Suspension TECH Including Brakes, Wheels and tires

          
Reply
 
Thread Tools Display Modes
  #1  
Old 03-07-2024, 06:52 PM
7t4mula's Avatar
7t4mula 7t4mula is offline
Senior Member
 
Join Date: Jan 2003
Location: Cedarburg, WI
Posts: 127
Question Upgrading to 1/2" studs on 1970 12 Bolt Rear axles?

I recently bought a 4 wheel disc brake upgrade kit from Wilwood and didn't realize the front hubs they provided had 1/2" studs. Now I have 7/16 on original rear axle and of course a mixed bag on lug nuts!

How hard is it to convert to 1/2" studs also for back to match the front? Can these be drilled/reamed out on the car easy enough? Wish I would've realized this sooner when I had the rear out for rebuild and new gears! (of course)

Any recommendations on methods or stud manufacturers appreciated! Thx!

__________________
*********************************
The 1970 Pontiac Firebird Formula... Lean, mean, tire-scorching machine!
  #2  
Old 03-07-2024, 07:27 PM
Jay S's Avatar
Jay S Jay S is offline
Ultimate Warrior
 
Join Date: May 2018
Location: Nebraska City, Nebraska
Posts: 1,708
Default

For dirt track stock car racing I recall all the GM cars were required to run 1/2” studs. Many get converted while the hubs and axles were installed on the car. The biggest thing is to find the appropriate drill size for the stud used, then just drill it out. Then shim it and tighten it up to pull it through. Most of the time a drill size can be found that works, but a reamer can work too if it is a little tight.
Attached Thumbnails
Click image for larger version

Name:	19B59B9A-5D6B-4140-ABCC-8B7E48504C8F.jpg
Views:	28
Size:	87.2 KB
ID:	630036  

  #3  
Old 03-07-2024, 10:37 PM
jwcfbd's Avatar
jwcfbd jwcfbd is offline
Chief Ponti-yacker
 
Join Date: Mar 2003
Location: Texas
Posts: 824
Default

When I bought my wilwoods I had the same problem. I brought my axles to a shop to have them replace the studs and to my surprise all they did was ran a drill bit through the holes and pressed in the studs. I could have done that but was expecting to see them use a drill press or something other than a run of the mill cordless drill. Just get the right size bit which matches the studs and have at it. You're not stepping up the hole size that much so it's easy to keep the hole straight. I got all my studs and lug nuts at the local auto parts store.

__________________
67 Firebird Convertible
  #4  
Old 03-08-2024, 03:59 PM
7t4mula's Avatar
7t4mula 7t4mula is offline
Senior Member
 
Join Date: Jan 2003
Location: Cedarburg, WI
Posts: 127
Default

Thanks guys this makes me feel a lot better about doing the job myself on the car. I'm a retired Tool & Die maker, so I should be able to drill some straight holes after 40+ years of that! LOL

I'll have to post some pics of the project once i have time. Its been a long time since I've been active here!

__________________
*********************************
The 1970 Pontiac Firebird Formula... Lean, mean, tire-scorching machine!
  #5  
Old 03-08-2024, 05:38 PM
Goatracer1 Goatracer1 is offline
Ultimate Warrior
 
Join Date: Oct 2003
Location: NH
Posts: 3,798
Default

If you have enough material after removing the old studs you can buy screw in 1/2 inch studs. I'm sure Summit has them.

  #6  
Old 03-08-2024, 08:45 PM
7t4mula's Avatar
7t4mula 7t4mula is offline
Senior Member
 
Join Date: Jan 2003
Location: Cedarburg, WI
Posts: 127
Default

That’s a good suggestion as well!
With the tap drill size for a ½-20 being 29/64 (.453”) there should be enough material I’d hope.

Once I get the car back from body/paint I’ll knock the studs out and see what I can do there! 👍🏻

__________________
*********************************
The 1970 Pontiac Firebird Formula... Lean, mean, tire-scorching machine!
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:07 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017