Hot Rear Brakes

scot in exile said:

About twelve years ago I wrote about the same problem, after talking with Aussiebiker dave(old name from the past) I removed my rear brake pads, clamped off the brake hose and took the bike for a ride , after about five miles checked the rear disc and it was still hot , like Rick I had checked everything but in the end we just have hot discs

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OOOOh Maestro. Now, where would that heat be coming from? These are Brembos! My final drive gets toasty but the disc gets hotter. I must guess that the pads never completely separate from the disc when the pedal is let go. In the end... this might just be a normal thing? HA! these Brit bikes. Will travel with a spare caliper and brake lines from now on. I have seen a clipper get hot to melt the brake line in my old milkman Yukon. A piston locked after a brake bleeding by "an expert mechanic". The truck has been traded.

Barba, No, I have not checked the disc thickness. It does not seem to have lipping or show abnormal wear. In any case; Ill let the master re-check my work. He might not even want to look at it since I have a CT mounted.

@1K9 Have someone use a temperature gun on their caliper and rotors,then compare temps to yours

1olbull said:

Twas only a joke, Amigo.
Was yanking yer chain.

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Your concern is not too far fetched. It happens. I had my stretching pegs in a position where my heel could end up resting on the rear pedal.

Fingers said:

@1K9 Have someone use a temperature gun on their caliper and rotors,then compare temps to yours

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Ill see how much a temp gun is and take it to MV and check everyone's rear rotor for overheating Well, everyone that wants me to. It might be an indication that you have a sticking problem in the rear end. The same for the front.

A hotter than necessary rotor might indicate that your pads are dragging and the caliper piston seals need service.

I checked the Valkyrie yesterday after a ride. The rear rotor was much hotter than the front. I am having the three caliper piston seals replaced and the lines flushed with fresh stuff. It is so easy that a cave man could do it.

1K9 said:

Barba, No, I have not checked the disc thickness.

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Rather than wear - see if it is warped. I remember my mate was having issues with a customers bike (Triumph Explorer) - And one of issues he came across was a front disc running eccentrically. But I've seen several warped discs there too - usually due to some ham-fisted tyre changes. My spare rear rim had a lightly dinged rear disc on - tbh probably my problem transporting in from the UK lying on the disc.

@1K9 Watch Harbor Frieght has them for around $20 on sale quite often .

Fingers said:

@1K9 Watch Harbor Frieght has them for around $20 on sale quite often .

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Will look. Good gadget to diagnose problems.

I had the same problem with mine initially - it was the front guide pin on the rear caliper partially ceased it would move but only with a hard tap - managed to free it up using WD40 until it floated nicely - hasn't been a problem since.

John Miller said:

I had the same problem with mine initially - it was the front guide pin on the rear caliper partially ceased it would move but only with a hard tap - managed to free it up using WD40 until it floated nicely - hasn't been a problem since.

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The guide pin boots have been cleaned and lubed with a dab of moly. They are free.

1K9 said:

The guide pin boots have been cleaned and lubed with a dab of moly. They are free.

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Prior to owning the R3 working on cars the caliper guide pins are usually a little stiff which is still acceptable, on the R3 it's not acceptable to have any real stiffness sliding the caliper on the guide pins for the rear caliper. This was causing the rear disc to get hot and I mean really Fkn hot. After pulling the pads on mine I tried to slide the caliper on the pins - it was a no go. Not until I found the front pin was binding/grabbing or stopping the caliper sliding did I fix the thing. Now the caliper will slide on the pins freely with almost no resistance - I now have a cool rear disc no longer does it get hot from just normal riding. I can grab the caliper and rock it on the pins and I feel the slightest free play or movement (before I cleared the front pin stiffness - it was solid with no free play at all) this was causing the caliper to bind on the pins with the brake applied and it wouldn't retract properly causing the pads to then bind because the caliper was sticking on the pins.

If it's not the issue on your machine then that's good, others however with a similar issue might want to check the caliper pins for freedom of movement before you start looking elsewhere - just remember the caliper should float on the pins with little or no resistance.

Hope this is helpful to someone.