suspended from the frame by means of spring bolts and attachments. The springs and spring attachments are provided with pressed-in rubber bushings with vulcanized sleeving.

All B10M buses with leaf spring suspension are also provided with hollow rubber springs, both front and rear. The hollow rubber springs make for greater stabilization.

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Both the front and rear springs may be of the conventional or parabel type. Suspension for both types is similar.

The conventional leaf spring has a high internal friction due to the fact that the spring leaves lie together and develop friction when moving against each other during spring movements.

In contrast to conventional springs the parabel spring has very little internal friction because the spring leaves are separated from each other.

Parabel-type spring leaves are thickest in the middle and taper towards the ends, whereas conventional spring leaves have the same thickness throughout their entire length.

Parabel spring low friction and spring leaf design result in a somewhat smoother bus ride than is the case with conventional springs. Other advantages with parabel springs are that they are lighter and last longer. On the other hand, however, parabel springs have less torsional rigidity and are more expensive than the corresponding conventional springs.

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Service Procedures

Replacing spring bushings

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1.Jack up the bus approx. 150 mm and place stands under the frame. Lower the jack to off-load the springs.
2.Remove the U-bolts, spring bolts and rear attachment plates. NOTE! The rear spring must be supported from underneath before removing the U-bolts.
3.Disconnect the anti-roll bar and move it aside to enable the spring to be removed.
4.Lift out the spring.
5.Place the spring in a press. Support under the spring eye with a ring made according to the drawing on page 6. Press out the bushing.
6. Grease the new bushing with a equal mixture of vaseline and paraffin wax.
7.Place a pressed-in sleeve made according to the drawing on page 6 on the spring eye. Place the bushing in the sleeve and press it in. Support underneath with the ring. After pressing in the bushing, make sure that it projects equally on both sides of the spring eye.

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8.Re-install the spring, fit and screw tight the attaching plates and spring bolts. Tighten the spring bolts to a torque of 390 Nm (39 kgf m).
9.Fit the U-bolts and connect up the anti-roll bars. Tighten the U-bolt nuts to a torque of 685 Nm (68.5 kgf m).

Testing a spring

The springs can be tested in a hydraulic press. One condition is that the press is provided with an adequately accurate pressure gauge. Moreover, the press must be such that it is not possible for the spring to slide out sideways.

1.Place the spring inverted in the press with a movable support at both ends.
2.Apply pressure to the centre bolt and press the spring past the testing position 3 times. This must be done in order to reduce material and frictional stresses.
3.Press the spring to the testing position (Meas. A) and read off the pressure gauge.
Concerning the size of measurement A, see "Specifications".

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4.Press spring still further downwards. Let it return to the testing position and read off the pressure gauge.
The average of the both read-off values should agree with that given in the "Specifications".
If the values do not tally, the spring should be overhauled or replaced.

Disassembling the Spring

Great care should be observed when disassembling a spring because of the large inter-tension between the spring leaves. A special spring press for disassembling and assembling spring leaves should, therefore, be used for this purpose. If no such press is available, use a couple of powerful screw clamps.

Checking and Replacing Parts

Check the spring leaves for cracks and wear. A faulty spring leaf must be replaced. Check also that the spring leaf lateral guides are riveted on properly.

Assembling a Spring

Place an iron ring of the same diameter as the centre bolt in a vice. Invert the main leaf and fit it through the iron ring. Lubricate the spring leaf with spring grease. Fit and lubricate the other leaves in the same way. Compress the spring and replace the circular bar with the centre bolt. Fit the spacer sleeves, bolts and nuts for the retainers on the spring leaves.

Air suspension (LUF)

Design and Function

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Note: Front Axle from B10M Mk III manual.
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Note: Rear Axles from B10M Mk III manual for Bus and Bogie (Tag) Axle Coach.

Note: The original text (immediately below) from the manual refers to "the above Fig." but the original manual did not have a diagram. Therefore these Mk III diagrams may not be accurate for the Mk I.

The air-suspension system for the B10M is constructed according to the above Fig. It does not have any leaf springs and for this reason requires a special front and rear axle suspension.

