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Discussion Starter #1
General question since the rear braking system is similar/same between all the models, but anyone got a good idea on what else to look for on dragging rear brakes?

Noticed after a chain/sprocket change the rear wasn't spinning really free. Took everything apart, doubled checked, greased, tripled checked alignment, looked at the master cylinder, greased the pedal and made sure nothing was bound up or seized. Just got back from a big trip so going through things was on the menu anyway.

Everything looks good, I can see the brake pads release when I let off the pedal, but apparently it's not quite enough. Piston pushes in and out pretty freely (took one gentle squeeze of my compression tool). It's still sluggish to spin by hand and a short ride heats the rear rotor up to too-hot-to-touch.

The only thing of note is the pads are on the end of their life and I have new ones ordered but I've never had a set drag before on this bike (09 Wee). Hose failing, delaminating maybe? I've had that in cars where it'll create a check-valve of sorts and keep a brake engaged.

I changed fluid last winter & re-bled the system, have put 6k on it without issue and the resevoir looks clean and the fluid is where it's supposed to be (halfway between the fill marks).
 

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New Mexico concrete mud is likely the culprit. ;)
 

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Are you sure the caliper is properly positioned in the retaining rib on the swingarm and not under or over it?

If you are sure it is I would take the pads out to make sure there is nothing there that does not belong like a rock or whatever else may have found its way in between the pads and the piston or back bracket.

If the system was without problems before wrenching its not likely anything hydraulic causing it, you did not use it and unlikely been able to damage it.
 

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Discussion Starter #4
Are you sure the caliper is properly positioned in the retaining rib on the swingarm and not under or over it?

If you are sure it is I would take the pads out to make sure there is nothing there that does not belong like a rock or whatever else may have found its way in between the pads and the piston or back bracket.

If the system was without problems before wrenching its not likely anything hydraulic causing it, you did not use it and unlikely been able to damage it.
Went through the mechanical/caliper with a fine-tooth comb...no debris or anything rubbing or out of place. Assembled it and disassembled 3 times to re-affirm it wasn't alignment or something stuck in there. If I pull the pads up and off the caliper, the caliper pushes in and out evenly and smoothly by hand....so no binding. The piston is clean as a whistle...no debris or binding there.

The rear tire is aligned about as good as I can get it (I have the Motion Pro tool), the rotor looks good, the pads look worn but every evenly and there's nothing gritty or messed up on them.

I took the pedal off and cleaned/greased it too, but it was pretty clean to begin with and snapping back to "home" very firmly. Didn't make a diff.

I'll re-bleed and give the hydraulics some attention when I get my pads and change them and see if that makes a diff.

Stumped tho. Never ever had a problem with the Strom's brakes on any of my bikes.
 

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Discussion Starter #5
New Mexico concrete mud is likely the culprit. ;)
The rear was spotless, believe it or not. Still a good coating of grease on the bolts.
 
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I think I have read about a similar problem in the past but can't remember what the cause was. Just odd that there appears to be all over sudden a problem with the hydraulics whilst nothing was done to them.

Greywolf to the rescue please.
 

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You seem to have the bases covered. New pads and another flush would be my next step. High humidity could put enough water in the fluid to make it boil or it may be easier to cock the pistons in the bores when they are extended. Do you have the #16 insulating pads installed?

 

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I had the same thing happen to my Wee and after going over the system heaps of times I decided there could be nothing wrong so I ignored it.

A month later there was no problem so I can't be any help to you.
 

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Pull the rear master cylinder reservoir cap and make SURE the vent hole is open in the rubber seal and cap.

Beyond that about the only thing that causes a rotor to get that hot is because the pads are not retracting enough. But, it sounds like yours move freely. I don't think new pads will change it, but since the pistons would be in a different position that might make a difference. I would probably pull the caliper and remove the piston for inspection. Wouldn't be surprised if there was some corrosion or dirt....
 

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Discussion Starter #11
Ok, I think I fixed it. But, unsatisfyingly, I have no idea what did it or where my culprit was.

I took the caliper out, removed the piston, and it was immaculate. The cup area was clean too. Reassembled, put new pads in, double checked my pins/pistons, reinstalled, bled the system, checked the cap vent holes (there are two, front and back) both were clean and clear.

After a re-bleed, it seems to be ok. Took the bike for a spin and it didn't get hot, and the rear is noticeably "freer" to spin on the stand with pads installed.

GAH! I hate not knowing, I'm going to go with fluid/gunk/air causing a slight pause to return the cylinder, but it's possible there was grit somewhere I didn't see or something.

Anyway, appreciate the advice it gave me something else to look for which is always good.
 

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I expect there was just enough of something behind the rubber dust cover that seals up the piston area. Doesn't have to be much, just something to act as a bit of a chock. Like a very small piece of grit between the piston and bore.
 

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I cracked both front discs on my BMW and all I had done was topped up the master cylinder with a 1/4" of new fluid in preparation for a long ride.

The brakes would warm up and pull themselves on, I was on a long ride and had to continuously stop and relieve the fluid pressure at the bleed nipple.

I then worked on two cars that had the same problem.

I never mix fluids, I always ensure it is a complete fluid change every time & I mean I go overboard to ensure it is a complete change as I never want that problem again.
 

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Swingset, I've also experienced your situation many times. In the 30 years of riding I've had my brakes drag to the point that the rotors were too hot to touch after a short ride. It follows me removing a wheel for a tire change, always on the front. It hasn't happened my Suzukis, but all my others it has. Like you, I go through the braking system multiple times and eventually the problem disappears, but I never know exactly why. Now I always clean the caliper pistons with brake cleaner and a toothbrush when I remove a wheel.
 
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If you go through much gravel or dirt as lots of us do its a wonder they work as good as they do with out in the open slides and pistons.Brakes are so much better than the stone age 60s and early 70s. I liked the big strong look of the huge cover with vents on some of the front old drum brake bikes.Brits had some on some of its big twins.Even a small modern disc is way better I bet? Some of my old Harleys made you better as you had to think about how much time and space you needed on anything but a hold at a stop light!:grin2:
 
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