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New Brake Pad Too Thick?


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I am in the process of overhauling the brakes on my '89 TC, starting with the rear brakes. I have the calipers off the car and have rebuilt them. The driver's side brakes went back together just fine, but I cannot get the passenger side pads to fit into the caliper. The seem to be about 1/16th of an inch too thick to fit.

I have disassembled and reassembled the piston assembly several times, and I am certain the emergency brake adjuster is fully retracted, and the piston is bottomed out in its cylinder.

I must be missing something in the reassembly process, but I can't figure it out. Has anyone else run into this problem before?

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I am in the process of overhauling the brakes on my '89 TC, starting with the rear brakes. I have the calipers off the car and have rebuilt them. The driver's side brakes went back together just fine, but I cannot get the passenger side pads to fit into the caliper. The seem to be about 1/16th of an inch too thick to fit.

I have disassembled and reassembled the piston assembly several times, and I am certain the emergency brake adjuster is fully retracted, and the piston is bottomed out in its cylinder.

I must be missing something in the reassembly process, but I can't figure it out. Has anyone else run into this problem before?

You did both your calipers, one works as planned and the other you have had apart several times and don't see a problem, good chance that one is correct, but piston depth should be measured against the working one without pads in place just to make sure.

Having done a thousand brake jobs I'm going to translate what you said into what I know and say that the brake pads fit into the caliper but won't slide on over the (new) rotor which can sometimes be a problem as there is never any play space left when pads and rotors are replaced even when calipers are perfectly and properly rebuilt.

Pretty easy to spot when pads are different size out of the box and this happens every now and then when multiple box's get dropped at the warehouse and loose pads get put back in the wrong box. If your new pads were cellophane wrapped in the box this probably didn't happen to you and you need to look at the rotors. Rotors come in separate box's and sometimes they will work on one side and not the other as metal parts are machined to tolerance + or - and a full - tolerance caliper with new pads can be a very tight fit on a full + tolerance rotor as there is no wiggle space so straight on is the only way they fit together and sometimes full + on wheel hub with full - on rotor hub makes this a tough assembly. Couple things you can do now; swapping rotors left and right could be the easiest way to overcome if this is your problem. Other things also come into play, tolerance on hub size usually fixed by deburring the rotor and cleaning the wheel hub also pulling the rotor flat to the hub with a couple of nuts on the studs makes the assembly easier. Using a little sandpaper to round the outer edge of the rotor also makes this a little easier, won't tell you any other way to do this until you can say for certain that depth between piston and caliper frame are same on both sides.

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  • 5 months later...
Guest wheelsport

I imagine by now you have the brake job done but did you know that there is an allen screw on the back of the rear brake caliper assembly that needs to be screwed out to allow the piston to go all the way in? Once the caliper is on, the allen screw is screwed back in to remove any gap between the rotor and pad.

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Wheelsport, Thanks for the tip. I do know about the allen screw adjustment in the caliper. It was fully retracted and the piston was in as far as it would go. The pads were just too fat to fit. After trying everything, I finally ground about 1/64" off of the inner and outer pads to get them to fit into the brake mechanism. My brakes have been rebuilt and working fine in my yellow TC for several months now; which is a good thing, because the master cylinder has gone bad in the red TC. They seem to take turns competing for my attention.

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