Rear discs need changing again.

[Mechanical Numpty]

Morning,

Once again the rear discs need replacing due to corrosion. And I'm told it looks like they haven't been assisting with braking at all. Does anyone know where the brake actuator/compensator is for the rear discs and what it looks like?As I'm looking to change them myself.

It's a 52 octy. 110 tdi.

Many thanks

Mn

[buddy]

looks like you need new rear callipers aswell i had this on my 130 tdi

[Mechanical Numpty]

Thanks for the reply. But why would I need new calipers?

Edited 30 April, 2013 by Mechanical Numpty

[Frisco]

Because if the face of the disc is rusty they aren't working

[rwbaldwin]

Do you have ABS?

If not, follow either rear brake pipe forward until you reach the brake power regulator. Assuming the spring isn't broken, increase the spring tension to increase pressure to the rear calipers.

It is extremely rare to see this arrangement with four discs.

[Mechanical Numpty]

Car definitely has ABS, the brake power regulator is what I want to check if it exists. Thanks for the replies.

[rwbaldwin]

Car definitely has ABS, the brake power regulator is what I want to check if it exists. Thanks for the replies.

As you have ABS, it does any proportioning so you don't need or have a brake power regulator.

Generally, you only have a brake power regulator if you have rear drums, but I have seen a car with four discs, no ABS and a regulator (really odd set of options).

Have you tried bleeding the brakes?

Do you get fluid out of the rear brakes?

Jack up one of the rear wheels, chock the others, release the handbrake and have someone press the brake pedal. Does it stop the wheel turning?

[trundlenut]

Is the whole disc corroded or just part of it?

The back brakes tend to get mucky especially over winter and on my old car the pads were not moving easily in the calipers and so were only coming into contact with part of the discs, leading to corrosion around the edges.

I cleaned up the callipers, pads and the little stainless steel shims that sit between the pads and callipers.