For some time now I have been having problems with the boot lock on my A4 avant not registering as closed so it does not lock. i have taken the lock out twice and found no damage but idenditifed that it was todo with the electrical contact which registered the closed position.
Today when investigating a leak from the rear washer i stumbled across the problem and hopefully have fixed it!
The water hose attaches to the wiper unit and this often comes off, however i had a more serious problem.
Essentially this is a hollow shaft on which the wiper arm is fixed, moving with a rubber seal on each end trying to hold high pressure water. The water was leaking inside the unit, filling the gears with water which was dripping out into the boot lock and shorting it out.
I completely removed the unit and using a Torx 10 removed the screws. Water was escaping all round the body.
This was what i found inside
Basically the seal between the wiper shaft and the input nozzle had failed and the unit was filling with screenwash. This has caused the mechanism to corode badly and become stiff.
I removed the motor from the unit as well to give it all a good clean, but be warned: It is fiddly to get it all back together. You need to take the plastic unit containing the motor brushes and mount this back on the motor spindle before carefully putting the whole lot back on the mechanism.
This is the offending part, notice the rubber on the end of the shaft has perished
This is the seal it goes into
Cleaning the whole lot up
When reassembling it, i used lots of general purpose grease.
After fitting the unit back on the boot lid, do not put the wiper arm on yet, but put the ignition on and the mechanism will return to the park position. You can then put the arm back on.
I am not sure if the seal will work with the level of corrosion on mine, but to be honest i don't use the rear wash that often and certainly won't be buying a new mechanism as the cost will be frightening.
Would be worth you guys checking before yours gets as bad as mine.
Matt
Today when investigating a leak from the rear washer i stumbled across the problem and hopefully have fixed it!
The water hose attaches to the wiper unit and this often comes off, however i had a more serious problem.
Essentially this is a hollow shaft on which the wiper arm is fixed, moving with a rubber seal on each end trying to hold high pressure water. The water was leaking inside the unit, filling the gears with water which was dripping out into the boot lock and shorting it out.
I completely removed the unit and using a Torx 10 removed the screws. Water was escaping all round the body.
This was what i found inside
Basically the seal between the wiper shaft and the input nozzle had failed and the unit was filling with screenwash. This has caused the mechanism to corode badly and become stiff.
I removed the motor from the unit as well to give it all a good clean, but be warned: It is fiddly to get it all back together. You need to take the plastic unit containing the motor brushes and mount this back on the motor spindle before carefully putting the whole lot back on the mechanism.
This is the offending part, notice the rubber on the end of the shaft has perished
This is the seal it goes into
Cleaning the whole lot up
When reassembling it, i used lots of general purpose grease.
After fitting the unit back on the boot lid, do not put the wiper arm on yet, but put the ignition on and the mechanism will return to the park position. You can then put the arm back on.
I am not sure if the seal will work with the level of corrosion on mine, but to be honest i don't use the rear wash that often and certainly won't be buying a new mechanism as the cost will be frightening.
Would be worth you guys checking before yours gets as bad as mine.
Matt
