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Front Brakes Drag--Out of Ideas

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So i have a 2000 DRZ 400e, stock Nissin master cylinder/Caliper. About a month ago, I fried my front rotor. Turns out my brakes had been dragging from the time I put on my supermoto wheel setup. (I checked it, they will also drag w/ the stock dirt setup)

 

With the old rotor gone, I sprung and updated the brake system:

 

  • New Pads
  • New 320mm rotor
  • New SS Line, banjo bolts
  • Master Cylinder rebuild
  • Caliper clean/grease
  • New Fluid
  • Brakes bled (Standard way & reverse bleeding)

 

That firmed up the brakes, but I get the same amount of drag. The wheel can make a 1/2 rotation after a good push, but not much more. The brakes heat up after a 2 minute ride WITHOUT using the front brakes.

 

I've tried multiple variations in brake fluid levels in the master cylinder and even threw the old pads back on. Still nothing.

 

Since theres still drag with the old pads, I ruled out corrosion playing a role in the dragging. I suppose it is still a possibility. Maybe brake cleaner from the PO ruined some rubber in the caliper?

 

The supermoto setup is a honda front hub with custom machined spacers. The wheel is centered, and the caliper bracket has spacers to accommodate the skinnier hub. With this setup, the rotor is centered with the pads so that the wheel will spin if I separate the pads just a little bit in either direction. Sounds sketchy -- but the brakes still rub with the completely stock wheels (I know that rotor is straight). The only reason I mention it is for the possibility that it could have caused the failure of some part in the caliper. (Im really reaching at this point)

 

 

Does anybody have any ideas as to what is causing this drag? Corrosion, caliper problem, bad rubber in the caliper? 

 

Any help is appreciated so help away! 

 

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Sounds like you eliminated a lot of possible culprits, maybe check to see if the cable on your lever is adjusted properly??

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Sounds like you eliminated a lot of possible culprits, maybe check to see if the cable on your lever is adjusted properly??

WTF cable on lever???

 

 

Check to make sure your brake lever is releasing all the way. Common enough that the lever is adjusted in so that the master cups don't clear the return port to the reservoir. You then have trapped brake fluid which heats, expands, and applies brakes.

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&%$#@! cable on lever???

 

 

Check to make sure your brake lever is releasing all the way. Common enough that the lever is adjusted in so that the master cups don't clear the return port to the reservoir. You then have trapped brake fluid which heats, expands, and applies brakes.

Yup no cables in this lever but he has the right idea so thanks for the suggestion...

 

As to the lever not fully releasing, unfortunately Ive already checked that and its fine. If it ever was a problem, rebuilding the master cylinder should have fixed it. Thanks man

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:face palm: typo Thinking about drum breaks cus always working with them on the vintage bikes. But yes I was trying to get at maybe lever wasn't fully releasing

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Did you grease the brake pads pins?

Yes I did, No luck. I also cleaned the clips the pads go in.

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Replace the seals in the caliper. That's the only thing left. And they will get hard over time.

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Replace the seals in the caliper. That's the only thing left. And they will get hard over time.

That's what Im coming too, but it bugs me that I havent discovered a clear cut reason for the failure rather than potential degradation over time.... ugh motorcycles

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You did a nice job ruling out potential issues.  Maybe someone else has mentioned this?  I had a similar issue and pulled the caliper pistons, put them on a drill (wrapping rubber tape around the right sized grinding stone and inserting that into each piston, I spun the pistons and used increasingly fine sandpaper to get them totally polished)  No more retraction issues.  The other thing to double check is those wheel spacers, as you know and already did.  Clean up those pistons and my guess is you will have found your problem.  It is a super easy and very inexpensive job, by the way.  Pull them out with needle nose pliers wrapped a couple times with rubber electricians tape.  The gaskets themselves cost very little.  Good luck.

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Take.the wheel off and the pads, work the brake extending the pistons out then squash them down with c clamps, use a bit of brake fluid on the pistons if theres corrosion or overly dry/stiff movements. Work them in and out and work them against the clamps at varying depths. I bet your problem is gone after that.