The front end is suspended in rubber-journalled reaction stays which are attached by means of brackets between frame and front axle. Longitudinal forces are taken up by four reaction stays, two on each side, and placed in front of the front axle. Lateral forces are taken up by a transverse reaction stay, attached between a bracket in the chassis frame and front axle. Roll is dampened by an anti-roll bar suspended from a rubber journal and placed behind the front axle (see Group 76, page 35).

The rear axle is attached to two longitudinal members, one at each wheel pair. Fitted at the ends of the members are the air bellows.

The members and rear axles are vertically located by two lower and two upper rubber-journalled reaction stays. The two lower stays, which take up the longitudinal forces, are attached between the air-suspension members and brackets on the chassis frame.

The two upper stays, which take up the lateral forces, run at an angle from the chassis frame towards the rear axle casing where the ends are fixed to attachments welded to the rear axle.

Roll is taken up by a rubber-journalled anti-roll bar fitted behind the rear axle (see Group 76, page 35).

The bellows and shock absorbers must work within the stipulated limits. Therefore, where so required because of the tolerance situation at the suspension members and reaction stays, shims are placed between the upper stays and the rear axle casing and between the lower stays and the chassis frame attachments. These shims are available in thicknesses of 2 and 4 mm and compensate for difference in level between the rear axle's front and rear air bellows (see Group 70, "Specifications", page 2).

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The air-suspension consists of six rubber bellows with pistons. Two air bellows are placed between the front axle and the chassis frame. At the rear axle there are four air bellows, two on each side and placed between the frame and air-suspension members. Ail six bellows have a height of 249±3 mm. Compressed air is supplied via the four-circuit protection valve. A common level valve regulates the air in both the front bellows. The air in the four rear bellows is regulated by two level valves, one for each side. This makes for increased anti-roll in long bends because the air pressure is able to counteract the roll in time, The level valves are provided with check valves and air filters (see page 19 and page 20).

In order to obtain a greater suspension, bellows pistons are used to increase the volume. The total suspension volume for the front pair of bellows is 25.5 dm3. For the 4 rear bellows the total volume is 48.0 dm3.

Some B10M buses with the air-suspension system have manual level control. Bus level can thus be raised about 50 mm higher from the ground. Level control is intended to be used where there are large differences in levels, e.g., when driving onto and off ferries.

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Level control is of the electro-pneumatic type. Engaging the push-button ("LEVEL") on the dashboard, sends an impulse to a solenoid valve in the compressed-air circuit of the spring system. On being engaged, the solenoid valve releases compressed air to the level control working cylinder (see air springing layout diagram), which is placed on the control rods for the level control valves. These control rods are shorter than those on vehicles without level control. When air is forced into the working cylinder, this extends the control rod to raise the level valve lever. The valve opens and releases more air into the bellows to raise the chassis frame until the lever is in neutral position (horizontal).

When the ("LEVEL") switch is switched off, the compressed air in the working cylinder is exhausted and the lever goes down so that the chassis frame sinks until the lever is in the neutral position.

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Level Valves

The level valves are placed on the chassis frame and are actuated from the axles by their respective control rod and lever. The length of the control rods is adjustable in order to adjust the height of the bellows.

A level valve consists of two main parts: a compressed-air part and a hydraulic part (damping part). Both are operated by the lever (1), spring (2) and piston (3) and the rotatable control shaft (4) in the valve housing. When the lever (1) is turned, the spring (2) tries to turn the control shaft. Through the action of the spring, a determined idling movement during driving is obtained between the lever and the inlet and outlet valve, during which time the damping part of the valve starts functioning.

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Function, Compressed-Air Part

During constant load (A), the inlet and outlet on the level valves are closed and the air bellows have a pressure corresponding to the load.

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When the bus is loaded (B), the load actuates the lever to push the guide and open the inlet valve. Compressed air flows to the bellow/bellows and the bus chassis is raised. The raising of the bus actuates the lever to such an extent that when the correct level is reached, it shuts off the flow of compressed air to the bellow/bellows.

