Brake Pressure

[garethbowers]

I have posted simmilar before but didnt really get the jist. I have an obp pedal box. Can i clarify that i should have the 0.7 cylinder to the front brakes and the 0.75 to the rear? Also on the setup, is the front master the left or right cylinder?

 

I also have a prob with my hydraulic cluth in that i dont have to push the pedal much to get it to dis-engage, now would i use a bigger or smaller master cylinder to remedy this?

 

Kind Regards

 

Gareth

Edited February 6, 2011 by garethbowers

[Guest webby]

hi gareth

as a general rule you use the smaller cylinder on the front it always sounds odd but a smaller cylinder gives a higher pressure but piston has to move futher. dependant on what brakes you are using you may need to go down to a 5/8 (.625) cylinder on the front to gain sufficient brake pressure ,no hard and fast rule trial and error im afraid if your happy with the brakes go with it if not try a smaller front cylinder,the rear sounds about right and if its an adjustable pedal box you set it to suit the rears. as for the clutch have you got a bit of free play, dont set it up too solid the pedal rod should have bit of spring travel before it pushes the piston, if not you again try a smaller cylinder it will give more pedal movement.

i like the xes rule but not for long.lol ive not finished my upgrade yet.(378 hp)

i hope this helps a bit im no expert brakes but ive fiddled around over the years nick

[garethbowers]

Cheers for thereply mAte, so am I right in thinking that fir the clutch I could use a larger master to allow the bite to be further down? At the moment I dint have to push the pedal much for the clutch to slip.

 

I am using sierra front disks/calipers and sierra rear drums.

 

Cheers

 

Gareth

[garethbowers]

Also what is the smallest the cylinders go down to? I'm using a .625 cor the clutch and I have had to put spacers between the body and the cylinder to move the pedal back if you get my drift

[Guest chris brown]

so am I right in thinking that fir the clutch I could use a larger master to allow the bite to be further down?

 

Cheers

 

Gareth

No Gareth, use either a larger slave cylinder at the clutch end or a smaller master at the pedal end that way the clutch will release more slowly and takeup will be smother (greater pedal movement for the same clutch movement). But first do as Webby says and ensure you have free movement in the pedal.

[garethbowers]

Right im with you. I cant change the clutch slave as it was an sbd jobbiw for the type 9 and cost a small fortune. Im using a .625 with it at the moment and the bite is still to high and very sharp. Is .625 the smallest you can get? My only other option i suppose "last resort" is to remove the box and have the slave collar adapter machined down so the slave has to travel futher...

[garethbowers]

http://www.sbdev.co.uk/Clutches/Clutch_Release_Mechanisms/Clutch_Release_Mechanisms.htm

 

spacer is clt hcs 30

[Guest webby]

hi not 100% on what sizes available definetly a .6 avaiable probably down as far as .5 in 25 thou increments basic rule of thumb smaller master cylinder moves less fluid so gives more travel at the pedal . youll never get the same feel with a hydrualic clutch as a cable clutch.i personally dont like them.as for the brakes. a .75 or .7 sounds about right for the rears, i think youll need a .625 for the fronts but its trial and error im afraid depends on pads calipers etc dont use too hard a pad as brakes need to generate heat to work and as these dont weigh a lot there is less force to generate heat, your calipers are designed to stop a 11/4 ton sierra not a 700 kg hood so you dont need redstuff i hear mintex 1144 are good but i use a different brake set up so i cant comment hope this helps a bit nick

[garethbowers]

Cheers nick, thats cleared things up lots. What setup do you use? Ill have a mine one weekend and reprt back.

[Guest webby]

hi ive been lazy on this car ive got cosworth 4 pot calipers on the front with 283 mm discs,running the very basic ebc pads . xr4x4 rear end with again ebc basic pads but ive cheated ive got a cosworth master cylinder and best of all a servo,probably a bit over braked. my friend has a tiger with a similar set up to you and has .625 on the front. .75 on the rear, again ebc pads works well but he is going to try the mintex pads cheers nick