problems with break piston seals

hello lyka builders,
3 of the 4 piston seals from my brakes are leaking. i use dot 4 brake fluid and installed the seals very carefuly.
I do think i did something wrong and now i try to install new seals. the manual says 38 x 28 x 8 but i can not find these seals in my country. does anyone now what kind of car/bike they come from ?

best regards'

roel

STW sends me new seals.
I think this will solve the problem.

best regards

roel

I had the same problem. Installed brake fluid and the next day it was on the ground. The way I fixed the wheel cyls
was to install o rings behind the rubber seals. When you remove the seals you will see a grove on the back side of it. Get an o ring thats the diameter of the grove but just a little thicker then the grove, with the piston removed and the seal in place push the o ring to the bottom of the cyl. The first one took about 20 mins the rest took about 5 mins. Then use a tool with a 90 degree ell like a small Allen wrench and pull the o ring up and inside the grove in the seal. This will tighten in i.d. of the seal. Then lub with silicone spray and slowly press the piston in. The reason to do it slowly is so the seal will move around the piston as you press or you will cut the seal. I did this six months ago and no more leaks.

Roel,

I had a similar problem on only one wheel. After replacing the seal twice with no success I was advised that the piston was too good a fit in the cylinder and insufficient pressure was getting past the piston to expand the seal. We machined a small groove down the side of the cylinder from the seal to the bottom. I have not had a leak since.

Peter.

ok.
i will first try new seals, if that does not work i will try your options.
thanks a lot.

roel

today i received the new seals stw send me - thanks for that -. The seals are a little bit thinner, so oil can get to the insite of the seals better. Problem solved.

best regards,

roel

Hi does anyone know where to get replacement brake calliper seals
Thanks Paul