correct orientation of french locks on 1/2 shaft flanges

[Tim D.]

Question 1: Does anyone have a photo of the correct orientation of the french locks that hold the 1/2 shaft bolts to the outer flange? My AIM shows each of them attaching as shown in the first attached photo. However, all of my parts catalogs as well as photos of Bloomington cars and David Burroughs', "Art of Restoration" car show them attaching as shown on the 2nd and 3rd photo. Which way is correct?????? Picture the U shape at the outer end of the 1/2 shaft as a football goal post. Do the french locks span across the opening of the football goal post as if kicking a field goal that is GOOD? Or, do the french locks span across the clips on the outer edges of the U shaped/football goal post? Hope my question makes sense!

Question 2: Any tricks I am missing in order to keep french locks from bending totally out of shape while trying to torque bolts to 60-90 ft. lbs? I tried using anti-seize between the bolt head and the lock....this helped but they still bent around 50 ft. lbs. of torque.

I have the thin steel 63-64 french locks....no good.....keep bending. I decided to order from Paragon the 65 and later stainless steel locks that have the arched ribs in them to help keep them from bending and rusting. I know they are not correct for a 1964 but I'm tired of my 64 locks bending totally out of shape.

[John H.]

Re: correct orientation of french locks on 1/2 shaft flanges

Question 1: Does anyone have a photo of the correct orientation of the french locks that hold the 1/2 shaft bolts to the outer flange? My AIM shows each of them attaching as shown in the first attached photo. However, all of my parts catalogs as well as photos of Bloomington cars and David Burroughs', "Art of Restoration" car show them attaching as shown on the 2nd and 3rd photo. Which way is correct?????? Picture the U shape at the outer end of the 1/2 shaft as a football goal post. Do the french locks span across the opening of the football goal post as if kicking a field goal that is GOOD? Or, do the french locks span across the clips on the outer edges of the U shaped/football goal post? Hope my question makes sense!

Tim -

Functionally, it doesn't make any difference. That said, the lock location/orientation was changed for 1965 start of production to span the trunnion formation on the flange, and is shown that way as Change #2 on the '65 A.I.M. sheet (UPC 4, sheet A2).

[Tim D.]

Re: correct orientation of french locks on 1/2 shaft flanges

Thanks John. I really appreciate your help as usual. Do you have any tips to keep the french locks from bending when I torque the outer 1/2 shaft bolts to the flange?

Tim

[Joe L.]

Re: correct orientation of french locks on 1/2 shaft flanges

Thanks John. I really appreciate your help as usual. Do you have any tips to keep the french locks from bending when I torque the outer 1/2 shaft bolts to the flange?

Tim

Tim------


This is a common problem. I think the best you can do is use the anti-size AND use the stainless steel locks. The stainless steel is more resistant to bending than plain carbon steel, but it will still bend as you've found.

It's hard for me to imagine that the factory folks did not have the same problem with these french locks bending, especially since they didn't even have the option of the more bending-resistant stainless steel variety.

[Tim D.]

Re: correct orientation of french locks on 1/2 shaft flanges

Joe,

Yes, it sounds like many other NCRS members have had the same experience with the french locks bending. I do wonder how the factory got around this issue? Do you think they didn't bring them up to full torque? Obviously there was a reason they changed the design in 65 or so.

I am planing on doing exactly what you said.....I ordered a 1965 and later SS french lock set. I will apply anti-seize to the underside of the bolt head and the surface where the bolt head strikes the lock. Hope it works!

Tim

[Tom L.]

Re: correct orientation of french locks on 1/2 shaft flanges

Tim, FWIW I did no research on the posibility of bending the locks, maybe I should have. When I installed mine this past winter I simply followed the diagrams in the AIM, torqued them to the stated torque and noticed no bending. Didn't use anti-sieze or lube of any kind. And they were stainless by the way. Good luck!!

[Jim T.]

Re: correct orientation of french locks on 1/2 shaft flanges

Many years ago, 1978, I had the left rear wheel bearings replaced on my 1970 by a mechanic that had previously worked for a Chevrolet dealership and had opened his own repair facility.
I remember asking why he did not use the french locks on the bolts. He said lock washers are better.
Some time later the same year the same rear wheel bearings failed and actually locked the rear wheel when I tried to leave a parking lot.
The lock up happened in a different state so I did get "some" mileage from his wheel bearing work.

[Tim D.]

Re: correct orientation of french locks on 1/2 shaft flanges

Lynn, thanks for your input. I think/hope my problem is that I was using the correct thin metal, flat top french locks that are correct for a 1963-64. In my opinion, they are junk. No wonder GM changed the design in 1965 to the arched/ribbed style. Hopefully, when I receive my new SS 1965 style locks, the issue will be solved.

