Found a Bolt and Lockwasher on Garage Floor...

[David C.]

Hi all,
I found a greasy bolt and lockwasher on my garage floor as I was returning from a short drive this morning in my 1973 convertible.

The bolt is 7/16" x 1" with "L5" marking and 3 lines. Pic attached. I did not find the source on a cursory look underneath.

Am reluctant to drive the car further without locating where the bolt/lockwasher came from. I do not have access to a lift, only ramps.

I know many of you have turned wrenches all over these cars. Would really appreciate your help -- where should I look?

Thank you.
Dave

[Richard M.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Dave, Tough to see the scale of the bolt without a reference item, but is that 7/16" the diameter of the thread portion, or the wrench size?

Rich

[David C.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Rich, it is 7/16" thread diameter.

[Leif A.]

Re: Found a Bolt and Lockwasher on Garage Floor...

It will be interesting to see where this bolt goes. Even more interesting, is how it "backed off" with a lock washer in place.

[Richard M.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Okay, First place I'd look is at the Front Suspension lower control arms inner pivot bolts where the bushings are, both front and rear. IIRC, those are 7/16".

Another might be rear differential area, and outer half shaft flange bolts, but those flange bolts should be Grade 8, ie 6 lines and captured with French Locks, but NO lock washers. Unless someone did them incorrectly.

Rich

[Edward J.]

Re: Found a Bolt and Lockwasher on Garage Floor...

David, also take a look at the rear cross member support cushions, there is one on each side, and rear bumper brackets. I think the bolts Rich is referring to are 7/16 fine thread.s it appears as the pictured bolt is a coarse thread.

[Richard M.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Edward, You are correct, those I mentioned are fine thread. Good eye.

[Rich P.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Check the transmission mount to bracket. THEY use 7/16 x 1" grade 5 bolts

[Richard M.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Good idea.

Probably can see the ends of the threads from underneath if one of the 4 is missing by viewing the rear diff mount flange above the spring.

[Edward B.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Another example of the bolt fairy messing with an owner's head. She loves to slip into the garage while you're out and leave small pieces around just to get you doubting your own thoroughness and attention to detail.

[Joe R.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Also, it looks like she slips in some garages and sprays Lonoclad on the bottom side of rear springs. Most originals have the spray between the leaves and not on the bottom.

JR

[Paul A.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Check the front body mount at the radiator support, those bolts are 7/16 course thread.

[David C.]

Re: Found a Bolt and Lockwasher on Garage Floor...

Mystery solved! Thanks all for your suggestions.

It turns out the bolt / lock washer is that which secures the transmission mounting assembly to the transmission itself, passing through the exhaust pipe clamp.

Were the holes lined up? Of course not. I loosened the bolts which secure the mounting assembly to the bracket which attaches to the crossmember, did some banging and tapping, and was able to get the bolt through and secured.

I had a hard time getting purchase on the bolt because of the recessed nature of mounting assembly with no room for the head of a ratchet, extension, wrench, etc. I used a small breaker bar and socket which was not ideal, and did not work when I tried to tighten the companion bolt. Any ideas? Flex head wrench?

Thanks again.