[Givindabird]

I have a '78 T/A I am putting an '81 T/A disc rear into.I have the master cyl.,prop. valve.Are there any other parts I need to change?Will the brakes work properly without the emergency brake cables hooked up?Do the cables need to be hooked up to keep adjustment correct?I plan on getting cables eventually but can't right away.Thanks from the new guy.

[Givindabird]

I have a '78 T/A I am putting an '81 T/A disc rear into.I have the master cyl.,prop. valve.Are there any other parts I need to change?Will the brakes work properly without the emergency brake cables hooked up?Do the cables need to be hooked up to keep adjustment correct?I plan on getting cables eventually but can't right away.Thanks from the new guy.

[Skip Fix]

Having the master and prop vavel is a good start. I personally prefer and adjustble one for the rear but if you have a working factory one it would be worth a try.

You DO need to set the E brake intermittently to keep the pads closer to the discs. You might could do it manually by cycling the levers. I hope you got the levers for the parking brake setup as they are discontiued.

Did you get the power brake booster? If you did you need to get the 4WD brake pedal as it has LESS leverage than the 2WD pedal. You should be able to keep the 2WD booster.If you swap to the $WD booster the 2WD pedal gives you no pedal "feel" (did that ) Main difference in masters from a 2wd to 4wd is the residual pressure valve that is in the master under the flare fitting for the brake line at the master. 79-80 had a cast iron 1" master and 81 had the aluminum 1 1/8". You can exert more pressure with a smaller piston but less volume.

If you are not going to hook up an E brake I think the front calipers from some of the mid size cars have the same bolt pattern.

[Givindabird]

Thanks for the excellent info. Skip Fix.As luck would have it I also swapped to the 4 SPD(ST10) from the donor car(my '78 was auto.) so somewhat by accident I do have the brake pedal along with the clutch pedal I needed, and when scavenging the master I also kept the booster as an afterthought seconds before the car was hauled off.I'm not usually nearly so lucky!Am going to use your idea about the adj. prop. valve.
Anybody know where I can get either the needed emerg. cables etc.,or what model calipers would work in place of the rear adj. ones?LOL

[Skip Fix]

I switched a 79 Camaro to a stick from and auto. I hope you got the brakcet that bolts to the frame that holds the Z bar. The holes are already in the frame just need tapping for the bracket.

The key measurmenet for the calipers is the distance between the bolts. My guess would be a G body to look at. Probabaly can have them pull one at the auto part store to look at.

Not sure if anyone is reproing the E brake cables.

I'm just adding the rear discs to the 79 Camaro with a 12 bolt I had built. Luckily I got the extra E brake cables years ago. I did have to have someone fabricate a copy of the E brake bracket for one side.

[larry davis]

Skip, what's up with reusing the OEM 2WD pedal?

I retroed my 78 T/A w/ 79 T/A rear disc set up.
Brand new rotors, calipers, 79 4WD booster, & fine lines 4WD proportioning valve. Spliced a wildwood adj. valve into the rear line.

Is that 2WD pedal going to cause problems? Haven't got it all back together yet.

[Skip Fix]

I don't know if you guys are old enough to remember thge Hot Rod article where they retro fitted a 77 or 78 with rear disc, WS6 and had Andretti(or some other hot shot driver) take it on a road course. In the article it incorrectly decsribed the 2WD pedal as having less leverage than the 4WD and that you needed more with 4WD.It actually has MORE leverage. I think Pontiac addressed it with the booster. I think it is a "dual diaphragm" design and must give more assist. If you keep the 2WD booster it will probably "feel" OK. When I put the 4WD booster and kept the 2WD pedal it stopped great but I think I could have used my little toe to push the pedal. TOO easy and no feedback, at least for me.It may feel OK for you. You might could just redrill the hole in the pedal to decrease leverage if you can't find a 4WD pedal.

You will need the correct spring clips that hold teh pad to the piston GM#18004026. Probabaly discontinued as most of the parts are. I do not know if Bendix or other sources make a replacement one.Luckily I stocked up with an extra set a few years back.

You may need to "tweak" the backing plates as wrecking yard ones are probably bent and may not line th pad parrallel to the rotor.I was meesing with one yesterday. Maybe OPH can chime in on how to tweak them. Rotor is a touch over 11" so a decent sized one.

Caddilac used a similar caliper on their cars. A friend used those on his 4WD 55 Chevy truck. Their backing plates are alot smaller than the Pontiac one. He used the plain front calipers for awhile til he had to get it inspected and needed an E brake.

[larry davis]

Geez Skip. Just when you think you know all the answers, they change the questions?

I'm gonna run it first, & see what's up.
All my parts are new, except the backing plates.
Those rotors & calipers are EXPENSIVE! I believe the calipers were $60.00 each & the rotors $55.00 (special order of course). That was 6 years ago.
One good thing was that the OEM drum brake lines adapted just fine w/ just a little rebending.
As fate would have it, I'm switching over to stainless lines. Never satisfied to leave well enough alone.