Now that it's getting cool enough to work in the shop, I'm wanting to change from 8 lug drums to 6 lug discs. Anyone done this before? I was thinking that if I used these roller bearings and topped them with these disc brakes everything should fit together. But I've been wrong before. And if you don't believe me, just ask my wife. Honestly, if I need to stay with drums all around, I'm OK with that as well, but still want to make the front and rear match rims.
The whys of what I'm asking:
I have a 6 lug rear end already mated up with my driveshaft. If I absolutely have to, I can swap axels and make them 8 lug drums in the rear to match the current fronts. I'm really trying to keep a matching set of rims all the way around so I don't have to carry 2 spares. And since everything is still in pieces, what better time than now to get the brakes out of the way.
How do you intend to work around the different dimensions of the spindle? I'm pretty sure the diameter, and possibly the length of the spindle is different on the 3600. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The previous owner of my '52 GMC 152 (3/4 ton, same spindle as F18Delta's 3604) had the front spindles turned down to 1/2 ton spindle size to accept similar (maybe the same?) spacer/adapter parts to allow the kit to fit on the 3/4 ton spindles. Worked fine until one of the bearings failed after about 40,000 miles and wiped out the spindle.
I had a local machine shop cut down another 3/4 ton spindle to match the dimensions of a 1/2 ton spindle with the spacer adapter installed.
Picture below shows failed 3/4 ton spindle that had been cut down to 1/2 ton size with spacer added on the left. The spindle on the right is the 3/4 ton spindle the machine shop cut down for me.
Last edited by Bill Hanlon; 09/06/20249:17 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
I believe I'd prefer to stay with the heavier 3/4 ton spindle/hub assembly, and fabricate an adapter plate to switch to the 6 lug bolt pattern. That would require about a 1/2" thick disc of steel attached to the existing hub with flat head Allen bolts, drilled for the 6 lug bolt pattern. Not much of an effort for most well-qualified machinists. That would also allow the use of an 8 lug disc and caliper for better braking capabilities. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
How do you intend to work around the different dimensions of the spindle? I'm pretty sure the diameter, and possibly the length of the spindle is different on the 3600. Jerry
Bigger hammer? This is why I ask. I haven't taken the tires off the front at all yet, so I'm at a disadvantage of knowing what's behind door number 1. Usually, I do the wrong thing and buy the stuff and then find out that the spindles (or other parts) aren't the same.
Bill, I'm not sure I'd be willing to have a shop turn the spindles down. I think that 40k miles would zip right past me and leave me on the side of the highway wondering how I'm going to explain it to the wife. I suppose the options for the 3/4 tons are out there, but like hen's teeth. Thank you both for the replies!
There are 8 lug disk brake kits now. Have a friend who installed this kit on his GMC 3/4 ton and is very happy with the results. Kit is for 47-59 Chevy/GMC 3/4 and 1 ton models.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
That 8 lug brake kit is outrageous! Jessee James had to use a gun to rob people! When we wanted disc brakes on the round track cars, we just clamped a caliper to the disc with air pressure, and built our own brackets to mount it. Find a disc that has the right back spacing for the spindle, pick a suitable caliper, and make your own mounting hardware. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
It's also possible to use a front caliper for a mid-1980s Corvette that has four pistons, two on each side, which does not "float". That one is mounted rigid to the spindle and it's easier to design a mounting bracket. That design has been copied by some of the racing equipment manufacturers. Rock Auto has those calipers in stock for a lot less cost than the race guys. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
There are 8 lug disk brake kits now. Have a friend who installed this kit on his GMC 3/4 ton and is very happy with the results. Kit is for 47-59 Chevy/GMC 3/4 and 1 ton models.
The good news is that the link you shared says suggested retail price. When you get to the seller, the price drops to $680 for the plain Jane setup. I may be able to swap out the front axle to a 3100 as well. That should open some more options too.
