G oog le BadWeB | Login/out | Topics | Search | Custodians | Register | Edit Profile

Buell Forum » XBoard » Brake pad clearance « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Clydesdale6
Posted on Thursday, July 25, 2019 - 11:10 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Can someone tell me what the clearance should be between a new front brake pad and the rotor?
Top of pagePrevious messageNext messageBottom of page Link to this message

Akbuell
Posted on Thursday, July 25, 2019 - 11:28 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

With a flat rotor, after the first brake application the clearance should be essentially zero. When the piston pushes the pad against the rotor, there will be a slight bit of drag from the piston O ring. That drag MAY torque the O ring a really tiny bit, and when the hydraulic pressure is released, that torque will relax, pulling the piston back.

Do you have an issue?
Hope this helps, Dave
Top of pagePrevious messageNext messageBottom of page Link to this message

Clydesdale6
Posted on Thursday, July 25, 2019 - 11:44 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Dave, I did. Yesterday my front brakes locked up on me while riding. Not a cool situation. After they cooled, I got back to the house and I just finished flushing and adding new brake fluid. Trying to troubleshoot right now.
Top of pagePrevious messageNext messageBottom of page Link to this message

Nillaice
Posted on Thursday, July 25, 2019 - 11:49 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

aftermarket brake lever?
Top of pagePrevious messageNext messageBottom of page Link to this message

Clydesdale6
Posted on Thursday, July 25, 2019 - 12:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Original OEM lever
Top of pagePrevious messageNext messageBottom of page Link to this message

Meggadeath
Posted on Thursday, July 25, 2019 - 12:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I would be more inclined to diagnose this as a master cylinder malfunction.
Top of pagePrevious messageNext messageBottom of page Link to this message

Clydesdale6
Posted on Thursday, July 25, 2019 - 12:35 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Master seems to be working okay. Used the rebuild kit to replace most of it.
Top of pagePrevious messageNext messageBottom of page Link to this message

Shoggin
Posted on Thursday, July 25, 2019 - 01:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

"Most of it"?! There isn't much in the re-build kit. What did you NOT replace?

I can't think of anything that would allow pressure to be held in the system, unless you put the return spring in the M/C on the wrong end? Wrong M/C piston? M/C piston seals stuck in the bore?

Take the line off at the caliper and put it in a container. The lever should compress the piston and it should RETURN to the snap ring by itself.

And just for giggles make sure both holes in the bottom of the reservoir are clear. One is really tiny so I use welding tip cleaners or a set of jewelers drill bits to clean them. The piston must be removed first or you'll nick the cup seals on it.
Top of pagePrevious messageNext messageBottom of page Link to this message

Akbuell
Posted on Thursday, July 25, 2019 - 01:58 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ah, I see. Yeah, after brake release the pad should 'just barely touch' the rotor, but not enough to cause heat.

I'm going to be in the master cylinder crowd, but . . . If you have never had the pistons out of the caliper, crud ( a scientific term,LOL) may have built up and be causing a piston or more to hang up and not release. Might do to have a look.

Hope this helps, Dave
Top of pagePrevious messageNext messageBottom of page Link to this message

34nineteen
Posted on Thursday, July 25, 2019 - 03:03 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

This ^^^^^^

All of my XB's have had sticky caliper pistons to varying degrees and have benefited from removing the pistons, cleaning and replacing. The brake has much less drag and subsequently runs much cooler.

So far, on all of my XB's, I've been able to do this without a rebuild kit with complete success. But you may want to have a rebuild kit handy just in case.
Top of pagePrevious messageNext messageBottom of page Link to this message

Tpehak
Posted on Friday, July 26, 2019 - 10:21 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Air in brake line. It heats up, builds up pressure, expands and presses the pads.

(Message edited by Tpehak on July 26, 2019)
Top of pagePrevious messageNext messageBottom of page Link to this message

Clydesdale6
Posted on Monday, August 05, 2019 - 09:33 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Shoggin, okay, poor choice of words on the most of it. LOL! I utilized the repair kit on the master...
Top of pagePrevious messageNext messageBottom of page Link to this message

Clydesdale6
Posted on Monday, August 05, 2019 - 09:36 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Thanks everyone for the suggestions and info. I bled the lines haven't had a repeat of the brakes locking up.
« Previous Next »

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Password:
E-mail:
Options: Post as "Anonymous" (Valid reason required. Abusers will be exposed. If unsure, ask.)
Enable HTML code in message
Automatically activate URLs in message
Action:

Topics | Last Day | Tree View | Search | User List | Help/Instructions | Rules | Program Credits Administration