The Stovebolt Site Forums The Shop Area Driveline 3600 wheel studs

I have a '50 3600 that has a front disk brake conversion. I am planning to replace the current wheel studs (1/2-20) with 9/16-18 thread studs to match my rear wheel studs.

I am wondering is anyone know the details of the original studs (spline diameter/count and length) to provide a starting point for my search for new studs or insight why this is a bad idea.

My alternate plan is to remove one of the existing studs to measure, which I may do before ordering but thought if someone here has information as a starting point it may save some time/effort on my part.

WICruiser - A check of a 1929-53 Chevy Master Parts Book shows your 1950 3600 existing front wheel studs are listed as GM# 3680899. The chart below show the part number and specific dimensions of the wheel stud for you to use in stepping up to a 9/16-18 stud. Hope this helps you find what you want.

Gdads51, thank you for this great information. Too bad the chart does not indicate the diameters and spline count as well but this certainly does help. I may even be able to get some GM part numbers for 9/16" studs that would be a good starting point from the information included.

The very last stud listed in that chart is a 9/16-18. Not significantly longer and perhaps adaptable to your need.

I tried looking at the GM numbers that were 9/16 thread from the chart (including the 5238559) but none of them cross referenced to anything current and I could not find their respective serration diameters.

I removed one of the existing (original) wheel studs and the serration OD is approx. 0.555. It seems that 9/16 threaded studs would not pass through the serration opening.

All of the 9/16 thread studs I can find are 0.625 to 0.655 serration OD so it appears if I am going to pursue this I may need to have the hubs bored slightly to accept a larger serration.

These things are never easy.

I did a little deeper dive in GMPartswiki to see if I could find something more current. I found GM# 3997956 as a front wheel stud, 9/16-18 x 2-1/8" that was used on 1971-90 something 3/4 and 1 ton trucks/van/RVs with front disc brakes. I couldn't locate a serration size for the GM part, but a Dorman 610-181-1 lists as a replacement 9/16-18 x 1-7/8" wheel stud for those vehicles. It does lists a serration size of 0.623".

Either way, if you are wanting to upgrade to the 9/16-18 studs it will require reboring the hub stud holes like you said as they are significantly larger than the original 1/2" studs. Does your disc brake rotor slip over the existing studs onto the hub? If so, those may require reboring too.

Gdads, thank you for the additional research.

I need to talk to my machinist about the potential to have the hub holes machined larger.

The rotors slide over the 1/2" studs onto the hub and I belive the holes are large enough for the 9/16" studs but I need to confirm. I know the existing wheels (rollers) fit over the 9/16" studs I have on the rear as do the wheels I plan to use once I get tires.

I talked to my machinist and ordered some studs that I believe will work out fine. There are a lot of variations of studs available in theory but restricting the selection to those available at a reasonable cost helps trim down the options significantly.

I did some searching on the internet and general concensus seems to be the holes need to be 0.007-0.017 smaller than the measured size of the knurl and reamed (not drilled) but it would be nice to get confirmation from someone with experience.