Warm rear brake rotor?

[winkeldc]

Sorry to rehash an old thread, but I put new brake pads in this last weekend and noticed for the first time that I had the same problem with the back brake that y'all mentioned. I stumbled across the old thread, but didn't see if anyone resolved it with the grease or if it just helped a little. As always, I never check to see what the thing felt like before I actually changed something. Even with the frigid week we had in Cleveland this last week, the rear rotor gets fairly warm with little usage. I don't burn myself when I touch the rotor, but its definitly warmer than the front. I tried the high temp grease that you suggested when I changed the pads out, but the rear brake still drags a bit; you can hear it when rotating the wheel. Did you ever solve the problem or is it just how the caliper is mounted?

David

[deilenberger]

Sorry to rehash an old thread, but I put new brake pads in this last weekend and noticed for the first time that I had the same problem with the back brake that y'all mentioned. I stumbled across the old thread, but didn't see if anyone resolved it with the grease or if it just helped a little. As always, I never check to see what the thing felt like before I actually changed something. Even with the frigid week we had in Cleveland this last week, the rear rotor gets fairly warm with little usage. I don't burn myself when I touch the rotor, but its definitly warmer than the front. I tried the high temp grease that you suggested when I changed the pads out, but the rear brake still drags a bit; you can hear it when rotating the wheel. Did you ever solve the problem or is it just how the caliper is mounted?

David

You can make it better - but I doubt if you'll entirely eliminate all drag from the rear rotor (that's why one pad starts out thicker then the other..) A floating caliper (where the caliper moves) design does this. The fronts are dual piston, the rear a single piston floater.

Actually - mine needs treatment again. Building up a nice coating of brake dust on the rear wheel.. (it's so uniform it looks as if the inner part of the rim was painted a darker silver.. looks rather nice actually.. sort of like my Porsche two-tone rims..)

[MTBeemer]

I was re-rounding my rear Pilot-Road-2 with the belt sander (a subject for another posting sometime..)

Don, Did this ever happen? I'm interested.

[winkeldc]

Thanks, that's what I kind of thought, but I usually am wrong. I appreciate it.

[deilenberger]

I was re-rounding my rear Pilot-Road-2 with the belt sander (a subject for another posting sometime..)

Don, Did this ever happen? I'm interested.

Kevin,

Sure did. Luckily the PR3's seem much more resistant to making the lumps on the rear tire then the PR2 was..

Just use your handy belt sander at an angle to the rear tire (wear a dust mask, although not a lot of dust comes off) - bike out of gear - on the centerstand - and set the angle so as it grinds the rubber it turns the wheel slowly. Takes about 30 minutes to get rid of lumps on a PR2.. using 80 grit paper. Makes the tire nice to ride on again (and I usually got 11-12,000 miles out of the Pilot-Road.)

[Caroanbill]

Don (bit of a dulicate post) - do you have to remove the caliper to replace the rear pads or can you just remove the rearward pin, pull out the old pads (aftre working tem to ease the piston back, then slide in and "hook" the forward end, and finally replace the pin .... ? With no torque wrench, I'm loath to touch the caliper bolts - so if the caliper has to come off it'll be the dealer who does it.

[deilenberger]

Don (bit of a dulicate post) - do you have to remove the caliper to replace the rear pads or can you just remove the rearward pin, pull out the old pads (aftre working tem to ease the piston back, then slide in and "hook" the forward end, and finally replace the pin .... ? With no torque wrench, I'm loath to touch the caliper bolts - so if the caliper has to come off it'll be the dealer who does it.

You actually can wiggle them out.. but the trick then is to reposition the caliper and retract the piston so the new pads can be wiggled in. The front edge of the pad has a lump/hook sort of protrusion that sits in a recess in the caliper.. you have to make sure this is seated correctly.

Doable that way? Yeah.. but I'd remove mine to do it (I have multiple torque wrench syndrome..) FWIW - the cheapo ones at Harbor Freight aren't all that awful for accuracy. I checked one I bought (1/2" one needed for Porsche wheel lugs - 110Ft/lbs) against my horribly expensive Craftsman digital. It was within 10%. Just don't put it away with pressure on the spring (ie - unscrew the handle all the way). Or a simple beam type (cheap) can't go out of adjustment and would be more then adequate to use for this job.

[Bob Ain't Stoppin']

[quote="deilenberger"] FWIW - the cheapo ones at Harbor Freight aren't all that awful for accuracy. I checked one I bought (1/2" one needed for Porsche wheel lugs - 110Ft/lbs) against my horribly expensive Craftsman digital. It was within 10%. Just don't put it away with pressure on the spring (ie - unscrew the handle all the way). /quote]

Don, I would be very interested to hear if you have confirmed the accuracy of your Craftsman torque wrench. Torque wrenches, in general, are really not very precision items, and Craftsman is not necessarily a leading brand. Being digital doesn't mean much in terms of how accurate the thing is. Any comments on this? (By the way, I'm not saying I know who makes one you can count on for accuracy at all.)