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When the load reduces, this actuates the lever to open the outlet valve. The bus chassis level drops until the lever has returned to its initial position, at which point the outlet valve closes. With this arrangement, floor height is kept constant irrespective of the load.

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Function, hydraulic part

The input shaft and guide pins are linked to the inlet and outlet valves and to the damping piston operating in the oil.

The damping mechanism is at rest in the neutral position.

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The lever is freely journalled on the input shaft. Lever movement is transferred to the input shaft via a spring-loaded piston. This causes a certain delay so that the level valve does not react to minor road unevenness.

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When the lever is turned, it tries to turn the input shaft with it, and this in its turn tries to push in the damping piston working in the oil. The oil is forced to pass from the one side of the damping piston to the other. The only passage is between the damping piston and housing. The resistance to the oil flow which arises prevents the damping piston, and thereby the input shaft, from moving just as quickly as the lever. Instead, the piston in the lever is displaced, the springs are compressed and the piston presses on the shaft.

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This pressure is reinforced by the reduction, the input shaft is actuated by a turning moment and strives to take up the same position as the lever. The time it takes will depend on the resistance provided by the damping piston. The delay is approx. 1.5 seconds.

Check Valve

The check valve, which is mounted on the inlet side of the level valve, prevents air from flowing from the level valve to the reservoir for extra equipment. This is necessary when the pressure in the air bellows becomes greater than the pressure in the feed connection due to bus movement or for any other reason.

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Air filter

An air filter is mounted on the outlet on the level valve to protect it against dust.

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Air spring

The air bellows are of the roller type. They consist of an outer layer, of rubber, two layers of cord and an inner layer of rubber. The rubber quality is selected with a view to resistance to temperature and oxygen in the air. The cord layers are laid at an angle in relation to each other in order to achieve smooth bellows swell when pressed down by bus load.

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The bellows seal at the top against an upper plate and at the bottom by a so-called roller-type piston. The sealing is more or less the same as that for an ordinary tubeless tyre. In order to get the greatest possible air volume in the bellows, the pistons open so that also the air inside the piston can be utilized. Large air volume provides good travelling comfort.

When bus load presses down the bellows, they roll over the piston, and when load is reduced the bellows roll back and expose a large part of the piston's outer surface. This surface is so designed that it can provide a suitable rolling radius for the bellows from the viewpoint of lifetime. When the bus takes a bend at high speed, spring deflection will be large on the one side. The rubber buffer, which is attached to the underside of the bellows upper plate, is then pressed against the top side of the piston and limits spring movement. Similar situations arise when the bus is suddenly driven over a dip in the road. The rubber buffers also provide a safety factor in the event of sudden loss of pressure in the air springing system.

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Service Procedures

Testing air springing function

Special tools: 2795, 2788

1.Detach the control rod from the level valve. Lower the lever and let the air out of the compressed-air reservoirs.
2.Disconnect the connection for the air bellows at the level valve outlet. Fit instead the T-piece prepared with connection nipple 2788 between the level valve and the hose to the air bellows.

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3.Connect test instrument 2795 to nipple 2788.
4.Move up the level valve lever and fix it in this position. Charge the compressed-air system. Observe at the same time the bus's gauges and test instrument gauge. When the air system has been boosted to 460-490 kPa (4.6-4.9 kgf/cm2) (bus pressure gauge), air should start to flow through the level valve and cause the test pressure gauge pointer to indicate a rise in pressure.
If the pressure is greater than that specified for the opening pressure for the air suspension, the four-circuit valve should be removed and adjusted and, if necessary, overhauled (in which case see Section 5 "Brakes").
5.Move the level valve lever to the neutral position. The test instrument gauge pointer should not move.
6.Move down the lever. Air should now flow out through the level valve and the pressure gauge pointer should drop towards zero. Move the lever up to the neutral position again.
7.Rapidly push up the lever from the neutral position, note the time it takes for the test pressure gauge pointer to rise, that is, the damping time.
Move the lever back to the neutral position. Quickly move down the lever and note the time it takes for the test instrument gauge pointer to start to drop.
Repeat the tests 3 times in order to get reliable results. The damping time should be 1-2 seconds. If it is not, adjust the level valve, in which case see under "Testing and adjusting the level valve".
8.Connect the control rod to the level valve lever. If the bus chassis height above the ground is to be checked or adjusted, this could suitably be done before connecting up the control rod. In which case see under "Adjusting the height of the bellows".
9.Lower the pressure in the reserve reservoir and, on the gauge, note the pressure drop in the air bellows.
The pressure drop must not exceed 20 kPa (0.2 kgf/cm2) in one minute.
If pressure drop is excessive, this is generally due to a faulty check valve.
10.Remove the hose from nipple 2788 and the T-piece between the level valve and the hose to the air bellows. Connect the hose from the air bellows to the level valve outlet.

