Cam Lay Posted June 1, 2011 Share Posted June 1, 2011 Got the Lemans back together, went for a short ride. The rear brake seems to be dragging slightly, making the disk very hot. I took the caliper off, forced it apart, re-assembled, went for another short ride. Same thing. Separated it again, adjusted the plunger and pedal so that there was way too much slack (so that the brake barely engaged), went for a ride around the block, returned to find the rear disk fry-an-egg hot. It seems to pinch fine, but then not let go. Front calipers do not do this - calipers release and disks cool off immediately. Help? Thanks, C Link to comment Share on other sites More sharing options...
NPS Posted June 1, 2011 Share Posted June 1, 2011 It sounds like the pistons in the caliper are not free to move back. This is likely to be corrosion of the piston/Cylinder walls. You can try pumping out the pistons by operating the brake with the caliper off the bike. Once out clean the piston and cylinder of any corrosion and reassemble with a little brake grease. Change fluid and bleed. Hopefully the seals are not damaged. Sometimes the corrosion comes from water in the brake fluid. Sometimes from damaged piston seals. Link to comment Share on other sites More sharing options...
pasotibbs Posted June 1, 2011 Share Posted June 1, 2011 Got the Lemans back together, went for a short ride. The rear brake seems to be dragging slightly, making the disk very hot. I took the caliper off, forced it apart, re-assembled, went for another short ride. Same thing. Separated it again, adjusted the plunger and pedal so that there was way too much slack (so that the brake barely engaged), went for a ride around the block, returned to find the rear disk fry-an-egg hot. It seems to pinch fine, but then not let go. Front calipers do not do this - calipers release and disks cool off immediately. Help? Thanks, C It maybe the master cylinder not returning fully due to corrosion, I'd check that first(it was with mine anyway!!). Link to comment Share on other sites More sharing options...
felix42o Posted June 1, 2011 Share Posted June 1, 2011 Also, if you haven't done so, bleed all the fluid out and replace with fresh. There's a tiny orifice in the master cylinder that allows for the heat expansion of the brake fluid, and it can plug easily if the fluid is dirty. Link to comment Share on other sites More sharing options...
gstallons Posted June 2, 2011 Share Posted June 2, 2011 Get the rear wheel on a stand. Have someone press and release the rear brake pedal. Try rotating the rear wheel. If there is a drag on the rear wheel, break loose the bleeder screw WITH the dust boot on the screw. This allows for pressure release without introducing air into the hydraulic system. If it (the rear wheels) loosens and rotates freely the problem is NOT the caliper. It could be the hose or master cylinder. If it remains tight, the caliper is at fault. I do not know what parts such as rebuild kits are available. You can watch eBay for parts too. Link to comment Share on other sites More sharing options...
IBA 270 Posted June 2, 2011 Share Posted June 2, 2011 I'm going waaaaaay out on a limb here, but... I've never been a fan of rear brakes that took less than a very concerted effort to manipulate. In fact, I like them down right squishy. It's the crash pedal...and the less "influence" the better. Now...more than likely it's a caliper issue. It can probably be fixed with brake cleaner and effort, but if not, they aren't rocket science to clean up properly and rebuild if neccesary. I have found in the past that clean, used calipers are cheaper than rebuild kits sometimes. YRMV Link to comment Share on other sites More sharing options...
gstallons Posted June 2, 2011 Share Posted June 2, 2011 Hmmmmmmmmm. Link to comment Share on other sites More sharing options...
Tom M Posted June 3, 2011 Share Posted June 3, 2011 The rear brake calipers on these bikes tend to stick if they aren't removed cleaned up fairly frequently. Here's a thread from the how-to section that might help. http://www.v11lemans.com/forums/index.php?showtopic=8476 I usually have to clean mine up about every 5k miles. Once I pull the pads out of the caliper I put a thin piece of wood between the pistons and pump the pedal a few times to extend the pistons, then hit 'em with brake cleaner and a brush. Bleed the caliper while it's out with the bleeder facing up then put it all back together.I've read here that there are no rebuild kits for these calipers available in the US so be careful not to tear any seals when cleaning the pistons. Cam, did you get your compression issue sorted out? Link to comment Share on other sites More sharing options...
rossoandy Posted June 5, 2011 Share Posted June 5, 2011 U say bike back together...did U have the rear wheel out? Wondering if you have a washer/spacer in wrong? May be nothing to do with brake caliper... Link to comment Share on other sites More sharing options...
Cam Lay Posted June 7, 2011 Author Share Posted June 7, 2011 Thanks to all who responded! I took the rear brake off again and cleaned it, figuring that was the easiest fix and most likely culprit. Worked like a charm when I re-assembled it. Some one asked about the compression issue - no, not fixed. It was right down on the edge between "OK" and "several hundred bucks for new valve guides" so I just buttoned it up and figured I'd ride it another couple of months. Then we (the Goddess and I) both got good job offers in Montana. I figure I'll ship it out there and have the heads re-done over the (long) winter. :-) And then I'll ride it through the Rockies!!! Thanks, C Link to comment Share on other sites More sharing options...
Chuck Posted June 8, 2011 Share Posted June 8, 2011 Thanks to all who responded! I took the rear brake off again and cleaned it, figuring that was the easiest fix and most likely culprit. Worked like a charm when I re-assembled it. Some one asked about the compression issue - no, not fixed. It was right down on the edge between "OK" and "several hundred bucks for new valve guides" so I just buttoned it up and figured I'd ride it another couple of months. Then we (the Goddess and I) both got good job offers in Montana. I figure I'll ship it out there and have the heads re-done over the (long) winter. :-) And then I'll ride it through the Rockies!!! Thanks, C Isn't it too cold for bugs in Montana? Link to comment Share on other sites More sharing options...
docc Posted June 9, 2011 Share Posted June 9, 2011 I still can't figure how the guides, that are separated from the combustion chamber by the seats, could affect compression or leak down. I'm thinking it's more from sticky rings and gummy seats from too many months/years sitting and it will all be solved by more frequent heat cycling and a couple oil changes. Yet, Montana may be more conducive to machine-work than miles! Beware of Hagan's garage warming methods: Link to comment Share on other sites More sharing options...
gstallons Posted June 9, 2011 Share Posted June 9, 2011 That's because they have very little if any affect. Link to comment Share on other sites More sharing options...
docc Posted June 9, 2011 Share Posted June 9, 2011 I gues if the guides are bad enough to let the valve wobble, the seating would be compromised and compression affected. Not so much from "leaking" guides, but the subsequent wear on the seats. Link to comment Share on other sites More sharing options...
gstallons Posted June 9, 2011 Share Posted June 9, 2011 And that's why I said "very little affect". Link to comment Share on other sites More sharing options...
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