The Stovebolt Site Forums The Parking Lot Tons 'o Fun 1 Ton Disc Brakes for 1947-53

All,
Like many others I am working on adapting disc brakes to my 1951 GMC 1 Ton. I think that I have the rotor and caliper that I am going to use figured out and I am working on my template for the mounting bracket for the caliper and want to know if caliper placement makes a difference. I have looked at various years and various makes/models and have seen the caliper at the 3 o'clock, 12 o'clock and 10 o'clock position looking at the drivers side assembly on the different vehicles. Before I get to far I would like to clarify if position makes a difference or if it is just about clearances with the steering and suspension.
Thanks for your input.
Dave

Here is what I'm doing for my '38 that now has a '51 axle:
disc brakes instruction

The most important thing to remember is that you need to be able to bleed your brakes, so the bleeder needs to be facing up.

To answer your question, the system I'm working on is more in the 2:00 position. With the size of my caliper, there wasn't room any other way. At the 10:00, it wouldn't clear the steering arm, at the 12:00, it wouldn't clear the kingpin. Coinscidentally, the 2:00 position is where the calipers were set up on the 07 van I took them off of.

www.photobucket.com/whitedog76pics

Thanks for the input. Here is where I am at with mine. The caliper clears the king pin and the plan right now is two L shaped brackets off the top of the spindle to the disc brake bracket itself. I am mocking those out of plywood this weekend to make sure it works before I machine them out of metal. I will post more pics once I have the brackets mocked up. For the bearings, I bought roller bearings from Chev's of the 40's.



Dave




Disc Brake Pics

To mock mine up, I used some carboard and then transferred it to light sheet metal. My first attempt wasn't going to work, unless I planned on driving in a straight line and not turning.

I saved a metal cookie tin to hack on for my second attempt. LOL!

I got inner roller bearings from Chev's of the 40's and outers from Classic Truck Parts. I saved a little green that way. I waited on the seals until I got the bearing. I'm kind of glad I did. An OEM Felt seal won't work, it has to be a rubber lip type.

I did the same. Did the cardboard first, then plywood and I am doing metal mock up to ensure that my measurements are good. By the looks of it, it looks as if it will work. Thanks for the heads up on the seal, I seen that in your other post. Have you checked out 40973S which is a nitrile material vice felt.


Dave

Actually, that's the the seal I bought. Mine are Timken, I don't know if the National Seals are the same. I'm guessing so. It's a little tight around the bearing, though. I'm thinking it would be best to snap it onto the bearing then drive it in.

I haven't done anything since I ordered my parts. I'm wrapped up in a kitchen remodel project plus I need to get my hubs to a parts washer to remove the remainder of the 50 year old tar-like grease that's in them.

Good luck Dave.

Mock up is done and will add pics later tonight. There is enough clearance with the rims so it will accept the stock rims so that will not be an issue. The only question is what wheel studs to use. The current are to short and with the new rotor the hole in the rotor are larger than stock wheels studs. Does anyone have any ideas what wheel studs and lug nuts to use? I realize that the hubs will have to be drilled out to accept larger wheel studs.
Thanks Dave

What rotor are you using? The rotors I'm using came from an 07 van with M14-1.5" studs. I'm not planning on using the M14's, but I believe I am going to upgrade to a 9/16 stud to match the early 14 bolt rearend that I'm going to install. If the rotors centers itself good, you may just get by with longer studs and not have to drill anything out. I've replaced alot of car rotors that had way bigger stud holes than they had studs.

If you feel inclined, you can download the Dorman catolog. They have thousands of different wheel stud combinations.

Thanks for the info on the studs. I went through the Dorman catalogue and found the combo that I am going to use. I have updated and added photo's to the link above. The calipers, rotors and pads are fronts from a 2010 Chev Express 3500 and I believe they are the same as what you are using.

Dave

Yep, the 2500 and 3500 calipers are the same. Mine wouldn't fit in the 12:00 position though. Check out Jegs for stainless brake lines. They have Russell stainless lines with the M10 banjo fitting and 3AN on the other end in a variety of lengths.

i have a 1947 3/4 ton with the 8 bolt lug pattern i found a company that made me a disc brake conversion for my truck the company is called RPM eng. the owners name is RON his phone # 760-329-1886 the cost was a little bit more than the 1/2 ton kit cost it works great my kit was the first one they made so i got to correct any problems if you have any ? you can contact me at faynel@prodigy.net

Do you have any pics of their system? Interested to see what they used and how they mounted the caliper.


