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+--- Thread: Funked up Brakes - Help (/showthread.php?tid=7557)
Funked up Brakes - Help - Ginger - 08-13-2008
OK - I installed a radial master cylinder on my DRZ. RJ gave it to me because it was busted as delivered from an ebay auction and wouldn't draw in any fluid. I replaced the piston and it works.
Kind of.
As I use it, and not entirely predictably, more and more pressure will build up in the brake line, causing the brakes to apply themselves. This seems to be associated with use of the front brake, but can build up without being used. This is bad.
I didn't do a full flush when I changed the master because I wasn't worried about building up so much heat as to get a spongy lever at the moment. Is it possible that the air in the line is expanding and causing the brakes to apply? Alternatively, I wonder if the master cylinder is allowing extra fluid in the line?
Has anybody experienced a problem like this before? I'd rather not order a new master, as I'm looking a little bit of a bill for that, but I don't want to ride it around to "test" unlikely solutions.
And to preempt the obvious - I'll be doing a full flush tonight.
- Mike - 08-13-2008
full flush and then come back... air in the lines is the only thing i could guess.
- Ginger - 08-13-2008
Full flush done. I'll probably ride around the block in an hour... or report back at the end of tomorrow. Work's only 3 miles away, so it's not a terrible test, and it's evoked the problem twice now. A few things seem different this time, maybe something worked.
:knock on wood:
- PDenbigh - 08-14-2008
Alison had this exact problem on her Nighthawk 650. It was a while ago but I think I finally determined that it was a blocked hole somewhere in the MC. Her's would get so bad that it'd eventually stop her in the middle of the road. I completely dismantled and rebuilt the MC using lots of brakeclean and compressed air, then dismantled/cleaned the calipers, flushed the lines, and it solved the problem. There are some very small/tight spots in there so any little particle can cause a problem.
- Ginger - 08-14-2008
Cool, thanks, Pete. That's exactly what I'm experiencing... like, to a T. The master was sitting around in RJ's garage for a while, after sitting around in some ebay'ers parts box for a while... then went to me, where it sat in my house for a while before I installed it, so it's quite likely that some kind of contaminant could have gotten in there.
I rode it to work today after the full flush, but it's too soon to tell anything. It normally manifests itself after two to three shorts rides. It'd be great if whatever was causing it unproblemed itself, but I'm not holding my breath.
-Andrew, keeping his 8mm handy.
- Mike - 08-14-2008
Ginger Wrote:-Andrew, keeping his 8mm handy.
isn't it always? muahahahaha :lol:
- ViPER1313 - 08-14-2008
Happened to my roommate's old DSM - master cylinder issue (although we didn't tear it apart to find out what part of the MC failed / was clogged.)
- CaptainHenreh - 08-14-2008
ViPER1313 Wrote:Happened to my roommate's old DSM - master cylinder issue (although we didn't tear it apart to find out what part of the MC failed / was clogged.)
Wuz UR bffs dsm mc fubar? omg.
- ViPER1313 - 08-14-2008
I'm still lost - because I was too lazy to write "I don't know" and used an Internet acronym I now have a "bff" named Jill?? :dunno:
- ViPER1313 - 08-14-2008
Wait, I just got it - you were trying to be funny and make fun of the fact that I said "IDK"
It was so unfunny I just got it.
ZOMG go figure.
- Ginger - 08-16-2008
Well, that was a small waste of money. I did a full flush, and it tried to kill me again. I totally disassembled it, cleaned it out with brakleen and compressed air, put it back together all lubed up and right-like (according to the FSM, even), did another full flush, and it still tried to kill me. I give up.
I took the original master off because one of the reservoir screws was seized in to the body... there's still fluid in it, though, and I'll be reinstalling it later today. Hopefully I can get the seized screw out so that I can order a replacement... I don't want to buy another master.