Author Topic: 80 Trans Am Parking Brake and brakes..... The Never ending saga......  (Read 982 times)

Rickard080TA

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  • 1980 TA SE
    • 1980 TRANS AM SE
I have had the car for 6 years now. The brakes have never been good. For a while they were good to drive after i had the master cylinder replaced, but it sat most of the winter and when I brought it out a few weeks ago the pedal was soft again. I will call it ebrake to make it easier instead of parking brake. The ebrke really didn;t work last year either, but regular brakes did. Anyway back to this spring. Brakes are week, I know its partially due to ebrake not working. I try to adjust it based on some videos I read, but i actually made the regular brakes softer. So I bring it to a mechanic. They say they fix it, I drive it home, and ebrake has zero power. Brakes were soft almost as soft as before I dropped it off. So today I go and try to look at the brakes again. I start with the passenger side because easier to get to all parts. I remove the spring and cable, and test. I can spin the wheel just fine. I press on the ebrake lever and wheel spins just fine. OK, well it obviously needs to be fixed. Let me try the passenger side. This is where I gets interesting. The lever works in reverse. If the lever is pushed all the way out where the spring would push it open, the brakes apply and wheel won't spin. If I push on the lever all the way close like if putting on the ebrake, the wheel spins. Makes no sense? watch my video... https://www.youtube.com/watch?v=Y8Xs_fMgN-U Now I took the spring out for testing, keep that in mind. This is the driver side, and per the assembly manual the lever parts would be on the bottom of the caliper, where the passenger would be on the top. I have been to three mechanics already, two who claim to work on muscle cars. And still weak brakes. I am in Louisville, so if anyone knows who will fix these I would be greatly appreciated. 

Edit:  So i looked at old emails and searched for when I replaced the rear calipers soon after I got the car  and ordered A-1 CARDONE 18-4140 LR, and 18-4141 RR. Maybe I mounted them backwards, which means its possible the ones I replaced were also backwards or just wrong. I will try to find some time tomorrow to jack it up and take wheels off again and see if I can see any other markings on them except the casting of 451. 

Edit2: ok, so the caliper that is on my drivers side seems to be (looking from outside the car) Counter Clockwise to tighten. Clockwise to losen. Can i just flip that bracket that is on there and make it work? For the passenger side, will it also be counter clockwise? How does the clockwise or counterclockwise affect the regular braking?

I guess what I am really asking is can anyone provide pictures of their rear calipers from a car that has great brakes? I would like a view from inside and outside of each caliper. Thanks.

EDIT3: I corrected my mistype on the RR and LR.
« Last Edit: June 03, 2021, 11:31:38 AM by Rickard080TA »
Drive it like it's a rental.

Zajani

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You have the calipers on the wrong side. Caliper part # 18-4141 is for the right rear.  Look at the bleeder screws, they should be higher than the banjo bolt that holds the brake line on the caliper so you can properly bleed the brakes, if the bleeder screw is lower, than they are on the wrong side.

firebirdparts

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Trans am rear disc brakes are actually staggered due to the staggered shocks, per Firebird tradition, so they can't be installed upside down.  The reason they come in left and right is the direction of the acme screw that applies the parking brake.  If you have them reversed, or maybe you have two left feet, then you can certainly see the lever working backward on one side or both sides. 

I think the hydraulics will work if the parking brake never cranks up, but I guess the shop manual may differ on that.  Maybe that is the root problem.

I am also of the opinion that the attitude of the master cylinder is a real problem.  I never did actually try this, but I thought I would like to tilt my '77 enough to get the master cylinder level and see if I could get it to clear out once in a while.  My 77 never had any brakes either.
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Rickard080TA

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  • 1980 TA SE
    • 1980 TRANS AM SE
acme screw that applies the parking brake

So I think that is the key. The caliper is probably fine, but the parking brake bracket and lever is what is wrong on it. That's why i was asking for pictures. I read somewhere multiple times that the 80-81 (or could be 79-80) rear disc brakes were different that previous versions.
Anyway, back to the bracket. There is just no physical way the caliper can work with the bracket and lever that is on it right now.

Here is a picture of some replacement brackets:
Notice the brackets and levers are mirrored to each other? That's how my brackets and levers are on the car now. They can only be mounted on the caliper one way , and that way on the right rear is wrong because it works backwards. I ordered a new caliper that comes with bracket and lever so hopefully that will fix it.


Trans am rear disc brakes are actually staggered due to the staggered shocks

Yes, and my video shows the driver side mounted correctly, so that leads me back down to the bracket and lever.

Here is what it should look like: https://postimg.cc/wtybbz8Z


Here is what mine looks like: https://postimg.cc/xqzNj4nQ
Notice how the when the parking brake is applied, it will pull the lever tight on the spring, when that happens, brake power is released, but when parking brake is released, and spring is uncompressed it applies the brake.

The bracket can't be swapped to the left side, nor can it just be flipped.



You have the calipers on the wrong side. Caliper part # 18-4141 is for the right rear.  Look at the bleeder screws, they should be higher than the banjo bolt that holds the brake line on the caliper so you can properly bleed the brakes, if the bleeder screw is lower, than they are on the wrong side.

I initially thought you were wrong. but now I am thinking about it, maybe, just maybe this it. First off, I corrected my original post for RR and RL, but maybe that what I did. there are no markings on the calipers to say which is which. But I will check this out also.
« Last Edit: June 03, 2021, 12:05:01 PM by Rickard080TA »
Drive it like it's a rental.

Rickard080TA

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So this weekend I took the rear calipers off and they were redversed. Swapped them, but not the brackets. Everything is so much better. The parking brake will hold the car in neutral and I try to push it, but slightest gas and it moves easily. I think that stills needs to be adjusted just a tad more.

Anyone know how taught the parking cable from front to back needs to be?
« Last Edit: June 21, 2021, 10:37:52 AM by Rickard080TA »
Drive it like it's a rental.


81Blackbird

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Tighten the parking brake cable adjuster so the cable just pulls the lever off the stop on the caliper.  Push the cable where it connects to the left and right brake cable back and forth to be sure
it's centered correctly and pulls both of those cables evenly.  From this point, as the pads wear down the lever on the caliper will self adjust and ratchet to the next tooth just like a ratchet in your tool box.
« Last Edit: June 18, 2021, 03:08:48 PM by 81Blackbird »

Rickard080TA

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  • 1980 TA SE
    • 1980 TRANS AM SE
Tighten the parking brake cable adjuster so the cable just pulls the lever off the stop on the caliper.  Push the cable where it connects to the left and right brake cable back and forth to be sure
it's centered correctly and pulls both of those cables evenly.  From this point, as the pads wear down the lever on the caliper will self adjust and ratchet to the next tooth just like a ratchet in your tool box.

OK, so looks like I need to tighten it some more. The plastic covering of the cables has melted parts on it so I assume that should be expected?
I tried moving it more centered, but I can't get it very close. I assume the c clip looking thing that holds both cables that go to the calipers is centered, so I tried to get i close to that but its a "sharp" turn from when it comes out of the frame to turn in that direction.
Drive it like it's a rental.

81Blackbird

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Sorry...I should have said to move the adjuster back and forth to be sure it's centered.  The left E-brake cable is the longer one and is fed through the adjuster plate and then to the "C" clip were both are connected.  Looking at it, the adjuster will pretty much pull evenly if the cables are able to move freely in the sheath.  If you have them off, see if they move easily on both left and right sides.  If so they should pull equally to set the brake.  If the e-brake adjusters are working correctly you should be able to manually move the lever against the spring about an inch or so.