Hey Guys,
My 2023 Birel brake calipers are leaking from the piston. I had replaced both seal kits last October so the brakes have only 2 or 3 races since all new seals and brand new fluid put in. Any advice on parts that may be causing this or does anyone ever experience this and can share any advice or tips?
I have just ordered new seals and pistons to see if this may help. Pics also attached.
Were the pistons ok when you replaced the seals? Did you give the pistons a light sand with a fine wet and dry sandpaper , something like a 600 grade. Just to remove any build/lip around the edge of the piston. ( you can see this in your picture as the dark ring around the top ) Is this smooth to touch or can you feel a lip?
Also what brakefluid are you using?
Were the seals oem freeline parts?
Hi,
The seals are OEM. The fluid I am using is Motul 600. I did not replace the pistons when I replaced the seals. I did inspect them and there were no obvious issues from what I could tell. I did not sand them as you mentioned.
Forgot…the piston feels smooth to the touch.
In looking at your caliper I notice the outer o-ring is not in place. Granted the inner square o-ring does the major sealing the outer ring keeps the piston square to the body. Also, the caliper body has a little wear…notice where the anodizing is down to silver aluminum. If you are missing the outer ring this would cause more wear and eventually need to be replaced.
How much fluid is leaking? A small amount I would say is acceptable but if there is enough to cause drips that probably is not good.
The seal was just not inserted for the pic, not to case confusion.
Brakes are important…if in doubt replace parts and rebuild.
I did pistons and seals on our old OTK brakes when we kept fighting a persistent loss of feel and softness on the pedal. After rebuild and good bleed, much better.
Also, need to confirm your brake fluid. Many karts are designed to run on DOT 5.1, which is not compatible with DOT 5. It can affect seals and if mixed the oils may react with each other and not perform well. DOT 5 is silicone oil based, DOT 5.1 is glycol based. I think Motul 600 is a DOT 5 silicone fluid…
I would replace the piston in the caliber and the pump as well.
Dont use Dot 5, i use Dot 5.1.
Dot 4 is what we use with Motul 600
