Good afternoon.

Long story short:

We replaced the ABS pump twice (first because fluid was blocked to one wheel causing hard pedal and then because we thought a thread on the replacement was damaged) and also a flexi brake line. We bled the brakes all three times, and then more times because we didn't know why the pedal still didn't feel right. All of these times we did not use the block under the pedal technique, as we weren't aware this causes seal damage. Now it seems that the problem with the brake pedal is because of this, as it feels firm after a little bit of travel, then gradually sinks to the floor with maintained pressure while servo assisted, in about 30 seconds. We also changed the front brake pads after the first pump but before the flexi line. I'm aware with new pads it should feel softer, but surely not this soft.

It seems to get enough pressure to stop most of the time, but you don't know what it will do in an emergency, so we have decided to replace the master cylinder. The first thing I wanted to ask is if it sounds like this is definitely the problem.

This car has the "19 FTE 5615" brake master cylinder. Two replacements we have been looking at our the Delphi LM80267 and the LPR 1056. The LPR is cheaper, but I don't know if there is any reason it won't be good enough.

There is a gasket between the brake servo and the master cylinder, which you are supposed to replace if it has perished. I can't tell if it has perished or not without removing the master cylinder, and I'd rather have one ready than needing on part way through the job. I would normally just reuse whatever was there, but this could cause a vacuum leak if it isn't perfect and I can't be bothered with it becoming a longer story. The problem is that I can't find what the part code for this gasket is. I spoke to customer service at autodoc, and they gave me the number of a generic part labelled as being for a BMW but also used on other cars: 357 611 243. Google Gemini, which I was using to help with diagnosing the problems, reckons this is actually a seal for the pedal side of the servo, not the master cylinder side, but it couldn't get the numbers of compatible master cylinders right to save its life, so I would take that with a grain of salt. That being said, I don't know what the correct part is. I couldn't find it in the Fabia chassis manual from this website either, though maybe I was looking the wrong place. That also is for pre facelift Fabias and lists larger diameter master cylinder so may not be correct for my 07 anyway.

I'm not in a rush to get this sorted as the car is useable and we have other cars, but it would be nice not to drag it out. Any ideas?

The car is an 07 Fabia Mk1 Ambiente with BME engine, if it makes any difference.

Kind regards,

Elliott

Part number seems correct as shown here, and the description matches the position you want.

21 hours ago, Breezy_Pete said:

Part number seems correct as shown here, and the description matches the position you want.

Excellent, thank you very much!

What part of the manual is that from?

That's a screened from partslink24, a subscription parts website.

2 hours ago, Breezy_Pete said:

That's a screened from partslink24, a subscription parts website.

OK, thanks. That's good to know.