£1500.00 PLUS VAT????
The sum of the parts is definately worth more than the whole........I should buy mine quick whilst you've still got a chance
DH Dove
Brake master cylinder
Moderators:davidr, BigCatXJS, dhdove
Gordon
£1500.00 PLUS VAT????
The sum of the parts is definately worth more than the whole........I should buy mine quick whilst you've still got a chance
DH Dove
£1500.00 PLUS VAT????
The sum of the parts is definately worth more than the whole........I should buy mine quick whilst you've still got a chance
DH Dove
XJS Bulletin Board Moderator
2013 Mercedes Benz SLK55 AMG, 420bhp. Plenty for me, thank you.
2013 Mercedes Benz SLK55 AMG, 420bhp. Plenty for me, thank you.
Gordon,
Assuming that you've decided to fix yours and not buy DH Dove's "spare" car....
I'm now assuming from your update that you have a relatively early facelift car (91/92 - VIN pre198334), in which case effectively the master cylinder is an integral part of the servo-hydraulic booster which also contains the ABS valve block.
The whole of this assembley is indeed £1600 + VAT (befoe any discount that you can negotiate).
Within the valve block there are three pairs of solenoid valves. One pair controls both rear wheel brakes. The front wheel brakes each have a pair of valves. A reduction in brake pressure on one wheel could well be the result of one pair of valves being partially closed.
However, the valves only come into play when the ABS side of the system comes into play. In other words, under normal braking with no locking of a wheel being sensed, the valves should be fully open. When a wheel starts to lock, the wheel sensor sends a signal to the ECM which in turns controls the relative solenoid valve to adjust the brake pressure on that wheel circuit (A locking of either rear wheel will cause the pressure across both rear wheels to be reduced)
So if this is the cause of the problem then one of the valves has stuck in the partially closed position even under normal braking, or else a wheel sensor is sending a false signal and causing the ABS system to kick in unnnecessarily.
It seems to me that one way to clarify whether the problem is being caused by the wheel sensor or the valve block would be to shut off the ABS system and try the brakes and see if the problem is still there. If the problem goes away then that would seem to indicate that the problem is not in the valve block but is perhaps in the wheel sensor or ECM.
I don't know what would be the best way to do this and wouldn't want to mislead you from a safety perspective. Perhaps there is a fuse that controls the ABS or maybe you could just pull the ECM plug from the servo-booster unit. I'm sure your mechanic will know the best (and safest way to try this)
Hopefully this might help you to find the problem in the cheapest and quickest way. I'd hate to think that you could end up changing the whole actuator unit if the problem is somewhere else like a wheel sensor.
Hope that helps again.
Paul
Sheepy - I'm aware we're focusing a lot on Gordon's issue. Are you any clearer on the way forward for yourself, seeing as you started this thread?
Assuming that you've decided to fix yours and not buy DH Dove's "spare" car....
I'm now assuming from your update that you have a relatively early facelift car (91/92 - VIN pre198334), in which case effectively the master cylinder is an integral part of the servo-hydraulic booster which also contains the ABS valve block.
The whole of this assembley is indeed £1600 + VAT (befoe any discount that you can negotiate).
Within the valve block there are three pairs of solenoid valves. One pair controls both rear wheel brakes. The front wheel brakes each have a pair of valves. A reduction in brake pressure on one wheel could well be the result of one pair of valves being partially closed.
However, the valves only come into play when the ABS side of the system comes into play. In other words, under normal braking with no locking of a wheel being sensed, the valves should be fully open. When a wheel starts to lock, the wheel sensor sends a signal to the ECM which in turns controls the relative solenoid valve to adjust the brake pressure on that wheel circuit (A locking of either rear wheel will cause the pressure across both rear wheels to be reduced)
So if this is the cause of the problem then one of the valves has stuck in the partially closed position even under normal braking, or else a wheel sensor is sending a false signal and causing the ABS system to kick in unnnecessarily.
It seems to me that one way to clarify whether the problem is being caused by the wheel sensor or the valve block would be to shut off the ABS system and try the brakes and see if the problem is still there. If the problem goes away then that would seem to indicate that the problem is not in the valve block but is perhaps in the wheel sensor or ECM.
