Hot Rear Brakes

[Journeyman]

It's dirt! Will come right off with a brush and brake fluid. Since the caliper does not come apart… how do you take the pistons off? How do you get to the seals and replace them? There are pistons only on one side so I guess that's how you get to that.

That's good news. You can push the pistons nearly all the way out with the pedal before disconnecting the brake line, then either protect them with rubber and carefully pull out with pliers (you risk marring the pistons). See video.

If they're stuck you can use compressed air. If you do that you want to "pad" the area on the caliper where they will hit when they pop out and where they can "exit." I did it this way on my Thunderbird Sport that has a similar design and despite the warning that they can pop out like missiles, I was not ready for what happened and just lucky that no animals were harmed in that experiment. Be really careful if you go that route - you can lose a finger, or worse.

I've also heard some people use a grease gun, more gentle method, but then you have to clean the grease out of the caliper- not that big a deal I guess. I may actually try that way this time if a gentle tug with the needle nose pliers and a piece of inner tube doesn't work.

The seals will come out and go in easily, as will the pistons. Make sure you orient the seals properly- check out that video and feel the ridges before pulling the old ones out so you understand what he means.

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I'm also doing this project sometime soon and found a couple of new tips. Once the brake line is disconnected I'd rather not let it drain and then fight to get trapped air out of the lines. I guess on the back system you can simply raise the line above the master cylinder, but on the front I'm going to try depressing the font lever just slightly- supposedly that will prevent much fluid from going out- like a finger on a straw.
Also, I'm going to run the banjo bolt back through the line with a circle of nitrile from the finger of a glove covering the hole in the bolt and add a nut.

 

[FE_rex]

......................Once the brake line is disconnected I'd rather not let it drain and then fight to get trapped air out of the lines. I guess on the back system you can simply raise the line above the master cylinder, but on the front I'm going to try depressing the font lever just slightly- supposedly that will prevent much fluid from going out- like a finger on a straw.
Also, I'm going to run the banjo bolt back through the line with a circle of nitrile from the finger of a glove covering the hole in the bolt and add a nut.

push a rubber automotive vacuum cap or rubber hose through the the banjo fitting to temporarily seal it.

 

[1K9]

After thorough cleaning and adding new pads, heating continued. Not as bad, but they should not get hot unless you are going downhill. Ordered both a rear and front seals kits. They are 12 years and 50 k miles old.

Ordered front and rear sets for the Valkyrie too. The just have 20k miles but they are 22 years old . Murphy will get me at the oddest of times. Ill let Marco @ Iron Mike's do that for me.

 

[Jvheli]

I've fixed similar on other bikes. What caused them was trapped air, which expand as the bubble is heated, causing the brake to extend.

Another thing I've found is a very tiny return hole in the reservoir is plugged , causing much the same result.

 

[1K9]

I've fixed similar on other bikes. What caused them was trapped air, which expand as the bubble is heated, causing the brake to extend.

Another thing I've found is a very tiny return hole in the reservoir is plugged , causing much the same result.

How did you clear the return hole. Did you have to service the master cylinder? Where do you think this bubble was. I guess you just bled the line. is that how you got it out?

The caliper is coming off and getting new seals and pads. The lines are getting a good bleed. If this does not fix it, it will have to go to the shop.

 

[Jvheli]

How did you clear the return hole. Did you have to service the master cylinder? Where do you think this bubble was. I guess you just bled the line. is that how you got it out?

The caliper is coming off and getting new seals and pads. The lines are getting a good bleed. If this does not fix it, it will have to go to the shop.

I cleared the small metered hole with a torch tip cleaner. The hole will be inline with the master cylinder piston. Mind, I haven't done this on a Rocket but its pretty standard.

Also, if youve bled the brakes, check it again. If there are bubbles you likely have a leak someplace sucking air.

 

[Scholle]

I cleared the small metered hole with a torch tip cleaner. The hole will be inline with the master cylinder piston. Mind, I haven't done this on a Rocket but its pretty standard.

Also, if youve bled the brakes, check it again. If there are bubbles you likely have a leak someplace sucking air.

I have had this problem before. It may happen that the channels in the foot brake cylinder are clogged with dirt, so that the brake fluid can no longer run back freely. For this you have to dismantle the foot brake cylinder and disassemble. All very thin channels must be cleaned carefully with a very, very thin wire or needle and then cleaned with compressed air.
After that the problem should be solved.
Georg

 

[1K9]

I have had this problem before. It may happen that the channels in the foot brake cylinder are clogged with dirt, so that the brake fluid can no longer run back freely. For this you have to dismantle the foot brake cylinder and disassemble. All very thin channels must be cleaned carefully with a very, very thin wire or needle and then cleaned with compressed air.
After that the problem should be solved.
Georg

Thank you for that info. As others chime I can see the that the master might need service too. I will let Nick at Pasadena Triumph service that. They might object to work on the bike because it has a CT on. I use the rear brake often so I need it to be perfect.

 

[1K9]

Lookie heereee what I found.

FORUM Seized rear caliper, boiling brake fluid

Discussion in 'Rocket III Resources' started by alpental, Nov 20, 2016

 

[barbagris]

Another thing I've found is a very tiny return hole in the reservoir is plugged , causing much the same result.

4500psi pump will shift that