After recently getting the estelle road legal its brakes have failed. no sudden dangerous giveway just seemed to fade out over an hour or so, it now takes alot of road to stop from a snails pace . heres some symptoms any knowledge would be massively helpfull.

      engine off ,brake pedal is half hard and will pump up,turn engine on pedal goes to floor with little to no resistance and very little braking power.I think the fact the pedal goes to the floor when engine starts indictes the servo is working, but i checked that anyway,

           firstly i started the car and listened to it run at idle, no major inlet leeks, then i removed inlet servo vacum obvious inlet air mix leak so i place finger over inlete vacum pipe port and i runs the same as with servo connected.this indicating servo vacum pipe is ok.

   i then tested the servo end of the servo/inlet manifold pipe resulting in the same diagnosis that the pipe is ok.

 another thing to note is that the fluid levles have not changed throught this hole episode, indicating that im not losing brake fluid or introducing air to the system.

 when the rain stops i will have a go at bleeding the system but i cant see where any fluid could have been lossed (without levels in fluid resevoir dropping) in order to draw air? any ideas ? cheers

 

What you describe sound like a brake fluid leak with it loosing brakes gradually... Start at each brake and work you way back to the master cylinder looking for leaks.

Hi h39,

l would suspect the master cylinder seals have failed if the car has not been used for some time. The master cylinder is of the twin ciruit type & if the seals fail fluid just flows between the two circuits. Check for fluid contamination coming from the dust cover around the pedals. Pete

thanks for the quick replies. is the dust cover around the pedals the atmospheric pressure port for the servo?? am i looking for fluid around the port? or looking for contaminents in the brake fluid reservoir? now its not raining for five mins i will inspect all the brake lines/pipes ,although im sure i would see a drop in reservoir level if i was leaking fluid?. again thanks gentlemen.

Is it worth checking the rear drums? The cylinders are prone to leaking brake fluid and this might not be entirely obvious. You could jack up the back end and apply the handbrake sufficient to give resistance under normal circumstances, leaking fluid will contaminate the pads so you should see more wheel rotation than expected. This could be on just one side though.

Hi h39,the brake master cylinder sits vertically on top of the servo, operated via a pushrod from the brake pedal. If the cylinder is leaking ,fluid dribbles down the back of the brake peddle in the foot well. Pete

This will almost certainly be caused by a failed brake master cylinder leaking internally. They rarely leak externally in my experience. Seal kits and/or new master cylinders are available from Skoparts International.

 

If there was a problem with the brake servo or the vacuum hose that goes to it the symptom would be the opposite, a rock hard pedal.

This will almost certainly be caused by a failed brake master cylinder leaking internally. They rarely leak externally in my experience. Seal kits and/or new master cylinders are available from Skoparts International.

 

If there was a problem with the brake servo or the vacuum hose that goes to it the symptom would be the opposite, a rock hard pedal.

i removed the master cylinder and inspected inside the cylinder and also the pistons and springs ,it was pretty skank. although after cleaning off any stubborn residues it wasnt to bad. this is the insides before cleaning.

 

i think this seal was the main factor.

 so a quick trip to local motorbitzofactors and no seal kits available , apparently according to them "no ones repairing them these days, your a few years late. ha" so......

  skoparts international here i come. thanks

 forgot to mention i rebuilt the cylinder and bleed the system quickly at the master cylinder. drove 15 odd miles with a good responsive pedal! although i think rears need some work as im locking up at the front before noticing any real "action" from rear brakes.

Edited 7 January, 201412 yr by h39