1960 Lower Control Arm Bolt Part # 146 8512

[midwestisbest]

Looking for a replacement bolt(s) for the lower control arms on my '60 Sedan Deville.

Master parts book lists the part number as follows:
146 8512

Photos attached.

The specs for the bolt are:
7/16" - 20 x 1 1/2

The problem has been finding a bolt with the same DIAMETER head. The head on this old bolt is larger than new grade 8 bolts. A 3/4 wrench fits around the hex head of the old bolt.

[midwestisbest]

Long story short: I think I'm going to have to get a flange bolt. McMaster has a bolt with the correct thread & length. And the flange width is 3/4. So this matches the spec of the old one.

The downside(?) is that the new bolt is a 12 point bolt. I have a set of 12 point sockets but its only a 3/8 drive set.

I'll keep you updated.

[Caddylackn]

You might be able to Weld a nut onto a lug nut stud.  That is a common lug stud size.

I would run the stud through the nut then weld it to the stud from both sides.

[Daryl Chesterman]

Is there a problem using the old bolt?  The threads have a worn area, but it is not worn past the root of the threads, so the strength of the bolt should be as good as it was when new, unless there is a problem with it that the picture doesn't show.

Daryl Chesterman

[Roger Zimmermann]

I personally would not reuse this bolt. However, this bolt was used for many years, it should not be a problem to find a good one.

[midwestisbest]

The challenge has been finding a bolt with the same head diameter.

New bolts (with same spec) have a smaller 5/8 head.

The original has a 3/4 head.

I now have 12 point flange bolts with the exact specs (including the head diameter) on order through McMaster.

[David King (kz78hy)]

For a practical repair, use the new grade 8 with a washer under it.  So what if you have to use a different wrench size...my 2 cents.

[fishnjim]

Probably a "heavy hex" bolt.   But won't find today in 7/16".    1/2" and up.
You might try Fastenal HQ and see if they know if even made anywhere.     
There's 3 types of bolts: reg, heavy, and structural.   

[David King (kz78hy)]

I looked it up in my 63 MPL and the bolt he is looking for is used from 46 to 60.  I was hoping that a 63 would be the same and Jason Edge would likely have them, but the size increased to 1/2" in 61.  This is for the lower control arm shaft, a washer and new grade 8 bolt would be fine in my opinion.

[midwestisbest]

UPDATE:

I ended up purchasing a replacement from McMaster Carr. The replacement is not exactly like the old one but will suffice.

https://www.mcmaster.com/products/screws/thread-size~7-16-20/head-type~12-point/