UPDATE: A startling event with the rear brake.

[John Schmidt]

Yesterday on my way to meet up with some other riders for breakfast, from time to time I noticed something that smelled like hot brakes. I stopped once to check but all was moving freely, and shortly thereafter the smell went away. No indication of anything dragging...pull in the clutch and it kept on rolling freely. Later after eating, I was headed north on a country road and tapped the rear pedal to disengage the cruise, and when I did I heard a loud bang/snap from the area of the rear brake. It was sharp enough that I felt it in the seat. Yet the bike continued to roll freely and I didn't experience anything the rest of the day. Today, after taking some bike pictures I had to use the rear brake when waiting to exit the park which has a rather steep incline driveway. I pressed the rear pedal and it didn't want to hold very well, bike still wanted to slowly roll back. When I finally pulled out I had some scrapping/dragging noise which disappeared when I tapped the pedal. But a moment later....bang! Same thing it did yesterday and again felt it in the seat rather sharply. After this, the bike rolled along real nice....while I held my breath all the way home, about two miles. When I think about yesterday just prior to the "bang" I remember one stop light has a sharp incline in the street and I used the rear brake to hold while I released the clutch. Same scenario as today; sharp incline using the rear brake, after clutch release I experienced a loud bang. Normal braking doesn't cause this, apparently high pressure from the brake pedal does.

I haven't looked at it yet, will remove the left saddlebag in the next day or so to take a closer look. The pads are roughly 75%, the rear end was pulled down within the last six weeks for normal maintenance and I found no issues. I did the double row bearing mod, reassembled and gave it a good test ride. No issues until now and it's been a few hundred miles since I did that. So....any suggestions what to look for, has anyone experienced this in the past? This is a first for me on any bike I've ever worked on, but there's a first time for everything. Just glad it didn't cause trouble on yesterday's ride.

UPDATE: Had to remove the left bag to see it but it was that large retaining pin. Sucker had worked its way out far enough to have the exhaust keep from it coming out all the way. I had used a slight amount of anti-seize when I installed it, don't know if that's a contributing factor or it's entirely possible I missed torquing in down. First time for everything I guess. Took some doing to get it out and realign the mounting bracket so I can reinsert it. This time I think I'll use a little blue glue, just in case. Found a couple other minor things to address while in there so I'm not back on the road just yet. Live and learn.

[Skinhead]

No suggestions other than look for loose bracket bolt or caliper pins.  You have my curiosity peaked.

[Daniel Meyer]

Sounds like either...

The caliber is seizing on the pins...it's supposed to float...

or

The caliper mount plate is moving...perhaps the pin bolt through the swing arm is missing or not in the hole in the plate?

[John Schmidt]

It almost strikes me as a sticking piston, but the release with a bang doesn't follow that. It sounds and feels like someone hits the frame with a large hammer. I'll post what I find, sure hope I don't have to pull the entire brake assembly. That can be done without pulling the wheel, just pull the axle back far enough to remove the brake mount. I'll do whatever is necessary obviously.

[Valkpilot]

...perhaps the pin bolt through the swing arm is missing or not in the hole in the plate?

Mine  worked its way out on a recent trip.  Caused the same symptoms.

[salty1]

No suggestions other than look for loose bracket bolt or caliper pins.  You have my curiosity peaked.

+1 I really want to find out what has happened.  ???

[Michvalk]

Mine had a pad release from the backing plate

[pancho]

As a couple have mentioned, I would first look at the pin bolt through the swingarm that holds the caliper mounting plate in place........  the symptoms and when they happened fits perfectly for it missing the hole in the backing plate.

[John Schmidt]

See my update in the original post.

[Daniel Meyer]

I had used a slight amount of anti-seize when I installed it, don't know if that's a contributing factor or it's entirely possible I missed torquing in down.

I use anti-seize on this bolt (it's a must, really...it likes to corrode in place) and have never had one come loose...

Blue will be fine though...it comes loose with hand tools and IS also an effective corrosion blocker for steel into steel (this bolt is)...I hesitate to use it for steel into aluminum as I've had experience where it didn't work so well in fasteners exposed to severe outside conditions (conventional anti-seize mucho better there).

Glad ya found it!

PS: Check the torque on the axle while there...it's unlikely, but possible that the moving of the plate could spin/loosen something....

