Sunday, October 5, 2014

5 rear caliper failures?

Somehow in the course of 50,000 miles of roads, gravel and sane, (both FL and Mohave Desert...) and all the scheduled service calls up to 36,000 miles, no one has mentioned maintenance required for the rear caliper on these bikes...   Now in the last month I have witnessed 5 instances of the rear caliper locking up on a variety of BMW's.   What's wrong with this picture?

Actually, the first time mine locked up was in central FL last year at about 10,000 miles.   I had been on sand and gravel roads two weekends around Daytona Bike Week.  One trip was cross state with Dixie Dual Sport and the other was with the ADV Rider group.   Both treks were from Daytona to Cedar Key and back.   More sand than I could ever have imagined and definitely dropped the bike a couple times as the front wheel plowed when it should have planed...   The learning curve on sand riding is pretty challenging when you are knee deep in it the first couple times...

So the following week I was down toward Sugarloaf Mt (no mountain to be seen, but that's what it's called...) and heading back to Wildwood after lunch with a friend...   on pavement going thru some little town I stopped at a traffic light and found the rear brake had fully engaged while I was stopped...   Attempting to move on, my bike wouldn't budge...   I called some kid from the sidewalk to help me DRAG the bike out of the street and up onto the center stand...   The brake pedal was stuck (so it seemed) and the rear break tighter than a rock and burning hot...   The day before I had made an adjustment on the lever position in order to have a better angle while I was standing... apparently the adjustment was too extreme and caused the pads to drag enough to start heating the system beyond it's design.   I called BMW Jacksonville and they told me how to un-adjust the lever until the brake released.   Then it seemed fine, but I took it in for inspection.   They replaced the hose and caliper under warranty and I was on my way again.

Then no problems with the brake for more than a year...  and I had not heard of anyone reporting brake problems.

At the SARA Trail of Tears Rally last month one of the guys on the dual-sport ride fell behind and we learned that his rear caliper had locked up...   and he had just made an adjustment on the pedal lever the night before...   sound familiar?   He was able to un-adjust the thing along the trail (mountain fire road) and caught up with is in about 15 minutes.

Next occasion:   About three weeks ago I was at Grassroots BMW in Cape Giradeau, MO for new tires.   I commented that my new boots (Sidi Combat Touring) seemed to position my foot so that I was depressing the brake when not intending to apply it.   The mechanic attempted to make an adjustment to allow the pedal to be in a lower position.    When I left that day I made it 9 miles into IL and suddenly (at 55 MPH) the rear brake started applying itself and I slowed to a halt in must a couple hundred yards...   tighter than a drum, the brake was hot as a pistol and locked up tight.   Calling the dealer, they came out with a trailer but the mechanic was able to loosten the adjustment so it appeared that the problem was taken care of.

Setting aside MY story, the next report came from Drew Corl on arrival to
Cherohola Mt Trails M/C Campground for the Ridge Runners Bootlegger Dual-Sport tour.  Drew lost his rear brake and it appeared that the rear caliper had frozen in the open position.   The opposite of the other instances.

On Sunday morning while we were breaking camp Drew pulled the rear wheel off of his bike and tried freeing up the caliper.   I believe he said that the bike was at 150.000 miles or so.   Drew is a motorcycle mechanic at Knoxville BMW and I figured he knew his stuff.   It appears that the floating portion of the caliper had hung up on the guide posts and wasn't going to budge....   Drew tried prying, hammering and applying colorful language, but the caliper wasn't going to let go.   Hence Drew undertook his two-day portion of our tour with no rear brake.

Fortunately, Drew's riding skill, throttle control, engine braking and body english were enough to get him through.   This on day one included more than 100 miles of gravel roads and fire roads in the Smokies.   I think it was Monday afternoon when he left us at Mile High Campground and headed home and to his dealership location to make the repair on Tuesday.   I'll have to send him a note to see how he made out.

OK, back to MY story...   At about 13,000 miles after my 36,000 mile checkup I had finished the week, and 1,200+ miles of dual-sport adventures and was headed back to So IL on Rt 24.   A sunny
brisk Sunday and many 80+ mph interstate miles found me in the HOV lanes through Nashville with plenty of early afternoon traffic...   I had slowed from the 80mph pace to about 65 going through the city and all of the sudden could feel an invisible hand starting to drag at my momentum...   Very much like the caliper lock-up from a few weeks back, but not as severe.   I could tall the bike was dragging but was able to apply more throttle and maintain my pace with the traffic.   I had my eye on the upcoming exit ramps thinking I may need to get myself off the road quickly...   then suddenly things released and I was back to "free wheeling."   The tug went away and the bike felt like normal...   normal, that is, until I was 50+ miles down the road and looking for a gas stop...   NO REAR BRAKES!!!

I had headed to an exit ramp and when I toed for the pedal it went right to the 'floor.'  Front brake was fine and kept things under control.  I made it to a fuel station and got off to take a look...   NO inside brake pad at all.   the inside surface of the disk was scorched, gouged and pitted...   the brake pad must have been dragging and then separated from the steel backing plate and wedged itself against the disk...   I'm lucky that it didn't just lock up the rear entirely at highway speeds!!

Nursing the bike on to my destination, (and new home), I called Grass Roots and took the bike in on Wednesday.   They stripped things down and reported that under the layers of grime they found the caliper must have been leaking and yes, the pads were shot.   They estimated $550 and a couple days to rebuild the caliper so I left the bike, intending to go back the following Tuesday.  They called Tuesday to tell em that they also found a leak in the brake line and had a part on order from Germany...   (same as when the system failed in Jax last spring.)

So... assuming that it all goes back together...   I guess occasional maintenance needs to be on the "MUST DO" list.   Shouldn't there be a warning label somewhere?

Sorta like when I drove all the way from IL to MN with oil pumping out over the side of the fill cap, only to discover that, "Oh, didn't we tell you?  You have to check the oil level with the system HOT!"   Where was THAT warning label?

OK... so now I will post on FB and the forums that I wasn't maintaining things properly and suggest that everyone take this story as a reminder to do an annual "clean and inspect" on the brake calipers...

Can hardly wait for the feedback on this one...

Here's a link or two that I found on the procedure:  Bike Bandit  MAINTENANCE LINK <<<


Note from Drew Corl about his caliper fix:  "
Drew Corl
October 5 at 3:20pm
Hey Jeff, Got the caliper working again, following removing the caliper from the bike, soaking the float pin in penetrating lubricant and then heating the caliper around the floating pin. A few solid hits from a hammer and the carrier FINALLY separated from the carrier. The years, 164k miles of pavement, dirt n gravel, and bunches of water crossings had led to corrosion of the floating pin on the caliper carrier, keeping the caliper from sliding and making proper pad to rotor contact. A little time on the wire wheel to clean everything up and some anti-seize on the floater pins and its working. In the long term I will be replacing the pins and probably the protective boots. Following my experience on this trip, my suggestion to everyone: (Especially if you do a lot of offroad) When your replacing your pads, pull the caliper apart from the carrier and clean and lube your pins and replace your protective boot if you find any cracks or tears. My boots looked good by the years miles dirt, grime and water crossings took a toll. Much as we wear our Dirt on our Adventure Bikes as a badge of honor... still gotta thoroughly clean em once in a while to keep moving parts happy! ;-) ~Drew Corl

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