Faulty brake valve....any tips please?

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
JohnT
Posts: 344
Joined: 27 Dec 2003, 21:29
Location: United Kingdom
My Cars:

Faulty brake valve....any tips please?

Post by JohnT »

1995 XantiaTD. Replaced all spheres. After standing for a short time there are no brakes. On start up the car rises slightly after 15 seconds then settles down again. Any tips please on the problem, a previous post suggested it was a faulty leaking brake valve? Is this an easy job?
jeremy
Posts: 3959
Joined: 20 Oct 2002, 16:00
Location: Hampshire, UK
My Cars:
x 2

Post by jeremy »

Presumably the warning light is coming on? How fast is the regulator ticking?
jeremy
JohnT
Posts: 344
Joined: 27 Dec 2003, 21:29
Location: United Kingdom
My Cars:

Post by JohnT »

No warning lights Jeremy, only the top up light for the LHM which stops flashing after a few seconds.
jeremy
Posts: 3959
Joined: 20 Oct 2002, 16:00
Location: Hampshire, UK
My Cars:
x 2

Post by jeremy »

I think you will find that the 'top up' light for the LHM is linked to the pressure system and so will light on low pressure as well. I'm surprised it doesn't illuminate the STOP light as well - on BX it does as does a failure in oil pressure and excessive temperature (I think)
I don't think your problem is anything to do with the brake (doseur) valve but is an accumulator problem - so how often does it tick? If you run the car for a couple of minutes at normal height, turn off the engine and sit in the boot, what happens? It should sink and rise again to its original height after about 30 seconds.
Jeremy
RichardW
Forum Treasurer
Posts: 10814
Joined: 07 Aug 2002, 17:12
Location: United Kingdom
My Cars: MK2 '17 C4GP 1.6 BlueHDi 120
'13 3008 1.6 HDi GripControl
x 984

Post by RichardW »

"only the top up light for the LHM which stops flashing after a few seconds"
Orange one? If so that's the engine oil level. If it is a red one, flashing in line with the STOP light, then it's more likely system pressure, and your accumulator is probably flat. I would explore all avenues before touching the brake valve - replacing it is a night mare (have you seen where it is???[}:)]) and there's some suspicion that the tooling is worn out, and new ones don't last very long at all[:D]
JohnT
Posts: 344
Joined: 27 Dec 2003, 21:29
Location: United Kingdom
My Cars:

Post by JohnT »

The only light to have flashed is the 'top up LHM' light.(Have done). I have tried running it and sitting on the boot and it does not rise again but is still bouncy. At this stage I have no brakes (engine not running). Pump ticks every 12 seconds. When I try Citrobics the car will not rise from low to high at the rear, but if I go from low to middle the rear will eventually rise, then I can take it to maximum height from there. Weird eh?
JohnT
Posts: 344
Joined: 27 Dec 2003, 21:29
Location: United Kingdom
My Cars:

Post by JohnT »

Am hoping to keep this post alive, and Jeremy and Richard might get back to me please?
RichardW
Forum Treasurer
Posts: 10814
Joined: 07 Aug 2002, 17:12
Location: United Kingdom
My Cars: MK2 '17 C4GP 1.6 BlueHDi 120
'13 3008 1.6 HDi GripControl
x 984

Post by RichardW »

John,
Still not sure what light you are referring to as "top up LHM" but no matter, that's a side issue.
12 seconds is far too often. So either: 1. The accumulator is flat or 2. the system is losing pressure very rapidly somewhere. Or both!
Is it a hydractive car, or just an ordinary one?
You might be able to trace the return line from the brake valve, and pull it off somewhere to see if it is leaking excessively.
How's the LHM - changed recently, filters cleaned?
You say new spheres - did this include the accumulator? Were they new, or regassed ones?
jeremy
Posts: 3959
Joined: 20 Oct 2002, 16:00
Location: Hampshire, UK
My Cars:
x 2

Post by jeremy »

I agree with Richard.
I do not think its the brake valve - by all means replace it but I think after a week when the new LHM has mashed up everything will be exactly the same.
Regulator/accumulator problems are common and often cheap to solve.
I still think you have a unique warning light.
Your car has the 2 outlet pump and the smaller part (2 cylinders) feeds the brakes and suspension which means that the suspension can take its time to rise.
have a look at this thread particularily at the end.
http://www.andyspares.com/discussionfor ... C_ID=15188
jeremy
JohnT
Posts: 344
Joined: 27 Dec 2003, 21:29
Location: United Kingdom
My Cars:

Post by JohnT »

Thanks for that to both of you! It is not a Activa, yes it was a new sphere,LHM not changed yet. I think that I will remove that 'ball' as per Jeremys archive post and do a hydroflush. I will let you know of the outcome, thanks again.
Post Reply