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Discussion Starter · #1 ·
I have a very soft brake lever. When first pulled, it will go all the way back to the grip. It can be pumped up a few times and that improves matters for a short bit, but soon it will return to its original wishy-washy feel. It's not safe the way it is, and I would sure like to correct it. Here is what I've done thus far:



1) New USA Motrocycles Master Cylinder

2) New Stainless Brake line from JDA Enterprises

3) Polished caliper piston

4) New caliper seal - Honda OEM

5) New Caliper rubber dust cover - Honda OEM

6) Completely cleaned caliper

7) New bleeder, sealed with teflon plumbers tape



I have bled and bled and bled - there is NO air in the system. It seems that all would be well if I had another inch of brake lever travel. (Perfect straight line for someone.) My wife is getting a tad upset that I have spent as much as I have, so hopefully it's a fairly simple fix.



Any ideas from the gurus? Or Nagus?
 

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Reverse bleed. Take a syringe (the bigger the better!) and push fluid through the bleeder fitting. Be careful as this will quickly fill-up the master cylinder. This is a great way to get air out.



Also tie the brake lever against the handlebar overnight after you pump it up, this can expel some air too.
 

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Well if their isn't any air in the system and the crush washers along with everything else are new you could try another MC. What did your stock one do if you still have it?



Oh which MC did you buy? not that it should batter much.
 

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I know this will sound strange, but it did work for me to get my new MC bled. I was having the same result as you with the traditional way of bleeding. I finally just left the bleed screw on the caliper open and pumped the handle. To my surprise, a bunch of air finally came out and after it stopped, I closed the bleed screw. The handle now had great pressure and it's been a year now without any problems.

Good luck, I hope you get it.
 

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Be sure to take you tank off for all these steps. No sense messing up the paint.



One more off the wall thing that I saw work. Take the caliper off with the bleeder closed, but loose. Put a block of plywood in the caliper and raise it higher than the master cylinder and try bleeding it in the air. Any air in the line should rise to the top. Weird, but I saw it work one time.



At the same time several people on the forum have had problems with bad new MCs bought on-line. Let us all know how you solve it when you do.
 

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Be sure to take you tank off for all these steps. No sense messing up the paint.



One more off the wall thing that I saw work. Take the caliper off with the bleeder closed, but loose. Put a block of plywood in the caliper and raise it higher than the master cylinder and try bleeding it in the air. Any air in the line should rise to the top. Weird, but I saw it work one time.



At the same time several people on the forum have had problems with bad new MCs bought on-line. Let us all know how you solve it when you do.


David, that's exactly what I was thinking.....if he has NO or very little lever pressure that would lead me to believe that the new M/C isn't pumping fluid at all.



And I see where he got his from the same guy I got mine from....It took him sending me THREE new M/C's before I got one that worked right !
 

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Check diameter of piston in M/C. some were 1/2", and some were 9/16". May "feel" different to your old one. But, if its still spongy, there is air in the system. No brake fluids are compressible, so the spongey has to be air. Sorry, I know that doesn't help. Get a bud to help you with bleeding, its easier if someone pumps, and fills up the M/c, and the other fella does the bleed nipple thing.
 

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Discussion Starter · #9 ·
Thanks for the suggestions. After spending some time with it yesterday I am inclined to believe the problem is in the caliper. Either the caliper pins or the holes they go into might be worn. When I squeeze the lever the lever still goes all the way to the handlebar, but when I do this and look at the caliper, I can see it moving sideways away from the rotor a good half inch or a bit more. The bolts are tight, so I think it may be in this area. Does that make sense?
 

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Thanks for the suggestions. After spending some time with it yesterday I am inclined to believe the problem is in the caliper. Either the caliper pins or the holes they go into might be worn. When I squeeze the lever the lever still goes all the way to the handlebar, but when I do this and look at the caliper, I can see it moving sideways away from the rotor a good half inch or a bit more. The bolts are tight, so I think it may be in this area. Does that make sense?


There IS supposed to be a LITTLE movement of the caliper....in other words on one that is working perfectly you could bend over and grab the caliper with both hands with it mounted perfectly on the forks and wiggle it a little bit, that is normal ! (I'm not sure about a half inch though)
 

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How far did the lever compress when you bled the lines? If it went all the way to the handlebar and you got fluid coming out of the bleed screw it might be a leak in the lines or at one of the banjo bolts. If you tie the brake lever back its a good idea to put a quarter inch piece of wood between the bar and the lever.
 

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If the caliper moves more than a fraction of an inch something is missing.

Make sure the brake pads are in the caliper, both pads. You may need to dismantle

the caliper and make sure the piston is not binding.
 

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Also, if the piston inside your caliper was squeezed all the way back, it will take a lot of pumping to get the pads to grip the rotor. The calipers are self centering, so the guide bolts need a little grease on them to allow the caliper piston to "center" the rotor between the 2 pads.



Does that make sense?? The piston pushes the pad on one side, until the pad touches the rotor, then, the "whole" caliper moves the opposite direction to pull the other pad to the rotor.
 

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Discussion Starter · #14 ·
Also, if the piston inside your caliper was squeezed all the way back, it will take a lot of pumping to get the pads to grip the rotor. The calipers are self centering, so the guide bolts need a little grease on them to allow the caliper piston to "center" the rotor between the 2 pads.



Does that make sense?? The piston pushes the pad on one side, until the pad touches the rotor, then, the "whole" caliper moves the opposite direction to pull the other pad to the rotor.


Yes, it does make sense, and I appreciate the thoughts. Looks like there are still a few things to try. I'll let you know when it's fixed and what was messed up.
 

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Discussion Starter · #15 ·
FINALLY sorted it out. Well, not me but a local expert in all things motorcycle. It seems the shims that lay on top of the pads were somehow binding slightly, enough to cause the brakes to drag. All is good, and I'm back on the road. Thanks to all of you for your thoughts, ideas and suggestions.
 
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