Quote:
Originally Posted by Chris Cussen
Sorry to throw a spanner in the works. But before I do let me say I have a cabrio with standard sierra brakes disc/drum setup but without the "deceleration sensitive valve" and I can categorically state that the fronts lock up first on a dry road.
Not withstanding that: the Hayes manual ISBN 1 85960 090 5 "Ford Sierra 1982 to 1993" states in the intro to the braking system (Section 10.1)
"A deceleration sensitive valve on Saloon, Hatchback and Estate Models not fitted with ABS ... is incorporated into th rear brake circuit. The Valve regulates the pressure applied to the rear brakes hydraulic circuit and reduces the possibility of the rear wheels locking under heavy braking"
Section 10.23 of the same manual discribes the removal/refitting but does not detail any deassembly.
So I'm afraid Peter is incorrect in stating Haynes does not mention the dreaded valvle.
BUT it seems in the light of various tests the thing doesn seem to matter one jot.
Sorry to seem like a barrack room lawer.
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No Chris, I'm sorry but you seem to have misunderstood my original concern.
I was concerned about a Residual Pressure Valve that is fitted to some brake master cylinders designed for rear drum brakes.
I am fully aware of deceleration sensitive valves and/or Load apportioning valves used to regulate the amount of pressure applied to the rear brakes. These are fitted to most cars including the Sierra and BMW donors. These are desirable and most of the recently built BMW Sportsters have the BMW valve fitted to pass the SVA/IVA tests.
For the avoidance of any doubt to anyone else, DO NOT REMOVE these valves.
My concern was about an inbuilt Residual Pressure Valves (RPV) which have been reported as causing a problem when used with rear disk brakes.
It seems that the Sierra M/C doesn't have an RPV, so it was a non issue.
I hope that is clear now?