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rear disc brake idea

KansasTwister

KansasTwister

1/2 ton status
Joined
Jun 19, 2009
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Lawrence, ks
Has anyone thought about running 1/2 ton calipers in the back and 3/4 ton calipers in the front when they did a brake swap? I know the 3/4s have a bigger piston thus more stopping power, and lots of people complain about the brake swap, but what if you were to use the smaller pistoned 1/2 ton calipers in the rear, thus giving you a majority of the braking force up front. Think you might also be able to keep the same master/booster setup since the ratio would be more in the favor to the front? Its 2:30 and im about to crash and just having random thoughts i guess. :popcorn:
 
Technically a drum system has a residual valve in the m/c to keep a small amount of pressure on the wheel cylinder to prevent it from drawing the shoes in too far, and making brake response sluggish. If that were to be used on a disc setup, it would keep a small amount of drag on the pads at all times. There are also specifics on the diameter, and stroke of the piston in the m/c, the pedal ratio, which relates to the amount of fluid moved for proper brake application.
 
1/2 and 3/4 tons share the same calipers.

Same part number at your local parts store for remanned units, new ones, etc.

Two different calipers are the 1st and 2nd designs of which both are identified thru the banjo bolts and the overall appearance of both housings, too. Otherwise pistons are the same size on both designs.

Unless you know something that we don't? Care to share the info?
 
There is 2 different calipers for a 3/4 ton. You have a JB6 and JB7. The JB6 being the same as a half ton. The JB7 being the bigger piston one. I ran the JB7 on the front and the JB6 on the back on my old truck. never had any problems with it.
 
Do those numbers apply to all parts stores? I'm gonna have to go verify this in person just to see the differences.
 
Thanks bronc, i didnt have any part numbers for reference. Just is what ive heard and im glad i didn't seem to make it up this time!
 
I believe those "other" 3/4 ton brake pads are similar if not the same as the one tone pads, they have little tabs at the tops of the pad backing plate sticking upwards.

I'm personally running the 1/2 ton pads, yes the backing plate for the 3/4 ton front brakes moves the pads out further, this is to accomodate the larger diameter of the rotor. I used 1/2 ton calipers on the rear, so all my brakes take the same pad.

The first time i installed them, i ran through the rear pads rather quickly, wasn't sure why, i installed a new set and still have them on well over a year now.

Actually i believe the problem was a blockage inthe rear dist block, lost my rear brakes on a wheelin trip, replaced the M/C, still didn't work so i started cracking lines and realized no pressure after the dist blockon top of the diff. Cleaned everything out, brakes work great. Even with the stock master cylinder. :D
 
The JB7 are bigger pistons. I have those on the back of mine because the cores came with my front axle. While I used the JB6 up front. Horrible pedal. What I did was put a JB7 master on mine for the same year, I have an awesome pedal and it stops fine, but on the master the line sizes were different. So to do it quick I swapped the lines front to back. Now most of my braking is on the rear, which I don't like.

I was thinking of putting my old 1/2 master back on, and swapping the calipers front to rear, putting the JB7 on the front, and JB6 on the rear and see how it does. Unless someone has done this and doesn't have a good pedal.

I think this is an issue that will always remain. Some company needs to build a good rear caliper just for these with a good e-brake. The caddy calipers just cost too much if you can find them with no core.
 
Just a thought here, i haven't heard or seen anybody talking about them, but my '88 IROC had rear disk brakes that i am pretty sure used the same brake pad, was there some issue as to why these couldn't be used, spacing, bolt pattern or something?

I know the have e-brake levers too and don't use the drum in hat setup either.
 
4xcrazy said:
Just a thought here, i haven't heard or seen anybody talking about them, but my '88 IROC had rear disk brakes that i am pretty sure used the same brake pad, was there some issue as to why these couldn't be used, spacing, bolt pattern or something?

I know the have e-brake levers too and don't use the drum in hat setup either.
Click to expand...

They have the smaller bolt pattern.
 
bronc3buster842001 said:
They have the smaller bolt pattern.
Click to expand...

OK, any other reason they wouldn't work, is the piston too small do we think for rear use on the trucks? afterall it is only a control brake out back anyways, with all these CNC machines around, and people cutting steel for use with the 1/2 ton front calipers, why not cut some for certain calipers, like the IROC calipers, see if they work?
 
Cornfield creations said:
What I did was put a JB7 master on mine for the same year, I have an awesome pedal and it stops fine, but on the master the line sizes were different. So to do it quick I swapped the lines front to back. Now most of my braking is on the rear, which I don't like.
Click to expand...

When I did my hydroboost swap the line sizes were different and I had to do the front to back swap. However, the chambers moved, meaning the small chamber went from the back to the front (small chamber is for the drum brakes). Now correct me if Im wrong but in essence, nothing changed except where the fluid is stored. :dunno:
 
I thought maybe thats what happened, but the when it comes time to stop hard the rear will almost lock up, and won't do a nose dive as if the front are really grabbing. Plus the rotors in the front were new and are barely worn, where the rear ones are now smooth in comparison.
 
KansasTwister said:
Has anyone thought about running 1/2 ton calipers in the back and 3/4 ton calipers in the front
Click to expand...

I've been running half ton fronts on both ends for awhile now without any problems. Only issue I've ran into is my own fault when I installed them. Had a backing plate spin on me since I didnt have the bolts tightened enough.

12b thread

After running this setup for so long I finally have to change out pads since I recently started getting a little squeeling during stops. This is after 3+ years as a daily driver. I have yet to work on a good ebrake setup for it. Thats about midway down my to-do list of projects.:doah:

Z
 
Cornfield creations said:
I thought maybe thats what happened, but the when it comes time to stop hard the rear will almost lock up, and won't do a nose dive as if the front are really grabbing. Plus the rotors in the front were new and are barely worn, where the rear ones are now smooth in comparison.
Click to expand...

well could be b/c (unless read wrong) that you have the 7's on the back and the 6's on the front. Could be b/c you have the larger ones on the rear they will bite harder. Also as I recall the rear brakes apply before the fronts (in the stock drum setup), so you are magnifying that with the larger rear calipers. Again, this is all conjecture, no hard & fast facts.

I have 7's front & rear on mine and it feels like it bites evenly. I did however adjust the height sensing prop valve in the back of my truck (you may not have one, dont recall what came w/ em). But I had the rod taken out of mine so its just a valve, gave it a little twist to take some back brake out b/c the brakes seemed too sensitive when I first did the mod.
 
k20 said:
well could be b/c (unless read wrong) that you have the 7's on the back and the 6's on the front. Could be b/c you have the larger ones on the rear they will bite harder. Also as I recall the rear brakes apply before the fronts (in the stock drum setup), so you are magnifying that with the larger rear calipers. Again, this is all conjecture, no hard & fast facts.

I have 7's front & rear on mine and it feels like it bites evenly. I did however adjust the height sensing prop valve in the back of my truck (you may not have one, dont recall what came w/ em). But I had the rod taken out of mine so its just a valve, gave it a little twist to take some back brake out b/c the brakes seemed too sensitive when I first did the mod.
Click to expand...

Yeah I don't have that rod. Could be as you say. Maybe my 1/2T proportioning valve, since I never touched it, is holding it back. :dunno:
 
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