The Stovebolt Site Forums The Parking Lot Big Bolts Disk Brakes on a Big Bolt

I have two big bolts, a '51 and a '52. One of them is going to be moderized.

Instead of moving the cab to a new frame, or trying to adapt IFS to the truck, I've been thinking about adapting disk brakes to the big straight axle.

I have P30 (1-ton Chevy) disk brakes (with the rest of the P30) and am considering adapting these 8-lug disks to my 4400. I plan to use the rear from the P30 also, so front and rear will match.

The P30 is too wide to do a cross-member swap and any other IFS swap makes getting the dually type wheels on it difficult. Plus I kind of like the idea of running a big straight axle anyway.

I know someone put disk brakes on the front of a 1-ton panel, but is anyone aware of an attemp to put disks on a big truck? Any idea what complications I'll run into?

This is still just in the thinking stage, so I've lots of opportunity to change the plan.

This isn't a 3/4- or 1-ton, its a 1-1/2 ton with 20 inch wheels and the big 5-lug hubs in front and 10-lugs in the rear.

The hubs on it aren't going to work with the disks I have, and I'm wondering if its possible to adapt the disks with integral hubs to the big spindles.

I've also considered looking for a 3/4- or 1-ton axle to use the approach you suggest. However, if I go that route I fear the dually type wheels I want to use are going to be too close to the springs and inner fenders.

ya might look at the straight axle on a late model 3500 series gmc heavy ton truck or a heavy duty van or r.v. . 10 bolt wheels and 19.5 tires, and a much taller rear end ratio. i know i am looking for one.

The 95 Chevy motorhome chassis I've been working on recently has 10-lug wheels, and disc brakes all around. It might be worth looking into adapting the rear brake rotors and caliper mounts from one of these rigs to the spindles and hubs of your oldtimer. The spacing of the caliper brackets might be pretty close to the right size. Don't know whether the lug bolt circle is correct or not.
Jerry

I already have a '78 motorhome with the 8-lug stuff and was planning to use it... I've been watching prices on newer stuff like the '95 and haven't seen any that I'd be willing to pay for.

I've not looked at other trucks, but I suspect any truck new enough to have disks on both ends and cheap enough I'd pay for it, has probably already been beat to pieces...

i'm always jealously looking at school busses since they always have decent tires i could use. lately, it seems they have disc brakes in the front too! that was a surprise. maybe something worth checking into - big straight axle, wide enuff for the old iron, and the right size and look to the wheels?

School buses are an interesting idea. I know in lots of places the law does not allow them to be used as school buses past just a few years.

I'll check into that and see if anything turns up.

oldsub i just put a 1980 chevy C-30 front and rear on a 1953 1 1/2 ton frame it looks good so far.I can send pics this weekend if you want to see it.

I'd very much like to see those pics!

If I understand correctly what I've been told, my P30 front is wider than the C30 front, but my P30 rear will be narrower than a C30 rear.

Please share you pictures!

I created an album of my project truck pictures tonight.The frame has a 1945 body on it but the frame is a 1953. I did narrow the frame and front but it was because the rear was to narrow and i wanted the front tires farther under the truck, the front would have fit without cutting the frame. Some pictures are fuzzy i will work on getting some more 1945 chevy

Thanks for posting the pictures!

The crossmember appears to fit the frame just right. You indicated that you narrowed both, but that it would have fit without making any changes. Did I understand that correctly?

I know someone who was trying to sell a motorless 80ish C30 not long ago. Maybe I should find out if its still available.

The C30 crossmember is a little wider but most people just add a metal plate to make up the difference.The front tires may stick out a little depending on how wide your body is(an 1 1/2" on both sides of my truck before i cut it).Also on the rear the old frame was 1 3/4" wider than the C30 but as long as you use the wider rear you can change to the frames spring brackets from a narrow rear.
Take a tape measure to check out the truck and compare it to your P30 before you buy .It might be as easy to put your body on the P30 ?

The C30 is 200 miles away, so not handy to measure.

I couldn't see any plates between the IFS and frame on yours, does that mean you narrowed the IFS just enough to fit the frame?

Dropping the body on the P30 frame is certainly one of my options. But the P30 IFS is about 10 inches too wide...

Yes i cut mine to fit .It's not a hard job but it takes some time to get it lined back up right.

Cutting and welding the tie rod is the part of that narrowing the crossmember that gives me pause.

The center drag link is the only one to cut .It is 1" round bar i cut a pipe 7" long and 1"inside slid it on after i cut the bar then tapered the bar to a point .Build it up with weld then grind it smooth and slide the pipe over the weld and weld both ends.

I'm guessing you have more welding experience than I do... Just the thought of welding a key part of the steering system makes me nervous. I'd have to pay a pro to do that part.

I am in the end stage of putting the rear end of a 1991 p-30 school bus in my 1940 1 1/2 ton. Just grind spring perch and move out about an inch on each side. Rear disc brakes!! Then it gets better,front spindles from p-30 and 1940 front axle are put together with sleeve in spindles and spacers top and bottom of axle.New kingpins and back into the truck.Use steering links from p-30 [shorten tie rod tube-cut and re thread]I have not put in the drag link yet.that is the stage I am at right now. now I have 4 wheel disc brakes.parking brake is drum on the back of th400 trany with a 235 in front.

Winky do you have pictures of how you did the front? That is exactly the kind of approach i was hoping someone would suggest!

I took some picts and they came out lousy let me try picts again and I will show them. the reason for keeping 1940 front axel was so that when new wheels went back on [19.5]the look will be the same as stock. the rear was done too so all 6 wheels would be the same.

web page lets see if this link works ,I put in a lot of picts. Steering links are different color primer and show up real good

Great pictures Winky! I need to study them a while to see if I can use any of your ideas. I'm off to see if either of my big trucks will even start today...