Hot Rear Brakes

[barbagris]

Even if fluid seems to moving without restriction? 4500 will take your skin off. Maybe a few hours in an ultrasound bath will work. When I take it apart I will have the shop clean it, OK? Where in the reservoir would the restriction be? Just take the reservoir off to clean too

Ultrasound - yes, micro gritblaster - yes, jet reamers, yes. But if 4500 wont shift it you have issues - that's close to the max pressure of many hoses. What I know also works is ZOTAL - it's really an industrial sterilizer sold over here - but is a biocide - so eats away anything organic - leaves aluminium sparkling.

 

[Journeyman]

I'm glad that this happened here and not going downhill in MV

My only doubt right now is the issue of cleaning the grooves. I am guessing these groves are where the new seals will rest. Are there any other "grooves" I need to worry about? The reservoir is clean and fluid comes out easy so I don't get that part of the deal. Ill probably take it to my dealer and ask them to give it a blast of air or cleaner.

Yes, just the groves for the seals. No scratching allowed- a wooden toothpick if you need some extra umph.

 

[1K9]

Yes, just the groves for the seals. No scratching allowed- a wooden toothpick if you need some extra umph.

I will be very careful once the pistons come off. Soft tooth brush with brake fluid and 80 psi is all I have. How about a few blasts of brake cleaner aerosol? I think that stuff evaporates and leaves no residue.

 

[1K9]

Ok here's an update. Got a used caliper from eBay. Caliper, base and brake line for 41$ delivered. Cleaned it real well. The pistons compressed rather easy. Came out easy with 80 psi. Cleaned them. Re-sat them. Went on easy. Removed the stock and installed this one. Tire spins, stops hard and lets go well in the garage. Good pedal pressure after good bleed. Quick Bleeds are great for this.

Went for a ride. The problem is mitigated but not resolved. The disc still gets hot. Not piping hot but hot. Huuummmm Is this normal?

The bike has to go in to replace the yoke bearings. Will have the front brake seals and pads replaced and have Nick place new seals on the back too. The disc is straight. The pedal returns well and quick.

Going to run the bike with no rear pads on to see if the disc gets hot.

The leak from the fork seals stopped after cleaning.

 

[Journeyman]

Went for a ride. The problem is mitigated but not resolved. The disc still gets hot. Not piping hot but hot. Huuummmm Is this normal?
Going to run the bike with no rear pads on to see if the disc gets hot.

Wondering if it gets hot if you don't use the rear brakes at all?

I'd reconsider taking the pads out before a test spin- if you accidentally step on the brake you're going to have a bad outcome.

 

[Ishrub]

Wondering if it gets hot if you don't use the rear brakes at all?

I'd reconsider taking the pads out before a test spin- if you accidentally step on the brake you're going to have a bad outcome.

All seems like a complete waste of time but if you must - make up some plywood pads and if they are rubbed or burnt without applying the brake no issue.
If you do accidentally touch the brake they will grab the disc and quickly glaze and burn where contacting the disc.
You could also do this as another test after testing without using the brake.

 

[1K9]

Wondering if it gets hot if you don't use the rear brakes at all?

I'd reconsider taking the pads out before a test spin- if you accidentally step on the brake you're going to have a bad outcome.

Yeah, I think they do. They don't look they are dragging at all when I lift the bike but if that were the case they should stay cold if I go out and don't touch the rear brake. How fast do the discs stay hot after a few stops?

 

[barbagris]

How fast do the discs stay hot after a few stops?

I've never tried - BUT Stainless is a TERRIBLE thermal conductor.
One thought has crossed my mind. Have you checked the disc for run out? I mean properly with a dial gauge.

 

[1olbull]

You were a Cop so you have used an Iron. How about Ptsss hot, ready to iron. And no, Im not stepping on the rear pedal unless I want to stop.

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

 

[scot in exile]

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