The Baron
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| posted on 4/5/08 at 06:40 PM |
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Brake Proportioning Valve
Does any one know the correct angle to mount a brake proportioning value from a sierra? I know it’s supposed to be mounted longitudinally along the
car.
Also, which end is plumbed nearest to the master cylinder? The small diameter end, or the large diameter end,
It was one of the things the SVA man failed me on, but I can’t remember what he said.
Cheers,
B....
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chris_harris_
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| posted on 4/5/08 at 07:17 PM |
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I thgink they have to be mounted at an angle too. can't remember for sure, most people either bin them and don't have one at all, or fit
an aftermarket, adjustable one, like a willwood. Sorry if thats not much help.
Regards Chris
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stevec
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| posted on 4/5/08 at 07:41 PM |
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Bin it, you don't need it,
Steve,
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RichardK
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| posted on 4/5/08 at 07:52 PM |
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I think its 30 degrees but don't hold me to it  I put mine here:
I worked on the principle that Ford reckoned they needed to stop the rear wheels potentially locking on a car as heavy as a sierra so with a slightly
lighter car I thought I would fit it. As said loads of people ditch it without problems its one of those each to their own things.
Cheers
Rich
Gallery updated 11/01/2011
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richard
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| posted on 4/5/08 at 08:02 PM |
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Our book chassis and spec 2 litre pinto was close to failing this recently and the inspector recommeded that when we bring it back for the retest on
other brake related things we should fit something that would allow us to adjust it if needed.
We already had the sierra one mounted on the car, must have been at the wrong angle, so we decided to leave it in place as it was tucked well in at
the head of the tunnel and fitted an adjustable one from Rally design, same as the CBS but £ 15 cheaper. This goes in the rear pipe line, we had to
get a couple of adaptors from them as well as the threads they come with are not right and I was able to bend the pipe from the MS into it and then
make another from the valve to the MS.
I drilled a small hole in the top of the threaded shaft and three in the knob and made a bracket with holes to fit it to the chassis and bleed it in
the fully open position. When we had the retest we did not have to adjust the valve but he watched us lockwire it in position. Do you want some
pictures.
By the way we originally mounted uor sierra oneat about 5 def, think it should be nearer 15 and the pipe from the MS went in the big end that should
be at the back.
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nick205
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| posted on 4/5/08 at 10:44 PM |
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You shouldn't need to use the original Sierra proportioning valve for a 7 type car. The Sierra valve is designed to compensate for load - i.e.
to allow more braking force to the rear the more heavily loaded the car is. Bear in mone the Sierra would have had to be designed to cope with 5
adults and their luggage. Depending on the exact components and weight distribution, you may need to fit a bias adjuster (Rally
Design/CBS/Merlin/Burton etc) to limit the brake force applied to the rear brakes and ensure that the fronts lock up first - an SVA requirement and
preferrable driving characteristic.
SVA however will want any adjustment device to be locked in position.
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Bluemoon
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| posted on 5/5/08 at 09:32 AM |
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I think the sierra item is dynamic, i.e. the car needs to be decelerating for it to work (it's not much more than a valve operated by a weight
and and a spring). So it will not help with the SVA as this is done on rollers, even if you get it at the correct angle. A proportioning valve is only
needed if the front set up is more efficient than the back, from what I can attain reading posts the standard sierra package manages this in a seven
without a proportioning or sierra type valve.
Personally I am not fitting any, and will see how the sva goes, if it's a problem I will fit an adjustable proportioning valve (pressure
sensitive type thing) off a production car (can't remember which one, a search should find it!).. In your case you might want to go this
root?
Dan
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britishtrident
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| posted on 5/5/08 at 10:03 AM |
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As Sierra valve won't work for the SVA test it only works it works purely on G force. Inside is a a little ball bearing that runs up a slope
under deceleration and shuts ofd the port to the rear brakes, simple and effective but not suitable for a Seven or SVA test friendly.
Also
Quote from post by NSDev
----------------------------------------------
"...........and avoid the wilwood!!!
They don't work, we had to bin the one off the race caterham last weekend and replace it with an aP one which did work"
-------------------------------------------------
End Quote
Also avoid converting early Mini pressure shut off valves --- they are expensive and need internal mods (stiffer spring) to make them properly
adjustable.
If you want a valve fit a Fiat Uno or Strads/Ritmo valve -- about 16 quid from Brakes Int.
To make it adjustable you need to make a bracket with an adjustable screw to push down the plunger - the more the plunger is pushed down the higher
the regulated pressure to the rear brakes.
Do a site search on "Uno" in the "Running Gear" section for more info and photos.
[Edited on 5/5/08 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Bluemoon
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| posted on 5/5/08 at 12:49 PM |
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That's the bunny!
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