Hi
I have the above car with above Lucas-Girling ABS system which uses a lot of mechanical levers and valves to get the job done with no electronic components. I posted a queery to this a while ago at www.honestjohn.co.uk/forum/post/index.htm?t=9373&v...f .
Being as there's been a fair turnover of BR members since then I thought I'd put it up again and ask if anyone has had any success with freeing up this kind of system? Quick recap, the "Anti-Lock" bit works fine, it just doesn't want to apply the brakes again (well, for a while [an hour] at least!). All curtosy of my gran who owned the car for 13 years and never ever used the ABS or (by the look of it) never had the brake fluid changed! I'm tempted to buy some second-hand modulators off e-bay and maybe try them out if push comes to shove, or to take apart and have a look inside! They go for peanuts.
I look forward to your comments!
Mike Farrow
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From curiosity, rather than being a serious suggestion to fix the fault, does it reset if you perform an abrupt braking application in reverse?
If it does, then perhaps getting some new brake fluid through the device, and subjecting it to some externally applied angular accelerations may free it off without any stripping down. (Perhaps a longer bit of cambelt driven by an electric drill, - swapping forward to reverse?)
I would avoid the temptation to strip it down unless you have the experience and appropriately clean facilities to work on hydraulic valves. They can be jammed very easily - the radial tolerance between spool and sleeve valves, especially when leakage must be minmised is very tight.
number_cruncher
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Thanks for that quick reply.
It does look like the pressure relief valve is sticking open, this would explain why the pedal feels hard afterwards. I haven't tried the reversing trick, but worth a go! Could just be the valve being stuck open or flyheel not returning properly. If it's the flywheel getting stuck, am I correct in presuming that this is external to the hydraulic bits? The flywheel casing just has a plastic cover, so I assume it's not meant to be pressurised.
Just as an aside, I am scepticle as to whether the garage who replaced the dirty brake fluid bothered to bleed through the modulator, as this is a seperate procedure.
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I tried free spinning the modulator shaft today while someone else pushed the brake pedal. As expected, the pedal went hard, indcating the pressure to the wheel has been cut off. Now, there are two probably explanations for this, looking at Haynes and Bosch's Automotive Handbook. Either the pump piston isn't moving (it should spring up with pressure from the foot brake), or the relief valve isn't closing. I suspect the former, as I feel no resistance when turning the shaft after I 'lock' it. This is unfortunate, as it is an internal jobbie.
I've bought some modulators off e-bay, so I may swap the dodgy one and give it a whirl. Does anyone know what else I could try? There isn't a 'brakeflush' or similar is there?
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I think the cheapest & probably the easier option is to convert the brakes to a non Abs system .This will need a different master cylinder & a rework of the brake pipes.The Abs system on these models (or SCS as it was known) only works on front wheels anyway.
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Hi
Well, it depends if I can do it myself! I have considered the coversion route, but wouldn't I have to declare this the the insurance company? I'm unsure as to how they'd take that! I'm not surprised having owned a car with the mechanical Stop Control System that it didn't become too popular!
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