Tim

[Tim D.]

Re: correct orientation of french locks on 1/2 shaft flanges

Jim,

That sounds like my kind of luck. I wonder if the wheel bearings simply failed again due to incorrect installation/set up. Or, did the use of lock washers in lue of french locks, cause it? I would think properly installed lock washers with grade 8 bolts and torqued to specs would work just fine. But then again, I am not a GM engineer. LOL

I am getting close to being back on the road. I'm just waiting for parts and finishing up a few loose ends. I'll report back after I road test.

Tim

[Joe L.]

Re: correct orientation of french locks on 1/2 shaft flanges

Jim,

That sounds like my kind of luck. I wonder if the wheel bearings simply failed again due to incorrect installation/set up. Or, did the use of lock washers in lue of french locks, cause it? I would think properly installed lock washers with grade 8 bolts and torqued to specs would work just fine. But then again, I am not a GM engineer. LOL

I am getting close to being back on the road. I'm just waiting for parts and finishing up a few loose ends. I'll report back after I road test.

Tim

Tim-----


I would say it's just about a certainty that the lock washers in lieu of french locks had absolutely nothing to do with the failure. Those would be 2 separate issues entirely. The "connection" might be that the person doing the work was equally uninformed about setting up the bearings as he was about the proper fastener locking system to use.

Here's my opinion on the french locks and lock washers:

1) If GM engineers had felt that lock washers would do as well as french locks, that's what they would have originally used. Why get "fancy" with special parts (and, new part numbers) if common, 'ol lock washers will work as well?

2) In my opinion, lock washers are a nearly useless fastener locking device. DEFINITELY not to be used for critical fastener locking applications.

[Gary R.]

Re: correct orientation of french locks on 1/2 shaft flanges

Hey Tim I thought you would have had the gear broken in by now!! Come on Man!

Here is the way I setup my 72, I used new GM locks at the time and they twisted like paper at 50 ft/lb. I then switched to the SS and haven't looked back since. I bent the link down a little, put the NS under the bolt head so it won't catch on the lock,torque it in steps up to 75 ft/lb. Bend up the tabs over the hex bolts and then bend the link back and rotate the wheel to make sure it clears everything.




FYI- When I build the super 10 and 12 bolts, I use grade 8 bolts and lockwashers, no locks. They work fine.

Rear bearings, once properly setup & greased, should last many thousands of miles, 75K, 80k, 100K. Now most guys only put on a 1000 or 1500 miles a year on their old vettes, that is why rebuilders offer lifetime warranties. The process and parts didn't change per say over 50 years we just don't drive the cars like we once did. Marketing 101.

[Tim D.]

Re: correct orientation of french locks on 1/2 shaft flanges

Gary, thanks for the photos. I received the new SS 1965 and later french locks late this afternoon. Then, HAD to watch the Cardinals/Texas World Series game. Luckily, we have another game tomorrow night. The fact that the Cards are in the World Series is killing my work time on the car.

I should have it ready to go and on the road this weekend. Can't wait to try the 373 gears and break them in.

Go Cards!
Tim

[Ronald L.]

Re: correct orientation of french locks on 1/2 shaft flanges

Gary,
GM did not have this problem with the evidence being rusted crusted originals that are not all twisted up - why?

I have two suggestions, both (or all 4 bolts) were torqued at one time, or torque sequence.

Which bolt do you torque first? The leading or following if you are looking at these in a clock wise fashion.

[John H.]

Re: correct orientation of french locks on 1/2 shaft flanges

I have two suggestions, both (or all 4 bolts) were torqued at one time, or torque sequence.

Ron -

They were torqued one at a time (in the rear suspension subassembly station in the basement); the only multiple-spindle air tool in the plant was for the lug nuts.

[Tim D.]

Re: correct orientation of french locks on 1/2 shaft flanges

Ok guys....update on the 63-64 french locks bending issue. I ordered SS 1965 and later french locks from Paragon. I put anti-seize on the back of the bolt head and also on the french lock where the bolt head contacts it. I torqued them to 75 ft. lbs by stepping the torque up gradually starting at about 35 and working it in 5 lb. increments up to 75. They torqued as smooth as silk with no bending issues what so ever. IMO, even though the 63-64 flat design is correct for my car, I think they are JUNK. They bend like paper around 50 ft. lbs. and they rust in no time. The SS 1965 and later design have the nice rib for strength and they don't rust. Thanks to everyone who replied with advice on this topic. You guys are GREAT!

Tim