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Level valve

Removal

1.Release air from the wet tank.
2.Disconnect the control rod from the lever and move down the lever to release air from the bellows.
3.Disconnect the hoses from the valve.

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4.Remove both retaining screws and take down the valve.

Installation

1.Set up the valve and fit and tighten up the screws.
2.Fit the hoses to the valve.
3.Fill the compressed-air system with air. Check the height of the bellows and connect the control rod to the lever.

Testing and adjusting removed level valve

Special tools: 2788 (two), 2800

Use test bench 2800 for testing and adjusting the level valve. Also required for testing are: connection nipples, stop sleeve, stop bolt and adjusting drift. For the making of these, see Group 70, "Special Tools".

Note: Service Bulletin 7-72-08 'Shorter lever when testing level valve in fixture' may apply.

Setting up level valve in fixture

1.Secure the fixture in a vice. Invert the valve and secure it in the fixture.
2.Remove the check valve and air filter from the level valve.

Mechanical basic adjustment

3.Remove the lock ring, cover washer and 0-ring. Lift up the guide pin.

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4.Insert the adjusting drift in place of the guide pin in the valve. Make sure the drift bottoms. If necessary, raise the lever slightly.
5.Fit securely the stop sleeve and stop screw on the valve lever. The narrow end of the sleeve must face the fixture. It should now be possible to insert the sleeve in the fixture recess without having to alter the position of the lever. If necessary, adjust the position of the lever in relation to the valve.

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6.Remove the adjusting drift. Insert the guide pin with the narrow end in first. Fit the 0-ring, cover washer and lock ring.
7.Turn the fixture in the vice so that the valve is correctly positioned.

Checking function of and adjusting valves

8.Fit test nipples on the valve. Plug one of the outputs on the bellows.

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9.Turn the stop sleeve so that the wide end faces the lever.
10.Prepare test bench 2800 as follows:
K1: closed R: screwed out K2: closed
K3: closed K4: open K5: closed
Connect test bench to workshop air supply.
11.Connect hose D to valve inlet marked "1" and a hose to the nipple marked "2" in the bellows outlet. Insert the other end of the hose in a bottle containing water.

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12.Screw in R on test bench until pressure gauge M2 indicates 0.1 MPa (1 kgf/cm²). Move the lever to the zero position. No air bubbles should now form in the bottle.
13.Move up the lever until the stop sleeve goes against the fixture stop. If the inlet valve is correctly adjusted, air bubbles should start rising in the bottle first when the stop sleeve reaches the upper stop. Permitted tolerance is ±1 mm. With correct function, continue from Step 15. With faulty function, continue from Step 14.
14.Disconnect hose D from nipple. Remove nipple. Remove inlet valve lock washer. Adjust inlet valve with a crosshead screwdriver. If valve is screwed inwards, it opens earlier and if it is screwed outwards it opens later. Lock valve with lock washer. Fit nipple and connect hose D. Repeat Step 13.

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15.Disconnect hose D from valve. Transfer nipple from inlet marked 1 to outlet marked 3. Connect hose D to bellows outlet marked 2 and connect a hose between outlet and bottle containing water.

