Brake woe's.....any hints or tips please

[Kingsford G]

Going to have it looked at on Thursday, fingers crossed it's found/fixed cheaply.

If u were near I have a good master cylinder and could sort it out whatever it is.

[960kg]

Only trying to help......

So many people when changing pads etc. don`t open the bleed nipple when pushing back the caliper piston, this can make the valves in the ABS unit get £££££e in them as well as forcing fluid the wrong way it was designed for in the Master Cylinder!

This results in MAYBE dirt from the old brake fluid blocking the ABS valves and also reversed lips on the master cylinder seals.

Although these things are possible they don`t often happen but one should always take precautions and do things the fail proof way.

To check the master cylinder get someone to look in the reservoir with the top off when another pushes the brake pedal on the FIRST stroke and if faulty you will see the brake fluid stirring
because of the backward flow of the fluid.

Because these things are pretty rare i would first look at the caliper pistons as i would bet one or more is sticking with a rusty ring around cylinder bore.

Squirt some WD40 onto the piston seal and passed the seal to see if it solves the problem then you will know more where your at.

[Brett855tdi]

I wonder if you have a bleed nipple sucking air when its hot? just a thought...

When you bleed it again and get your temporary fix... do you get any air out?

[V70 Graham]

When you bleed it again and get your temporary fix... do you get any air out?

Last time I bled them was after the braided hoses were fitted so not really ideal to check.

[Harvey]

When the pedal goes soft does the car stop in a straight line or does it pull to one side a bit (which is not normal for it).
If so then its a good chance it the master clyinder or

If you drive along with the windows open and turn left or right at low speeds near full lock can you hear the pads dubbing on the discs,this would be a pad sticking in a caliper,or a worn wheel bearing,or
(if you have had a couple of track days warped discs from high speed stops )

If the pedal is getting soft all the time,get the brakes tested on a brake rollers MOT type then that would show up any problems.

[V70 Graham]

It does stop in a straight line, though if it was a rear calliper it should still stop without wandering.
Wheel bearings were replaced last Autumn, did TRAX and MAYBE a disk is warped, but.....it still wouldn't explain why after bleeding the pedal firms up and after using the brakes hard pedal travel is longer and will stay that way till I bleed again !

[Harvey]

It does stop in a straight line, though if it was a rear calliper it should still stop without wandering.
Wheel bearings were replaced last Autumn, did TRAX and MAYBE a disk is warped, but.....it still wouldn't explain why after bleeding the pedal firms up and after using the brakes hard pedal travel is longer and will stay that way till I bleed again !

No i was only jokeing about the warped disc as you would feel it in the steering wheel.
It does sound like a master if you brake hard the seals in the master would take the brunt of the force.
see if you garage would do a brake test I think it would show up the part at fault.

If the master is at fault the n/s to o/s would be way off on locking force.

[V70 Graham]

Still no further forward, was going to go for the master cylinder but the place I was at yesterday was sent the wrong one

Will let a few of the guy's have a look at the meet tomorrow, see if they have any ideas.