LHM leak

moremeba · Post by **moremeba** » Thu Dec 14, 2006 8:27 am

Hello all. My Phase 2 16v has just developed a lhm leak, its not totally dumping the fluid, but enough to make the stop light flicker on when braking or going round corners. Can anyone suggest where to start looking to diagnose the problem?

Any help/advice greatly appreciated.

Barry

cavmad · Post by **cavmad** » Thu Dec 14, 2006 9:28 am

Moremba, it could be from one of a number of places mate. Might be worth putting the suspension in `high` and leave the engine running and then carefully looking around under the bonnet and also under the car itself to see where it`s coming from.

tim leech · Post by **tim leech** » Thu Dec 14, 2006 9:32 am

Like he says, but for gods sake dont crawl under the car if its not supported on axle stands etc!

jeremy · Post by **jeremy** » Thu Dec 14, 2006 9:35 am

If the stop light flickers when going round corners - then the LHM level is too low and it should be topped up immediately.

LHM level can drop if a sphere goes flat. make sure all your spheres are OK - can all corners be compressed when the car is at normal height - or is one or more rock solid?

The accumulator can be checked by getting the car to normal height, letting it run for a couple of minutes, then turning off the engine and sitting in the boot. The car should drop a long way then rise to its original position after 30 seconds or so - just like it does with the engine running.

If you think the leak is to the outside try parking it on a clean bit of ground, leaving it for a few minutes and then moving it and seeing where the drips are. This should give you a clue where to look.

cavmad · Post by **cavmad** » Thu Dec 14, 2006 10:24 am

tim leech wrote:Like he says, but for gods sake dont crawl under the car if its not supported on axle stands etc!

Good point Tim. That`s what I meant to say (hence `check carefully`) but I should have written it better.

tim leech · Post by **tim leech** » Thu Dec 14, 2006 10:45 am

N worries Billy, I did it myself once when sorting my backbox out and it sank a bit and scared me to death!

Never again

Way2go · Post by **Way2go** » Thu Dec 14, 2006 12:23 pm

jeremy wrote:The accumulator can be checked by getting the car to normal height, letting it run for a couple of minutes, then turning off the engine and sitting in the boot. The car should drop a long way then rise to its original position after 30 seconds or so - just like it does with the engine running.

I know that this is a favourite test of yours Jeremy but in my experience it does not work in ABS cars as the rear brake circuit is attached to this suspension.
Much simpler & reliable to listen to the clicking interval of the pump at idle and when it becomes too frequent you know the accumulator is due for a change.

moremeba · Post by **moremeba** » Thu Dec 14, 2006 1:29 pm

Many thanks for the advice gents! i will have a look this coming weekend, to see if i can find the source of the leak.
BTW in your experiences are these faults costly to resolve? IE non easy diy job as i see there is a nice tzd for sale @£300 and was wondering whether to go for that as a quick fix and work on the 16v myself when i have more time.

Cheers
Barry

Philip Chidlow · Post by **Philip Chidlow** » Thu Dec 14, 2006 1:42 pm

For what its worth, I think that's a rather nice TZD for the money (T & T too)... and probably a better (dare I say

) day to day car... I was tempted when it was offered on this Forum, but I was really after an estate...

Even if the leak is easily fixed, there's nowt wrong with having two BXs

DLM · Post by **DLM** » Thu Dec 14, 2006 1:44 pm

I know this is repeating what's been said already, but if there's no obvious leak then there may not be one at all.

If spheres haven't been changed for a while (often the rears, given they're the more awkward ones to change), then the lhm level naturally falls as the gas diaphragms in the spheres are pushed in more by system pressure and hence occupy less space. I've been fooled by this one before.

tom · Post by **tom** » Thu Dec 14, 2006 5:58 pm

To correct what has been posted by Way2go: Jeremy's test for the rear suspension works perfectly well whether the car is equipped with ABS or not. All BXs have rear brake proportioning controlled by the height corrector feed to the rear suspension. Tick time is not always controlled by the accumulator sphere. Wear anywhere in the suspension system or any leak will cause the tick time to become shorter.

DLM · Post by **DLM** » Thu Dec 14, 2006 6:13 pm

I'll certainly back up Tom on the last point about tick time - my TZD is currently ticking like there's no tomorrow despite a very recent accumulator. Diagnosis suggests it's due to a faulty doseur valve. It's not the first BX I've had to do that with a faulty doseur, either.

Way2go · Post by **Way2go** » Thu Dec 14, 2006 6:47 pm

tom wrote:To correct what has been posted by Way2go: Jeremy's test for the rear suspension works perfectly well whether the car is equipped with ABS or not. All BXs have rear brake proportioning controlled by the height corrector feed to the rear suspension. Tick time is not always controlled by the accumulator sphere. Wear anywhere in the suspension system or any leak will cause the tick time to become shorter.

Well, I have just checked this again on my GTi ABS car with good suspension performance and I do not notice this lift.

Also I replaced the accumulator sphere when ticking got to 15-20 secs and that certainly put the time interval substancially up.

So if you disagree with this actual situation, what is the reason for cause and effect as seen?

tom · Post by **tom** » Thu Dec 14, 2006 8:30 pm

It is impossible to disagree with a situation. I disagree with your incorrect assumption. At the risk of being accused of condescention, I shall attempt to explain.
If the ticktime is 20 seconds and the accumulator is flat then if you change the accumulator the time may increase because you have cleared up one of an as yet undefined number of faults. If your rear suspension is not operating correctly (and it is not, failure of Jeremy's test shows that,) then you have a problem which (in as far as diagnosis can be done blind,) will be due to wear in one of three components. If the rear falls but fails to rise, then it is due to a fault in the doseur valve, the height corrector or the struts themselves, (Assuming that the rear arms are not siezed.) If the rear fails to fall, then your height corrector linkage is sticky or poorly adjusted. The standard return checks will, of course tell you a lot but the tick time for a healthy system should be of the order of one minute.

jeremy · Post by **jeremy** » Thu Dec 14, 2006 10:37 pm

Interesting - way to go - what ABS system does your car have?

My BX TD Estate is 1989 with the Teves system which has worked continuously for the last 6 1/2 years - and still does as one of my neighbouring cats will testify - he wouldn't have had such a sprint it it had been useless!

The car hasn't had much use recently and as its MOT was doe in October I started it up a few days before and took it for a drive round. To my horror the hydraulics were cycling about every 8 seconds very quickly - a sort of 'THp' noise. Hope its the accumulator and nothing else I thought - stood on the towbar and grabbed the roof rails - sink and no rise! - Engine on - sink and rise - so accumulator.

In fact it passed the MOT with only a recommendation about a frayed rear seat belt - and I then drove it to EuroCar Parts and got a new sphere and filtted it - and it now rises properly.

In fact with a good sphere it will rise when I fill the tank fully with fuel - which must look a bit strange to others around. This is one of the things I look for to make sure its OK.

This car has had the regulator non-return valve re-seated - in fact it was for this one that I worked that trick out. What is curious is that initially I couldn't stop it cycling every 8 seconds or so - even after replacing the accumulator and attention by so called experts. After re-seating it was so slow that I got bored timing it and its stayed like that. What's interesting is that with the flat sphere now it makes a quick 'Thp' noise rather than a longer rattle that it always made before.

Of course the ABS brake valve does nothing at all at any time unless the brake pedal is pressed - when with the engine running and car in motion it will switch from static but monitoring state to active but monitoring for wheel locking state. Only when a wheel is sensed as locking will it actually do something.