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Wheel cylinders part 2
prawnabie - 19/1/10 at 09:10 PM

Hi

I am using a transit master cylinder with a 23.81mm bore. Cortina calipers up front with standard MK2 drums (8". CEC car so weighs a fair bit.

What wheel cylinder sizes should I be using on the rear? I currently have 22.6 but I am redoing the rear brakes so wondering If i should get these or the 19/17mm ones.

Cheers

Shaun

woolly - 19/1/10 at 09:27 PM

are the rear brakes too powerful at the moment.

woolly

prawnabie - 19/1/10 at 09:38 PM

Not that i have noticed, but tbh I don't drive it that hard

woolly - 19/1/10 at 09:42 PM

reducing the rear wheel cylinder size will reduce the braking effort and give you slightly less pedel movement.
sorry if you know that.

woolly

prawnabie - 19/1/10 at 09:43 PM

I don't tbh lol

Im just looking at wheel cylinder books now to order and all the mk2's are either 17 or 19 mm bore.

woolly - 19/1/10 at 10:00 PM

mk2 escorts and cortina 3s used the girling 8 and 9 inch rear drums.
i think one of the cortina estates had the big cylinder.
really testing my memory now.

woolly

marcjagman - 19/1/10 at 10:04 PM

Can't you just drill holes in the brake shoes?

britishtrident - 20/1/10 at 07:55 AM

Worry more about the master cylinder bore --- way too big

prawnabie - 20/1/10 at 10:21 AM

Sorry master cylinder bore is 22.2mm

britishtrident - 20/1/10 at 11:44 AM

quote:
Originally posted by prawnabie
Sorry master cylinder bore is 22.2mm


7/8" is way too big for use without a servo.

MikeR - 20/1/10 at 12:44 PM

look up the posts by dick axtell - i think it was he who did some maths on the subject when he worked for girling.

it will be 4 or 5 years ago at a guess (maybe more)

whitestu - 20/1/10 at 01:32 PM

I changed from a 22 to 19mm MC and is does make a worthwile improvement. Not that the brakes were in any way bad with the 22mm, just felt very sloid and a bit woody!

the 19mm gives more pedal travel, but more power and progression.

britishtrident - 20/1/10 at 01:51 PM

Back to wheel cyilinders -- based on experience with Imp rear brakes which were 8" inch drums almost identical to the MK1 Escort. increasing the wheel cylinder bore runs into the law of dimishing returns. A difference could be felt swapping from 0.75" bore to 0.7" bore rear cylinders but changing up from 0.75" to 7/8" bore cylinders made no difference.

With drum brakes the distortion of the mechanical bits ie shoes and drums starts to have a bigger effect when you try to put too much force into them.

prawnabie - 20/1/10 at 05:20 PM

Ok thanks for the replies. I will try a set of 17.8mm cylinders and see how it goes!