Hello all,

I am based in the UK.
When I was changing my rear brakes on the Ford Focus ST MK3.5 TDCI 2015. I noticed the piston rear seal was torn.
I checked the master cylinder and noticed it was quite dirty and used a brake measuring tool for moisture content level and it was below 1 below the threshold.

The last brake fluid change was 13/06/24 Miles: 74585. The current mileage is 90,000 so its due a change.

Does anyone know the OEM number or aftermarket part for the seal?
I can't seem to find anything online.

I did not grab a picture, but here is an example from online.

Once I have everything, I will re bleed the whole brake system.

Thanks!

Hi,

Ford don't sell these seals separately. So there is no part number.

I would recommend contacting a brake refurb specialist such as Bigg Red.

It's just a standard Ford rear caliper, either change it for a good conditioned used one or a new one.

Then bleed the entire system

Repair kits (both seal kits and replacement piston kits) for these ATE/Ford brake calipers are widely available from parts suppliers or eBay.

I usually rebuild calipers instead of replacing them. Repair kits are quite inexpensive, and rebuilding a caliper (including glass bead blasting, cleaning, degreasing, and painting) takes less than an hour. Rebuilding these calipers is far more cost-effective than buying a brand-new original Ford or ATE caliper. I always avoid the cheap Chinese knockoffs because of their generally poor quality.