Skoda Octavia Mk 1 brake problem

[carosio 188]

Octavia 1.9 TDI 2000 (off road)

 

Fault is brake pedal slowly sinks down when engine is running, but rock solid when switched off. Today I discovered what appears to be split vacuum pipes and the braided one I think might be punctured underneath the frayed part. I don't know what the function is of the attached valve.

 

Skoda websites mention probabilities as master cylinder seals, ABS system etc but none mention the symptoms as described. Hopefully it's a lack of vacuum.

 

Anyone any suggestions please?

 

http://s665.photobucket.com/user/carosio/media/DSC06453.jpg.html?sort=6&o=0

http://s665.photobucket.com/user/carosio/media/DSC06452-1.jpg.html?sort=6&o=2

[Jabroni 10]

Does sound like master cylinder seals to me mate. Have you checked everywhere for brake fluid leakages?

[carosio 188]

Does sound like master cylinder seals to me mate. Have you checked everywhere for brake fluid leakages?

 

There's no leaks, the system has been bled but i know that bleeding with the wrong technique can damage the seals, but why would the pedal be firm when engine is not running?

[choogling 15]

Octavia 1.9 TDI 2000 (off road)

 

Fault is brake pedal slowly sinks down when engine is running, but rock solid when switched off. Today I discovered what appears to be split vacuum pipes and the braided one I think might be punctured underneath the frayed part. I don't know what the function is of the attached valve.

 

Skoda websites mention probabilities as master cylinder seals, ABS system etc but none mention the symptoms as described. Hopefully it's a lack of vacuum.

 

Anyone any suggestions please?

 

http://s665.photobucket.com/user/carosio/media/DSC06453.jpg.html?sort=6&o=0

http://s665.photobucket.com/user/carosio/media/DSC06452-1.jpg.html?sort=6&o=2

clamp off all the flexi hoses and retest, then release clamps one at a time retesting every time,report back with results.

[carosio 188]

clamp off all the flexi hoses and retest, then release clamps one at a time retesting every time,report back with results.

 

Ok, although I read somewhere that some hoses are PTFE lined or something and don't take kindly to being clamped.

 

I might not get opportunity to do anything for a day or two and will have to dodge weather.

[choogling 15]

never known it, flexis are just two rubber tubes.

[H Damnation 10]

If it is slowly sinking to the floor you either have a fluid leak somewhere or the seal in the master cylinder is letting fluid past.

 

If you are not losing fluid than it is the master cylinder seal.

[Digitalis 10]

Don't clamp the rear hoses near the axle pivot, they are indeed lined and can be damaged by clamping.

[choogling 15]

Don't clamp the rear hoses near the axle pivot, they are indeed lined and can be damaged by clamping.

All flexis are lined and all could be damaged by over clamping, what makes skoda hoses special.Just done a google search and can find no mention of brake pipe failure due to clamping or special construction of skoda pipes.

[Shogun 10]

If the pedal is going down it is either air in the system a leak in the seals of the master cylinder or one of the wheel cylinders is leaking.there is also a chance that the vacuum pipes to the master cylinder might be leaking air.if the brake fluid level is not going down that would indicate that there is no leaks of fluid in the system.I would guess that the master cylinder is not functioning correctly for some reason.

[choogling 15]

The Ford galaxy had a very poor master cylinder fitted we have one that has had three fitted by ford, we fitted the last one supplied by SDL and that seems to be lasting OK been on three years.

[carosio 188]

I'm sure its not leaking fluid as it's been stood a few weeks and I've had all the wheels off, cleaned the discs, examined brake pipes etc. Over the next few days I'll seal the suspect vac pipes and check again, but I do suspect that it is the cylinder as has been suggested. If it is, it looks a devil to get out.