Rear brake limiter

[simonpen]

My S1 Rallye S has a limiter valve for the rear brakes. Do these come apart for servicing? Mine appears not to let any fluid past it..

[nistri]

Dores it have a bleed nipple? Andrea

[simonpen]

Yes

[simonpen]

To answer my own question. I have now found a schematic in a manual, (this valve is also found on the GTE), which comes with overhaul instructions. It contains various rubber 'O' rings  and a ball bearing. A good internal clean is also required. Omicron may have the parts and do offer a rebuild service. 

[nistri]

Good to overhaul the limiter: I assume you could not bleed through its bleed nipple. However, please bear in mind that an important issue is to bleed the servo, not a very simple thing to do, Andrea

[simonpen]

Andrea. We had been able to bleed using the nipple on the limiter and at one point had some rear braking. Later however while bleeding through the rear callipers we were unable to get any fluid out, although we had previously ejected a lot, along with some air. It was the sudden change that made me think that something had gone wrong with the limiter internals. As for the servo, the front brakes seem to be fine with an instant bite from the pedal. All this was done without the engine running.

[nistri]

A simple test would be to just slacken the outflow tube from the limiter to the rear brakes and see if there is any fluid coming out. Then one might try to see if doing the same to the inflow tube to the limiter, indicates that fluid is reaching the limiter OK. Andrea

[simonpen]

I have now rebuilt the limiter and have braking on all four wheels. The device itself did not look too bad disassembled, a bit of 'gunge' but other than that ok. Perhaps one of the seals was letting by. Anyway, a worthwhile exercise, should have done it when the engine was out.