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Running 1/2 Ton calipers on 14 Bolt disc bake swap?

82355 said:
The dust shield is unnecessary. You can discard it.

Unless you run wheels with stupid offset, you have to grind for 15" wheels with 3/4 ton calipers and rotors.

Martin
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The wheels I have my eyes on are all 3.5" backspacing. If I have to grind on the 3/4 ton calipers I'm guessing it shouldn't be much at all. I read a tech article on here awhile back and the OP was fitting 15" wheels on a D60, if I remember correctly he only had to knock off about 1/8" of material from the 1 ton caliper.
 
I have both.

The one ton is a LOT of grinding, but it doesn't hurt anything.

Martin
 
Yeah the calipers seem like they have plenty of material... can't see it being an issue.

Here are some pics of the TMR brackets.

chevy_60_front_disc_brake_bracket2.jpg

chevy_60_front_disc_brake_bracket4.jpg

chevy_60_front_disc_brake_bracket5.jpg

chevy_60_front_disc_brake_bracket6.jpg

chevy_60_front_disc_brake_bracket7.jpg

chevy_60_front_disc_brake_bracket8.jpg
 
I went through this same debate a couple months ago, ordered 15x12 wheels with a 3.5 backspacing and it took a good bit of grinding to get them over the one ton calipers. Couldnt bring myself to buy the tmr or lugnut4x4 brackets to switch to 3/4 ton stuff, then after looking at tires for awhile I sent the 15" wheels back and ordered 17s. All that grinding for nothing....
 
I have calipers ground for 15" wheels on my 1990 Blazer. I broke it on the river one day. Had to drive it off the river. Destroyed the wheels bearings and spindle in the process. Here is when I got to the point where we get off the river.







You can see the only thing holding the wheel on is the caliper and mounting bracket.





Here you can see the grinding required to run 15" wheels, plus the additional grinding done by driving over a mile with the steel wheels riding on the caliper.





I was able to remove the hub/rotor without disassembling anything after I removed the caliper.





That was several years ago, and that caliper and caliper mounting bracket are still in use. So I maintain that grinding calipers has no ill effect on them.

Martin
 
Tweekls1 said:
I went through this same debate a couple months ago, ordered 15x12 wheels with a 3.5 backspacing and it took a good bit of grinding to get them over the one ton calipers. Couldnt bring myself to buy the tmr or lugnut4x4 brackets to switch to 3/4 ton stuff, then after looking at tires for awhile I sent the 15" wheels back and ordered 17s. All that grinding for nothing....
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The lugnut4x4 brackets look super flimsy for whatever reason.
 
I run 15X14 wheels on my blazer and you can get away w/ a BS of 2.5-3. 3" is kinda pushing it, you would have to grind a little but not much @ all. Those wheels I have now PO told me they were 3"BS...turned out to be 5", so when I called him back he sent me the wheel spacers he had. He was running after marked BEAR brakes so they didn't hit @ all on his setup but did on a standard setup. Here's a pic of the old wheel/tire combo I had w/ 2.75" BS on where I had to grind the calipers....which wasn't much @ all.
 
i fit 3.5" b/s 15x10 rims on a 60 1 time for a guy . I felt o.k. with the amount I removed .

but if you ask me more than 3.4" b/s + grinding = crazy thin scary stuff.
 
Tweekls1 said:
The rear brackets I got from him are solid, cant speak on the front ones.
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His 14 bolt brackets look good like everyone elses but his Dana 60 brackets look really thin and the bends where he (or whoever makes them for him) don't look like clean brakes.
 
My buggy has already been converted to rear disk, my problem is I can't get the rear brakes to hold. I switched to a disk/disk Proportioning valve hoping that would help but it didn't. I just picked up one of the wildwood valves with the adjuster as mentioned earlier and am hoping to start the install today. If I hold the brake pedal to the floor and give it a little gas it spins the rear tires no problem. It has 47" tires and I need to be able to hold it still when on the rocks. I have a lot of pedal travel, not sure if I need to change the master cylinder or what. The sensor for the brake lights on the wildwood valve can be removed and plugged if not needed.
 
Honestly, I have to agree with Martin that you might be over thinking this. With as many (converted) rear disc trucks as there are, I would think if front vs rear piston size was a critical factor of overall function then there would be thread after thread about issues or at least a cut and dried recipe of parts to use. As you've seen yourself, many times aftermarket parts are lumped together based on interchangeability with little regard for the fine details (piston size). Theoretically, you could buy calipers from Autozone with different left & right piston size even though they are the correct part number per their catalog. Does this make it right, no but if this were causing problems they certainly would have corrected it by now with the volume of parts they sell.

@doubletrouble Imo, the fact that you have a lot of pedal travel would seem to indicate a master cylinder or bleeding problem.
 
handloader90 said:
Autozone lists their 1/2 ton and 3/4 ton calipers as the same P/N...
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They are wrong. GM parts manual clearly specifies there are two calipers used on 3/4 ton trucks, and it had to do with which braking RPO the truck had. Yes, one option used the 1/2 ton calipers, the other however used a larger piston. Others have provided the diameter difference in the piston in other posts. J-something RPO's denote the difference.
 
doubletrouble said:
My buggy has already been converted to rear disk, my problem is I can't get the rear brakes to hold. I switched to a disk/disk Proportioning valve hoping that would help but it didn't. I just picked up one of the wildwood valves with the adjuster as mentioned earlier and am hoping to start the install today. If I hold the brake pedal to the floor and give it a little gas it spins the rear tires no problem. It has 47" tires and I need to be able to hold it still when on the rocks. I have a lot of pedal travel, not sure if I need to change the master cylinder or what. The sensor for the brake lights on the wildwood valve can be removed and plugged if not needed.
Click to expand...

Can you post the results of the Wilwood unit once you have it installed?
 
doubletrouble said:
My buggy has already been converted to rear disk, my problem is I can't get the rear brakes to hold. I switched to a disk/disk Proportioning valve hoping that would help but it didn't. I just picked up one of the wildwood valves with the adjuster as mentioned earlier and am hoping to start the install today. If I hold the brake pedal to the floor and give it a little gas it spins the rear tires no problem. It has 47" tires and I need to be able to hold it still when on the rocks. I have a lot of pedal travel, not sure if I need to change the master cylinder or what. The sensor for the brake lights on the wildwood valve can be removed and plugged if not needed.
Click to expand...

What master are you using??
 
I got the Wildwood adjustable proportioning valve installed, it has the same mounting bolt pattern as the original valve but with the adjuster knob it will not clear the top of the crossmember in the stock location without cutting out some of the crossmember lip. On this project I was fine with cutting a little metal out otherwise I would probably mount it somewhere else. Two of the lines I had to use short conversion lines. It works great, since it's a trail only rig I have the rears set up to lock up just before the fronts do.
 
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