Dave

i have pic but dont know how to upload yet thet used 87 rotors and calipers chevy they made the back plates and sleeves/spacers for the rotors i had to grind the turn stop down to get them to turn

I often wondered why no one was doing the 8 lug disc for these trucks. Especially when you see the interest on this website. I'm guessing it's due to the fact the 1/2 tons share the same dimensions with the cars. The 3/4 tons are divided pre-53 and 53-59. Not to mention the SRW 1 ton and DRW 1 tons.

Any way It's good to see some initiative out there.

One of my original ideas was similar to this: POL Disc kit

I figured the same method could be applied to the front.

Here are my pics. I added a couple pics of a bale of hay loaded on my truck for my cows.

http://s1262.photobucket.com/albums/ii616/faynelong/

I like the looks of it. I wonder where they got the hubs.

Are your front wheel out further now? Part of the problem I've been having is finding a rotor/caliper combo that will clear the rims. I would think they would have to had moved the WMS out to fit everything in.

the hubs are off of a 1987 chevy they are out about one inch i used stock 16 inch rims i thought you might realize that those hubs cost about 150.00 each then you add the calipers thats about 40.00 each also figure the roller bearings are about 200.00 it doesnt take long for this setup to add up you still have to figure the time and labor of building the back plates and you also need spacers

Nice looking setup. It looks like it will work well. How much was it for the spacers and back plates?

Dave

What about bearings? Did they machine the hubs for the OEM style bearings?

thanks when i bought the kit the spacers and back plate came with the kit so i dont have any idea what they cost by them selves i think everything is from the shelves the only thing they did was built some spacers that i put on the hub so the bearings would slide on the hubs

I think you mean spindles not hub?
In the pictures it looks like they made bushings so the late model wheel bearings (for the new hub) fit on the smaller original spindles.

Looks like a pretty clean and simple setup.

Grigg

YOUR RIGHT I DID MEAN SPINDLES if someone wants to buy just the back plates and spacers they can call the # on my first reply

Finished the bracket for mounting the caliper this morning and looks like it will work out well. The bracket is the same as the mock up in my photobucket except of being two pieces is now a one piece bracket the bolts to the top two mounting holes on the spindle. Will post pics tomorrow of the finished product. The calipers and rotors are off the shelf and bearings are new rollers from Chev's of the 40's.


Dave

Brackets are now done, just need to paint. For those interested I have loaded new pics of the brackets for the brakes. The pics show the clearance with a 17"rim, and how they mount and caliper as well. If anyone is interested I have the drawings for these in a PDF file and in solidworks.

Dave

Disc Brakes

Might want to add some fillets to smooth out your sharp corners and reduce any chance of stress concentrations.

Any reason you didn't try to catch either of the other two mounting holes on the hub?

Can you give a summary of the parts needed?

Is this on an axle with dual front wheel offset or single?

All off the shelf except the bracket?

Is that an aluminum bracket?

I'd think you'd be better off with steel with higher elasticity and yield strength.

I wonder if you could put bushings over the studs to keep the original smaller stud size...

I'm also concerned about only using two mounting holes. The original backing plate used 4 and you now have more brake capacity with half the support. I'd feel better with three, four if possible.

Is there any room to cant the caliper forward or back any to assist with bleeding, you may never get air out of the other piston? Ideally the bleeder is the highest point.

Looks like steel to me and it should be, I wouldn't trust aluminum either.

Larger studs are a good idea, no reason to use bushings on small ones, just replace with the larger 9/16" studs.

Grigg

The bracket is milled from one piece of steel. I am also a little concerned about only hitting two mounting holes and would prefer hitting all four holes but in order to mount the bracket on the backside of the spindle without interfering with the tie rod end this seemed like the only way. This is only my first kick at the "cat" so this is why I am looking for some feedback and some more ideas to either improve what I have or hit the drawing board again.

WRT the wheel studs, the intent is to change over to larger studs, just haven't had time to find the proper size and length.

Dave

Any updates? Excited to see if we have a solution!

Sorry, no updates yet, just the pics that I have posted. Been busy with work and family, and no time for the truck. Hoping to get back to it shortly.

Dave

Thanks!

Family first!

That's why all I've got to do with my truck is look at it since i bought it