Diff locks on 86 b2q

90 B2 quattro · 29-12-11, 07:54 AM

Hey guys, I was wondering if you could help shed some light on why my diff locks don't seem to be working?

I was at the beach recently going along a sandy track and tried to engage the diff locks but they didn't engage at all?

The lights on the rocker panel didn't come up wen i flicked the knob, even after pulling off? IS this a common fault? If anyone can help me with some ideas that would be greatly appreciated.

Cheers in advance Adam.

Tonks4x4 · 29-12-11, 08:10 AM

Usually the difflock actuator linkage seizes on the diffs, or you have a vacuum leak.

90 B2 quattro · 29-12-11, 08:48 AM

Thanks for the quick responsw Tonks, where are the linkages located, also where abouts is the most likely place for vacuum leaks. Ta

Tonks4x4 · 29-12-11, 09:12 AM

Can you hear the vacuum working behind the dash when you move the switch?

The linkage usually seizes on the end of the actuating rod on the read diff itself.
If you jack up the rear left and support it on axle stands, the actuator is mounted on the top LH side of the diff. give it a spray with some WD40 and see if you can manually move it back and forth. be very carful as the plastic components are very brittle.

Vacuum leaks can be in the engine bay where it gets the vacuum, where it passes through the bulkhead it can get damaged, on the back of the selector switch the rubber can deteriorate, the actuator on the side of the gearbox and the one on the diff can actually split in half if the metal shield around it has gone rusty.

ChrisG · 29-12-11, 03:29 PM

I would suggest doing the actuators first --very common problem and if they are siezed then no amout of vacuum will help !
I had a prroblem with this ( the car was about 6years old when I got it) but it turned out to be vacuum in the engine compartment. The plastic pipe was very brittle and had various breaks on its way to the bulkhead. I just replaced all of it with a new length of hose, longer lasting than thin plastic !
Didn't have any more trouble during the next 18 months -- after which I moved on to a B4 2.8 quattro!

90 B2 quattro · 31-12-11, 06:41 AM

Thanks for the that, I did the actuators and they seemed fine and weren't seized, found the problem to be the same as ChrisG, the plastic pipe had broken where it comes out of the bulkhead next to the battery. Thanks again for the advice.

29-12-11, 08:10 AM	#2
Tonks4x4 4 ring whore! Classic Audi Club Member Join Date: Oct 2008 Location: Huthwaite, Nottinghamshire Posts: 2,607	Usually the difflock actuator linkage seizes on the diffs, or you have a vacuum leak. __________________ http://www.tonks4x4.com

29-12-11, 08:48 AM	#3
90 B2 quattro Grown up member Join Date: Mar 2011 Location: Dunedin, NewZealand Posts: 168	Thanks for the quick responsw Tonks, where are the linkages located, also where abouts is the most likely place for vacuum leaks. Ta

29-12-11, 09:12 AM	#4
Tonks4x4 4 ring whore! Classic Audi Club Member Join Date: Oct 2008 Location: Huthwaite, Nottinghamshire Posts: 2,607	Can you hear the vacuum working behind the dash when you move the switch? The linkage usually seizes on the end of the actuating rod on the read diff itself. If you jack up the rear left and support it on axle stands, the actuator is mounted on the top LH side of the diff. give it a spray with some WD40 and see if you can manually move it back and forth. be very carful as the plastic components are very brittle. Vacuum leaks can be in the engine bay where it gets the vacuum, where it passes through the bulkhead it can get damaged, on the back of the selector switch the rubber can deteriorate, the actuator on the side of the gearbox and the one on the diff can actually split in half if the metal shield around it has gone rusty.

29-12-11, 03:29 PM	#5
ChrisG Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: Bracknell, Berks. Posts: 1,465	I would suggest doing the actuators first --very common problem and if they are siezed then no amout of vacuum will help ! I had a prroblem with this ( the car was about 6years old when I got it) but it turned out to be vacuum in the engine compartment. The plastic pipe was very brittle and had various breaks on its way to the bulkhead. I just replaced all of it with a new length of hose, longer lasting than thin plastic ! Didn't have any more trouble during the next 18 months -- after which I moved on to a B4 2.8 quattro!

31-12-11, 06:41 AM	#6
90 B2 quattro Grown up member Join Date: Mar 2011 Location: Dunedin, NewZealand Posts: 168	Thanks for the that, I did the actuators and they seemed fine and weren't seized, found the problem to be the same as ChrisG, the plastic pipe had broken where it comes out of the bulkhead next to the battery. Thanks again for the advice.