Rear Brake Question

[desertdog]

Started out on a ride today, only got a couple of miles and wife says she hears rubbing coming from the rear wheel.

Turned around and came back home, put the bike up on the jack and pulled the right side saddle bag.

When turning the wheel, it appears that the rear pads are rubbing slightly. The rear disc did not seem to get very hot on the ride so if its dragging its slight.

Is this normal, or should the pads be releasing completely so it does not rub at all?

And what is the cause and possible solutions??

Its an 08 Nomad with 15K miles on it.

[Kawhead]

I would try changing the fluid if you haven't already. Get the clutch and front break while your at it. Hope that helps.

[cactusjack]

Disk brakes don't really retract when you aren't using them, in the same way that the old-fashioned Bendix drum brakes did. You apply hydraulic pressure via the foot lever and master cylinder. This forces fluid from the master cylinder to the rear caliper, which forces the pistons to apply force against the outside pad and rotor. This action also forces to inside pad to apply pressure to the inside pad and rotor. When the lever is released, the pressure applied is gone, but the pads are still riding very closely to the rotor surface.

I would be concerned if the caliper pistons were continuously applying pressure, which would generate a lot of heat and cause premature wear to your brake components. This doesn't appear to be happening in your case. You could always remove the rear caliper, then remove the pads and spray the pistons good with brake cleaner, then rinse with water and re-assemble.

[ringadingh]

A light rubbing sound is considered normal. As long as the wheel turn freely with very little effort its ok. If it takes some force to turn the wheel by hand, something is wrong.

[classic1]

I replaced the rear brakes at 21,000 and 37,000 miles on my 06. I use the front brakes more than the rear and haven't replaced them at all.

[desertdog]

Thanks for the replys. The wheel seems to turn normal when on the jack, so I am thinking its not a problem at this point in time. I will put it back together and do a few mile run and check the rear disc for heat.

I don't use the rear much, except for parking lot practice or tight parking lot turns.

If it seems to be hot I will have to pull the caliper and follow Cactus Jacks suggestion.

[cnc]

+1 on what Catusjack and Ring have said. I don't think you have a problem from what you have said. If the brake was dragging, you would not be able to touch the rotor after even the few miles you drove.
Stop the bike on a slight incline and hold it there for a second with the rear brake only. Take your foot off the brake, if you start to roll back, it is releasing properly.

[AlabamaNomadRider]

Very good advice CNC also Scott and Steve gave good advice. All disc brakes still rub slightly even when the brake is released. I would advise not to ride with your hand or foot touching the brake levers as the slightest touch will tend to cause the pads to engage. You see a lot of cars going down the road with their brake lights on and more than likely they have their toe resting on the brake pedal. They are putting premature wear on their brakes and don't realize it.

[cnc]

Originally Posted by AlabamaNomadRider

Very good advice CNC also Scott and Steve gave good advice. All disc brakes still rub slightly even when the brake is released. I would advise not to ride with your hand or foot touching the brake levers as the slightest touch will tend to cause the pads to engage. You see a lot of cars going down the road with their brake lights on and more than likely they have their toe resting on the brake pedal. They are putting premature wear on their brakes and don't realize it.

Gene up around here we call those people two footed drivers.
I always wonder how the heck they would drive a standard. Also if they really did have to panic stop, would they get the other foot off the gas or just plow the gas pedal harder in the heat of the moment.

[macmac]

CJ, has it. Test it anyway. Drop the bag and go ride say 4 miles. Then see if the caliper or rotor are hot, I mean real hot, so take care to feel air before you get brave.

If you could keep you hand there forever, then the system is fine.

BTW don't use the brake for this test.

AND!!!!!!! When the dy comes to do rear swing arm service, it is a good bet you will push the pads in, one way or another. When you do pump the brake pedal/lever depending on which sets get moved back into their bores untill you have pressure again!

That could take several pumps before you would have brakes!!!!!!!!!

[AlabamaNomadRider]

Makes you wonder CNC what they would do. That is probably the reason you hear of people running through the front of buildings and stuff and they say I thought I was applying the brake but I hit the gas.

[Yellow Jacket]

Originally Posted by AlabamaNomadRider

Makes you wonder CNC what they would do. That is probably the reason you hear of people running through the front of buildings and stuff and they say I thought I was applying the brake but I hit the gas.

Most of them swear that they were pushing on the brake pedal as hard as they could but the car just wouldn't stop. Rarely will they admit that they were pushing the gas pedal all the way down instead.

[recumbentbob]

Mine did that at 7000 miles; on the rear of the caliper there are 2 pins that mist slide. Mine were all gunked up from riding in the rain.

Cleaned them up and sanded the pads lightly with 80 grit sandpaper and every thing is fine now.

[blowndodge]

All disc brakes rotors have a minimal amount of runout or "wobble". This is so it will push the pads away from the rotor when you remove the pressure from the hydraulic lines. This makes a sound as the runout hits the pads.

[macmac]

Oh just so you guys are aware, that black dust is corrosive to mag wheels and chrome. It will pay to pull calipers, and clean them with a chemical brake cleaner, brushing helps too, so pick up a parts brush.