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Rear Cylinder Size
johnemms - 5/3/12 at 10:52 AM

Ok.. IVA says no brake adjusting valves allowed..

M16 calipers front - Escort Master Cyl - 8'' rear drums Escort Mk2 Axle.

I have found 3 rear Mk2 Escort cylinder bores available:

BWC 5080 20.6mm (which I think I have)
BWC 5090 19.0mm
BWC 5084 17.8mm

I may have fitted a pair or even worse - odd cylinders during the build up ..

If I fit a pair of small bore 17.8mm - It should reduce the chance of rear lock up at IVA

Does anyone know of other sizes?
cheers
jon

[Edited on 5/3/12 by johnemms]

wicket - 5/3/12 at 11:46 AM

I have M16 on the front and 8" drums on a Cortina axle at the rear and the cylinders are 0.65" dia front and 0.7" dia rear and they work fine.

loggyboy - 5/3/12 at 11:47 AM

quote:
Originally posted by wicket
I have M16 on the front and 8" drums on a Cortina axle at the rear and the cylinders are 0.65" dia front and 0.7" dia rear and they work fine.


I think hes talking aboout the rear wheel cylinders, not the master cylinders?

britishtrident - 5/3/12 at 11:59 AM

Wheel cylinder sizes make more sense in imperial sizes

17.8mm = 0.7"
19mm = 3/4"
20.6m = 13/16"

BWC 5084 20.6mm 0.7" should give you a good safety margin as O.7" was more or less the standard size on most RWD small cars in the 1960's and 70's which used P14 calipers on the front.



***** edit ******

Post should read BWC 5084 17.8mm 0.7" should give you a good safety margin as O.7" was more or less the standard size on most RWD small cars in the 1960's and 70's which used P14 calipers on the front.

My own blood fault posted when rush to go out.

[Edited on 5/3/12 by britishtrident]

Dusty - 5/3/12 at 01:11 PM

Isn't the rule, for a given effort on the pedal:

The smaller the bore of the master cylinder the more power to the pads/shoes.
The smaller the bore of the wheel cylinder the less power applied to the shoes.

I get confused easily by things like this.

johnemms - 5/3/12 at 01:56 PM

Rear brake slave cylinder:

Smaller bore - reduce pressure on shoe - reduce pedal travel - reduce rear lockup

Bigger bore - more fluid surface area - increases shoe pressure - increases pedal travel - more rear bite..

Got a pair of these 17.8mm to try out : eBay - The UK's Online Marketplace

pstirz - 17/11/13 at 09:21 PM

I have replaced the 20.6mm rear cylinders with 17.8mm and I have a Mondeo bias valve in the post. I think a combination of both will do the trick for my retest on the 29th November.

Thanks again for all your help.

johnemms - 17/11/13 at 09:34 PM

Yep i passed easy with M16 front calipers & 8" drums small bore rear cylinders