I don't know what would be the best way to do this and wouldn't want to mislead you from a safety perspective. Perhaps there is a fuse that controls the ABS or maybe you could just pull the ECM plug from the servo-booster unit. I'm sure your mechanic will know the best (and safest way to try this)
Hopefully this might help you to find the problem in the cheapest and quickest way. I'd hate to think that you could end up changing the whole actuator unit if the problem is somewhere else like a wheel sensor.
Hope that helps again.
Paul
Sheepy - I'm aware we're focusing a lot on Gordon's issue. Are you any clearer on the way forward for yourself, seeing as you started this thread?
1995 XJS 4.0 Convertible
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)
-
Gordon@1962
- Posts:186
- Joined:Mon Mar 06, 2006 6:41 pm
- Location:Hull
Hi Paul,
Yes, you are right my master cylinder is an integral part of the servo-hydraulic booster which also contains the ABS valve block.
We weren't quite sure what to do next so we took the plunge and bought a good S/H unit.
The funny thing was when I explained over the phone to the breakers yard my problem, he said he'd had someone else with the same problem last year and the new unit fixed it.
So fingers crossed.
Yes, you are right my master cylinder is an integral part of the servo-hydraulic booster which also contains the ABS valve block.
We weren't quite sure what to do next so we took the plunge and bought a good S/H unit.
The funny thing was when I explained over the phone to the breakers yard my problem, he said he'd had someone else with the same problem last year and the new unit fixed it.
So fingers crossed.
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Gordon@1962
- Posts:186
- Joined:Mon Mar 06, 2006 6:41 pm
- Location:Hull
The S/H master cylinder I ordered arirved complete with pedal box and was fitted Saturday morning.
With that completed we've just taken it out for a short spin and it seems to have sorted out the problem!
I'm getting the car MOT'd this week so we'll know for sure when its put on the brake test.
Just thought I'd take the oportunity to recomend the breakers yard I used.
Its called Grublogger and their web site is at http://www.grublogger.co.uk/
Ask for Graham he's really helpfull and everything is on computer so he knows what he has and what you need!
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Gordon@1962
- Posts:186
- Joined:Mon Mar 06, 2006 6:41 pm
- Location:Hull
Thought you'd like to know my car passed its MOT. 
It turns out there were 3 pipes coming off the master cylinder. One for the rear and two for the front.
Also when I spoke with Graham at Grubloggers he'd told me someone last year had the same problem as me with their brakes and a replacement master cylinder fixed it too!
It turns out there were 3 pipes coming off the master cylinder. One for the rear and two for the front.
Also when I spoke with Graham at Grubloggers he'd told me someone last year had the same problem as me with their brakes and a replacement master cylinder fixed it too!
Gordon,
Really pleased to hear that you got the problem solved and at reasonable cost! Another good recommendation also for Grublogger. As I've mentioned to some people, I've always found Graham Hallett hugely helpful, friendly and professional in his dealings with owners.
If as Graham mentioned, other people have had similar problems solved through the replacement of this unit, it definitely sounds as if it is a failure the integral ABS valve block in the unit, not the master cylinder part of the unit.
The three pipes that you mention are as I described in the earlier post - they are not the outputs of the master cylinder - they are the outlets from the ABS valve block with separate circuits for each front wheel but one ABS circuit for the rear.
I suspect that your pulling to one side was caused by the front ABS valve for that side being partially stuck closed. It's just a shame that you have to buy the whole unit rather than just the valve block.
I wonder if anyone has any experience of taking the valve block apart and seeing if you can free up stuck valves?
Really pleased to hear that you got the problem solved and at reasonable cost! Another good recommendation also for Grublogger. As I've mentioned to some people, I've always found Graham Hallett hugely helpful, friendly and professional in his dealings with owners.
If as Graham mentioned, other people have had similar problems solved through the replacement of this unit, it definitely sounds as if it is a failure the integral ABS valve block in the unit, not the master cylinder part of the unit.
The three pipes that you mention are as I described in the earlier post - they are not the outputs of the master cylinder - they are the outlets from the ABS valve block with separate circuits for each front wheel but one ABS circuit for the rear.
I suspect that your pulling to one side was caused by the front ABS valve for that side being partially stuck closed. It's just a shame that you have to buy the whole unit rather than just the valve block.
I wonder if anyone has any experience of taking the valve block apart and seeing if you can free up stuck valves?
1995 XJS 4.0 Convertible
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)
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