Differential bolt type and size
Thread Starter
Race Director
Joined: Jul 2004
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From: Scottsdale Arizona
Differential bolt type and size
I'm planning on putting my new 3.55 rear end in this weekend. One item that i didn't think of was the bolts for the differential cover. I suppose I could reuse the ones on the old one but I'd rather keep the cover bolted on there. A quick eBay check shows the following:
http://www.ebay.com/itm/GM-REAR-END-AXLE-DIFFERENTIAL-POSI-COVER-BOLT-BOLTS-RBW-FACTORY-CORRECT-10-PC-/390671782588?fits=Model%3ACorvette&hash=item5af5da52bc&vxp=mtr
I know that the stock rear end used Grade 5 bolts but as near as I can tell, they were not flanged bolts like the ones above but rather bolts and (lock?) washers. Anyone know what's correct? Also, what size/thread are they? I'd love to pick them up from the hardware store on the way home.
i also noticed that most of the differential rebuild threads replace the stock ones with Grade 8 bolts. I presume that's overkill but may do it anyways. If I do, I suppose the above is irrelevant as I'd have to go bolt and washer.
http://www.ebay.com/itm/GM-REAR-END-AXLE-DIFFERENTIAL-POSI-COVER-BOLT-BOLTS-RBW-FACTORY-CORRECT-10-PC-/390671782588?fits=Model%3ACorvette&hash=item5af5da52bc&vxp=mtr
I know that the stock rear end used Grade 5 bolts but as near as I can tell, they were not flanged bolts like the ones above but rather bolts and (lock?) washers. Anyone know what's correct? Also, what size/thread are they? I'd love to pick them up from the hardware store on the way home.
i also noticed that most of the differential rebuild threads replace the stock ones with Grade 8 bolts. I presume that's overkill but may do it anyways. If I do, I suppose the above is irrelevant as I'd have to go bolt and washer.
Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
Take one of your originals to any well stocked hardware store and purchase new ones from the open stock fastener section. My True Value Hardware Store was always the perfect place to go for fasteners.
Melting Slicks
Joined: Oct 2006
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From: Texas
Race Director
Joined: Dec 1999
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From: Forked River NJ
I know those bolts you have pictured from EBay are not correct at all. Those are for a stamped cover from a solid axle car. The Vette cover uses 7/16 bolts as I recall. These are quite beefy as they do more than hold the cover on. It supports the weight of the car because of the rear spring. I have socket head cap screws holding mine on. These are better than Grade 8 bolts and I never worry about them. Take a ride to the local Fastenal store with one of the old ones to get the correct length.
I just checked downstairs and they are 7/16-14 by 1 inch long. I had to buy a box of them and still have a bunch left. I used a lock washer under them.
I just checked downstairs and they are 7/16-14 by 1 inch long. I had to buy a box of them and still have a bunch left. I used a lock washer under them.
Last edited by Gordonm; Apr 10, 2015 at 05:12 PM.
