Differential Axle Question

[Gary R.]

Re: Differential Axle Question

FYI
The guy with the 65 did post more pictures on DC and what I saw was a 77-79 diff not a 65. So who knows what happened there. It could have been swapped out years ago, could be an exchange unit, or the vendor send him what ever they had. As sad as it sounds it was not a good deal since if it was rebuilt they didn't address the axles or ring gear bolts, I am guessing it was a swap out which I have seen before.

[Joe L.]

Re: Differential Axle Question

FYI
The guy with the 65 did post more pictures on DC and what I saw was a 77-79 diff not a 65. So who knows what happened there. It could have been swapped out years ago, could be an exchange unit, or the vendor send him what ever they had. As sad as it sounds it was not a good deal since if it was rebuilt they didn't address the axles or ring gear bolts, I am guessing it was a swap out which I have seen before.

Gary------


The only ring gear bolts available from GM for many years and now discontinued were the variety with flanged head and "serrated" seat. I once tried to use ARP bolts which I consider superior for every application. However, the ARP ring gear bolts, at least the ones available at the time, would not work properly on a 63-79 Corvette ring gear.

[Gary R.]

Re: Differential Axle Question

Joe
The GM flange head RG bolts will work if Loctite is applied to them and let harden 24+ hours. It is possible that particular diff was rebuilt with NOS GM RG bolts but I would bet against it since it is a later housing and the axles were not replaced. I replace the RG bolts in every job but I know others do not. The previous GM bolts were shouldered and had the hardened lock washers and were a very good bolt. Not sure why they were replaced other then to save some cash in production?

I use new ARP RG bolts and also believe them to be superior to the NOS GM or the common master kit grade 8 bolts. Again this is a money issue on selection, I like the best and use them. However, they have a larger radius under the head so the RG flange holes have to be countersunk. Once installed, using Loctite #271 or 272, I check them for full seating. They are 3/8-24 x .800 under head- same used for the 12 bolts.

[Joe L.]

Re: Differential Axle Question

Joe
The GM flange head RG bolts will work if Loctite is applied to them and let harden 24+ hours. It is possible that particular diff was rebuilt with NOS GM RG bolts but I would bet against it since it is a later housing and the axles were not replaced. I replace the RG bolts in every job but I know others do not. The previous GM bolts were shouldered and had the hardened lock washers and were a very good bolt. Not sure why they were replaced other then to save some cash in production?

I use new ARP RG bolts and also believe them to be superior to the NOS GM or the common master kit grade 8 bolts. Again this is a money issue on selection, I like the best and use them. However, they have a larger radius under the head so the RG flange holes have to be countersunk. Once installed, using Loctite #271 or 272, I check them for full seating. They are 3/8-24 x .800 under head- same used for the 12 bolts.

Gary------


I don't have too much faith in lockwashers. I suspect the later GM bolts were designed to help improve the liklihood that the bolts would not loosen, whether it turned out that way, or not. Being a specially designed bolt, I suspect that their cost might have been greater than the original bolts. However, from what I can find, I kind of doubt that the newer design bolts were ever used in PRODUCTION. It looks to me like they were first available in SERVICE about 1980. I think the "serrated" seat design of the new bolts was an early attempt to provide an improved "locking" in an era before thread locking compounds really caught on.

I would think that using Locktite 271, not available at the time these bolts were released, would pretty much ensure that they would never come loose. The problem then would be if one ever needed to remove the bolts!

[Gary R.]

Re: Differential Axle Question

Joe,
I have to say while some of the earlier RG bolts did back out, I think most of the bolts I saw back out were indeed the serrated ones. One of the things to look at when buying a used housing is the LH inside wall, a radial groove is a sure sign of a backed out bolt.

I use either #271 or #272 Loctite on the ARP bolts and that works. I experimented a couple of years ago with 271 because I was able to easily separate a grade nut & bolt. Those were cad plated and I didn't use the primer with them. So once I applied the correct primer, which I believe has metal ions, they were tight. Before that I had gone over to a completed posi I was working on and installed the ARP/271 the day before. I held the ring gear solid and figured I would be able to break the RG bolts loose. I stripped out the 12pt box wrench and injured my hand trying! However heating the bolts with a propane to about 250-300*F will break the bond and melt the Loctite.

There is a guy who copies my work, name and all, yet cuts corners his customers don't see, like RG bolts. You know the phase "a picture is worth a 1000 words". Lets just say I saw pictures of his build that he used my name on and I saw many areas that were cut including the RG bolts.