Quick help request: Rear brake clunk after service?

BigJ · May 18, 2012

Hey guys. We just serviced the rear brakes on my Raptor (2010 SCab), but I'm getting a loud clunk when the caliper first engages the rotor. After watching it and experimenting, with her ass in the air if I put her into drive and let the wheels roll, and then lightly tap the brake I can watch the driver side caliper 'jump' as it contacts the rotor; maybe its the piston engaging the pad? The movement coensides with the clunk.

But, lets say I bring the driver side wheel to stop (holding it with my hands) then repeat the tap, I can get the same exact movement/clunk from the passenger side as it start to bring the wheel to a stop.

Any thoughts? Suggestions? Thanks!

Smokinjo · May 18, 2012

Is it possible you have air in the line? Do the brakes feel spongy at all? Have you considered bleeding the rear starting at the wheel farthest from the MC to eliminate any possibility of air in the line? Did you remove top to MC when compressing pistons to install thicker pads? Do you have contaminated brake fluid? Are the brake lines original or aftermarket? Sound like air or a sticking caliper that clunks when finally releasing past the air or sticking point.

Hockster · May 18, 2012

BigJ said:
Hey guys. We just serviced the rear brakes on my Raptor (2010 SCab), but I'm getting a loud clunk when the caliper first engages the rotor. After watching it and experimenting, with her ass in the air if I put her into drive and let the wheels roll, and then lightly tap the brake I can watch the driver side caliper 'jump' as it contacts the rotor; maybe its the piston engaging the pad? The movement coensides with the clunk.

But, lets say I bring the driver side wheel to stop (holding it with my hands) then repeat the tap, I can get the same exact movement/clunk from the passenger side as it start to bring the wheel to a stop.

Any thoughts? Suggestions? Thanks!

The only movement the caliper should make is in and out towards the rotor. Something is missing/worn out/slide damaged. Check the axle hub bolts... Are you sure its the caliper moving and not inside the ebrake hub?

Wheela · May 18, 2012

BigJ said:
After watching it and experimenting, with her ass in the air

Giggety

BigJ · May 18, 2012

After more experimenting, it sure looks like the ears on the pads aren't the right spec. We pulled the wheels and can replicate the noise exactly if we let the thing roll in drive, then grab the caliper and pull up parallel to and in the direction of rotation. The whole unit moves up and clunks against the hanger. Whats strange is there's even a spring there as if its supposed to stop that movement from happening. I'll try and get a video.

wkeefe · May 18, 2012

Wheela said:
Giggety

Hillarious! :waytogo:

BigJ · May 18, 2012

Here's a quick video. This is happening on both sides. Pulling up (as seen in the vid) is simulating what's happening when brake pressure is applied via the pedal, and the pad grabs the rotor for the first time. Its being thrust into the hanger, creating a clunk.

When weight is applied from the tire and wheel, inside the cab this sounds like a crazy loud bang.

We're installing different pads now, but they looked the same on the table. Could my hangers have stretched on either side?

Phyguy · May 18, 2012

BigJ said:
Here's a quick video. This is happening on both sides. Pulling up (as seen in the vid) is simulating what's happening when brake pressure is applied via the pedal, and the pad grabs the rotor for the first time. Its being thrust into the hanger, creating a clunk.

When weight is applied from the tire and wheel, inside the cab this sounds like a crazy loud bang.

We're installing different pads now, but they looked the same on the table. Could my hangers have stretched on either side?

Ouch. Don't do that. LOL. Stage 4!!!! I knew it would happen .... :waytogo:

Hockster · May 18, 2012

That caliper should not move that way at all... Check Where the guys palm is on the mounting area. Something is worn out allowing the caliper to move. I think it uses round pins to mount. They must be worn out and allowing that caliper to move.

Jackemuphigh21 · May 18, 2012

Its like a hole is worn out or a spacer/washer is missing. There should not be any play in the caliper body at all. it should be solid.

Quick help request: Rear brake clunk after service?

BigJ

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Smokinjo

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Hockster

My 45ft Bluewater Party

Wheela

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BigJ

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wkeefe

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BigJ

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Phyguy

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Hockster

My 45ft Bluewater Party

Jackemuphigh21

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