hebrew hammer Posted March 5, 2010 Share Posted March 5, 2010 So my buddy and I was bleeding out the brakes and we tightned the bolt for the brake but something is wrong it. When I pull the brake it is super mushy but the it is also really hard to turn the wheel when it is on the center stand. I believe its the brake pad rubbing against the caliper, but when testing the brake by running at speed it does not really brake at all. I am stumped guys, what did I do wrong? Link to comment Share on other sites More sharing options...
hebrew hammer Posted March 5, 2010 Author Share Posted March 5, 2010 Or is it just due for a master cylinder rebuild? This bike has been sitting for almost 10 years and the brake fluid was dark and cloudy. Link to comment Share on other sites More sharing options...
2 Wheels Posted March 5, 2010 Share Posted March 5, 2010 For a start, that brake fluid is shaged! By right brake fluid should be changed every 2 years. Very impotant to have brakes so if I was you I would strip own the calipers and make sure all is ok with them and working properly. Then rebuild them, then flush out that shitty fluid and replace with new. If they are still mushy after this then you can check out the master cylinder. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted March 5, 2010 Moderator Share Posted March 5, 2010 So my buddy and I was bleeding out the brakes and we tightned the bolt for the brake but something is wrong it. When I pull the brake it is super mushy but the it is also really hard to turn the wheel when it is on the center stand. I believe its the brake pad rubbing against the caliper, but when testing the brake by running at speed it does not really brake at all. I am stumped guys, what did I do wrong? Classic signs of a dished disc, the disc should be absolutely flat. If not the caliper has to squeeze it flat before it can actually get on with stopping the bike. It will also cause the pads to drag. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 5, 2010 Moderator Share Posted March 5, 2010 more likely the caliper has seized, just strip it down and clean. i'd do the M/C while your at it! Link to comment Share on other sites More sharing options...
hebrew hammer Posted March 6, 2010 Author Share Posted March 6, 2010 more likely the caliper has seized, just strip it down and clean. i'd do the M/C while your at it! I hope it is only the brake caliper otherwise I would have to dish out a few pretty bones to get a new disc. By the way what is the easiest and sure fire way to check if the disc is warped? I just bought a brake caliper rebuild kit since I am going to strip this part down anyways. Link to comment Share on other sites More sharing options...
hebrew hammer Posted March 16, 2010 Author Share Posted March 16, 2010 ok so I rebuilt the brake caliper and now I can't even get the pads wide enough to fit on the disc! what now? edit: I got the piston to fit inside the caliper more by using a c clamp, a padded pole and a mallet. I fixed everything up and re-bleed the brakes. I got more braking power than before but it still feels mushy, is this normal for this old of a bike? The only other bike I owned is a cbr 600 which has super firm braking lever. Link to comment Share on other sites More sharing options...
2 Wheels Posted March 17, 2010 Share Posted March 17, 2010 ok so I rebuilt the brake caliper and now I can't even get the pads wide enough to fit on the disc! what now? Have you opened the bleeding nipple and pushed back the cylinder fully into the caliper. Then put in the shims (if you have shims) and pads and try again. Link to comment Share on other sites More sharing options...
2 Wheels Posted March 17, 2010 Share Posted March 17, 2010 CBR 600 ha ha------- tis a good bike ! That sounds like it was a big job to get that cylinder back, it shouldnt be that hard after a rebuild ! To bleed the brakes. Start the bike, let idle Close bleeding nipple and pump the brake lever 3 times hard Then on the 4th time keep the lever pulled and open the bleeding nipple slightly allowing fluid and air bubbles out The brake lever will be moveing in-words as this happens and you should close the bleed nipple before the lever gets fully in Repeat this until all air bubbles are gone and only fluid comes out. If the brake is still mushy then hav a look at your master cylinder. Link to comment Share on other sites More sharing options...
steveralls Posted March 18, 2010 Share Posted March 18, 2010 The piston should be a light press fit into the cylinder, ie with three or four fingers. It is common for corrosion to build up under the O ring in the cylinder, this can cause the piston to go tight or even sieze. The corrosion can be cleaned out using a wooden ( not metal ) scraper. Insert a new seal lubricated with hydraulic grease and preferably a new piston. perished hoses can also cause a mushy feel but from what you say I'd check under the seal - unless you've already done that. Link to comment Share on other sites More sharing options...
blackhat250 Posted March 18, 2010 Share Posted March 18, 2010 which has super firm braking lever. Another thing is it rubber hoses" , if so swap to stainless braided, the rubber can swell and give a mushy feel, Link to comment Share on other sites More sharing options...
hebrew hammer Posted March 22, 2010 Author Share Posted March 22, 2010 I got one more question, since I have clubman bars the master cylinder is tilted. Does this explain the mushy brake? I still hope its not the rotors, I am planning to rebuild the master cylinder now. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 22, 2010 Moderator Share Posted March 22, 2010 I got one more question, since I have clubman bars the master cylinder is tilted. Does this explain the mushy brake? I still hope its not the rotors, I am planning to rebuild the master cylinder now. it will if it lets in air! the SE models had a tilted M/C body due to the shaped bars Link to comment Share on other sites More sharing options...
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