audi 100 avant hand break problem, help please

[ktepf]

Hi, my audi has a very poor MOT reading for the hand break, it has just passed with a lot of leaverage.
In preperation for this predicted problem I have replaced the pads, discs, cables, and checked the callipers for wear, cleaned them and manually checked the handbreak leaver system on the calliper, all appears to be OK, but its not, the results on the rebuild are very bad, there is good feeling in the cable when pulled, just the correct travel has been set, yet still I can not get the handbreak to grab, can anyone give me some advice please?
Regards
Keith

 

[Burnerman]

The only thing I can (sort of) suggest here is that the cable levers, on the back of the caliper, should be right back against the stop before the cables are connected.
So, with the self adjusting mechanism hopefully having done their job, check that the levers are right back, touching the stop before you finally adjust the cable.
John

 

[ktepf]

The only thing I can (sort of) suggest here is that the cable levers, on the back of the caliper, should be right back against the stop before the cables are connected.
So, with the self adjusting mechanism hopefully having done their job, check that the levers are right back, touching the stop before you finally adjust the cable.
John

Thanks John, so is the following the correct procedure (with the ends of the cable removed from the calliper)
1. push back both arms on the callipers to there travel stops
2. press foot break with engine on to take up any piston slack
3. re fit the cables
4 tighten the cables with the nut on the adjuster near the tunnel to hand tight feeling.

I have noticed that the balance yolk on the cable adjuster has off set arms, is 'which way round' critical on re fitting , and why is it offset?

Regards
Keith

 

[^neo^]

You're going wrong on step 2.

The pistons self adjust by unscrewing, so any slop you have when you push the pistons right back needs to be taken up by unscrewing the piston. Very fine thread on it so may need to wind it out 20 turns before you notice any difference

 

[ktepf]

You're going wrong on step 2.

The pistons self adjust by unscrewing, so any slop you have when you push the pistons right back needs to be taken up by unscrewing the piston. Very fine thread on it so may need to wind it out 20 turns before you notice any difference

Thanks for that tip. Do I need to adjust the pistons for a handbreak that is ineficiant, as the MOT test for the foot break test past all OK, so I am asuming that the tolerances are acceptable?.
By way of interest how does the piston self unscrew, just by motion and rotation of the pad/disc?
Any more ideas about the balance yolk on the handbrake cable within the tunnel near the handbrake.?
Regards
Keith

 

[^neo^]

Basically, the piston works 'as a piston' for the footbrake, but the handbrake mechanism inside the caliper has a screw thread on the back of the piston. They're supposed to self adjust, but never come across one that does!