stripped rear spring to differential mounting threads
Thread Starter
Instructor
Joined: Jan 2005
Posts: 241
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From: Sebastian Florida
stripped rear spring to differential mounting threads
One of the threaded holes in my differential for mounting the rear spring is stripped. What are my choices? Heli coil? A longer thinner bolt that goes through the differential mounting hole then put a nut on the other side? Other choices? This was the last thing I was ding to finish my complete rear end restore/ rebuild. Thanks in advance.
Patrick
Patrick
Burning Brakes
Joined: Feb 2004
Posts: 758
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From: Ville de la Baie Quebec. A winner is just a loser who tried again.
I would go with a helicoil also,, but just for info the previous owner of my vette drilled the old threads out and put a longer bolts with nuts and lock washers, it does the job. 
Thread Starter
Instructor
Joined: Jan 2005
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From: Sebastian Florida
Ive never put a Heli-coil in before. Would I drill it all of the way through or would I have to leave a "Floor" in the newly drilled hole so when the bolt in threaded in it doesn't drive the Heli-coil out the other end? Does the Heli-coil get "guled" into place or just threaded in? Maybe there is a link about this?
Thanks,
Patrick
Thanks,
Patrick
Racer
Joined: Jul 2007
Posts: 397
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From: Warren IL
When you buy the kit it will come with instructions. Heli Coils you drill it with a bit they provide. Then tap it with a tap that they provide and thread in the insert. There is no need to glue it in it won't come out on its own. The only real problem they present is that they tend to come out with the fastener when it is removed the next time.
Race Director
Joined: Dec 1999
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From: Forked River NJ
If you have not installed the rear end yet I would just get a new cover. How are the other holes. If they are suspect then a new cover is in order. If it is just the one hole a heli coil will do.
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Instructor
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I guess you would be able to drop the rear crossmember and differential cover while leaving the differential mounted and just nudging it a bit down. Then you can change to a new cover if you want to. However, helicoils will do it just fine and make a better thread then the one you had.
The helicoils are usually put in a hole that "bottoms" so the heli comes to a stop. It can be a problem that it tends to come out when you take the bolt out again. However, I see no problem with smearing the outside of the helicoil with some glue or hardcore loctite to keep it where you want it.
The helicoils are usually put in a hole that "bottoms" so the heli comes to a stop. It can be a problem that it tends to come out when you take the bolt out again. However, I see no problem with smearing the outside of the helicoil with some glue or hardcore loctite to keep it where you want it.
Burning Brakes
Joined: Feb 2004
Posts: 758
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From: Ville de la Baie Quebec. A winner is just a loser who tried again.
Helicoils perform very well in through holes, the red coloured coils are self locking, you should not have to glue anything, but yes you can use a little loctite to help.
Not trying to be smart here,, just passing on experience, I install these reqularly at work
Thread Starter
Instructor
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From: Sebastian Florida
As I'm sure most of you know the rear spring mounting bolt threaded hole passes through the diff end cover thread boss. I think it would be best if whatever method I use also allowed for the bolt to continue through the threaded hole like the original mounting hole did. Otherwise the number of threads that attach the bolt to the diff will be less than original if I have to leave a little at the bottom of the hole so a heli-coil can seat.
Safety Car
Joined: Oct 2006
Posts: 3,930
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From: Calgary Alberta
This won't work. The only thing holding the diff in the frame is the differential cover and the front mounting bushing. Removing the cover and crossmember and just letting the diff hang puts 120 lbs of sagging stress on the front bushing mount, which you will bend.
Instructor
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Good point. I back off that earlier suggestion.
Le Mans Master
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From: Pittsburgh suburbs Pa.
Safety Car
Joined: Oct 2006
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From: Calgary Alberta
Cruising
Joined: Jul 2023
Posts: 12
Likes: 2
From: Belgium
Hi all,
I also have an issue mounting the leaf spring to the differential cover using the four 7/16-14 bolts. In one of the two rear facing bolt holes, the thread in the cover is gone. The previous owner has solved this by using a longer bolt going all the way through + a locking nut on top. Looks secure enough. I did the same for the other one next to it just for conformity & looks, even if strictly speaking not necessary.
The problem is with one of the two other bolts holes that go into the cover but aren't protruding anywhere so I can't put a nut on them but in one of them, the thread is NOK too. I'll try rethreading 7/16-14 but if that doesn't help I had the idea to use a slightly larger 1/2-13 and for that, drill the hole out with a 10.8mm drill and rethread for the slightly larger 1/2-13 (if that works do the same for the 2nd hole too).
However, I wonder if there's material enough in the cover to do that? Looks solid enough but just don't know for sure, don't want a leak either. Looks like a simple way to attach the leaf-spring securely after all without replacing the cover & all the work that goes with it. Just a 1/16 thicker bolt, should work. No? WDYT?
Any help is appreciated
G
I also have an issue mounting the leaf spring to the differential cover using the four 7/16-14 bolts. In one of the two rear facing bolt holes, the thread in the cover is gone. The previous owner has solved this by using a longer bolt going all the way through + a locking nut on top. Looks secure enough. I did the same for the other one next to it just for conformity & looks, even if strictly speaking not necessary.
The problem is with one of the two other bolts holes that go into the cover but aren't protruding anywhere so I can't put a nut on them but in one of them, the thread is NOK too. I'll try rethreading 7/16-14 but if that doesn't help I had the idea to use a slightly larger 1/2-13 and for that, drill the hole out with a 10.8mm drill and rethread for the slightly larger 1/2-13 (if that works do the same for the 2nd hole too).
However, I wonder if there's material enough in the cover to do that? Looks solid enough but just don't know for sure, don't want a leak either. Looks like a simple way to attach the leaf-spring securely after all without replacing the cover & all the work that goes with it. Just a 1/16 thicker bolt, should work. No? WDYT?
Any help is appreciated
G
Race Director
Joined: Mar 2017
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From: Virginia
It will take a while, and cost a fortune, but I'd just order a Muskegon rear diff cover.
And consider starting a new thread with your question!
https://muskegonbrake.com/products/1...erential-cover
And consider starting a new thread with your question!
https://muskegonbrake.com/products/1...erential-cover
Is my vette stock?? HAHA
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From: Im not allowed to tell you
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Do the heli coil first, it takes away less material than the time seats. If it fails then you can go to a time or keen sert but you can't do it the other way around
Cruising
Joined: Jul 2023
Posts: 12
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From: Belgium
That was my first post on this forum. Some forums prefer that you post into an existing similar topic ... anyhow, point taken
At some point in time I may need to swap the cover but that will be when I'm getting the diff out again to change its gearing together with a gearbox upgrade. For now I'm rather looking for the quick fix
At some point in time I may need to swap the cover but that will be when I'm getting the diff out again to change its gearing together with a gearbox upgrade. For now I'm rather looking for the quick fix