Rear disk brake troubles

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cryingbaby

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Im crying right now because it is nice out and i cant ride my bike. I cant stop crying. My rear brake is broken. When I took my bike out the rear brake got all stuck and was smoking and all hot. I put the bike up on the center stand and i couldn't spin the rear wheel. I went inside for a soda and when I was done drinking it i came back out nd i could spin the wheel fine. Since then I've taken the caliper apart and put it back together (I know i shouldnt expect that to fix anything but everything looked fine) I took the master cylinder apart and cleaned up a tiny bit of corrosion on the piston with some very fine sanding paper. I took the bike out for a text when I had it all put back together and it did better. it went longer before the brake stuck or whatever. I think the brake sticks because the pad rubs a lot and then the fluid gets all hot and whatever...

so here is my question.

When i took the bike out for the last time the brake pad screw fell off. I probably forgot to tihten it good or whatever. I looked at the one in the front cliper and it looks like it only has threads near the top and the rest is like a rough pin. Im not sure if its the shape of the part or its just worn down like that, it looks pretty rough, it might even be a replacement the previous owner invented or something. I wana put the right part in and if I dont find some answers soon im just going to take a screw and cut it down to look exactly like the one in the front caliper. The manual I have just calls the part brake pad screw and theres a picture of it in a diagram but it looks like it might just be a screw.

please anybody help me. My girlfriend said she would leave me if I dont stop crying but its impossible for me not to cry when my bikes making me so so sad.

any feedback is gr8tly appreciated, I have gotten a lot of good information from this forum in the past I hope someone can help me so that i can stop crying and my girlfriend wont break up with me.

Thank you
 
Well the first thing to do is calm down and tell us what bike you have (make model etc)
First the brake shouldn't rub unless brakes are applied, when putting back together what are you using to lubricate that piston? did you check and make sure your rotor good? maybe some pics would help.
 
You might need to replace the caliper piston seal - this is usually what causes the caliper piston to stick, but richard's questions are the best starting point. And stop crying.
 
Vlad, I have done that, haven't tried it, but i really dont expect that to be the issue. the old seal looked fine.

richard, I used brake fluid to put the piston in the caliper. its a 78 xs650 special. what would be a reasonable tolerance for the straightness of the rotor? i can measure the space from the rotor to the caliper but i really dont think thats the problem. how do i keep the brake pads from touching the rotor. you can hear one of them sliding on there very lightly when you spin the wheel on the center stand.

But please, what i want most of all is information about what the brake pad screw should look like and how i should replace it


thank you thank you
 
Did you remove the o-ring in the caliper and clean the groove?
Did you check the return/relief bleed hole in the m/c?
Does it get hot if you don't use it?
Carry a wrench in your tool pouch to open the bleeder valve to relieve pressure.
Unplanned stoppies aren't cool.
 
Pull the sleeves out and never seize them. Reinstall caliper be sure the caliper floats on mounts and enjoy summer.
 
Disk brakes binding when hot is very often a master cylinder issue. There is a very tiny "second port" from the reservoir to the piston. If it's blocked it does not allow brake fluid back to the reservoir. Pull that MC down again. A solid clue that this is the issue is that the brake pedal will feel very stiff with less than normal travel when the brake is hot.
 
Hi cryingbaby,
quit your snivelling, man up, hit "search", type in "spooge hole" and do what it sez to clean out that tiny little vent hole.
 
thanks a lot for the advice everyone. il be trying all of it when i get to it next week. i got to ride my friends bike around yesterday so i feel a little better. my pedal does get stiff when the brake gets stuck and hot so im hoping the spooge hole or whatever is nice and clogged.

im still looking for some information about the brake pad screw has anyone had to replace theirs? what should it look like?

thanks a lot for the advice
 
Yamaha doesn't sell that little screw individually but it is included in their brake pad kit. Besides the pads and that screw, you also get the little chrome shims or spacers that fit on the caliper bracket and that little springy thing that fits over top of the pads .....

http://www.boats.net/parts/search/Y...XS650SE-11/REAR DISC BRAKE-CALIPER/parts.html

If you're in need of pads, this isn't a bad deal. The stock pads work very well.
 
Thank you all very much. Thanks for the badass advice gggary i think im going to make that screw, that was my original plan if I didnt find a reason not to.

What would be a good way to clean the crap in the piston seal groove? its like crusty stuff. I didnt notice it before but i think that might be a good part of the problem.

Im feeling a lot better. Im still not riding and thats sad but i can control myself, Im crying a lot less now. Im thinking I'll do what I can to make sure its not the caliper before I take the MC down again because that took too long last time.

does my pedal stiffening up when the brake gets hot and stick necessarily mean the spooge hole or whatever is clogged? Im hoping fixing the piston seal groove thing does it.
I pulled the sleeve out and the caliper seems to be more floating on mount now should i grease it with some brake caliper grease type stuff from the car parts store?
 
The bleed hole they are talking about is very small. It plugs easy You might not need to do a complete tear down to fix it.
Open the M/C. this tiny hole is toward to hose fitting end. Often under parts of the reservoir, you may need to take the reservoir off.
Use a tiny wire, I like the twist tie off a loaf of bread or comes with your garbage bags. Strip off a bit of the cover, a 1/2 inch or so. This wire is thin and soft. Strong enough to probe the hole with out damaging it. Probe a bit, spray with brake cleaner. repeat till open.
With the brake line unhooked any crud will flush right out.
Leo
 
I posted this earlier for a front disc, but it's the same idea.

While it's in a bit of a drag situation, break the bleeder loose. That releases line pressure and if the wheel now spins freely your problem is master cylinder/line related. If it's still drags, you have a problem with the caliper not returning. Just helps to know where to start.
 
Just be careful not to gouge it! I'd suggest a brush with some brake cleaner and a little elbow grease. If you gouge it by accident, you'll need to replace the entire caliper if it begins to leak. Brush is safer (brass or softer).
 
Thanks a lot for the advice guys.

I cleaned the caliper pretty good an replaced the piston seal. Unfortunately I put it back together and went for a short ride today and when I got home and up on the center stand the brake was dragging pretty noticeably again. I cracked the bleeder and the wheel spun nicely, so I guess i'll be taking the MC down again and looking for that spooge hole thing. i think I know what I'm looking for but if anyone has any pics or anything to help me find it, it could be helpful.

I'm now having some unexpected suspected carburetor problems but i guess that should be a new thread if it comes to that. I'm terribly inexperienced with those things, I've been riding motorcycles since I was a little boy, but I was too much of a shithead to ever learn to work on them. I have the money to take it to a pro, but would rather not do that

Do any of you have any recommended literature for working on carburetors? could there b some other reason my bikes started dying when idling? I haven't rode it much but it definitely wasn't acting like that before. I put gas in it recently.
 
I Just replaced brake light switch from mechanical to hydrolic on my rear disc.
the brake light remains on even when not pushing the brake pedal.
any cures for a faulty switch? I got the one from mikes xs it didn't fit so
I put in a generic.
 

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