K&L caliper re-build kit-fits tight?? is that ok?

Hello newbie Deborah here.

I took one of the calipers apart, cleaned it up real good, using brake fluid, removed the piston, and when I put the seals on the piston it would not go into the caliper very far. I took the seals off and it fit fine. I guess there should be some resistance as it is supposed to seal from brake fluid flowing out.

I was going to order the ones from Chacal, but in his description, he says his are small, but still work ok, so if his are smaller, there will be a tighter fit.

Anyway-its this ok, any suggestions.

First time for re-building a caliper.

 

Just to clarify, the seals that I sell ARE correct for the 750 Seca model, they are "too small" (width-wise) for the 650 Turbo and 750 MAXIM calipers, and almost every place on earth is trying to sell the 750 Seca caliper rebuild kits as ALSO fitting the 650 Turbo/750 Maxim calipers (which are different from the 750 Seca calipers).......but the 750 Seca seals are NOT correct for the 650 Turbo/750 Maxim calipers!

 

Sorry-did not mean to offend, just did a quick read on it.

 

A couple of things to check... The seal grooves in the caliper bore sometimes trap some gunk (old brake fluid and seal bits) that has to be scraped out, otherwise the seals do not fully seat into them.
Check the piston for scoring or rust, buff out any burrs if necessary... Also, when you reinsert the piston, lubricate it and the seals with some fresh brake fluid. You should be able to fully seat the piston into the caliper with your thumbs.

 

When I cleaned up mine, I had quite a bit of crud in the grooves for the seals as stereo mentioned. It took some effort to scrape all of that out. Also, when re-inserting the pistons, it takes some time to get them to seat just right and move down. It took some time working with them to get them to seat and slide. I also coated the seals pretty good with silicone grease to help.

My calipers may be different, but hopefully some of the tips will help.

 

Hello: I did everything that you mentioned, but maybe I need to clean the grooves a little better. There is a little bit of wear on the ends of the piston, but not the part that goes inside the caliper. I did lubricate the seals prior to pushing them in.

I was just thinking maybe the K&L's do not fit well.

Thanks for the tips.

 

Thanks Joe: That really helps. I'll clean the grooves a bit better and try some silicone grease.

 

Debbiker, I would caution you to not use the silicone grease, it will contaminate the system (silicone and petroleum distillate aren't fond of one another). Use only brake fluid. I've just confirmed this issue with our SAE mechanics and chemical engineer. All said don't do it. Our mechanical engineer (who races) said for some reason brake systems do not like Dot 5 and drop/disintegrate at a faster pace than ordinary brake fluid systems.
Sorry about that.

 

Thank you Robert, so I guess the other guy should'nt have done that.'
I was wondering about that, cause i've heard don't use anything but break flluid to lubricate and clean your parts.

Thanks for the confirmation.

I will spend some more time cleaning it, then I guess its just supposed to be tight.

Thanks again

Deborah

 

Hey Deb, didn't take offense, sorry if it sounded that way, I just wanted to confirm for you that the 750 Seca caliper rebuild kit WILL have the proper sized seals in it for the 750 Seca models (and all 550 models and 1100 front calipers, too, as they are all the same calipers). So the K&L caliper kit that you purchased is probably not the cause of your dragging issue, I think the suggestions that everyone else came up with are sending you in the right direction!

 

Every bike shop (and there have only been a few) that I have dealt with (see previous comment) has advised using stock rebuild kits for longevity and correct fitment. Chacal talked me out of the K&L kits with the same reasoning.

 

thanks guys for all your help. I got Chacals kits, burned off the gunk with a torched, scraped it out, used Chacals paper to smooth out the bore, lubed up the seal with brake fluid and after the 2nd try, the pistons went all the way in.

 

Excellent!