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16.Move down lever until stop sleeve goes against fixture stop. If outlet valve is correctly adjusted, air bubbles should start rising in bottle when stop sleeve reaches lower stop. Permitted tolerance is ±1 mm. If function is correct, continue from Step 18. If not, continue from Step 17
17.Remove nipple from outlet. Slacken outlet valve lock washer. Adjust outlet valve. If valve is screwed inwards it opens earlier, and if it is screwed outwards it opens later. Lock valve with lock washer. Fit nipple to outlet. Connect hose. Repeat Step 16.

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Checking for leakage

18.Fit check valve and washer in inlet.
19.Turn stop sleeve with the narrow end facing the fixture. Lock lever by inserting sleeve in fixture recess.

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20.Screw in R so that pressure gauge M2 indicates 0.6 mPa (6 kgf/cm²). Check if air bubbles form in bottle. Maximum permitted leakage is one air bubble during 30 seconds.

21.Disconnect hose D from valve. Connect hose in bottle to outlet on bellows. Remove check valve. Transfer nipple from outlet to inlet. Connect hose D to inlet.

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22.Check if air bubbles form in bottle. Maximum permitted leakage is one air bubble during 30 seconds.
23.Disconnect hose D from valve. Remove nipples. On front level valve also remove plug.

Preparing level valve after testing

24.Remove stop sleeve and stop screws.
25.Fit check valve and air filter. Use new sealing washers.

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26.Remove valve from fixture.

Overhauling the level valve

Disassemble the parts according to their numbered sequence, 1 to 29. Remove the air filters (22,23) by levering loose with a suitable screwdriver. Removal damages the filters, so they have to be replaced by new ones.

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Wash thoroughly all parts and blow dry with compressed air. All sealing rings and other types of seals should be replaced in connection with a complete overhaul.

Check the moving parts for wear. Replace worn or damaged parts.

All moving parts, slide surfaces and seals in the compressed-air section must be greased for the compressed-air components.

Fill the damping section with approx. 5 cm³ silicon oil Bosch AK 250. During the filling, which is carried out between Steps 19 and 20 below, turn the lever back and forth in order to remove air.

Note the difference between the inlet and outlet valve. The slighter spring-loaded pin is on the inlet valve and the harder spring-loaded pin is on the outlet valve.

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Assemble the parts according to the numbered, encircled, sequence, 1 to 29. After Step 14 fit the lever complete with control shaft and O-ring in the valve housing. After Step 24, carry out the mechanical basic adjustment according to instructions on page 22.

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Note that the valve must not be locked by the lock rings 28 and 29 until final pneumatic adjustment has been carried out (see page 22). This check on the adjustment, function and sealing must always be carried out after a level valve overhaul.

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Check valve

If it is suspected that the check valve is leaking, depressurize the system and remove the valve. Blow it thoroughly clean and test it (see below). Replace if faulty.

Testing check valve

Special tools: 2788 (two), 2880

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1.Prepare test bench 2880 as follows:
K1: closed R: screwed out K2: closed K3: open K4: open K5: open. Connect test bench to workshop air supply.
2.Prepare check valve, see Fig. Connect hose A to check valve inlet (M14) and hose D to outlet (M12).
3.Slowly screw in R until M1 and M2 indicate approx. 700 kPa (7 kgf/cm²). During the charging, the pointers on the M1 and M2 gauges should also indicate a steady increase in pressure.
4.Close K3, K4 and K5. M2 must not drop. If it does, then valve is leaking and must be replaced.
5.Open slowly K1. Check M2 for 1 minute. Maximum permitted pressure drop 20 kPa (0.2 kgf/cm²).
6.Remove hoses and connectors.

Air filter

Wash the filter in petrol. Before re-fitting it, blow it clean and dip it in oil.

Checking bellows height

When check-measuring bellows height, the bus must be on a flat surface and all tyres have correct air pressure.

Boost the compressed-air system to full pressure. Measure height of bellows from underside of upper attaching plate to underside of the bellow-piston. Bellows height should be 249±3 mm for all bellows.

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Note! The edge of the bellow-piston is located approx. 4 mm lower than the underside of the piston (lower attaching plate).

