Rear shock upper bolt question

[Ronald D.]

The upper rear shock bolts on my 1971 LT-1 came from the prior owner with hardware store bolts, so during the restoration I am correcting this and a few dozen other things. My question is what are the bolt, washer, and nut finishes?, My book on Chassis Restoration by Joseph Tripoli says there plated, I bought a set from Paragon, they are black bolts, plated lock washer, plated nut, so I now am wondering what is correct?,. maybe they did them both ways, I just don't know, thanks in advance, Ron

[Alan S.]

Re: Rear shock upper bolt question

Hi Ron,
On my mid -January 71 the bolt and lock washer had a dark finish, I'm thinking manganese phosphate or black oxide. The thin nut had a bright finish, perhaps zinc or cad.
Note that the lock washer is under the bolt's head, not under the nut.
Regards,
Alan

[Ronald D.]

Re: Rear shock upper bolt question

Thanks for the detail, now I have it

[Gene M.]

Re: Rear shock upper bolt question

Ron,
Just as an aid in the future, the graded bolts (typical 5&8) are not electroplated. The cost is avoided by GM of heat treatment. Typical a Black/grey phosphate is used. There are exceptions but few.

In your example the lock washer has me puzzled. As not typical of grade 2 application. I would expect to see natural or zinc finish. But such a minor thing who really cares.

[Joe L.]

Re: Rear shock upper bolt question

The upper rear shock bolts on my 1971 LT-1 came from the prior owner with hardware store bolts, so during the restoration I am correcting this and a few dozen other things. My question is what are the bolt, washer, and nut finishes?, My book on Chassis Restoration by Joseph Tripoli says there plated, I bought a set from Paragon, they are black bolts, plated lock washer, plated nut, so I now am wondering what is correct?,. maybe they did them both ways, I just don't know, thanks in advance, Ron

Ron-----

The bolt was definitely black or gray phosphate as others have mentioned. Also, this was a special bolt in that it had a relatively long unthreaded shank with respect to the overall length of the bolt and the threaded length was relatively short.

[Paul O.]

Re: Rear shock upper bolt question

The bolt finish what is typical seen but the nut and washer are typical a silver finish.

[Rick M.]

Re: Rear shock upper bolt question

Ron:
Also make sure you install them with the nut toward the inside, bolt head and washer to the outside. Otherwise once the body is lowered on the frame you won't be able to remove the bolt without cutting off the head.

[Ronald D.]

Re: Rear shock upper bolt question

I have them that way, my only wrong part is the lock washer is plated, so I am going to back off the nut, tap the bolt out 1/4 inch, make the washer look black like the bolt, and re install, thanks for all the details, it helps a lot, Ron .

Ron:
Also make sure you install them with the nut toward the inside, bolt head and washer to the outside. Otherwise once the body is lowered on the frame you won't be able to remove the bolt without cutting off the head.

[Russ S.]

Re: Rear shock upper bolt question

I have them that way, my only wrong part is the lock washer is plated, so I am going to back off the nut, tap the bolt out 1/4 inch, make the washer look black like the bolt, and re install, thanks for all the details, it helps a lot, Ron .

I think that the lock washer should be plated. I believe that is also what a couple of the others also felt.

[Alan S.]

Re: Rear shock upper bolt question

Hi Ron,
I agree that you may want to follow Paul and Russ' thoughts about the washer's finish.
Paul has certainly looked at more shock washers than I have.
Regards,
Alan

[Ronald D.]

Re: Rear shock upper bolt question

Good, now I don't have to do anything more, plated washer will stay, thanks again