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i once had a problem simliar to yours, turned out to be some cheap aftermarket pads, they were too thick and a very tight squeeze on the disk, i thought they would eventually wear away but all they did was cause friction on the front disk which turned it purple with the heat, the disk expands from the heat and locks up the front wheel

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You did a nice job ruling out potential issues.  Maybe someone else has mentioned this?  I had a similar issue and pulled the caliper pistons, put them on a drill (wrapping rubber tape around the right sized grinding stone and inserting that into each piston, I spun the pistons and used increasingly fine sandpaper to get them totally polished)  No more retraction issues.  The other thing to double check is those wheel spacers, as you know and already did.  Clean up those pistons and my guess is you will have found your problem.  It is a super easy and very inexpensive job, by the way.  Pull them out with needle nose pliers wrapped a couple times with rubber electricians tape.  The gaskets themselves cost very little.  Good luck.

Thanks man, I can definitely try cleaning and polishing. I also have new seals on the way, hopefully that will straighten things out. 

 

remove the lever from it's perch, and check

 

I've done that, the problem definitely is not coming from the lever continuously pushing on the master cylinder assembly, and that assembly definitely does not stick as it is brand new. Thanks a lot for the response though

uhhhhh how are your front wheel bearings......

Not brand new, but only a few hours on them. No wheel wobble or anything like that.

 

Take.the wheel off and the pads, work the brake extending the pistons out then squash them down with c clamps, use a bit of brake fluid on the pistons if theres corrosion or overly dry/stiff movements. Work them in and out and work them against the clamps at varying depths. I bet your problem is gone after that.

Thats a great idea.. I guess the point is to get the pistons accustomed to varying depths which eliminates corrosion and maximizes their retracting ability.

 

i once had a problem simliar to yours, turned out to be some cheap aftermarket pads, they were too thick and a very tight squeeze on the disk, i thought they would eventually wear away but all they did was cause friction on the front disk which turned it purple with the heat, the disk expands from the heat and locks up the front wheel

That sounds like a PITA, but I've eliminated the pads as a cause because the problem persists with the old and new pads (Which werent cheapies) but I appreciate the help

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loosen the pinch bolts, both on the axle and on the triples. spin the fork UPPERS in the triple trees. tighten lightly. 

 

press the pads into the caliper.

 

elevate the front wheel, then pull the master lid off and check level, then slowly pump the pads back against the rotor while spinning the wheel. 

 

as it spins, check for warped rotor and caliper alignment against the rotor. 

 

it's entirely possible to reassemble the front wheel/end and get it in enough of a bind that the rotor grabs the pads and starts any water in the brake line to overheat, locking the front wheel, and killing both pads and rotor. 

 

good luck. 

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I can almost promise you what i posted will solve it. Fairly common issue. Calipers just get sticky and need to be worked in and out now and again. They dont get much action from braking when you get down to it, its only mm's of movembt clamping down and the pistons can travel much further. Just run them in and out like i said and report back. Also making sure the front end is lined up and cinched down straight is important but i don't buy it that it would heat the brakes up like that, the pads would wear down (unevenly) and would be the end of it.

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UPDATE:

So I ordered a rebuild kit for the caliper and installed the new gaskets. I worked the pistons out and cleaned everything then installed all the new rubber. I bled the brakes but still had no luck with the rubbing. I'm going to take the bike to my local shop on Monday to see what they say, I will post another update at that point.

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UPDATE:

So I ordered a rebuild kit for the caliper and installed the new gaskets. I worked the pistons out and cleaned everything then installed all the new rubber. I bled the brakes but still had no luck with the rubbing. I'm going to take the bike to my local shop on Monday to see what they say, I will post another update at that point.

Only thing I can think of is you mixed up spacers... Is it more 1 pad or both?

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Only thing I can think of is you mixed up spacers... Is it more 1 pad or both?

Thinking along the lines, alignment issue.

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