1963 corvette rear

[Timothy B.]

I am installing the rear carrier/cover assembly to the crossmember on my 63 coupe. I am not sure if the four bolts that go through the crossmember to the rear cover have plain washers or lock washers. The 63 AIM shows part # 446212 and calls out P washer and my 67 AIM shows the same part # and calls out L washer. Unless my memory is failing, I can seem to remember looking at some mid years at Carlisle and noticing plain washers but common sence tells me to use a lock washer.
Can someone tell me for sure what is used here, Thanks as always, Tim Barbieri

[Joe L.]

Re: 1963 corvette rear

Tim------

Notwithstanding what the AIM's might say, GM #446212 was a PLAIN (i.e flat) washer.

Now, as far as what to use, I wouldn't be too concerned about using a lock washer. Split lock washers provide VERY little, if any, real fastner locking. For all practical purposes, they are a "feel good" sort of thing. I could never figure out why the factory used them, at all. Four points:

1) no one is ever going to know what type of washers that you used at this location, so, from a practical standpoint, it makes no difference;

2) as I mentioned, GM #446212 was a plain, flatwasher. Regardless of how it's described in the AIM, that's what it was. So, which is more accurate---the part number or the description? I say the part number is more specific and, likely, accurate;

3) as I recall, the washers you described on my 1969 were plain flat washers;

4) use flat washers with Locktite 242 on the bolts. It will provide better threadlocking than lockwashers, even if they were originally used. And, as I say, no one will ever know the difference.

[Timothy B.]

Re: 1963 corvette rear

Thanks Joe, that's the info I am looking for about the flat washer. I will use a dab of Locktite and torque to 60 ft lbs. The spring pressure is pushing up at this point on the car so I guess the purpose of the bolt is to hold the rear centered and aligned. This is a grade eight bolt application along with the other crossmember mounting bolts.

[Philip C.]

Flat washer M bolt *NM*