[pancho]

OK, I see it..... so I wonder, what kind of condition is the shock in now?

[John Schmidt]

OK, I see it..... so I wonder, what kind of condition is the shock in now?

No effect on the shock, nothing with the rear brake comes anywhere near it. And yes Daniel...the same thought crossed my alleged mind, so checked it. All is OK now, took it for a spin and tested the rear brake moving both forward and coasting back down the drive. No movement, brakes are solid now.

[Rio Wil]

Any chance the caliper brake hose was over extended while that was flopping around?

[John Schmidt]

Any chance the caliper brake hose was over extended while that was flopping around?

No, it didn't move that far. The hose curves around from the rear and attaches to the caliper. The entire ass'y. would have to have turned well past 180 degrees in reverse from it's installed position before the hose would have been subject to any strain. Each time it banged, it was following using the rear brake on an incline where the bike wanted to roll back. That moved the mount less than an inch, I could get it to do it when on the center stand and spin the wheel while my wife pressed the brake. When I tested it after repairs, I rolled down our drive and slammed on the rear brake. Then got off and looked....never moved. Then when riding around the block I hit the brake and no bang. It's all good now and I'm rolling again.

[pancho]

OK, I see it..... so I wonder, what kind of condition is the shock in now?

No effect on the shock, nothing with the rear brake comes anywhere near it. And yes Daniel...the same thought crossed my alleged mind, so checked it. All is OK now, took it for a spin and tested the rear brake moving both forward and coasting back down the drive. No movement, brakes are solid now.

Hmmm, was it the caliper stopper pin bolt that goes through the swingarm that backed out??

[John Schmidt]

OK, I see it..... so I wonder, what kind of condition is the shock in now?

No effect on the shock, nothing with the rear brake comes anywhere near it. And yes Daniel...the same thought crossed my alleged mind, so checked it. All is OK now, took it for a spin and tested the rear brake moving both forward and coasting back down the drive. No movement, brakes are solid now.

Hmmm, was it the caliper stopper pin bolt that goes through the swingarm that backed out??

Yes. At this point I don't know if it vibrated out on its own due to using anti-seize or did I possibly forget to torque it down when I did rear maint. a few weeks back. Took some work to remove it because the caliper mount had banged against the end of it, causing it to be misshapen. Just put a bit of a burr on the end on one side, apparently from the mount hitting it a glancing blow from time to time. All's well that ends well....I'm back riding.

[pancho]

OK, I see it..... so I wonder, what kind of condition is the shock in now?

No effect on the shock, nothing with the rear brake comes anywhere near it. And yes Daniel...the same thought crossed my alleged mind, so checked it. All is OK now, took it for a spin and tested the rear brake moving both forward and coasting back down the drive. No movement, brakes are solid now.

Hmmm, was it the caliper stopper pin bolt that goes through the swingarm that backed out??

Yes. At this point I don't know if it vibrated out on its own due to using anti-seize or did I possibly forget to torque it down when I did rear maint. a few weeks back. Took some work to remove it because the caliper mount had banged against the end of it, causing it to be misshapen. Just put a bit of a burr on the end on one side, apparently from the mount hitting it a glancing blow from time to time. All's well that ends well....I'm back riding.

I gotcha Stuffy,, as long as the plate was hitting the bolt, it could not travel around until the caliper hit the bottom of the shock. Glad your back on the road without any serious damage.

[Brian]

I haven't been on this board for a few weeks and glad to be seeing this thread. I notice a brake odor yesterday here riding back country roads, thinking it the folks out front. Only smelt it one time. I am however experiencing dimensioning braking on the rear. I can use the rear to help slow down but doubt it will lock up the rear if needed. I plan to pull the rear bag to check this issue today about the pin although I am not hearing the noises. I suppose I am looking at rebuilding the rear master cylinder this winter.

So glad you found this problem now.

Take care everyone,

[Rio Wil]

Remove the rear brake pedal, clean the rust and corrosion from the pivot bolt, lube it up and reinstall....will seem like new brakes!!!!

[Tropic traveler]

Remove the rear brake pedal, clean the rust and corrosion from the pivot bolt, lube it up and reinstall....will seem like new brakes!!!!

Agreed, good observation!
Cleaning & lubing the rear pedal pivot worked wonders on my '97.