Doseur overhaul is covered in detail in the sticky at the top of this part of the forum.
Your flow is roughly 4 times what Tom states is correct. However its still only 14 cc (ml - virtually the same) which is very small in terms of the operation of this system. remember the accumulator is about 1/2 litre in volume as you'll discover when it goes up your arm as you unscrew a flat sphere. - although of course its volume is less when new and the pressure drops as it discharges.
The pump has an output of 4cc and revolves at 1/2 engine speed according to Haynes (I don't necessarily agree but it doesn't matter for these purposes) This means with the engine idling it has an output of 1.6 litres per minute if its working like new.
I'd reseat the valve as it doesn't cost anything and is relatively easy. If that doesn't work I'd then look at the doseur. It may be reasonable to get at on your RD - on turbo-diesels it is not and the engine has to be tilted to give any access at all. I had problems with my TD - and had a new one fitted which made no difference at all - and I think this is quite a common experience.
tic time not improved
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DLM
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A couple of points about the result you got. I had a nice confirmation of doseur wear on my BX last night without too much effort.
(1) Reseating the bearing may well help - but if it takes the tick-time way down, do see if it stays that way once the brake pedal has been stepped on. When I had a suspected doseur problem on previous BX , reseating the bearing caused an incredible reduction in tick time - until I applied the brakes. Straight away it was back to hiss-click-hiss-click-hiss-click....
(2) There is another good and simple way to check for doseur wear, which Tom demonstrated to me last night. Despite having run BXs for 15 years I'd never had predicted the result we got, though it makes sense now.
(i) At normal susp height with engine running - stand on the brake pedal.
(ii) Same as above, with suspension all the way down (to take suspension completely out of the equation).
Note any change in tick time for both and report back. I do feel that later BX doseurs wear more quickly, as I've had much more trouble with late BXs than earlier ones in this area. The change came in during 1988/89, if I recall correctly.
(1) Reseating the bearing may well help - but if it takes the tick-time way down, do see if it stays that way once the brake pedal has been stepped on. When I had a suspected doseur problem on previous BX , reseating the bearing caused an incredible reduction in tick time - until I applied the brakes. Straight away it was back to hiss-click-hiss-click-hiss-click....
(2) There is another good and simple way to check for doseur wear, which Tom demonstrated to me last night. Despite having run BXs for 15 years I'd never had predicted the result we got, though it makes sense now.
(i) At normal susp height with engine running - stand on the brake pedal.
(ii) Same as above, with suspension all the way down (to take suspension completely out of the equation).
Note any change in tick time for both and report back. I do feel that later BX doseurs wear more quickly, as I've had much more trouble with late BXs than earlier ones in this area. The change came in during 1988/89, if I recall correctly.
Back on two wheels and pedal power for the moment.
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cauchoiskev
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If the following is twaddle, don't hesitate to let me know. I can take it. Yes, I can.
The basic equation, assuming an ideal gas is : P1V1 = P2V2
The accu sphere has a volume of 400cc, and when new is at 62bar.
So, when the pressure regulator is charged to 170bar (cut-out point of the PR), the gas volume drops to :
(62/170)*400= 145.88cc
Then the system leakage (if the car is at rest) discharges the sphere until 145bar (cut-in point of the PR), which gives a volume of :
(170/145)*145.88= 171.03cc
Total change in gas (and LHM) volume in a cycle is thus 171.03-145.88 = 25.15cc with a new accu and a perfectly working PR.
Assuming the pump output is really 26.66cc/s (1.6l/min) PR on time will be roughly 1s if the system has no significant leaks. For me, this seems reasonably coherent with day to day observation.
With brake leakage of 13cc/min, and no other significant leaks your tick time with new accu (and pump) should still be around 2 minutes ! I had doseur leakage roughly equivalent to yours, but a tick time of 40s.
Assuming the accu is ok, and the pump decent, you must be losing around 10cc/s from somewhere in the system.
Conclusion : your doseur is tired, but it's not the main cause of your fast ticking time.
The basic equation, assuming an ideal gas is : P1V1 = P2V2
The accu sphere has a volume of 400cc, and when new is at 62bar.
