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Discussion Starter #1
Continue to have soft brakes after I installed, braided brake lines, new rotors, new kit in master cyclinder, new kit in calipers, installed speed bleeders, bought a used master cyclinder and installed a new kit in it and still soft brakes. Also had the dealership bleed the brakes with a machine and no air was found in system. I even took the calipers off and inserted an old disc between them and moved them around while bleeding through the speed bleeders no air. Has anyone had this problem?
 

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did you do the rebuilds? did you use any lube on the caliper pistons? any grease? l would remove the speed bleeders first and go from there.You can test the master by using an old brake line and plugging the end of it.Once you have bled the master properly and you`ve got a plugged brake line coming off of it,is the lever still spongy? you need to isolate the source of air or the reason for sponginess. Are the pads new? you will find that if for some reason the pad(s) aren`t hitting square on the rotors this presents as a soft,spongy lever.l`ve seen this happen because of improperly installed brake pads,front wheel not centered,calipers loose or improperly installed,loose rotor mounting bolts. But start with a very close visual examination and remove the "speed bleeders" .l use a mitivac pump and fill the system from the caliper__upwards__. yep, when the system is empty you use light pressure and pump fluid through the caliper bleed nipples_up the master. l have found this usefull method can cure stubborn sytems in many cases. keep posting,let us know how it goes...
 

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Discussion Starter #3
Yes I did the rebuild myself and after working on motorcycles and hot rods for more than 40 years this is the first time I can't figure out the problem. The speed bleeders are just a check valve bleeder plug, when closed they act just as a normal bleeder plug. Yep new pad, new rotors,new hoses, three rebuild master cyclinders, grease on the pistons. I haven't blocked off the master cyclinder as you say but I will try that. Also I modifided a master cyclinder cap and used a freon vaccum pump to pull fluid through the system as a last stab at the problem.
 

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I like your User name :)

You say your Brakes are soft is this even after pumping the Brake lever a good few times, Or does the lever improve after pumping up..?
 

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Discussion Starter #5
Just checked the master cyclinder by plugging it off with an old hose and it works as a new one so the problem is not the master cyclinder. Must be air in the system even the dealer can't seen to get it out. I removed the calipiers and held them in my hand while pumping and all piston move but not all at once, most likely because of trapped air. The level will never pump up but it will stop the bike but then lever is within 1/4" to the handle bar when it does stop. By no means will it lock the wheel just feels smooth and like the old drum brake use to feel back in the 60's when I road. I've spent too much money on the brakes and they still do not work. Know anyone who wants to buy this beast! I bought the bike new 16 years ago and now I have aged with the bike. So it's time we part ways.
 

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Discussion Starter #8
ELR658 thank you very much for your advice. I did tie my brake lever back for about three or four weeks, each day I tapped the calipers with a wooden dowel to make the air bubbles rise back to the master cyclinder. Also removed the front wheel and put a new tire on it so while this was being done I slipped the disc back between the calipers and pumped them up again and doing as you say tie the lever back. Rotaing the calipers while they were clamped to the disc I tapped the calipers with the wooden dowel and this maded more bubbles rise and each time I did this my brakes got better. I never would have thought of this so thank you for this suggestion and I hope others read this too if you have trouble with soft lever and you can't get he air out. Regards Tractor
 

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ELR658 thank you very much for your advice. I did tie my brake lever back for about three or four weeks, each day I tapped the calipers with a wooden dowel to make the air bubbles rise back to the master cyclinder. Also removed the front wheel and put a new tire on it so while this was being done I slipped the disc back between the calipers and pumped them up again and doing as you say tie the lever back. Rotaing the calipers while they were clamped to the disc I tapped the calipers with the wooden dowel and this maded more bubbles rise and each time I did this my brakes got better. I never would have thought of this so thank you for this suggestion and I hope others read this too if you have trouble with soft lever and you can't get he air out. Regards Tractor

He's been wrenching for 30 years. He should know SOME tricks by now!
 

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Im going to steal the thread if you dont mind because it has the title I need. The rear brake rotor on my 91 zx11 is got rusted from sitting while the engine was being rebuilt, anyways, now that it is up and running, I have been riding and the rear brake rotors rust will not disappear for anything. The pads and all were great before it sat and got rusted, the rear brake works like it normally does and stops the bike the same as before but the rust will not go away, this is the first time I have ever seen that, what could be going on with my brake pads that would cause them to not rub the rust off? or is it the rotor itself? Thanks
 

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Mine do that if it sits up for a long time. I use 120 grit sandpaper to knock of the bulk of the rust then take it for a ride and while riding I keep light pressure on the brakes till it cleans it off. Takes a while but it does the trick. I let off the brake at intervals to keep them from getting too hot.
 
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