Sticky rear wheel on bike

you shouldn't be looking at brake lines made especially for your bike, but find someone who can make them by the meter, i had mine at 20?/m, would've easily been the double if i bought some branded ones...

i've never heard about a sticky brake due to worn out lines though, most of the time that results in bad braking...
isn't it possible that it's the return valve in the pump that is stuck or sth?
 
you shouldn't be looking at brake lines made especially for your bike, but find someone who can make them by the meter, i had mine at 20?/m, would've easily been the double if i bought some branded ones...

Specific kits come with approval certificates, if you just get some made you'll have to get them approved by the T?V. Which would make them just as, or even more expensive than a kit.

Also, explanation of swollen lines as a source for sticky brakes:
A very common cause on these is a swollen brake hose...they deteriorate inside and swell up, causing the caliper to hold pressure and not able to return after pedal application..very common w/aged hoses.. pedal pressure is high enough to over-come the restriction and apply force to caliper , but return/release pressure is residual, so the hose acts as a one-way valve due to the interior swell/restriction....
 
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you have MOT on bikes? we can do anything we like on our bikes. as long as all lights are working, you're allowed to do anything you like....
(and mine were originally meant to go under a rally car, so i guess they're quite safe :D)

and that explanation sounds acceptable indeed :)
 
Yeah, that's possible, but you usually don't see that phenomenon on quality makers' brake lines before 15 years of age - at least around here, anyway.

What am I saying? This is BMW - quality seems to have gone out the window on those bikes some time ago. :p :mrgreen:
 
Usually, good braided stainless lines are less than what the big OEMs want for new rubber ones through dealerships.

It feels like I'm stating the obvious, but you're right, Spectre.
Called an independent garage today to see how much they want for changing the brake lines, and he confirmed that new rubber lines would be more expensive than steel ones: 60? for one new rubber line, and the cheapest set (front&rear) of steel lines I could find is about 70?.
I think I'll just get those and try to install them myself.

you have MOT on bikes? we can do anything we like on our bikes.

This is Germany, of course everything is regulated. :p

PS:
Harking back to an earlier tangent from this thread, "stainless steel braided" brake lines actually have a much simpler term in German: Stahlflex. :D
 
New line is on, problem still there. <_<

I don't think it's the caliper/piston, because the brake starts to stick even when you don't use it, just not as fast. If it was the piston not retracting properly, this shouldn't be the case.

I also just rode around a bit to get it to stick again, and then opened the bleeder valve - which made it unstuck immediately.

Another symptom: the pedal is relatively 'soft' - you can depress it quite far without much force. But the 'stickier' the brake becomes, the firmer the pedal.

There's a small hose from the brake fluid reservoir to the master cylinder that I didn't replace - could this cause the problem if it was swollen as well?
 
I think it could, though it is unlikely. That's not a pressurized hose in general, so you can replace it with locally sourced *hydraulic* hose of the proper diameter.

It could still be the piston or caliper. However, it is more likely to be the master cylinder; this is why I generally advise overhauling the entire system at once when you start having issues. There should be a rear master cylinder rebuild kit for the thing, unless BMW is 'proud' of that, too. :p
 
Master cylinder was a strong suspect already.

But could the master cylinder really cause the brake to drag even when it isn't used?
 
Ask CrazyJeeper, he just had a similar problem with some tiny particle clogging a return passage in his master cylinder.
 
Yup, I had the calipers rebuilt, twice. I did it once, had a local Honda dealer do it, and still had the same problem. There was a tiny particle blocking a relief port that was preventing the brake pressure from releasing. Since then, I've put about 650 miles on it, and it works great.
 
There should be a rear master cylinder rebuild kit for the thing, unless BMW is 'proud' of that, too. :p

I expected better of you, Spectre... so naive! Of course BMW doesn't have a rebuild kit, and they want 90? for a new master cylinder. God I hate that place.
However, I already found a new one on eBay for 60?, and used ones for 30?.
 
That's why I said they might be 'proud' of that.... which brings me to my next point - why do people buy these things in the first place? :p
 
I was young and foolish and had nobody to guide me.

Anyway, another thing that popped up recently: the front brake squeals quite badly when I use it to come to a stop. What could be wrong on that front?
 
I was young and foolish and had nobody to guide me.

Anyway, another thing that popped up recently: the front brake squeals quite badly when I use it to come to a stop. What could be wrong on that front?



But isn't German engineering supposed to be pure and perfect with nothing ever going wrong or any bad designs getting out? :mrgreen: I mean, MacGuffin and others assure us this is so - were they perhaps mistaken or lying? :mrgreen:

As for the front brake - check your pads, you probably have got them down to the wear indicators. Also check for front rotor damage.
 
I just took the front pads out and checked them, and they still look fine to me.
Stupidly I forgot to take pics before I put them back on. :idiot:
28_6620.jpg

28_6633.jpg

That's about 3mm of material left on each.

Disc seems ok too, just a bit grooved. Barely noticeable when dragging your finger across the surface.
 
Find out what your minimum pad thickness is supposed to be and if you have "squealers" for wear indicators.
 
The wear indicator on these pads is a chamfered edge, when the pads are so thin that the edge's disappeared you've reached minimum thickness. On mine the edge is still there.

And I think maybe squealing is not the best way to put it... it's more of a howl? Really loud as well. And when I apply the brake lightly and push the bike forward it makes a constant noise.

That said:
http://faq.f650.com/FAQs/Brake_Pad_FAQ.htm#Brake Squeal FAQ
I already tried to clean the caliper a bit and apply some grease to the back of the pads. Didn't work, but that could be because I used "long term grease" and not copper paste as suggested. :dunno:

//edit
Hm, could be that they're glazed over. I think I remember the noise only started when I made some aggressive stops in quick succession after I had rebuilt the rear caliper. :think:
 
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The master cylinder arrived today (after I had to poke the seller a bit with a stick...), and it looks as though that did the trick. After a short test ride with a lot of rear brake action it still didn't drag noticeably. I'll still keep an eye open for now though.
But so far, that's that problem finally solved. :D

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I also took out the front pads, cleaned the disc and sanded the pad's surface off, and after that the howl was gone!
... for about five minutes, now after the test ride it's just as bad as before. I'll just change the pads, they're not terribly expensive anyway.
 
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