midnightrider1300 Posted June 12, 2015 #1 Posted June 12, 2015 Ok , the top 2 decompressed NO PROBLEM, the bottom cylinders I can't get to budge..... any advice? I've tried C clamp, no luck.... Large channel lock nothing, I've loosened the bleed valve still wont budge.... any ideas?
Eck Posted June 12, 2015 #2 Posted June 12, 2015 You didn't mention if any brake fluid came out when you loosened the bleeder. If no brake fluid came out, then I would totally remove the bleeder in case it is plugged.. Now you know there is a way out (per say) for the fluid to escape. Next, check the fill level on the rear master cylinder. If it is TOO FULL....the brake fluid has no where to go when you push in on the pistons in the caliper. If the piston still doesn't go back in I am beginning to feel like your pistons are corroded and stuck in the bore of the cylinder. To be positive that this IS the problem, go ahead and remove the rear brake line from the caliper (your bleeding the brakes anyway)..Now with the bleeder removed and the brake line removed try once again to push the pistons in. If they do not budge they are frozen, corroded in place. I would pursue a new caliper if this is the case.......
midnightrider1300 Posted June 12, 2015 Author #3 Posted June 12, 2015 "You didn't mention if any brake fluid came out when you loosened the bleeder"... yes fluid came out... "Next, check the fill level on the rear master cylinder. If it is TOO FULL....the brake fluid has no where to go when you push in on the pistons in the caliper." top 2 compressed no problem so I'm taking this is out.... I"m thinking bottom 2 are froze/stuck or maybe a little offset maybe...
Zzyzx Posted June 12, 2015 #4 Posted June 12, 2015 Were the pads worn where the bottoms of the pads are much thicker then the tops? If so the bottom cylinders may have not been working at all and have bound up off kilter in the housing. You should completely remove the caliper from the bike and see if you can see any twist in the cylinders. Use a micrometer to check for differences if you have one. Make sure to plug the end of the brake line so it doesn't bleed out all of the fluid. You can try doing the C-clamp compression on the bench if the cylinders are not to far out of alignment. Open the bleeder valve all the way. Use an old brake pad and place the metal side against one side of the cylinders. Lay a rag over the bleeder hole area then slowly turn the clamp to compress both upper and lower at the same time but go slow. If that works do the other side the same way. Once you have them compressed check the outer seals to make sure they are not pinched or damaged then reinstall the caliper. Install the new pads and bleed the system. Remember to use only DOT-4 brake fluid. Hope this helps.
midnightrider1300 Posted June 12, 2015 Author #5 Posted June 12, 2015 "Were the pads worn where the bottoms of the pads are much thicker then the tops?" inside pad was wore out.... outside pad out 1/2 .... worn even otherwise......
BlueSky Posted June 12, 2015 #6 Posted June 12, 2015 Has anybody tried to remove the caliper and fill it with penetrating oil to see if it will loosen the pistons?
Eck Posted June 12, 2015 #7 Posted June 12, 2015 Has anybody tried to remove the caliper and fill it with penetrating oil to see if it will loosen the pistons? I wouldn't, but that is my opinion and does not mean it would not work...
Great White Posted June 12, 2015 #8 Posted June 12, 2015 If the caliper pistons are seized, they need to be removed, cleaned and reinstalled with a new seal kit. If the pistons are removed, inspected and the chromed surface is rusted; they need to be replaced. Don't go halfway when fixing brakes. Do it once, do it right, do it right, do it for your life....
midnightrider1300 Posted June 12, 2015 Author #9 Posted June 12, 2015 bike is still under warranty ... so I'm hoping if the caliper is seized that yamaha will take care of it
utadventure Posted June 12, 2015 #10 Posted June 12, 2015 I have had that and it was because of grime on the outside of the piston. I actually had to cause them to extend a little further so I could clean them and then compress them back in. I then worked them in and out a few times to make sure they were functioning correctly.
midnightrider1300 Posted June 13, 2015 Author #11 Posted June 13, 2015 I want t thank everyone on your input ....I came home from work, went to garage and tried again and it worked,, moved channellock pliers around to make sure it was wedged and poof ....they work great ...
dacheedah Posted June 14, 2015 #12 Posted June 14, 2015 before compressing them you want to make sure to spray cleaner on the exposed portions so as not to push the dirt inside, I saw that you have them back in and it wouldn't hurt to bleed them out so as to replace any old fluid here, watch the color and debris. If you have any refill and replace all the brake fluid.
midnightrider1300 Posted June 14, 2015 Author #13 Posted June 14, 2015 before compressing them you want to make sure to spray cleaner on the exposed portions so as not to push the dirt inside, I saw that you have them back in and it wouldn't hurt to bleed them out so as to replace any old fluid here, watch the color and debris. If you have any refill and replace all the brake fluid. it's all good ... bike only has 18k miles on it ...it was bought NEW in 2014 ....
Flyinfool Posted June 14, 2015 #14 Posted June 14, 2015 it's all good ... bike only has 18k miles on it ...it was bought NEW in 2014 .... That means that you likely have 5 year old brake fluid in there, way over due for a fluid change. It is not mileage that degrades the brake fluid, it is age. Sitting is worse for the fluid than racking up miles.
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