xantia slow to rise when temperature drops

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AndersDK
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Post by AndersDK »

Alexx & Jeremy :
I recognise this problem may indeed not be as simple as token first off.
<b>What are the FACTS here</b> ?
<font size="1">(suspension prob omitted)
1) <i>Problem first appears as :</i>
-a) System struggling to build up pressure - long warning lamp time
-b) Brake pedal pulsing
-c) Pressure regulator (PR) clicking every 2sec's
-d) servosteering had heavy left turn
2) <i>Actions taken :</i>
-a) The accumulator sphere (AS) was replaced - using a RENEWED (!)
-b) The servosteering "was replaced" ??
3) <i>Results after repair :</i>
-a) PR still clicking every 2sec's
4) <i>6 months later these symptoms are now present :</i>
-a) Warning lamp time is up on 5min's - seems to be temp related
-b) System struggling to build up pressure
-c) The front brakes are ineffective
-d) The servosteering has gone heavy
-e) PR clicking every 2sec's
5) <i>Crucial info :</i>
-a) Reservoir filters ok
-b) Reservoir level ok
-c) Pump suction hose ok
-d) Recent fluid
-e) '93 model - standard susp - BX type servo setup</font id="size1">
It's obvious the AS must be replaced again.
The PR can only click if the valves opens - which means the pump in fact feeds cut-in/cut-out pressure 145-170bar.
The fast PR clicking means a severe system leak is present - and has been so for long.
<font size="1">6) <i>The heavy servo means lack of pressure :</i>
-a) The pump feed may be weak by the PR + AS problem
-b) The pump feed may be weak by faulty FDV ??
-c) The pump itself may be tired
7) <i>System leak could be caused by :</i>
-a) The PR valve screw loose fit
-b) Leaking PR valve screw - wrong fitted bits
-c) Leaking non-return valve to AS chamber - ball-bearing reseating problem
-d) Brake compensator (pedal) valve leaking
-e) Any mix of above leaks</font id="size1">
Cleaner :
We need to know if the FDV was replaced with servosteering components in pt. 2)-b) above.
cleaner
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Post by cleaner »

Anders: As far as I know only the power rack was replaced (FDV was not causing the problem as I was told by the garage).
jeremy
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Post by jeremy »

Just a number of longshots.
1. Is the ball bearing still in place under the regulator bleed screw. This car seems to have had attention to the hydraulics on a number of occasions and it is possible that someone has unscrewed the bleed screw completely and lost the ball bearing - preventing it from sealing properly. If the bleed screw without the ball nearly sealed there would be a rapid leak from the accumulator as most of the oil was re-cycled. The screw normally sits a bit proud of the face and so is quite easy to find. Cleaner - you have had trouble finding it - perhaps this is because it is screwed fully in? Under these circumstances would the FDV shut down the steering?
Simple matters like drive belts being correctly tensioned - put some chalk on the pulley and the belt, run the engine and see if the belt slips in relation to the pulley. (The marks will move due to different pulley sizes but should not move when they are on the pulleys)
Jeremy
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AndersDK
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Post by AndersDK »

Cleaner -
I'm in line with Jeremy.
The PR is highly suspective for being "serviced" im-properly at some time.
I don't think the PR itself is at gross fault. Despite it happens they fails completely - they are known to be indeed incredible reliable - since it's the same component used ever since the ID/DS era.
This is crucial - as the PR is responsible for charging the accumulator correctly for brakes safety.
Same goes in fact on the pump - although quite a few owners have had this replaced - the pump is indeed a reliable component.
Most pumps are replaced simply for being suspect - but not really being guilty - other than in obvious cases with a main bearing fault.
The FDV is a known bugger - mainly because it's fiddly to replace and highly sensitive to dirty fluid.
Use the PR schematics URL submitted by Alexx - then give it a real good inspection - I'm pretty sure the main problem should be found here.
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