Floor Mounted Pedal Box Non Servo

[Guest Mark Stanley]

Hi all,

 

I have just fitted a floor mounted pedal box in my 2b project. The master cylinders are now lower than my clutch slave and also my brake calipers.

 

I am fitting my reservoirs 400mm above the master cylinders for ease of fluid checks. By doing this will I still need to fit 2lb residual pressure valves.

 

Any ideas

 

Thanks Mark

[Longboarder]

I have a floor mounted pedal box twin cylinders for brakes and the reservoir well above. Drums on the back axle. No residual pressure valves fitted.

 

Nigel

[IanS]

Try parking on a slope and chances are that there is a wheel cylinder above the master cylinder resevoir.

Happens all the time in hilley areas and no residual pressure valves fitted to 99.9% of cars.

We rely on friction in the seals to prevent drainback.

[Guest Mark Stanley]

Ok no valves it is, just thought I would ask before I start putting everything back together.

 

How do you fine non servo brakes on standard sierra brakes, would going up to 283mm cosworth discs help

[Guest snowy2]

choose the correct master cylinder bore size and you wont need a servo, servos DO NOT make poor brakes better they ONLY reduce the pedal pressure required to make the brakes work correctly.

if you get the required pressures on the brake pistons the brakes will work fine, if you can lock the wheels there isn't better braking available to you, only more efficient in terms of heat dissipation, thus you can use them in anger more often and not suffer brake fade (like on a track day....or the way i drive)

[Guest Kitcarkris]

I am fitting a floor mounted pedal box with sierra front callipers and rear drums, can someone suggest the correct bore size I would need for the master cylinders.

 

Sorry to tag this question into this thread but does seem slightly relevant...

[Guest snowy2]

A good friend of mine wrote this article some years ago on working out master cylinder bores pedal ratios and brake pressures, it refers to his then project of a Dutton B type and some Phaetons. the whole article is very interesting and will give you a good heads up on what you need to consider. It is all relevant to this thread.

http://www.andersensmith.freeserve.co.uk/brakes.htm

[Longboarder]

Or 0.625 for the fronts and 0.75 for the rears.

 

Nigel

[Guest Mark Stanley]

Those are the sizes that came with my kit. How come it is larger on the rear?

[Longboarder]

Strangely drum brakes require lower pressures than discs. Leading shoe has self servo effect, but they overheat and retain heat more than discs. So bigger rear master cylinder. Smaller master cylinder for discs gives increased fluid pressure. However this means the rear M/C delivers more fluid per stroke when you would like the front M/C to do that. So you have to set the balance bar skewed so the rear M/C push rod is set well forward and the front M/C pushrod is well back. When you push the pedal the balance bar virtually pivots on the end of the rear M/C push rod.

 

Nigel

[Guest Mark Stanley]

I have changed my rear subframe to a cosworth rear with solid discs then the smaller sierra vented fronts, should I use the same size master cylinder front and back then or do I just adjust the brake balance bar