#1  
Old 09-27-2022, 12:16 PM
8453johng 8453johng is offline
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Default 1980 Trans Am rear disc caliper piston adjustment

I have an 80 Pace Car Trans Am
I just received rear calipers fully rebuilt from E Bay
My problem is the piston is to far out to load the pads on the rotor

I believe you need to rotate the piston clockwise or counter clockwise for it to go in to allow loading of the pads to the rotor

Also the D hole in the piston needs to be at the bottom of the caliper for the brake pad nub to fit into it

After that there is a emergency brake adjustment

How do you rotate the piston with channel locks (it looks like they will tear up the piston) The passenger caliper only has the D hole. The driver caliper will not accept the AutoZone tool for rotating the piston

Last which way to rotate the piston to go in on the driver or passenger sides I think counter clockwise

Thanks again

  #2  
Old 09-27-2022, 01:52 PM
ta man ta man is online now
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The piston doesn't rotate, you turn the parking brake stud on the rear to move the piston in or out.

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  #3  
Old 09-27-2022, 04:29 PM
8453johng 8453johng is offline
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The e brake stud only rotates the piston out 1/8 to 1/4 turn.

My e brake stud is all the way in and there is still no clearance for the pads to load onto the rotor

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Old 09-27-2022, 06:41 PM
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Scarebird Scarebird is offline
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What I found on the Eldo calipers was I made a tool with that would bolt in place of the arm yet clear the stop so the caliper could be unwound.

Not GM's best design.

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Old 09-29-2022, 01:41 PM
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ta6point6 ta6point6 is offline
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You need to take the parking brake lever off along with the nut and use a c-clamp to push piston back in . It is easier if you set up your calipers correctly before putting on the vehicle and hooking up the parking brake. If you need to orientate the D slot to the top of the caliper you can use channel locks but be gentle. The e-brake lever will only push piston out not in. This is where the D slot should be positioned.
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Old 09-29-2022, 03:16 PM
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Skip Fix Skip Fix is offline
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Quote:
Originally Posted by ta6point6 View Post
You need to take the parking brake lever off along with the nut and use a c-clamp to push piston back in . It is easier if you set up your calipers correctly before putting on the vehicle and hooking up the parking brake. If you need to orientate the D slot to the top of the caliper you can use channel locks but be gentle. The e-brake lever will only push piston out not in. This is where the D slot should be positioned.
This has worked for me also.

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