Adjusting bellows height

The rear bellows should always be adjusted first. Start with the side which deviates most with regard to bellows height.

1.Remove the control rod lock nuts and the control rod from the attachment to the shaft (or air-springing member).
2.If bellows height is too low, move the level lever up so that the height becomes higher than that stipulated, and then lower the bellows to the correct level by moving down the lever. If the bellows height is too high, pull down the lever and let out sufficient air to reduce the bellows to correct height.
3.Adjust length of control rod and tighten up.

Replacing air bellows (applies to both front and rear bellows)

1.Jack up under the front axle, or rear axle if rear bellows are to be replaced. Place stands under the frame front end (or rear end).

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2.Lower the axle the max. permitted by the shock absorbers. Allow the jacks to remain.
3.Wait until the bellows are pressureless. With a jemmy or similar tool lever off the upper edge of the bellows.

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4.Pull out the bellows and piston. Hold tight the piston and pull off the bellows. Check the piston guide pin, and replace piston if pin is damaged.
5.Clean the bead plate and bellows piston.
6.Fit the piston in position. Make sure the guide pin is fitted properly in the guide hole.
7.Grease the edges of the bellows with Wabco West 1 or corresponding.
8.Squeeze together the new bellows and fit them between the piston and bead plate. Check that the upper edge of the bellows makes a tight fit against the plate.

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9.Release the level valve control rod (or working cylinder).

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10.Boost the compressed-air system. Move up the level valve lever to allow air to flow into the bellows. Press the bellows against plate and piston making sure it makes a tight fit. If necessary raise the axle slightly. Fill the bellows until they make a completely tight fit.
11.Lift under the axle, remove the stands and lower the bus.
12.Fit the level valve control rod to the lever. Wait until the bus chassis stops sinking (lever in neutral position). Check bellows height on both sides (249±3 mm). Adjust if necessary (see page 26).

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Replacing bushings on rear reaction stay

Special tools: 2000, 6616, 6617

Upper reaction stay

1.Jack up under the rear axle, place stands under the frame members behind the crossmember, at a height of approximately 600 mm. Lower the rear axle as far as the shock absorbers will permit (the rear wheels should be on the floor).
2.Remove the rear air bellows at the stay which is to be removed, see under "Replacing air bellows" on page 26. Slacken the clamp for the bellows feed tube. Remove the bellows upper retaining plate.

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3.Make a note of any shims at the reaction stay's front attachment (rear axle casing).
4.Remove the front retaining bolts and any shims.
5.Unscrew and remove the rear mounts for the reaction stay.

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6.Lift forwards and take down the reaction stay.

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7.Place the stay in a press. Position support ring 6616 under the end of the stay.
8.Press the bushing out of the reaction stay with handle 2000 and drift 6617.

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9.Place the new bushing on the reaction stay. Check that the attachment is at an angle of 90° in relation to the stay (concerns front bushing).

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10.Press in the new bushing with drift 6617. Support under with ring 6616. Press until the bushing projects equally from both sides.

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11.Invert the stay and replace the other bushing according to Steps 8-10.
12.Fit the stay. Also fit any shims that have been removed in the same position they were before removal. Fit but do not tighten up the retaining bolts. This is done when the rear end is lifted to the "neutral position", that is, corresponding to a bellows height of 249 mm.
13.Lift under the rear axle until the rear end is at the correct level in relation to the chassis frame (bellows height 249 mm).
14.Torque-tighten the reaction stay retaining bolts to a torque of 85 Nm (8,5 kgf m).
15.Lower the rear end.
16.Fit and screw tight the bellows upper plate. Tighten up the clamp for the bellows feed tube.
17. Fit the air bellows, see under "Replacing air bellows", on page 27.
18.Remove the stands.
19.Check bellows height: 249±3 mm, see page 26.

Lower reaction stay

1.Lift and place stands underneath according to Step 1 for "Upper reaction stay".
2.Note if there are any shims (these have to be replaced in their original position).
3.Remove the front retaining bolts (3) and the washers.

