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RSRBOB
RSRBOB, Technician
Category: Motorcycle
Satisfied Customers: 1078
Experience:  Former Factory Service Rep, Dlr Line Tech, Service Manager, General Manager, Store Owner
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I have a 08 sportster 883 installed new rear tire and brake

Customer Question

I have a 08 sportster 883 installed new rear tire and brake pads but the rear brake does not stop the bike. The pedal goes all the way down and the caliper moves. rear brake was working before.
Submitted: 1 year ago.
Category: Motorcycle
Expert:  RSRBOB replied 1 year ago.
Hi and thank you for your question.I am curious if you disconnected the brake line when you did the work on your bike. Either you have air in the lines or the pads are not moving like they should.Let me knowThanksRSRBOB
Customer: replied 1 year ago.

I only removed the larger sliding pin to get the tire off

Expert:  RSRBOB replied 1 year ago.
Thank you for the additional information.If you did not open or break the hydraulic system, I suspect the pads are not making contact with the disc.Take a look at the brake pads and see if there is a gap between the brake pads and the brake disc. If there is, have someone else, or you if you can reach and see, step on the rear brake pedal as you watch the pads. You are looking for movement of the brake pads. You should see them go in, but the seals may pull them back away from the disc. If that is the case, you will have to clean the pistons in the brake caliper so it can slide easily in and out past the seals.Take a look at that and let me know how it looks.ThanksRSRBOB
Customer: replied 1 year ago.

You can see the caliper move when applying the pedal and the piston moves freely

Expert:  RSRBOB replied 1 year ago.
Thank you.If the caliper is moving, you are losing your braking force to that. The design of the caliper is it moves over to allow both brake pads to be in constant contact with the disc. If the caliper retracts when you release the brake pedal, that will give you the symptom you are experiencing. Often when installing new pads, the caliper is riding on a different part of the pins that it moves on, and they will not allow it to return and stay so the pads remain against the disc. Unlike a car, a motorcycle master cylinder does not move very much fluid when you step on the brakes, so if the pad has to travel before it touches the disc, the pedal has no resistance. Since you put new thicker pads in, you should remove the caliper from the sliding pins, clean the corrosion off of them, lubricate them with silicone grease, and reassemble. That should fix you up.ThanksRSRBOB
Customer: replied 1 year ago.

I had cleaned and greased the pins when I put the rear tire back on

Expert:  RSRBOB replied 1 year ago.
OK.
Do you understand that as long as the caliper is moving, which is essentially moving out of the way, you will not develop hydraulic pressure in the brake pedal? The non moving pad, which is on the inside, should be in contact with the disc at all times. Not pressing on it so hard that it creates any kind of drag, but lightly in contact with it. Then as you apply the brakes, the piston pushes the other brake pad against the disc which is essentially supporting the disc and preventing it from deflecting and the two pads squeeze together.
Is it possible you have the spring that is above the brake pads installed incorrectly and not letting the pads stay in place? Customer
Customer: replied 1 year ago.

Pads are touching the disc and when I installed the new pads I had to push them forward to install the pin that keeps them in place.

Expert:  RSRBOB replied 1 year ago.
Thank you for the additional information.Since the hydraulic system was never opened, this can't be air in the lines. If the caliper is moving when you push on the brake pedal and the pads are against the disc, then they must be in some sort of a bind and not free to move. One tricky part about re-installing the caliper is making sure the tabs on the opposite end of the pads from the pin are engaged properly into the the caliper bracket. At this point, you have looked it over very closely and it doesn't sound like there is any visible problem. That leaves us in the position of having to remove the caliper again and inspect the brake pads and their installation. If you want to ensure the system is functioning correctly from the hydraulic stand point, when you have the caliper off, place the handle of a large wrench in between the brake pads to hold them apart, and step on the brake pedal. The pads should clamp down on the wrench handle and you should feel the resistance in the brake pedal. You may have to pump it a time or two but once you establish pressure, it should not go all the way down like you described it was when the caliper was last installed.Let me know what you find.RSRBOB

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