Caliper issues

[jewfzr]

Hey,
Put some Galfer wave rotors on my old cbr900 along with braided lines. "front end" The calipers are not opening wide enough to allow the wheel to spin. I have them bled out well enough. My next thought was to rebuild the calipers. Anyone have any ideas or directions to go? thanks

[Stromper]

1 st make sure they are the same thickness and maybe off set as stock

2nd Look to see if you screwed up and the are not mounted at a cant and or buttons not moving if you have buttons clean and free them

3rd sizable air still in system sometimes act as a spring pushing the piston back out. Bleed bleed also at banjos

4th Older calipers can/will get some corrosion behind the normal position of the pistons

this stops them from moving freely or sometimes even having you push them back. Small amounts of corrosion can be removed and polished but big pits and your screwed. Lastly the retraction of the piston is only by the O ring elastic rolling back which is a small force at best. IF you have new rubber it is stronger

[Jim]

i've done this on both my bikes this year, so i could offer some tips if needed. i've written up a thread about what steps i used, but this should work....


get a seal kit from your local dealer. they cost about $50.

open the calipers up in half by removing the pinch bolts, and keep everything organized (right, left, inside, outside).

leave the bleeder & banjo in the caliper. with compressed air, shove the air nozzle down the small hole inside for the fluid. make sure to aim the caliper pistons ina trash barrel, as they shoot out rather quickly. one the 1st piston is out. carefully place the 1st one slightly back in & put a c-clamp over it. then use the air nozzle to fire out the other piston.

clean the pistons and calipers with brake cleaner & use air to dry everything out. after inspecting the pistons for any scarring or damage, install the new seals in the calipers. make sure to use some brake fluid to lubricate the new seals. then install the pistons back in.

put the caliper halves back together using the pinch bolts.

bleed the system out for the rest of your life.

[jewfzr]

Thanks you guys. I'll give it a shot.

[Kurlon]

When cleaning the calipers, use a dental pick and really make sure the corners of the seal grooves are clean. That's where crap builds up, and it doesn't take much to cause the seals to 'jam' a bit against the pistons, preventing them from retracting properly.

[jewfzr]

Thanks a lot.

[BluGixxer]

When reassymblying the calipers what type of grease or lube do you sugest, I know some products make rubber swell over time.
Silicone grease,
Anti-sieze
Caliper slide grease
A little brake fliud,
Or dry ?
Sugestions ? Thanks
I'm going tru the same thing soon.

[Kurlon]

Brake fluid only, don't want anything in there that can contaminate the brake fluid.

[CBR929RE]

Brake fluid only, don't want anything in there that can contaminate the brake fluid.

Honda Service Manual for my 929 says to use Silicone grease on the dust seals (seals closest to the pads) and brake fluid on the piston seals (ones further inside the caliper)

[FireboltEric_MA]

That's how I did them on the R6 when I rebuilt them.