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4.Slacken the rear retaining bolts and tap out the bolts. Remove any shims.

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5.Bend down the rear end of the reaction stay with a jemmy.

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6.Pull the stay out from its front attachment.
7.Replace the bushings according to Steps 7-11 under "Upper reaction stay".
8.Lubricate the stay front bushing and pin on air suspension member with chassis grease.
9.Press the stay over the pin on the air suspension member and bend up the rear end of the stay towards the bracket with a jemmy.

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10.Fit the washers and the three front retaining bolts but do not tighten hard.
11.Tap in the tour rear retaining bolts and re-fit any shims.
12.Screw nuts on the rear retaining bolts but do not tighten hard.
13.Lift under the rear axle until the rear end is at the correct level in relation to the chassis frame (bellows height 249 mm).
14.Tighten the front and rear retaining bolts to a torque of 85 Nm (8.5 kgf m).
15.Remove the stands and lower the rear end.

Replacing bushings, front longitudinal reaction stays

1.Lift under the front axle, place stands under the frame front end (approximately 90 cm height above floor). Allow the jacks to remain.

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2.Lower the front axle and allow compressed air to flow out of the bellows.
3.Remove the shock absorber. Use a hammer and drift for removing the upper sleeves.

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4.Disconnect the control rod from the level valve.
5.Remove and fit the reaction rods one side at a time, starting by slackening the rear bolts in order to release tension.

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6.Lift the front axle somewhat higher than "normal position" (= 249 mm bellows height).
7.Release the front bolts on the lower stay, mark the stay position and note any shims (these must be re-fitted in their original position).

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8.Press down the stay front end and pull out the stay. If it jams, weld a nut (ex. 1/2" UNC) and a large washer (ext. diameter 52 mm) together. Weld the washer to the stay bushing. Screw in a bolt, length approx. 80 mm, and pull loose the stay.
9.Slacken, mark the position and remove upper stay and any shims. Press the stay down to the lower attachment, lower the front axle far enough for the stay to go past the bracket. Pull out the stay.
10.For replacing bushings, see under "Rear upper reaction stay", Steps 7-11.
11.Lubricate the bushings and pins with chassis grease. Start by installing the upper stay to its rear attachment. Press the stay up into the front bracket. Lift up the front axle, press up the stay and fit the retaining bolts but do not tighten up.
12.Fit the lower stay but do not tighten up the retaining bolts.
13.Fit any shims in the same position they had before removal.
14.Lower the front axle to the "normal position" (= 249 mm bellows height).
15.Tighten all retaining bolts to a torque of 85 Nm (8.5 kgf m).
16.Fit the shock absorber: Tightening torques: 140 Nm upper bolt, 245 Nm lower nut.

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17.Fit the control rod to the level valve. Fill the compressed-air system.
18.Remove the stands and lower the bus.

Replacing bushings, front transverse reaction stay

1.Jack up and place stands under the front axle according to Step 1, "Replacing bushings, front longitudinal reaction stays", page 30.
2.Lower the front axle and wait until the air bellows are depressurized. Disconnect the control rod from the level valve.
3.Remove the three retaining bolts on the front axle attachment.
4.Raise the front axle until the transverse stay is horizontal. Place stands under the axle.
5.Note any shims on the transverse stay right attachment.

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6.Remove the three retaining bolts and washers on the front axle attachment.

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7.Remove the four right retaining bolts and any shims.
8.Bend down the transverse stay right-hand end and pull out the stay from the pin on the front axle attachment.
9.Replace the bushings according to Steps 7-11 "Rear upper reaction stay" on page 28.
10.Lubricate the pin on the front axle attachment and the bushing in the transverse stay with chassis grease.
11.Press the stay onto the pin and press it up to the right-hand attachment.
12.Fit the retaining bolts, washers and any shims.
13. Lower the front axle until the distance front axle — chassis frame corresponds to a bellows height of 249 mm.
14.Tighten all the retaining bolts to a torque of 85 Nm (8.5 kgf m).
15.Connect the control rod level valve and fill the compressed-air system.
16.Remove the stands and lower the bus.

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