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Brake valve confusion
Posted: Sun Jan 02, 2011 2:14 pm
by Steve A
Hi, i have changed over to dry frames on the mk1 and fitted new rear brake backplates complete with brakes valves which i assume will be the later bigger bore. Which brake regulator should be fitted using the later rear brake assemblies and cooper s assemlies up front?
Any advice on fitting the single line system or 'mods' to make it safer as i am basically following the haynes lol.
Thanks again Steve
Re: Brake valve confusion
Posted: Sun Jan 02, 2011 5:44 pm
by ivor badger
My preference is the servo only connected into the front system with the rear on pedal pressure.
Re: Brake valve confusion
Posted: Sun Jan 02, 2011 6:00 pm
by Steve A
Not sure on how to do that on a single line braking system? regards Steve
Re: Brake valve confusion
Posted: Sun Jan 02, 2011 6:23 pm
by Ronnie
With due respect it will not matter which way it is connected, depending on the valve used it will limit the pressure( it shuts the pressure off) to 325 lb/sq in or 425-470 lb/sq inch(not sure of the exact pressures), on your rear wheels.
Re: Brake valve confusion
Posted: Sun Jan 02, 2011 9:18 pm
by pad4
To get the braking spot on on the rears just plumb in an adjustable rear brake valve - you can then fine tune it - got it on mine and its spot on.
Re: Brake valve confusion
Posted: Sun Jan 02, 2011 9:39 pm
by ivor badger
Steve A wrote:Not sure on how to do that on a single line braking system? regards Steve
put the front/rear T piece splitter before the servo and simply run the front pipe through the servo and run the other unservoed pipe to the rear brakes
Re: Brake valve confusion
Posted: Sun Jan 02, 2011 9:50 pm
by WNX700H
Probably best if you want to avoid the cost of an adjustable valve would be to fit the largest rear wheel cylinder size and then after bedding the brakes do some high decel stops on dry tarmac and check the vehicle is still stable. You need to do this on dry tarmac as this surface gives you the largest weight transfer ie rear end is lightest therefore worst case for causing rear wheel lock. If you get rear wheel lock then go down a size in wheel cylinder to reduce the output from the rears.
To be legal fronts must lock before the rears. Although this is not altogether relevant depaending on what you are using the car for.
Also very important to ensure the fade characteristics of the front and rear friction is similar since if the rears fade easily you will have under utilised rears when they fade or if the fronts fade first you could then end up with an unstable vehicle as this will have the effect of creating greater rear output .