2wd brake questions

cbtoyz

cbtoyz

Vaginatarian
I took my 12 valve out to the test n tune day at our local track this weekend. I am having a really hard time staging. I can only build 5 to 7 pounds of boost before my rear tires begin to chirp and bounce all over the place. I am going to go over the whole brake system, I suspect a bad master cylinder, and need to re-adjust my rear brakes. I am thinking of installing a line lock for the burn out, and a proportioning valve to give it more rear bias. What is everybody else doing with the brakes in their 2 wheel drives? How much boost can your brakes hold?

Oh, I ran a 12.51 at 120 mph! LOL
The printer for the timing lights was screwed up all day, so they just hand wrote our 1/4 mile time and our speed. :bang
 
Rear drums on my 95 wont even hold that lol and thats with proportional valve shoving 60% to the rear and 40% to the front. I was thinking of going with a disc brake conversion for the rear but I have been told that the conversion kit calipers are weak if you get a conversion pay to upgrade calipers.
 
cbtoyz said:
I took my 12 valve out to the test n tune day at our local track this weekend. I am having a really hard time staging. I can only build 5 to 7 pounds of boost before my rear tires begin to chirp and bounce all over the place. I am going to go over the whole brake system, I suspect a bad master cylinder, and need to re-adjust my rear brakes. I am thinking of installing a line lock for the burn out, and a proportioning valve to give it more rear bias. What is everybody else doing with the brakes in their 2 wheel drives? How much boost can your brakes hold?

Oh, I ran a 12.51 at 120 mph! LOL
The printer for the timing lights was screwed up all day, so they just hand wrote our 1/4 mile time and our speed. :bang
Click to expand...

Put in 3500 rear Wheel cylinders that will help
 
I think that's the direction I'm gonna go for the rear brakes. I saw that Pure Diesel Power had some upgraded wheel cylinders in different bore diameters. I may get a large bore wheel cylinders and proportion it down if I have problems locking up the rears under hard braking.
 
I am running dual 4 piston Willwoods on my truck. It will hold till I blow the trans :rockwoot:
 
I put the larger wheel cylinders in. I still can't build boost. Is anybody using a pinion brake?
 
Is your truck hydroboost or vac boost?

I had no issues holding back 20+psi with the hydroboost set up, but my friends 94 with vac boost barely stops let alone holds the tires at the line.
 
Hoss said:
A couple extra calipers are much cheaper than a pinion brake.
Click to expand...

Really? It is cheeper to narrow, convert to semi float, new axles, replace the ends with 5 lug ends, buy 4 calipers, new rotors, might as well put a spool in it by now, new wheels and slicks? That's the direction i would like to go, but I figured I could fab up a pinion brake much cheeper than pay someone to do all that.
 
Hoss said:
A couple extra calipers are much cheaper than a pinion brake.
Click to expand...

Really? It is cheeper to narrow, convert to semi float, new axles, replace the ends with 5 lug ends, buy 4 calipers, new rotors, might as well put a spool in it by now, new wheels and slicks? That's the direction i would like to go, but I figured I could fab up a pinion brake much cheeper than pay someone to do all that.
 
I would start checking all the vacuum lines and removing anything you don't need.

My 95' Junker was having trouble staying put when RPM would drop to idle at a stop light. I removed and plugged some of the unneeded vac lines like cruise control and the melted one going to heater and now it stays put and stops even better.

On my truck, if I build enough boost to overpower the breaks, the tires won't hold the launch anyway. Seems like 7-10psi is the most I can get the 285/75/16 all terrain's to hold. If I really get on the brakes hard, I can hold 15psi boost without spinning or pushing through the brakes.
 
cbtoyz said:
Really? It is cheeper to narrow, convert to semi float, new axles, replace the ends with 5 lug ends, buy 4 calipers, new rotors, might as well put a spool in it by now, new wheels and slicks? That's the direction i would like to go, but I figured I could fab up a pinion brake much cheeper than pay someone to do all that.
Click to expand...

Sorry I did not even think about where you were with your truck :doh:
You are right it would much easier and cheaper for you to do a pinion brake.
 
Ya I would probly switch to discs and put 2 calipers on each wheel. But my old 2wd first gen used to hold up to like 25 lbs no problem, and that was completely stock brakes.
By the way, was that 120mph fuel only?
 
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