Brake failure

This should be a simple one for you guys. I noticed when I last used my B that the brake pedal needed to be pressed twice to get good braking power. Now, after a few weeks of non-use the pedal just goes straight to the floor. No brakes at all!! On checking the fluid level it was now low so I topped it up. This has made no difference.
Ok. Obviously I have a fluid leak and now probably air in the system as well. The question: How do I find where the leak is. I have pumped the pedal with the car in the garage but am not getting fluid on the floor. Is it likely to be a pipe union or the master cylinder? If its the Master Cylinder, can these be repaired easy? I think the MOSS catalogue shows a "seal kit" Is this what I need to repair it??

Ian,
If it is not leaking under the car or at any of the wheels , then it most likely the master cyl. You can try a rebuild. I usually just buy a new cyl and bleed the system carefully.
Good luck.

Steve

This could be something as simple as running out of fluid and air entering the system, all the way up to needing new BMC and new wheel cylinders. Pull off your rear wheels I bet you have a nice gooey substance on the inside of the rim and wheel.

Meaning the fluid is leaking out the wheel cylinder or cylinders. They'll need to have new seals inserted or new cylinders, it depends on the cylinders themselves and your skill level.

If you happen to see no fluid at the rear wheels, then I would suspect the Brake Master Cylinder, and these can either be rebuilt, which I normally do, or a new one can be sourced easily enough.

B

Clean everything up well, then refill and bleed the system. Press hard on the brakes and hold for a while. Wherever you find something wet, that's your leak. Use talcum powder to make it easier to spot the fluid if necessary.

Usually the malady starts with the warning of having to pump the brakes. Then often nothing.
Sounds like MC failure. As the others said, if it aint leaking out, the m/c is dead. Half the time you can successfully 'rebuild' it by disassembly, replacing the internal parts, polishing the interior of the bore, reassembly, bench bleed, then reinstallation. ++Be glad the brake failed while you were stopped.++

As you are looking for the usual culprits of wheel cylinders, MC's, etc remember to inspect every connection.

Many thanks to all you guys for your input. At least now I know what to look for and am probably looking at replacing the MC. But as Scot says, I am eternally grateful that they failed when the car was in my garage!!!
Ian

I'm not sure what type of MC they used on european spec cars, but if it's the dual circult type, they are pretty tedious to rebuild w/ the seal kit you mentioned. There are two spring clips that are a bit difficult to remove and a plastic ring that is also a pain to remove. When the time came to rebuild mine I just replaced it w/ a new one.

Cheers - Paul

The master cylinders are quite rebuildable - as long as they have not corroded and developed pits. The rebuild kit is a fraction of the price of a new cylinder.

BUT - and I may be misreading your skills - but doing the rebuild requires a fair amount of skill and experience. Given that it is your brakes you are dealing with, you may want to pick up a new master cylinder.

BUT - if you are meticulous, it isn't that bad of a job. Let us know if you plan to go the rebuild route and we'll tell you all of the tricks to doing it right.