So, when the pressure regulator is charged to 170bar (cut-out point of the PR), the gas volume drops to :
(62/170)*400= 145.88cc
Then the system leakage (if the car is at rest) discharges the sphere until 145bar (cut-in point of the PR), which gives a volume of :
(170/145)*145.88= 171.03cc
Total change in gas (and LHM) volume in a cycle is thus 171.03-145.88 = 25.15cc with a new accu and a perfectly working PR.
Assuming the pump output is really 26.66cc/s (1.6l/min) PR on time will be roughly 1s if the system has no significant leaks. For me, this seems reasonably coherent with day to day observation.
With brake leakage of 13cc/min, and no other significant leaks your tick time with new accu (and pump) should still be around 2 minutes ! I had doseur leakage roughly equivalent to yours, but a tick time of 40s.
Assuming the accu is ok, and the pump decent, you must be losing around 10cc/s from somewhere in the system.
Conclusion : your doseur is tired, but it's not the main cause of your fast ticking time.
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mountainmanUK
I would still be looking towards the pressure regulator / bleed screw itself.
Although I'm FAR from an expert in Citroen hydraulics, I do have a good few years experience of driving and maintaining the things, and every single time that I've come across a car with a tick time that fast, it has always, without fail, been connected to the regulator.
Jeremy's suggestion of the ball valve behind the bleed screw sounds very plausible; it would also be worth checking all the pipe unions entering the regulator. Considering that you do not have evidence of any massive LHM leakage (no pools of green blood under the car!), IMHO it points to either air getting into the system, or allowing pressure to leak away at a fast rate!
You may still have problems with a tired doseur etc., but my gut feeling is that there is some much simpler problem that you just havn't discovered yet!
Would it be possible for you to try exchanging the regulator for a known working one? Are there any other BX owners near you that may be willing to let you try their reg?
Keep at it! Sooner or later you will find the fault, and then get it fixed!
There are lots of members on here, who are much more knowledgeable than I, but every sensible idea is worth trying, if only for elimination purposes!
Although I'm FAR from an expert in Citroen hydraulics, I do have a good few years experience of driving and maintaining the things, and every single time that I've come across a car with a tick time that fast, it has always, without fail, been connected to the regulator.
Jeremy's suggestion of the ball valve behind the bleed screw sounds very plausible; it would also be worth checking all the pipe unions entering the regulator. Considering that you do not have evidence of any massive LHM leakage (no pools of green blood under the car!), IMHO it points to either air getting into the system, or allowing pressure to leak away at a fast rate!
You may still have problems with a tired doseur etc., but my gut feeling is that there is some much simpler problem that you just havn't discovered yet!
Would it be possible for you to try exchanging the regulator for a known working one? Are there any other BX owners near you that may be willing to let you try their reg?
Keep at it! Sooner or later you will find the fault, and then get it fixed!
There are lots of members on here, who are much more knowledgeable than I, but every sensible idea is worth trying, if only for elimination purposes!
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cauchoiskev
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One explanation is that when the car is totally down there is no pressure on the rear brakes, so no leaks from the doseur rear brake circuit !dumbtime wrote:The tick time for when the car was in normal hieght and standing on the break was 4 seconds, it still hissed but when it didnt it was 4 secs.
when the car was all the way down the amount of time it didnt his for was 10 seconds.
what does this mean?
Another is that the car has leakage in the suspension (cylinders or height correctors or both). Have you checked for that ?
Has the situation improved, as you mentioned continuous hissing at idle at the start of your post ?
I suppose a riugh indication of the presence of the ball bearing valve under the bleed screw is the visibility of its neck. On the regulators I've seen about 6mm or so of the bolt neck is visible - and probably (and I've never tested it - if the ball was missing the neck would not be visible and the bolt would tighten home.
This of course all depends on the length of the both used. Citroen probably used the same length - but knowing what production is - if there was a shortage - a longer one could have been substituted to keep production going. (like the 1.9TD engines that escaped with non-turbo connecting rods - a number of which ended up in Majorca - where its reasonable to assume that mileages would be lower - and - more would survive the warranty period or the retirement date of the person who authorised the fitting!
