No Rear brake after sitting for a few weeks.

Rick Morris

"Have you seen Junior's grades?"
Joined
Jul 14, 2015
Messages
1,541
Location
Cape Cod, MA
Ride
2011 Rocket III Roadster
2011 Roadster 16,000 miles. OK, so this is not the first time someone has posted this question. But I have not seen a good answer yet. I will start at I replaced the front & rear pads and bleed the front & rear brakes and added new brake fluid in October last fall. All was great, excellent brake feel front and rear no problems at all. I had not rode the bike for a few weeks and in May I took it out and there was absolutely no rear brake. Pump the heck out of it and get a spongy feel. Bled the rear again and get a perfect rear brake. Took it out yesterday and no rear brake again. I know this can be a master cylinder issue in a car but it in a car it happens very frequently, like you go a mile hit the brakes and get a very bad fade. In a car you can actually hold the brakes and feel the pedal go to the floor slowly. With this issue its fine all day after you get the brake feel back. Let it sit a few days or a week or so and nothing. Has anyone replaced the master and fixed the issue or has anyone rebuilt the rear caliper to cure the problem?
 
Mine's done that twice.

First time I bled it, was fine until 18 months later when it sat for 6 months and then had to do it again, was fine after the second bleed as well.

EDIT: I should add, the second time i opened the reservoir and the seal had collapsed a bit, reseated it no further problems.
 
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Happened to me once. I removed the master cylinder, gave it a good clean out, put it back together, and it never happened again. However, I did not have ABS on my 2006 Classic, so you may have to take care of a couple of things when putting it all back together and bleeding.

They do not like to left alone and ignored. ;)
 
Happened to me once. I removed the master cylinder, gave it a good clean out, put it back together, and it never happened again. However, I did not have ABS on my 2006 Classic, so you may have to take care of a couple of things when putting it all back together and bleeding.

They do not like to left alone and ignored. ;)
Thanks, I may give that a go. And I agree, He gets pretty ornery if I dont give him a twist every few days. But I have a few others that have been getting more attention lately. I feel like I am cheating , you know what I mean.
 
Was the rear brake soft from the get go, or did it go soft after you'd been riding a bit? How long since the fluid has been flushed and replaced?

If there is any water in the system, it will function as expected when cold, but once it gets hot - and the Rocket does get hot - the water will boil, putting air in the system and a soft pedal. Let it cool, and the brakes will work again - until they get hot.
 
Was the rear brake soft from the get go, or did it go soft after you'd been riding a bit? How long since the fluid has been flushed and replaced?

If there is any water in the system, it will function as expected when cold, but once it gets hot - and the Rocket does get hot - the water will boil, putting air in the system and a soft pedal. Let it cool, and the brakes will work again - until they get hot.
did you read my post?
 
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