[grumble1_1]

Just a couple of questions about rear brake discs on my Harley, Front disc seems to be always cold , rear disc is always hot and discoloured but i don't use rear brake any more than front brakes, i have a 2004 dyna with S&S slash cuts on it ,thought maybe exhaust may be making rear disc hotter than should be.Bike only has 4000km's on the clock , is this heat and discolouration normal ? any help would be great thanx,

[chucktx]

have you had the rear wheel off?? has this problem since youhave owned the bike?? the rear disc should be no hotter/cooler than the front. your problem is a rubbing problem. a little more info would help....

[grumble1_1]

G'day Chuck ,No i have not had the wheel off at all , i have put over a thousand kms on bike since i bought it second hand with three thousand kms on.It was doing this when i got it and when the bike had the original slip ons attatched.I thought that if i maybe replaced brake pads this would make calipers have to go back in a long way maybe fixing problem?

[hotroadking]

I would guess a warped ass rotor (rear rotor)

Either the rotor is warped or the caliper is out of alignment with the rotor.

It should not heat up and discolor like that.

[ringo912]

In additon to what HRK said, I would to check and make sure the pads are returning to the relaxed position after applying pressure to the brakes. You could have a caliper piston that is starting to seize up. This would keep constant pressure on the brake pads resulting in heat build up and discoloration. Hope this helps.

[voodoochild]

My rear rotor was hot as well, but it is an alignment problem from when I did the 240 rear tire kit. My spacers were not cut exactly to the proper size. After 1K miles it has since worn the brake pad and runs cool again. I didn't fix it, the brake pad just wore down. I would check your alignment, but since the brake foot is on the axle it would be hard to have an adjustment problem, at least I think. (please correct me somebody if I am wrong!) I would tend to think it might be a piston hanging up, (like stated before), sortof like a cage would do. (my work truck does it all the time it seems) Good luck and let us know what you find.

[chucktx]

grumble, do you have a manual?? get the rear up and a good light source. turn the wheel and look at the pads/rotor. check the rotor for trueness. use a stick or something and place it very close to the rotor, holding the stick on the caliper for support. dont let the stick move and check rotor runout. look at the cups in the caliper. they should return when the pedal is released. push the pedal and watch the pads/cups. when you release the pedal the pads should return a bit. also check the pad alignment pins....i saw a dyna that had bad pins and would hang the pads......

[ironhorse]

as ringo said I have had the caliper sieze/bind and cause this little heat problem like yours, just one of the many posibilitys

[grumble1_1]

G'day fellas , i changed pads today ,cleaned caliper pistons and checked and cleaned pad alignment pins. i also changed brake fluid and noticed a hell of alot of fine metal particles in expended oil, any ideas on what this could be? Will take for a spin tomorrow and let you's know if i still gotta problem.

[chucktx]

the metal is comming from your piston....the master cyl. should be checked, metal in the brake flluid is dangerous!!! the whole system needs flushed. all pistons and bores need to be checked. possibly replacement will be needed, depending on how bad your system is. i usually change my fluid once a year. let us know what ya find!!

[ironhorse]

Originally Posted by chucktx

the metal is comming from your piston....the master cyl. should be checked, metal in the brake flluid is dangerous!!! the whole system needs flushed. all pistons and bores need to be checked. possibly replacement will be needed, depending on how bad your system is. i usually change my fluid once a year. let us know what ya find!!

ditto

[grumble1_1]

Hey fellas just to let you know that metal in fluid did come from master cylinder found that inner and outer had been rubbing together making alot of metal in fluid. Rear pistons in calliper seemed quite stiff too , have drained whole system ,replaced master cylinder assembly new seals and pistons in calliper will let u's know how it is all going shortly.