Help needed with rear brakes

78YZ

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I spooned on a new rear tire and installed new rear brake pads. When I test rode the bike, the rear brake pedal goes all the way down and applies little brake force. However, when I pump the pedal two or three times, I can get full brake force and ABS activation. Since I never opened the hydraulic circuit, I wonder what happened. Any guidance would be greatly appreciated.




FYI - It is a 2013 with 13.5 k miles.
 

Dogdaze

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Did you check the brake fluid level?

Ignore the sentence above, I had assumed you had primed the pads after changing them out, but go with the what others have said, and its just the pistons need to be pumped back into position.
 

Checkswrecks

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Normal when you change a rear tire. Part of it is pushing the pads into the calipers. Once the new tire is on you need to pump the pedal a few times to move the pistons back to contact the disc. Just check your fluid level and go ride.
 

brianhen

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Is this an ongoing issue with the soft brake or low brake pedal. Usually once the new pads are installed and after the initial brake application the pads will seat in place and the pedal should feel normal again. On my stratoliner however once I changed the pads I guess somehow air got in the line as I could not get a good feeling brake pedal until I bled the lines using a brake bleed tool I bought from Princess Auto (similar to Harbor Freight south of the border) I guess the caliper hanging down allowed air to et in the line. Never the less after the brake pedal is applied a couple of time it should feel normal or perhaps there is air in the line. Just a thought.
 

Squibb

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With current, ever more complex linked & even cornering ABS on some bikes, it is a good idea not to just push the pistons back into the calipers, when changing the pads as it can upset the braking system. A tech I know reckons it is now best practice is to connect a tube to the bleed nipple, open it & waste away the fluid as you retract the pistons, rather than risk back pressure & dirty fluid being pushed back up the lines through the ABS module/pump.

Personally, I usually leave these jobs to the pros these days, although I still run a spanner over their work, just to check the vital components afterwards. Sounds a bit OCD, but so be it, better safe than sorry.

...................... KEN
 

WJBertrand

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Squibb said:
With current, ever more complex linked & even cornering ABS on some bikes, it is a good idea not to just push the pistons back into the calipers, when changing the pads as it can upset the braking system. A tech I know reckons it is now best practice is to connect a tube to the bleed nipple, open it & waste away the fluid as you retract the pistons, rather than risk back pressure & dirty fluid being pushed back up the lines through the ABS module/pump.

Personally, I usually leave these jobs to the pros these days, although I still run a spanner over their work, just to check the vital components afterwards. Sounds a bit OCD, but so be it, better safe than sorry.

...................... KEN
This is my method. Also, I found there was too much fluid for the master cylinder to accommodate without overflowing just pushing the pistons back.

One caution when using the bleeder relief method is to make sure the master cylinder is up to the full line before exercising the pedal to return the pads after installation.


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78YZ

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I am back needing more assistance. I took the bike or a ride and I still need to pump the rear brake pedal at least twice to get full braking. Even after multiple applications of the rear brake alone, the pedal action never gets firm on the first time. When pumping, I am able to feel the ABS pulsing and there are no CELs. The front brake works fine but I assume the linked braking is not yielding full brake force on the rear. The brake fluid is full and, as mentioned, I am not getting any CELs or weird ABS lights during operation.


Does this sound as though I have air in the rear brake line? I've never had to troubleshoot a brake problem and I'd like to solve this at home. I do have a brake bleeder kit in my garage but I'd like to hear from the brain trust here before proceeding.


Thanks!
 

Checkswrecks

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78YZ said:
I am back needing more assistance. I took the bike or a ride and I still need to pump the rear brake pedal at least twice to get full braking. Even after multiple applications of the rear brake alone, the pedal action never gets firm on the first time. When pumping, I am able to feel the ABS pulsing and there are no CELs. The front brake works fine but I assume the linked braking is not yielding full brake force on the rear. The brake fluid is full and, as mentioned, I am not getting any CELs or weird ABS lights during operation.


Does this sound as though I have air in the rear brake line? I've never had to troubleshoot a brake problem and I'd like to solve this at home. I do have a brake bleeder kit in my garage but I'd like to hear from the brain trust here before proceeding.


Thanks!

Yes, it sounds like a bit of air in a line. One of the downsides of ABS systems is that it's super easy to have some small bubbles get stuck in the pump. You can never hurt things with bleeding though.
 

WJBertrand

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If thorough bleeding doesn't solve it, you may have a bad rear master cylinder. Haven't heard of any failures on that component but there's always a first time.


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78YZ

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Given my lack of experience in this area, I made an appointment for my dealer to bleed the rear brakes. I've had a relationship with this dealer for decades and they are very good. Thanks again for the responses.
 

2daMax

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Be aware that bleeding out air in the lines requires the abs pump to actuate to fully evacuate all air. You may need to bleed, cycle abs, bleed,cycle abs ...a few times to remove all air.

Air is known to be trapped in the abs unit. Simply bleeding the lines won't remove trapped air in the abs pump. Only cycling the abs pump will remove trapped air.

Had a case where the rear brakes felt like there is no resistance. Bleeding n cycling the abs solves it temporarily n symptoms reappear after a few km of riding. There was still air in the abs pump. So redo the procedure mulitple times until all air is evacuated. Since it uses a lot of brake fluid...it is probably good to recycle the fluids. Also a hose is used connected to the zerk fitting n the other end submerged with brake fluid in a bottle. This prevents back flow of air back into the zerk.
 

HeliMark

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78YZ said:
Given my lack of experience in this area, I made an appointment for my dealer to bleed the rear brakes. I've had a relationship with this dealer for decades and they are very good. Thanks again for the responses.
Might as well just have the dealer do the front also. Never hurts to have fresh stuff front and back. Shouldn't be much more.

Heck, if the clutch has never been done, seeing that you have a 2013, have it done. Your bike will thank you.

Mark
 

78YZ

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Thanks again for the suggestions. I do plan to have then do all three circuits.
 
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