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Volvo Bus Service and Maintenance Manual

 Sensitive door seals
101 Check the sensitivity setting and that the warning buzzer sounds when the door seals sense an obstruction. If the warning buzzer does not sound, check the tightness of the plastic tube connections and the door seals.
 Door cylinders
102 Make sure that the cam disc, switch and switch bracket clamp nuts and bolts are tight.
 Every two years, disassemble, clean and lubricate the door cylinder (applies to city buses). Use Bosch Ft 1v5 grease.

Sensitive door seals

Normal type city bus door

The sensitive edge of the rear doors must automatically open the doors when something sticks between them.

Mostly the automatic system consists of air inside the sealing strips forming a pressure wave which actuates a diaphragm in an electric shut-open switch.

Tightness, therefore, is important to the function.

Normally the shut-open switch can be adjusted if the automatic system reacts too late.

It should be possible to activate the automatic system during door closing. Check that the end position switch cuts out the automatic system when the door is open.


Normal type tourist coach door

If the automatic door system is fitted, very often it is built into the door mechanism. The rotating movement of the drive column stops if a passenger should get trapped beween the door panels and the portal. However, the cylinder piston moves the rotating column and the worm gear axially further. This action is transferred on a bearing hub mounted electric microswitch by a rotating column mounted switch ring with groove. The microswitch activates a solenoid valve and the door opens.

Door switches
Door switches
Door cylinder
Door cylinder