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Thread: Front brake pads dragging afternew pads were installed

  1. #1
    Rideaway rideaway's Avatar
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    Front brake pads dragging afternew pads were installed

    After I put new brake pads on the front they drag much more than they should. Has anyone else dealt with this problem. I am guessing the pucks are dirty and it's preventing them from retracting properly. I'm hoping I can just clean them up. I was supposed to be leaving for Georgia in the morning. Hopefully I don't need new parts.

  2. #2
    A bozo on the bus deilenberger's Avatar
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    Need more info for an intelligent answer.. please read: http://www.bmwmoa.org/forum/showthread.php?46055 - and in this case, the info is nowhere in your posting (title, body or sig.)

    1 - Model/Year?
    2 - BMW pads or aftermarket?
    3 - Did you relieve brake pressure by opening the bleed valve when you pushed the pistons back in?
    4 - Have you checked the fluid level?

    Reasons for the questions:

    1 - Different models use different calipers and ABS systems and that info is needed. Whizzy brakes are a lot different from EVO-II brakes.
    2 - Some aftermarket pads are sometimes not an exact fit. Pad material may be too thick, or the backing plates may be too large and binding in the calipers.
    3 - If you didn't relieve the brake pressure - the reservoir may be overfilled
    4 - If the fluid level is too high the system will keep pressure on the pistons, causing the brakes to drag

    --------- DIAGNOSIS POINTS ----------

    #1 - If the bike is an early hexhead it's possible if the brake fluid hasn't been changed at the factory spec'd intervals that some corrosion has occurred which is now causing problems with the pistons fully retracted. It's also possible the return port (which relieves pressure) in the master cylinder is plugged up and keeping the system pressurized. If the bike has whizzy brakes - it's possible there is a problem there.

    # 2 - Was there any binding when you pushed the new pads into the calipers? If so - I'd be checking that the pads can move freely in the calipers. Even with stock pads it's good practice to clean the inside of the caliper when you're replacing pads. Brake dust can build up and cause binding if the dust isn't removed. A toothbrush (or similar, I have some parts cleaning bristle brushes similar to a toothbrush but bigger) can be used to clean the calipers and around the pistons.

    #3 and #4 are related. People and dealers often "top-off" the brake fluid between pad changes. This sounds like a good idea, but it actually isn't. The reservoir is designed so if the fluid level is at max with new pads, it won't drop below min with fully worn pads. That means topping off the fluid will put too much fluid in the system which can keep the system from relieving pressure on the caliper pistons - result is dragging brakes when the new pads are installed. Also - if the bike has whizzy brakes (2004-2006) the actual piston circuit reservoir is located IN the ABS module, so again, the year/model of the bike is pretty vital info to make an educated suggestion.

    Sticking pucks? I assume you mean pistons?

    Hope you sort it out before your trip..
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders New Sweden BMW Riders
    '07 R1200R (current ride) and some bimmers.. and a Porsche

  3. #3
    Rideaway rideaway's Avatar
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    Quote Originally Posted by deilenberger View Post
    Need more info for an intelligent answer.. please read: http://www.bmwmoa.org/forum/showthread.php?46055 - and in this case, the info is nowhere in your posting (title, body or sig.)

    1 - Model/Year?
    2 - BMW pads or aftermarket?
    3 - Did you relieve brake pressure by opening the bleed valve when you pushed the pistons back in?
    4 - Have you checked the fluid level?
    Thanks for the feedback.

    R1200RT 2007, EBC pads, didn't open bleed valve but did remove some fluid. Will be checking all the things you mentioned this morning. Thanks for the feed back. I know on cars I have had to clean the pistons before. I've always changed the fluid at recommended intervals. I've had the bike since new, it now has 95,000 KM on it. No whizzy brakes.

    Hmm, EBC pads slightly larger and are rubbing on the edges of the disk that aren't as worn down, I thing this is the problem and will just have to wait for them to bed in I think. Cleaning up piston sides while I'm in there.
    Last edited by Rideaway; 04-24-2013 at 01:16 PM.

  4. #4
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    FWIW, you should never simply pop in pads without cleaning pistons and the caliper interior so pads slide freely in the caliper and the pistons don't hang in their seals. Also a very tiny touch of caliper grease on the point where the pad load is transferred to the caliper body when the brake is applied is a good idea on most calipers- be darn sure not to overdo it- you don't want it finding its way to the pad surface due to sloppy application...

    Sticking pistons are pretty common on older bikes especially if pistons don't ever get cleaned.

    Less common today due to better DOT4 fluids, far more common when DOT 3 was normal, is the fact that brake fluid can form a very sticky glue like gum at seal edge where it meets the piston. These deposits interfere with and in extreme cases can completely prevent piston retraction. This typically happens after the bike hasn't been ridden for a few months- like over winter storage. Yeare ago when I was less careful about my bike maintenance, I had a Honda do this to me about a mile from my house- when I had no tools on board. Applied the brakes and they wouldn't back off- could barely push the thing home- couldn't ride it.. Quick caliper disassembly and clean fixed it but that was the last tie I ever made that mistake...

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