Hello all.
First - thank you all for contributing to this forum. Can't be said how invaluable this site is.
Now here's my issue - after about 30 minutes of riding, my front brake will slowly start closing. I'll notice that the bike will start slowing down, and by the time I can get to the side of the road, it's to the point I can't roll the bike. In order to get home, I break the bleeder valve, a bit of break fluid comes out and the brake is released. It will operate fine afterwards, but I've had instances where after about another 10 minutes of stop-go riding, it will seize up again.
Rewind - The bike was sitting for about 4 months and the front break lever had no effect on the brakes. I assumed air in the line, so I bled the brake. The next ride after, I got the above described issue. I bled it again thinking I had done something wrong (not much experience with brakes), but got the same response after. I promptly went out and order new brake pads (ones on there were due a change anyway), new SS brake line (figured might as well eliminate one potential cause and upgrade at same time), and a caliper rebuild kit.
Well, I've changed the pads, installed the new brake line and torn apart the caliper and master cylinder. I've cleaned a lot of crap out (there was quite a bit of brown looking crud), but I wasn't able to use the rebuild kit (the seals were the wrong size). However, I did take a good look at the exisiting seals, and they were not torn.
After bleeding the brakes about 5 times now, I'm at my 'out of ideas' point. Maybe I'm using the wrong brake fluid? I know it calls for DOT 4, and I've been using DOT 3/4...
Any other ideas would be greatly appreciated.
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Probably the seals. When the pistons push out, they can't come back.
I'd say why fight it? Order a front caliper from a good used bike from Pinwall on ebay. Usually $14.95 with good pads from like a 2009 bike with 1000 miles or so. Drop it on and you're ready to go. Cheaper and easier than rebuilding. Cheaper than pads and a rebuild kit.
I've been doing that to all my bikes. Never a problem. Will do my bike Trey this weekend. Has the 1994 calipers. There's a tiny leak somewhere. Why bother? Just drop on a caliper from a 2009 and either toss the old one or give it to someone that likes to rebuild things. Plus I have the newest calipers - not rebuilt, obsolete ones that are 20 years old. I always keep a few in my parts bins.
Are you using that Synthetic DOT 3&4 in the blue and white can? Valvoline? Good stuff!
Quote from: adidasguy on April 11, 2012, 06:05:53 PM
Probably the seals. When the pistons push out, they can't come back.
I'd say why fight it? Order a front caliper from a good used bike from Pinwall on ebay. Usually $14.95 with good pads from like a 2009 bike with 1000 miles or so. Drop it on and you're ready to go. Cheaper and easier than rebuilding. Cheaper than pads and a rebuild kit.
I've been doing that to all my bikes. Never a problem. Will do my bike Trey this weekend. Has the 1994 calipers. There's a tiny leak somewhere. Why bother? Just drop on a caliper from a 2009 and either toss the old one or give it to someone that likes to rebuild things. Plus I have the newest calipers - not rebuilt, obsolete ones that are 20 years old. I always keep a few in my parts bins.
I went this route (ordered used caliper from Pinwall) and all was good until yesterday (having had a couple trips on the replacement caliper). I had a passenger and about 15 minutes into the ride, the brake seized up again. Any other ideas? Thinking maybe it's time to replace the master cylinder or rotor? These are really the only two pieces left in the puzzle, right?
How old is the fluid? Are you lubing the moving parts and bleeding properly?
Seen this happen before, and typically it's caused by a bubble somewhere causing pads not to return. This causes heat which can cause failure.
Use a vacuum pump and make sure you have fresh dot-4 with no bubbles in lines. Also, lube any moving parts.
My 2 cents.
Check your master cylinder.
Not sure on this bike, but on most MCs I've looked at there are two holes going from the MC reservoir to the piston, one large, one small (needle sized). If the small one plugs it can cause odd problems like this where the brakes don't completely release. All brake fluid boils... sounds like the pads are still dragging.
It's not air, but water, that would cause this, tho sounds like you've completely replaced the fluid at this point. Is bike parked outside in rain?
Warped rotor would cause pulsing at wheel / lever.
Quote from: noiseguy on June 25, 2012, 08:36:36 AM
...It's not air, but water, that would cause this, tho sounds like you've completely replaced the fluid at this point. Is bike parked outside in rain?
I hope not, because he has a two car garage. If it is outside, he needs to change some priorities there. Time for wifeys car to experience the weather. :icon_mrgreen:
- Bboy
Quote from: jestercinti on June 25, 2012, 08:06:29 AM
How old is the fluid? Are you lubing the moving parts and bleeding properly?
Seen this happen before, and typically it's caused by a bubble somewhere causing pads not to return. This causes heat which can cause failure.
Use a vacuum pump and make sure you have fresh dot-4 with no bubbles in lines. Also, lube any moving parts.
My 2 cents.
The fluid is brand new - I've had to bleed the brakes 4-5 times trying to troubleshoot this thing.
Quote from: noiseguy on June 25, 2012, 08:36:36 AM
Check your master cylinder.
Not sure on this bike, but on most MCs I've looked at there are two holes going from the MC reservoir to the piston, one large, one small (needle sized). If the small one plugs it can cause odd problems like this where the brakes don't completely release. All brake fluid boils... sounds like the pads are still dragging.
It's not air, but water, that would cause this, tho sounds like you've completely replaced the fluid at this point. Is bike parked outside in rain?
Warped rotor would cause pulsing at wheel / lever.
You're talking about the piston in the MC, not the piston on the caliper, correct? So it would be number 2 on the Front Master Cylinder parts fische... I can check that out. Worth my time to get a rebuild kit? http://www.bikebandit.com/k-l-master-cylinder-rebuild-kit?m=22235
Ok, then I don't think its a warped rotor, which narrows it down even more. I've replaced caliper and brake line, so onto the MC!
And yes, it sits in the garage. :cheers:
I've since ordered and installed a master cylinder rebuild kit. I also got the one way valve to make life a little easier.
(http://img856.imageshack.us/img856/2391/imag0457yw.jpg)
Before.
(http://img401.imageshack.us/img401/6053/imag0459vq.jpg)
Removing the dust cover. Then a dreaded snap ring.... trip to Autozone to pick up snap ring pliers... I think taking this stupid ring out took the longest part of this job.
(http://img94.imageshack.us/img94/3655/imag0464p.jpg)
Out she comes.
(http://img716.imageshack.us/img716/5695/imag0468z.jpg)
Yup, its gross. Definitely needed attention.
(http://img62.imageshack.us/img62/7605/imag0469m.jpg)
New and old.
(http://img809.imageshack.us/img809/9380/imag0471l.jpg)
I've cleaned the MC once out before, but never got under the silver tab(?). Its pretty rusty, so I figured I'd get under it and clean it out.
(http://img846.imageshack.us/img846/7647/imag0473v.jpg)
Sure enough, there's supposed to be a hole under there! Noiseguy wins the prize for calling this one. If you look real close, you can see a tiny hole behind the big hole (technical term :icon_lol:).
(http://img803.imageshack.us/img803/846/imag0476n.jpg)
Cleaned up a bit and can see the hole from above.
(http://img163.imageshack.us/img163/3316/imag0480y.jpg)
Reassembled.
(http://img31.imageshack.us/img31/9807/imag0482r.jpg)
Put it all back together, filled with brake fluid and bled. Went on a 2 hour ride this afternoon and didn't have any issues! Hope this one is put to bed! :woohoo:
How full is the master cylinder? You say the brake oil is new... Did the problem start after changing the fluid?