I have just renewed the pistons and seals in the rear calliper of my Evo 250. Unfortunately I damaged one of the seals as I was putting it together. Is there a source for seals only as it seems a shame to spend another 30 odd quid when all I need is one seal?

I had the same problem with mine and, unfortunately, wasn't able to source any from anywhere else so had to buy a complete kit again.

Are you not using red rubber grease when rebuilding the calipers?

19 hours ago, trapezeartist said:

I have just renewed the pistons and seals in the rear calliper of my Evo 250. Unfortunately I damaged one of the seals as I was putting it together. Is there a source for seals only as it seems a shame to spend another 30 odd quid when all I need is one seal?

Strip the caliper again and measure the seals.  Quick google found a seal supplier might have the ones you need.

On 1/15/2020 at 11:24 AM, rcgods said:

Strip the caliper again and measure the seals.  Quick google found a seal supplier might have the ones you need.

Measuring the main dimensions is one thing. Getting the exact right profile and the right material is another. I bit the bullet and bought another kit (and some red rubber grease!).

This one just runs and runs. I got the new seals in, then had a nightmare to get it bled. Finally I think I have all the air out of it. Next problem is the massive amount of travel before the brake comes on. The bike is still on the stand with numerous bits still to be refitted so I haven't ridden it yet, but it looks as though there is too much roll back on the seals. I'm just hoping I'm wrong once I get to riding it, or maybe riding for a bit will persuade the pistons to move out a bit closer to the disc.

What make are the callipers?

AJP?

Did you clean out the seal grooves in the calliper?

You're right that it may sort itself out when ridden, mine had loads of travel last time I changed seals and it was fine after riding.

33 minutes ago, johnnyboxer said:

What make are the callipers?

AJP?

braktec, I think.

3 minutes ago, totty79 said:

Did you clean out the seal grooves in the calliper?

You're right that it may sort itself out when ridden, mine had loads of travel last time I changed seals and it was fine after riding.

Oh yes. The grooves were pretty crappy and took a lot of picking at with a metal scribe.

Your second comment is encouraging. Depending on how it turns out, I may go to a practice ground next weekend instead of doing a trial. That way I can do the things I need to do to encourage the brake to behave rather than having to follow the route. And I can stop whenever I like to adjust the pedal and top-up the fluid.

52 minutes ago, trapezeartist said:

braktec, I think.

Aren’t they Grimeca?

i had a google on a few sites and they said Grimeca, since 2005

Maybe wrong though 

You still have air in it. The rear caliper has to be higher than the m/c to bleed out. I also use 3 ft of clear hose over the rear fender. Gravity is your friend this way.

Edited February 2, 20206 yr by lineaway

9 hours ago, johnnyboxer said:

Aren’t they Grimeca?

i had a google on a few sites and they said Grimeca, since 2005

Maybe wrong though 

Possibly. I was just going on the seal kit, which came in a Braktec bag.

On 2/2/2020 at 11:39 AM, trapezeartist said:

This one just runs and runs. I got the new seals in, then had a nightmare to get it bled. Finally I think I have all the air out of it. Next problem is the massive amount of travel before the brake comes on. The bike is still on the stand with numerous bits still to be refitted so I haven't ridden it yet, but it looks as though there is too much roll back on the seals. I'm just hoping I'm wrong once I get to riding it, or maybe riding for a bit will persuade the pistons to move out a bit closer to the disc.

Did you do the master cylinder seals too?  Usually you have to work the brake a bit to get the pistons to sit out where the brake will engage, then they settle in, but it shouldn't take more than ten or so enthusiastic squeezes (after which the reservoir usually needs topping up).

If it continues and gives a spongy braking feel then it's air ... after much farting around the best way for me has been to do "bottom up" bleeding with a syringe, but everyone has their own home remedies for successful brake bleeding, lol

2 hours ago, turbofurball said:

....  but everyone has their own home remedies for successful brake bleeding, lol

I haven't!?  I did get the pistons to push out properly in the end but I'm still stuck with the long travel and spongey feel. I tried reverse bleeding. I tried taking the whole assembly off so that I could have a nice smooth uphill run for the air to find it's way to the bleed nipple. I used a T-bar to push the m/c piston to make sure I was using the full stroke. Having reached the point where I was just about feeling something at the end of the pedal travel and I had done numerous pumps with no air coming out, I decided the air must be caught in the banjo on the master cylinder. So I cracked off the banjo bolt and gave the pedal a squeeze. Fluid came out without any sign of bubbles (it's hard to be sure) and then I completely lost the pedal again. More conventional bleeding and I got back to the spongey long-travel brake, but no further. I've now given up and I'm taking it to a motorcycle mechanic tomorrow.

It seems to me the integral reservoir in the master cylinder is the problem. You only get three pumps before you have to stop and top-up. If there was a remote reservoir it would be possible to disconnect it, put a big syringe on instead and push through a whole system-full of fluid in one smooth action. I thought about getting another m/c top and aralditing in a piece of metal tube that I could then put a syringe on, but it's easier to just take the bike to someone else to do (I wish I'd done that from the start).

Make sure they know what they are doing. I've just been told by a BMW dealer that (despite having done the same job previously in an afternoon) new calipers will require the bike being kept overnight so that the brake lever can be tied back to bleed the brake as that is "the only way it can be done". B¥€€¥#&s.