Thread: Best front disc brake setup

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Originally Posted by Itoldyouso

The reason that sometimes disc brakes from a larger American car aren't ok is weight and rotating mass. Those brakes are designed for a 3-4,000 pound car and weigh probably twice as much as an aftermarket set like Wilwoods. Not so critical on the original car but on a rod that weighs a lot less and probably has a beam type axle setup heavier brakes can cause some ill handling issues.......like deathwobble.

We were told by Mickey from Total Performance that we were not going to like the GTO disc brakes we installed on my Kids T bucket, but we had them and they were chromed () so we used them. He was right, the car handled very badly and after switching to Wilwoods it was so much better.

Stock brakes aren't very pretty either IMO, especially in a fenderless car.


Don

Don, I thought you had the Death Wobble because these reasons?

We also rushed building the car for Daytona Turkey Run, and built it in 88 days, start to finish, so we missed some things in our rush. As soon as the car hit the street we had handling issues. I have built a few cars and they always ran right down the road right out of the chute, so this one really puzzled me. The worst problem was death wobble that was very violent and you never knew when it would happen. You had to hit the brakes hard to get it to stop and it would scare the bejesus out of you.

So we pulled the car off the street for a complete suspension and brake redo. I found the wheelbase was off 9/16 of an inch side to side, so we realigned that. Our Flaming River steering box had too much play, which we adjusted out. Our caster was way too much at 9 degrees, so I took it back to 6. Toe in was off, it was 3/16 instead of 1/16 to 1/8. One brand new wheel was bent out of the box. Coker sent us a new one and we painted it today and will install it this week. We had all the wheels spun balanced on a very sophisticated machine.

We also found our spindles had been machined badly and the outer wheel bearing had 5-6 thousandths slop, so we pulled those and bought new forged ones from Speedway. While we were at it, we scrapped the GM brakes and have ordered a new Wilwood setup from Speedway too.

Bottom line, everybody seems to agree that for some reason the GM brakes are too heavy or something to make them work well at speed. I see lots of buckets with them, so some must work, but there are many people who don't care for them. We just couldn't take a chance and decided to go with the lighter Wilwoods. We should know this week how all of this worked out when we test drive the car again.

Don

Freds thinking was precisely our thinking in not putting the GM brakes back on. For $ 700 the Wilwoods cost it wasn't worth going through installing the GM's back on the new spindles and wondering if and when the problem would reoccur. I wish the GM's would have worked as they are all plated and painted up, but my Son's life comes first, and I don't want him driving a car that might get him hurt.

Don




There are many different kinds of light weight calipers & rotors out there and cheaper to buy. Who ever said anything about "larger American" cars???
I am using disc's & rotors from a '91 Nissan 300ZX on all 4 wheels on our "T" (With the name removed) They are light weight calipers, & rotors as many factory cars have. New calipers only cost $70.00 with pads, (rebuilt are about $36.00-$40.00) and rotors were $25.00 and I can get parts any where, they are a shelf item. And they fit most aftermarket mounting plates for 4 puck fixed calipers.
I have used VW calipers, and they also were light weight.

People just need to go and look some where other than in catologs, or just because someone else says that is what you need to use, odds are, they are only using it because someone said it was the only thing to use!

There are many small cars that can stop on a dime and give you change, and that are shelf stocked parts for less $$$$

As far as Unsprung Weight Thats great if you want to save weight, but from the looks of what you used, it didn't look like the parts you changed were for the weight, or are you saying that everyone else out there is having unsprung weight problems? I would rather have the IRON pumpkin, and I'm using two marine electronic water pumps which weighs less, but I not using them because of that.

Pat

Yep, those were some of the causes, but even after correcting all that stuff the wobble would still occur occasionally. We pulled the brakes and put Wilwoods on there and it hasn't happened since.

We did have another problem where the brakes were dragging and creating a lot of dust. Speedway graciously sent him a new set of rotors, different pads (purple) and a proportioning valve. We haven't had a chance to dial in the new stuff because he got sidetracked on his boat project the last year.

Don