[deilenberger]

Don, I would be very interested to hear if you have confirmed the accuracy of your Craftsman torque wrench. Torque wrenches, in general, are really not very precision items, and Craftsman is not necessarily a leading brand. Being digital doesn't mean much in terms of how accurate the thing is. Any comments on this? (By the way, I'm not saying I know who makes one you can count on for accuracy at all.)

The Craftsman is made by the same people who make SnapOn's electronic-digital one.. (the resemblence is quite obvious..) Craftsman actually has a decent reputation on things like their better and more expensive tools.

For checking accuracy - you can certainly setup a test bed with a 1' arm on the torque wrench, then start adding weight to the end of the arm until it clicks (or reads out).. A chap named Joe Dille (in the MacPac did just this - and found even the cheapo ones were within reasonable accuracy - much better then an educated feel.. he tested a BUNCH of wrenches..) but I've also done a quick/dirty test by mating/torquing one torque wrench to another, and seeing where they click (or readout and beep in the case of the digital one..) I have about 5 torque wrenches (3 x 3/8" digital and 2 clickers, 1 x 1/4" - dial, 1 x 1/2" clicker) - from SnapOn, Sears, Proto and the unnamed Chinese one from Harbor Freight. Where they have overlapping ranges I've cross-checked them, and haven't found any that are grossly inaccurate.

That said - as I warned - for clicker wrenches make sure to back off the spring after using (unwind the handle) - since the spring can weaken if left compressed for long periods of time. Don't use a torque wrench as a breaker-bar (the temptation is really hard to resist - my SnapOn had to go back to SnapOn for repair/calibration because I yielded to the temptation once.) Don't drive over any torque wrench (I haven't - but people have..) and finally - don't turn your brain off. If it feels funny - STOP. Torque wrenches aren't infallable or all knowing - and some oil in a threaded hole can change the torque enough to allow you to pull the threads out before the specificed torque is reached.

Here is some good reading from Joe Dille: http://home.jtan.com/~joe/KIAT/kiat_3.htm

And good info on using and caring for them: http://blog.spacetec.org/tag/torque-wrench/

BTW - I should add - the one that can't go out of calibration (unless you repeatedly bend it in a pretzel shape) is a beam-type. If you need one to use as a "master" standard, it's probably worth getting a beam-wrench. Even a cheap one can't overcome the laws of physics..

[Bob Ain't Stoppin']

Interesting info Dan. Thanks!

[Caroanbill]

Don - do you have to remove the caliper to replace the rear pads ...

You actually can wiggle them out.. but the trick then is to reposition the caliper and retract the piston so the new pads can be wiggled in. The front edge of the pad has a lump/hook sort of protrusion that sits in a recess in the caliper.. you have to make sure this is seated correctly.

Thanks, Don. Looking at my pads I was sure this would be possible .. but of course I would be 'stuck' if I got the old pads out but couldn't get the new pads in! There is a post on a GS site that shows how to push the piston back by 'wiggling' the old pads before removal (after taking out the end pin). I'm going to give in a try.

Thanks also for the torque wrench tip - I no longer have a socket set since my machines are now mostly torx / allen bolts (and one brother begged for my old kit). I have a nice little ratchet driver for torx / allen, but it ain't suitable for a torque wrench.

[Caroanbill]

AAARRRGGGHH!
Pin has seized! Couldn't shift it to change rear pads.
Now I know why you good folk recommend ant-seize.

In the end I took the caliper off - replaced the 'felt' torque with the same 'feel' nipping up the bolts.
Lotsa wiggling, a little WD40, etc etc - stuck solid ... bahbahhumbug!
... at least with the caliper off I could see how much pad remains - easily 500km, probably 1500km.
(so why was the brake warning light on? Nothing else amiss as afar as I can see)
- so it can wait at least one more day ride

It'll be a quick nip into the local tyre place - tyre fitter rides an R12 and is happy to help.

[deilenberger]

Uhhh...

There is no pad wear indicator on motorcycles - if the brake warning light is on something is wrong with your ABS.

And the pin only comes out one way.. won't come out the other way even though it might look like it can. Before removing it, I pull the little clip holding it in, then used needle nose pliers to rotate it a bit to loosen anything that might prevent it coming out.

[Caroanbill]

Uhhh...

There is no pad wear indicator on motorcycles - if the brake warning light is on something is wrong with your ABS.

And the pin only comes out one way .. won't come out the other way even though it might look like it can. Before removing it, I pull the little clip holding it in, then used needle nose pliers to rotate it a bit to loosen anything that might prevent it coming out.

Yes, thanks again Don.

I checked after seeing how much meat was on the pad, and it's an ABS indication, though not clear what it means from the rider's manual. I tried a few full emergency stops and it's doing just fine - not sure if I actually triggered the ABS though. I'll trot over to the dealer Saturday to see about a diagnosis. Poor old thing needs a major service soon anyway - it's had a very lean year or so because I've been busy and most fluids come up to 2 years (my limit) in June. I want to try for a decent trip this winter, say July into August (escaping southern cold ... yep, it's all topsy-turvey here!! ) .. and I won't do that if there's any question about brakes!

As for the pin, I could see all that but it's still seized. It was my dealer who put these pads in, they can get 'em out!!