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Join Date: May 2011
Location: La Crescent, MN
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Tight fitting brake pads

I've heard a lot of differing opinions about how tight new brake pads should fit in the caliper (between the front and rear of the caliper, not between the pistons and rotor). I recently had all the calipers on my '89 C4 cleaned up and power coated. The main reason was that rear pads would never fit without the edges of the pad back plate being ground down (corrosion between the spring plate and caliper). The front pads always slid in with very little effort, but always squealed under braking (OEM pads) - reason #2.

With the reworked calipers, all the pads need to be tapped in. Not pounded in, but tapped with a hammer. They are in tight enough that they will require some effort to remove them. Is this too tight? If so, what problems could this cause and how best to correct?
Old 05-02-2011, 01:27 PM
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Yes, they are definitely too tight. The pads should slide in w/o any force. If you have to force them in, the pads will not "retract" when you get off the brake. As a result, you will get excessive pad and rotor wear and excessive heat. It is like having a stuck piston.
You need to remove the plates in the caliper, get rid of the corrosion under them and re-install. The screws are a pita to get out.... but don't drive for long with the pads stuck.
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Old 05-03-2011, 06:31 AM
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Thanks cjoenck.

The calipers were restored before powder coating, so there isn't any corrosion causing problems anymore. The paint is only a few microns thick, so I don't think that is an issue. Everything should be as original so I'm wondering why the pads fit so tight. Could it be the tolerance range in the size of the OEM pads? Do the spring plates ever need replacing?

At this point with the calipers restored, does it just make more sense to file down the pad backer plates? Is this common practice?

Thanks for any insights.
Old 05-03-2011, 07:02 AM
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Max Sluiter
 
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Powder coating can be quite thick. If they are powder coated that could certainly be the cause of the interference fit with new pads.
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Old 05-03-2011, 08:45 AM
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Powder coating can add more material than the tolerance for the caliper allows. Yes, people do adjust pads, mostly because they have corrosion under the plates. In principle, adjusting pads is fine as long as you keep the edge of the pads straight and you don't have to take off too much.
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Old 05-03-2011, 09:30 AM
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Old 05-03-2011, 09:30 AM
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