The 'E' Type Forum

I had a quick look at the pistons on my rear brakes earlier today. Three of the 4 pistons were well corroded, so it looks as though it's replacements for all.

I read on the forum that some members have used the front 2-1/8 on the rear when they've uprated the fronts to 4 pots because it brings front/rear balance closer to design.

As I need to buy new for the rear, is it advisable to go 2-1/8 or stick with the standard size.

I've have zeus 4 pots for the front.

Advise would be appreciated.


Alun

Have a look at these https://mossmotors.com/8777-2-cp-cobalt ... t_products

WRT balance calculate your front caliper total piston area, then see which of the available sizes gets you closest.

The stock calipers have 60% front bias.

Alum Wrote:

I read on the forum that some members have used the front 2-1/8 on the rear when they've uprated the fronts to 4 pots because it brings front/rear balance closer to design.

Hello Alum,
I can't see that at all working. The rear brake caliper incorporates the Hand Brake mount, which is not included on the front brake caliper.

Regards,
Bill

angelw wrote: ↑

Sun Jun 15, 2025 1:09 am

I can't see that at all working.

It does. You just put the 2 1/8" cylinders on the rear caliper body.

Hi Bill,

Yes it should work. I've checked the cylinders and the fronts (2-1/8) do physically fit the rear. Awaiting information from zeus about the size of their 4 pots.

Has a done done this already.

Alun

alunwill wrote: ↑

Sun Jun 15, 2025 3:54 pm

Has a done done this already.

Alun

Yes this is what I did when I fitted Coopercraft front calipers to my first E Type years ago. Moving the fronts to the rear maintained the brake bias at stock.

To be honest though I really couldn't feel any difference with the braking for day to day driving.

Does the S2 rear system offer any volume change?