1.9tdi B6 front brakes binding

[beano1]

Recently the front brakes have stated binding with all the normal symptons of heat rising from the disc brake area, the wheels getting very warm and the normal asscoiated smells.
I have stripped and cleaned the fronts calipers, which appeared to resolve the problem initailly but its back however I did notice that when cold the brakes appear Ok along with normal brake pedal operation, with a bit of slack on depression before the brakes appear to bite, when the binding starts the brake pedal is extremely sensative with just the slightest touch and the brakes bite.
This morning the brakes appear to be binding from cold
I have looked at all the threads asscoiated with brakes binding but not sure how to test the servo and master cylinder if they are posible candidates for replacements, especially with the price being asked.

Any suggestions would be appreciated

Regards

[Turbokiisseli]

It could be that water has collected in your brake servo. Check it there's water in the battery bay as it's a common problem and has been discussed here as well numerous times.

[Marco34]

This does sound like the servo sticking for sure! It's the same symptoms I had. It would only free up when I powered of the engine! New servo did the trick.

[tyberwan]

Does your wheel heat up diagonally? That is, the front left and the right rear at the same time? If it is, then it is either the servo or the master cylinder which is the result of a rusty servo due to the plenum chamber problem.

The only test for servo I know so far is from the garage itself. Looks like they know how it feels or sound, and they will open it. But a servo replacement is quite expensive.

[dubstar81]

Mine is doing that right now It is a right pain.
I checked for water near the servo and battery area and it is dry as a bone.
I am also getting brake fade at low revs aswell.
I have been told it is a weak vacuum pump. Maybe it could be connected.

[beano1]

I have decided to get the servo/master cylinder assembly out of the car and check rust etc, howvere at the moment Iam having difficulty getting the ball head on the servo mechanisim to come free from the brake pedal assembly.
Theres a sepcial tool T40024 which gets over this but at £74 a shot there must be other ways this can be achieved. Can you make up an improvised tool or is it just persevere with screw drivers or anything else which will pry the ball out of the plastic holder?????

[beano1]

Just fro info the problem was the Servo and kuckily the Master cylinder was OK. The only real issue was sepaerating the servo ball mechanism from the brake pedal assembly as UI was;nt going to spend £ 75 on an Audi special tool and the Haynes suggestion of using part of an Exhuast clamp did not work, so evtually had to remove the lever assembly from the brake pedal and get a nwe one £20 versus £75 no brainer bit would like to know how others have got the ball assembly out of the brake lever.
Thanks again for your assistance.

[tyberwan]

You mean you managed to remove the black round box (servo)? What was wrong with it and did you replace that? How much did that cost you? How about the brake fluid replacement?

[beano1]

Yep, Replaced the Servo which when I removed found to be rusty inside.
The cost was about £150 from Eurocarparts which includes a new rubber ring seal.
And last completedly bleed the brakes all round which was not as bad as I was expecting, especially with the ABS unit and some of the horror stories I have read on the forum.
Overall a reasonably easy job with the xeception of getting the servo assembly off the Brake pedal.