2000 r6 brake problems

Started by mattg, May 30, 2007, 10:23:02 AM

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mattg

 :wah:

My brakes have always been dragging, a lot.  I get about one revolution out of the front wheel when I spin it by hand.  I put new seals in my calipers (no tricks to that, right??), and re-bled the brakes.  I went the trackday at road america this weekend as was a little surprised when I didn't have brakes going into turn 6.  They were great into turn 5, but I had to put 3 pumps into them to get anything into 6.

I tried a new master cylinder, but it didn't help.  I'm not certain, but my lines may have been a little wet around where the stainless steel braiding meets the fittings.  Also, after I got back from a lap where this happened, my front brakes were dragging a lot, again.

I have stock 2000 R6 brakes, with goodridge S/S lines, and DP Race pads that have maybe 8-10 trackdays on them.

Any ideas?  I'm really at a loss.

mattg

Just wanted to add that my MC is the stock nissin, and the one i swapped in was from an 05r6, a yamaha OEM brembo MC.

tstruyk

any wierd feel coming through the lever?  vibration?  Is the drag intermitant or constant (does it pulse?)

thinking warped rotors...

the initial drag may be from a slightly mis-alligned axel.  re-measure your fork height but do it from the axel to the lower triple.  That may be causing SOME drag, and then if the rotors are warped, at speed it may be pushing the pistons back a hair (kinda like when you get a tank slapper) requiring you to pump to regain pressure... dunno, just kinda "thinking" out load.

I dont think its a air problem... pumping a lever with air in the line wouldnt rebuild pressure, I wouldnt think.
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mattg

braking is perfectly smooth, no shaking, vibrations, or anything.  no headshake at all.


tstruyk

what happened after T6?  brakes work?  still fade throughout the day?  was this a one time instance?
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mattg

every time I used them hard, I'd have to pump them back up.  I used two different fluids, both were supposed to be good. 

once back into the pits, they felt fine.  I could use them normally into 1, and still have fine feel into 3, but after braking for 5, I'd have to pull the lever a few times into 6.  Then again, I'd brake hard into 8 and not have much left for brakes into the chicane.

Sobottka

if you gotta pump em up you most likely have air... that'll make em drag too :thumb:
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mattg

really????

i've bled them a ton, I don't get any air out of the calipers.  When I was running that radial MC, I would maybe get one bubble out after a session.  but getting that bubble out wouldn't help the dragging.

I was thinking maybe a rotor is slightly warping under hard braking, and then cooling and then I need to pump the pad back to the rotor.  I did sometimes feel the brakes stiffen up towards the end of the T5 braking zone.

???

mattg

but then that still doesn't explain the dragging.


wills rims

Quote from: mattg on May 30, 2007, 06:48:36 PM
but then that still doesn't explain the dragging.


Have you tried bleeding you brakes at the banjo bolts and all the bleeder screws. Sometime air will stay at those locations and not go past. Try the mastercylinder banjo bolt too.

Super Dave

I've had my R6 rotors warp like a bowl.  No pulsing at all, but eventually, the bowled out shape would push that pistons back, and my initial pull was to flatten out the rotor.  Then, nothing to slow the bike.  It was so bad once that the rotor contacted the caliper itself. 

I thought it was more of a problem with the '03/'04 rotors because they had so few floating buttons to transfer heat.

Might be worth a look.
Super Dave

GSXR RACER MIKE

#11
Is your brake fluid reservoir full? If your reservoir is full the fluid has no place to go as it heats up and can cause braking issues. The fact that your having issues in or immediately after hard braking areas would add possibilty to this being a potential cause of your problem due to the tremendous heat just generated and not dissapated yet. You should keep the reservoir about 1/2 to 2/3 full so the fluid has a place to expand to.

Now wouldn't that be an easy fix if that was it! 8)
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Racing exclusively with CCS since '96
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