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Changing brake cylinder sizes.
dhutch - 4/6/09 at 03:15 PM

If i change the rear wheel cylinder (kr2 escort 8" drums) from 18.7 as they are now to 17.4 which is what i can get hold of. Will i notice much?

I calclate the reduction in area to be about 13% which doesnt seam like tooo much.

Will be swaping the pair.


Daniel

dinosaurjuice - 4/6/09 at 03:24 PM

is there a reason you cant replace with same size?

dhutch - 4/6/09 at 03:37 PM

Well, im just stuggling to find them is all
- This is what my local motor factors can get in.

I have in the past had the rears lock before the fronts (mainly noticed when i swaped from 205's tyres rear to 185's all round) although that may have been somewhat to be with the fact that the rather shagged wheel cylinders where dragging a little and may have been cauing the brakes to get a bit warm (i dont really know if they where geting warm or not)

Daniel

dhutch - 4/6/09 at 03:44 PM

Burton power dont do them anymore, graham goode has just managed twice to put me through to two diffrence places, and on to an answer phone. And GS escorts arent picking up the phone.

dinosaurjuice - 4/6/09 at 03:50 PM

if youve had the rear lock before fronts in the past then definately go slightly smaller. 13% isnt massive. better quality shoes (if available?) would soon bring the stopping power back up.

theconrodkid - 4/6/09 at 04:41 PM

smaller dia will equate to more pressure and therefore the wheels will lock easier

daviep - 4/6/09 at 04:47 PM

quote:
Originally posted by theconrodkid
smaller dia will equate to more pressure and therefore the wheels will lock easier


That would be true for fitting a smaller bore master cylinder. However fitting a smaller bore wheel cylinder will result in less force being applied to the shoes. Force = Pressure x Area

Cheers
Davie

brianthemagical - 4/6/09 at 04:51 PM

quote:
Originally posted by theconrodkid
smaller dia will equate to more pressure and therefore the wheels will lock easier


It's at the worng end of the system, so the pressure is still the same/constant, and with F=PxA, the smaller dia will give less force on the shoes, thus less stopping power.

Beaten to it, by a full 4 mins, darn.

[Edited on 4/6/09 by brianthemagical]

dhutch - 4/6/09 at 06:22 PM

quote:
Originally posted by dinosaurjuice
if youve had the rear lock before fronts in the past then definately go slightly smaller. 13% isnt massive. better quality shoes (if available?) would soon bring the stopping power back up.

Sounds about right to me.
- Ive got one fitted now, roughtly blead through with the old finger-over-the-nipple game and its working a treat. Will be picking other one up and fitting/bleeding fully tomorrow.

Daniel

lotustwincam - 4/6/09 at 08:20 PM

All sizes of wheel cylinders available here:
Ford Brakes