This of course all depends on the length of the both used. Citroen probably used the same length - but knowing what production is - if there was a shortage - a longer one could have been substituted to keep production going. (like the 1.9TD engines that escaped with non-turbo connecting rods - a number of which ended up in Majorca - where its reasonable to assume that mileages would be lower - and - more would survive the warranty period or the retirement date of the person who authorised the fitting!
Well I think my next port of call is to re seat the non return valve, DavidRutherford told me that he's got one I can try, but I'll go down that route after I try reseating though I dontt know when I'll get round to doing it.
hummmmm... I think iom right in saying there's no neck on mine, it screws all the way in!I suppose a rough indication of the presence of the ball bearing valve under the bleed screw is the visibility of its neck.
Was the owner of a BX 19RD 1984
If the bolt is right down - then its worth investigating. I'd have expected a cylcling frequency of about 9 seconds of so with just the non-return valve at fault - and much quicker with the ball missing.
The best diagram I know of is the parts book which you can download here (Katalog is a parts book - its in English.) The parts book gives the dimension of the ball bearing. The last time I wanted a loose ball bearing was on a bank holiday morning - and I found a helpful small motor cycle shop whose owner had a tin of mixed ones he kept as 'They might be useful one day! Just a hint as to where you might find someone prepared to sell a loose one.
http://citroeny.cz/servis/servis.htm
The best diagram I know of is the parts book which you can download here (Katalog is a parts book - its in English.) The parts book gives the dimension of the ball bearing. The last time I wanted a loose ball bearing was on a bank holiday morning - and I found a helpful small motor cycle shop whose owner had a tin of mixed ones he kept as 'They might be useful one day! Just a hint as to where you might find someone prepared to sell a loose one.
http://citroeny.cz/servis/servis.htm
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tom
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2024. TxD 1.9D estate. 'Wheelybin' - x 12
I suspect that the Haynes value of 4cc is misprinted and actually 0.4cc per pump cycle.
I reckon that there may well be other problems (for example sticky height correctors can still flow quite a lot even if the suspension is down) but my money is still on a very leaky doseur. When the LHM gets warm, it will come out of there like a hose. I'd also check that the LHM level is all it should be first, of course!
I reckon that there may well be other problems (for example sticky height correctors can still flow quite a lot even if the suspension is down) but my money is still on a very leaky doseur. When the LHM gets warm, it will come out of there like a hose. I'd also check that the LHM level is all it should be first, of course!
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DLM
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Recent scruffy diesel n/a estate - "The Red Shed" - is no longer mine. - x 9
Just for reference, on my TZD turbo
Symptoms:
(1) Fast rear-end sink after engine off
(2) Almost continual tick, suspension high or low
(3) Tick Time INCREASED with brakes applied, suspension high or low.
Action today:
(1) Replace doseur
Result:
(1) Tick time much increased
(2) Rear-end not sinking (as yet)
Conclusion:
Original doseur was leaking through badly in all states EXCEPT braking - i.e. it was leaking less when not in active state. Any hydraulic component on a BX can suffer leak-through in a "non-active" state as it's still connected to full pressure feed.
Symptoms:
(1) Fast rear-end sink after engine off
(2) Almost continual tick, suspension high or low
(3) Tick Time INCREASED with brakes applied, suspension high or low.
Action today:
(1) Replace doseur
Result:
(1) Tick time much increased
(2) Rear-end not sinking (as yet)
Conclusion:
Original doseur was leaking through badly in all states EXCEPT braking - i.e. it was leaking less when not in active state. Any hydraulic component on a BX can suffer leak-through in a "non-active" state as it's still connected to full pressure feed.
Back on two wheels and pedal power for the moment.
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DavidRutherford
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Just for even more reference... the DTR turbo. Worst Dosieur evAr.
Sinks like the titanic after the engine is stopped. Rear end is on the deck in 20-25 minutes. Front takes a few hours.
And yet the tic time is about 40 seconds, on an accumulator that is at the very least 4 years old, probably 5.
I think Mr. Dumbtime has a more serious leak than a dosieur. Ironically, I doubt it will be a serious problem to fix, as a dosieur must be one of the more difficult jobs to do on a BX.
