The Stovebolt Site Forums The Shop Area The HiPo Shop 1950 3600 spindles

Hi all. This is my first post here, so please pardon me if I've made any mistakes in doing so.
First I'd like to say what an fantastic board this is. "A wealth of information" doesn't even begin to describe it. I've learned tons just browsing the posts.
Now on to my question...
I just bought a 1950 3/4 ton chevy pickup and I'm doing a frame off resto/rod project. I've seen a number of places offering drum to disc conversion kits for my truck, but none specify if the kits work on both 1/2ton and 3/4ton. Can someone tell me if the spindles are the same size for 1/2ton and 3/4ton? If so, then the kits should work. If not, then I would assume they wouldn't unless I find a kit specific for 3/4ton.
I've searched the posts but did not find an answer to my question there.
Thanks much!
50-3600-Guy

50 owners should correct me if I'm wrong, but the 54-55 AD 3/4 ton front spindles are the same size as 1-ton, larger than the halfton with no interchangable parts from the frame down. I have not seen any bolt-on disc conversions for the 3/4 or 1-ton AD's, but I'm sure I haven't looked everywhere yet.

Any help from the other 'bolters?

Mr. Guy-Welcome to The 'Bolt. This is indeed a wonderful place to hang out. I've been pondering the 3/4 ton question myself lately, mostly cuz it seems as if there aren't any 1/2 tons left in my area...So some questions are in order from me to you. First, how do you wish to drive it? If you want highway speeds, you're gonna have to ditch that boat anchor full-floating rear axle in favour of something more modern. Taller (numerically lower) rearend gearing isn't really available for these early diffs. If you want to retain the I-beam axle and are swapping out the rearend anyway, just swap your FRONT axle for one from a 1/2 ton Advance Design truck-they are a bolt in swap. Now you can use any of the commercially available swap kits like disc brakes, power steering, etc. Any further questions, please post-someone will help you out.

Regards,
Wannabe

Thanks for the replies guys!
Wannabe - I have read on several sites that the pumpkin in the rear diff can be easily swapped out with the pumpkin from a 67-72 14 bolt 3/4ton chevy, giving it a 4:11 ratio, so that part shouldn't be a problem. Plus I've seen several sites that make 3:90 gear sets for the 14 bolt diff.
But I'd like to swap the front drums for discs utilizing the original front axle if possible. I just don't know if the spindles are the same size as the 1/2ton, makin it compatible wih all those conversion kits I see on the internet.
Anyone know for sure about the spindle sizes? If not, I'll keep researching it. Maybe call a parts store or two.
Thanks for any and all replies!

The spindle measurements are different.
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If you want to use the disc-brake kit you are talking about for the 1/2 ton,,, you can swap in a 1/2 ton front axle assembly

Mr. Guy-if you're wanting to retain the eight lug hubs and switch to disc brakes, there is a link at www.chevytrucks.org A gentleman by the name of JR Dorsey did the swap on his one ton panel. Looks good, however some folks here were concerned with fabricating the caliper brackets from plate steel-seems that there are different grades of steel plate, with different strength levels. You obviously would want to use the highest grade steel possible as this IS your brakes we're talking about! Check with local fabricating shops, etc. for different grades and qualities of steel. Hope this may be helpful.

Regards,
Wannabe

Thanks, Wannabe! I've been looking for that link since my last fried motherboard.

[img]http://www.ls1tech.com/ubb/graemlins/gr_bs.gif[/img]
Comments about the steel bracket are based on a lack of knowledge about the forces involved and the strength of steel. Figure you want to stop a 5000 lb truck decelerating at a rate of 1G (50mph to stopped in just under 84 feet). That means you have to generate 5000 lbs of stopping power. Say you only want to do this with the front axle because your back axle brakes have failed. Say you are using 11" diameter disk brakes with center of disk pad at 10" diameter (5inch radius)

Using your 5000 lb stopping force / 2 disks = 2500 lbs / disk. Lets say your tires are 30 inches tall = 15 inch radius, therefore your brakes must create 15inch x 2500 lbs = 37,500 in-lbs of braking torque. Take this same torque and apply it at the caliper location and you get . . . 37,500 / 5 = 7500 lbs.

Even a poorly constructed 10guage bracket will hold 7500 lbs. . . . brackets are the easy part as far as strength goes, the hard part is designing them so they allow the caliper to float for even pad wear.

Ken, I love that B.S. smiley, where did you get him?

Don't get me wrong, I was just relating something one of the other folks said the last time I posted this question (I believe it was FredT). My only concern is for Mr. Guy's safety, seems to me that overbuilding the brake system would be a smart move?

Regards.
Wannabe

If you look at the popular kits for 1/2 tons, they are cut from 3/8 inch steel plate, machined slightly on both sides.The ones on my 37 are made this way and use typical GM floating calipers mounted more of less like stock.I suspect the thick steel is used because it easier cheaper to manafacture than a built up sheet metal bracket. I bet the welded sheet steel bracket is less flexible.
Ken, modern super cars with the best brakes stop in from 115-125 feet from 60mph,they weigh around 3500 lbs.The brakes are a minumin of 4 piston(many have 6 pistons or dual calipers on each front wheel, each clamping down on 13-14 inch ventilated discs, the tires are ultra sticky V rated 275-375mm width tires.The super car brakes of course are designed primarly for triple digit speeds.Typical modern pick up trucks with antilock brakes stop in 150-175 feet at 60 mph.Can you figure G force from that?

[img]http://www.kinemation.com/Trucks/Images/braking.jpg[/img]

OH Sure, use a template :p :p (J/K)

Mech, I used to use the abucus for everything because that was the meaty way to do math. But, times have changed, I now use Excel -I know it is easier and probably for sissies but . . . it does allow me to design stuff faster and document what I did in one single step. Of course, this only works for engineering, not for any other topics that I might be thinking about.

Bolters:
As the owner of a 52-3604 I looked long and hard for a disc brake conversion for her. I coundn't find any. finally I contacted Carmen the owner of Master Power, who said that if I could provide him with the 3/4 ton spindles he could manufacture
a kit to do the conversion. Haven't located a set of spindles to send him and having just completely rebuilt the front suspension, I didn't want to tare mine down again. FYI, Carmen and I didn't discuss price. If enough Stovebolters were interested I am sure the cost of the conversion would be lower.

What are you doing with this truck road tacing? The factory style brakes can be very effective if everything is working correctly. Your driving to fast if yout think you need disco brakes.With a straight axle suspension you shouldnt be going faster than drum brakes can stop you..Why not try 1 ton big brakes.. A simple bolt in.This would give you plenty of stopping power.Add a hydrovac if you got whimpy legs.