ZX brake pressure regulator valve problem

Post by **CitroJim** » 24 Oct 2008, 12:41

Nope, that's not just a union TBONE, that is a pressure regulator/compensator. I've had experience of these on 205 and 309GTis where they fail for a pastime.

Usually they restrict the pressure too much and the car fails the MOT on low rear brake effort. I guess they can be dismanted but the couple I've tried have defeated me as they are done up so tightly. Secondly, it's a braking component and I take no chances there

The GSF one should be fine. They're a pretty common/universal component across the PSA range.

TBONE · Post by **TBONE** » 24 Oct 2008, 12:52

ahhh well but the chap isn't on about that valve ( whatever you want to call it

) hes on about a leaking union, no disrespect intended

Post by **CitroJim** » 24 Oct 2008, 13:24

TBONE wrote:ahhh well but the chap isn't on about that valve ( whatever you want to call it ) hes on about a leaking union, no disrespect intended

I'm pretty sure, after reading this thread about 10 times, that the picture of the device is the item he is speaking of unless I've having a bit of a senior moment (not unusual for me these days

). The item in the picture is exactly what RichardW has identified as the pressure limiter.

It does act as a convenient union though!

RichardW wrote:No, I don't know why it needs one for either side - why not just one in the main feed line?

The disc braked 205s and 309s have two Richard and I've often pondered exactly the same question. Maybe on account of the diagonal dual-circuit brake split perhaps or a terrible mistake in the PSA Parts procurement office where they ordered twice as many as needed and hid the error by fitting two to every car

Gets expensive when both fail at the same time.

citronut · Post by **citronut** » 24 Oct 2008, 13:50

aaaaah, what i thought you were talking about is bottom right in Richards picy item No. 2, i would have agreed with TBONE on those being just pipe unions, but Richard points out they are listed as pressure regulators so they must be more than they first look,

also the load compensating circuit dose not take a diferant route than the main feed, it just restricts the presure untill you have wheight over the rear axle

regards malcolm

TBONE · Post by **TBONE** » 24 Oct 2008, 14:07

at least we agree ( it just restricts the pressure until you have weight over the rear axle ) that's what a proportioning valve does compensator valve means the same thing and it diverts fluid according to the pressure on the rear axle, the other things are just unions and Ive done loads of them and glad of them because it saves a lot of pipe work because you only need to change a small section

in fact those unions are a good idea when doing standard break pipes and can be fitted half way down the car so you don't have to change the full lot so making the job easier

bv2991 · Post by **bv2991** » 24 Oct 2008, 14:13

Tbone,

the leak is not from the pipe union. It's from the valve body itself. There's a built-in pinhole on it, and fluid comes out from this pinhole.

I've seen a different type on a drum brake 306, but the valves are way smaller in size.

'Course, would be nice to just rid of this valve and modify the section, but since this is safety-related item, I'm not going to take chances my friend! ha ha....

TBONE · Post by **TBONE** » 24 Oct 2008, 14:18

so it has a pressure release valve in it and if that's the case your problem is over pressure from the main valve from what your saying and that compensator valve does get stuck with rust witch's make it in I would spray the linkage with wd 40 and work it loose, worth a try
I must admit I never really noticed that pinhole before let alone had any problems like that,

update: checked mine and it doesn't have that pin hole so its possible its a defect also the reason they are larger than the pug is because of the pressures involved