It appears disc brakes for front axles are getting hard to find, at least in my part of the country.
I put P3500HD front and rear disc brake axles under my ‘37 GMC T-18 HD. In looking for disc brakes for my ‘55 GMC 373, I used a D-80 I had laying around for the rear. I found a Snap-On truck that was built on GMC P 3500 HD running gear, which, unfortunately I was unable to obtain.
However ‘91 to ‘01 Snap-On trucks like this would be another source like in the picture for adding disc brakes to an older GM front axle, tie rod behind the axle. I have another solution for 3500 HD (non P) front axle, tie rod in front of axle, when I have finished the job. Instead of making a steel bushing to adapt original king pin bushings to slightly larger P 3500 HD gear, I found a place in Detroit that makes bushings, for about $12.00 each I got new ones made to fit. GM changed grease fitting locations from side to end of king pins, so need to allow for proper lube, whichever locations one has.
I have never found a P-30 front axle, so have no info on that conversion.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
Can you explain more on what you did to use the 3500HD axle (non-P)? With the steering being in front of the axle, it does make it more difficult for trucks such as my C50 that uses steering behind the axle. How did you tackle this?