Sinks like the titanic after the engine is stopped. Rear end is on the deck in 20-25 minutes. Front takes a few hours.
And yet the tic time is about 40 seconds, on an accumulator that is at the very least 4 years old, probably 5.
I think Mr. Dumbtime has a more serious leak than a dosieur. Ironically, I doubt it will be a serious problem to fix, as a dosieur must be one of the more difficult jobs to do on a BX.
this might be a signature
Those are similar stats to mine, as soon as the engine is turned off it starts going down. I haven’t re-seated the non return valve yet, will do that Saturday hopefully. Could the problem be not that one thing is leaking severely but a combination of everything leaking?
I fixed my leaky sunroof today as I had a nice pond in my car due to the crap weather. I had to take the roof out and found that the suspect tube had a sort of kink in it, I had put a zip tie round it to keep it open. I also found out what’s been rattling in the roof, all of the damping material on the metal roof panel had curled up and disintegrated. I’m going to replace it with some stuff that I can get through work (Acoustic Consultant).
Also can anyone tell me if the two vents at the rear sides of the car are important because I want to block them off, as a hell of a lot of sound comes from there. As you can tell I’m trying to sound proof my car though I think it’ll be a fools errand unless I completely rip out the interior, which I don’t have time for but would like to do it.
I’ll give an up date on the weekend regarding the non return valve.
I fixed my leaky sunroof today as I had a nice pond in my car due to the crap weather. I had to take the roof out and found that the suspect tube had a sort of kink in it, I had put a zip tie round it to keep it open. I also found out what’s been rattling in the roof, all of the damping material on the metal roof panel had curled up and disintegrated. I’m going to replace it with some stuff that I can get through work (Acoustic Consultant).
Also can anyone tell me if the two vents at the rear sides of the car are important because I want to block them off, as a hell of a lot of sound comes from there. As you can tell I’m trying to sound proof my car though I think it’ll be a fools errand unless I completely rip out the interior, which I don’t have time for but would like to do it.
I’ll give an up date on the weekend regarding the non return valve.
Was the owner of a BX 19RD 1984
The vents at the rear of the car will be an integral part of the ventilation system.
In the early 60's Ford made the amazing discovery with the Mk 1 A Cortinal that if you let air out of the back of a car you could feed more in and ventilate the passengers better. Ford called the system Airflow or something and the later Mk 1 Cortinals had it with nice big circular face vents etc.
Others quickly realised it was a good idea and numerous cars built by enlightened manufacturers sprouted rear vents and the Rover 2000 even had a sort of hat in the middle of the back shelf to prevent it being covered. The more expensive 3.5 litre as used by dignitaries never had one and was granted an exemption from the steering column intrusion legislation.
Even Ford developed the system so that by the time it got to the Mk 111 Cortinal it had plenty of vents but no decent airflow even after a facelift.
So they're supposed to be an essential part of the ventilation system and if you look at it the idea is that air comes in at the front or down the console tunnel, passes through the car, close to the back window surface to keep it from misting up, through the vent /gap past the back of the back shelf into the luggage compartment then through the side boxes and out of the vents. In truth if you block them it'll probably exit through the door seals.
In the early 60's Ford made the amazing discovery with the Mk 1 A Cortinal that if you let air out of the back of a car you could feed more in and ventilate the passengers better. Ford called the system Airflow or something and the later Mk 1 Cortinals had it with nice big circular face vents etc.
Others quickly realised it was a good idea and numerous cars built by enlightened manufacturers sprouted rear vents and the Rover 2000 even had a sort of hat in the middle of the back shelf to prevent it being covered. The more expensive 3.5 litre as used by dignitaries never had one and was granted an exemption from the steering column intrusion legislation.
Even Ford developed the system so that by the time it got to the Mk 111 Cortinal it had plenty of vents but no decent airflow even after a facelift.
So they're supposed to be an essential part of the ventilation system and if you look at it the idea is that air comes in at the front or down the console tunnel, passes through the car, close to the back window surface to keep it from misting up, through the vent /gap past the back of the back shelf into the luggage compartment then through the side boxes and out of the vents. In truth if you block them it'll probably exit through the door seals.