The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Melena on August 14, 2012, 11:12:55 PM
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I haven't been riding much this year. Too much other stuff in the way. But I'm trying to get my bike back on the road.
2 rides ago I noticed in the middle of the ride that my front brake was making a loud screeching noise. Not the squealing noise that everyone complains about. This was different and much louder. I kept mentioning it to my friend and riding buddy but he just said that's what the brakes do. I don't think he was listening. ::) ;)
So a few weeks later we went for another ride. In the meantime I had just put it off that maybe it was just normal. The first couple times I put on the brake it seemed almost normal. The screeching didn't seem as bad. But then I put the brakes on really hard and it was almost like the brakes let off a bit but made a horrible noise. I took care on how fast I was going and where I went. I took only back roads to get home. But the brakes kept doing that all the way.
When I got home and with the bike on the center stand I turned the front wheel and it sounds like sandpaper rubbing the disc. I don't know much about this so I had to do some research. I had to re-borrow the Clymer Manual and do some reading, plus read Snowbum's "treatise" on brakes.
I figured out how to take off the cover and was able to look in there and pull the brake lever at the same time. I didn't see any movement at all. I rotated the wheel and heard the sandpaper sound, then pulled on the brake again and it brought the wheel to a full stop. But I didn't see any movement of the caliper at all.
So, I'm thinking a stuck caliper. Is there anyway to unstick it without taking it all apart? If I do that I'll have to go replace all the seals and o-rings.
What do you suggest? Any other possibilities of the problem?
Thanks!
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Hi Melena
Any idea when your brake pads were last changed?
When was your brake fluid last changed? If a dark color, needs to be flushed.
The screech sound could be metal hitting metal due to worn pads.
Removing & cleaning calipers is not difficult - the clymer manual I have has good instructions - Motobins sells the kits for new rubber seals. You'll have to bleed brakes when finished.
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Also look for radial cracks on the rotor near the holes. When this starts the brakes will start to sing....quite loudly..
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Grit can get imbedded in the pads, so remove them and take a look. Clean up with some sand paper. Clean out the holes in the disc, remove all the built-up crud in them.
Pistons don't move very much, and I'm not sure if you'll see the movement. Usually the pistons get crud built up on the exposed surface, so try cleaning that up carefully. You may be able to fix it that way, but disassembling the caliper is probably the best solution. It's difficult to remove all the sludgy brake fluid that settles into the caliper, and taking it apart is the best way.
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You can remove the brake pads without removing the caliper .
Remove the dust cover remove one or two pins, depending on what make caliper you have .
Pull the pads and see if you have worn them to the back plate .
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The caliper pistons don't move very much at all just a few thou and you have to look very carefully to see the movement. They do move though or at least should when working correctly. This diagram illustrates how the caliper seal distortion that occurs when the brake is applied is supposed to retract the piston slightly when the brake lever is released. It's not uncommon though for the caliper pistons to stick through corrosion and then although they may still move enough to make the brake work they don't retract as they should and the pads remain in partial contact with the disc making the sound you described when spinning the wheel.
Sometimes exercising the caliper pistons a few times by manually pushing them in ( take care the master cylinder reservoir doesn't overflow) and using brake pressure to move them out again (take care the pistons don't come out too far) will help and provide a temporary cure. It's almost inevitable that one piston will want to move and the other wont. You can get around that by using a small G cramp to restrain the free piston and that will force the other to move.
When putting the pads back in make sure thay go in the same side they came out of.
In the end all of this is just putting off an inevitable caliper overhaul which if done soon enough may only mean a general clean up with replacement seals and dust covers. Left too long and new pistons might be needed if corrosion is excessive.
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Great! Thanks guys! I appreciate all the information. [smiley=dankk2.gif]
If I had just taken the brake pads out first I would have immediately known what was the cause of the screeching sound. Yup! Brake pads were completely worn through. [smiley=rolleyes.gif] I tend to think of the worst case scenario first. [smiley=wall.gif] Plus the last time I had it at the mechanic he said that there was plenty of life left on the pads. I forgot about all the riding I did in between I guess. Time flies.....................
My friend came over first thing this morning and we started the process while it was still cool out. Took one look at those brake pads and knew what we had to do next. I called the local BMW dealer and they had the correct pads in stock! Whew! And they are only a couple of miles from where I live.
Of course, when we go over there we get immediately caught up in the social thing. But how can you not when another R65 pulls up just as you're getting out of the car. How cool. But that's another story.
Got back and got the new pads put in and the brakes bled. Now I've just got to clean up the disc really well and get all the crud out of there so it doesn't grit up the nice new brake pads! ;)
The calipers seem to be just fine. But we'll probably do an overhaul on it this winter and replace the seals and o-ring(s?). I'm thinking that these brake pads may have been the originals. Nah! Maybe not. The guy I bought it from had put in a new stainless steel brake line and I would think that he would have put new brake pads on at the same time. You never know. But I've only put on about 6,000 mile since I've had it.
No ride today though. And tomorrow I've got other things to do. Maybe Friday I can start getting the brake pads worn in. I think things are finally coming together.
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Congratulations! You're bike will be all set for the Oregon Rally in 2013
[smiley=clap.gif]
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Congratulations! You're bike will be all set for the Oregon Rally in 2013
[smiley=clap.gif]
Yeah! ;D I'm looking forward to that. Now I have nice new brake pads and I'll feel much safer.
Hope to see you there Ken!