Driveshaft U-Joint Question...Help! trying to work on it right now

4085 Views 17 Replies 7 Participants Last post by TwinTurbo, Dec 1, 2007

1982VetteGuy

Discussion Starter · Jun 9, 2007

I noticed that I had a thump when I put it into drive....I'm assuming it's the driveshaft U-Joints.

rear wheels are up off the ground.....

I crawled under the car and it feels somewhat tight...a little play in the shaft, but nothing major.

The half shafts are def tight....no play or movement.

I'm going to go ahead and replace the driveshaft u-joints....when I replaced the transmission, I dropped some pins out of the front u-joint...I gathered them up and put them back...but I could have missed a few.

My questions are:

1. What is the EXACT size of the 12 point bolts that secure the u-joint straps in place. I used a 12 point wrench on the front, but replaced them with regular hex bolts about two years ago....I've since forgot the size.

2. How in the heck do you get to the rear bolts in the driveshaft??? There is almost zero room to get a wrench in there :surprised

Any special tools or sources locally that I could pick up to make my job easier?? Like at lowes or Autozone?

Thanks for the help!

1 - 18 of 18 Posts

big2bird

· #2 · Jun 9, 2007

1982VetteGuy said:
I noticed that I had a thump when I put it into drive....I'm assuming it's the driveshaft U-Joints.

rear wheels are up off the ground.....

I crawled under the car and it feels somewhat tight...a little play in the shaft, but nothing major.

The half shafts are def tight....no play or movement.

I'm going to go ahead and replace the driveshaft u-joints....when I replaced the transmission, I dropped some pins out of the front u-joint...I gathered them up and put them back...but I could have missed a few.

My questions are:

1. What is the EXACT size of the 12 point bolts that secure the u-joint straps in place. I used a 12 point wrench on the front, but replaced them with regular hex bolts about two years ago....I've since forgot the size.
1/4" 12 point
2. How in the heck do you get to the rear bolts in the driveshaft??? There is almost zero room to get a wrench in there :surprised
Add extensions to about 12", slip it back thru the tunnel.
Any special tools or sources locally that I could pick up to make my job easier?? Like at lowes or Autozone?
12" extension
Thanks for the help!

Check the snubber on the diff. Might be the source of your clunk.:thumbsup:

1982VetteGuy

Discussion Starter · #3 · Jun 9, 2007

Thank you very much!

I actually had both of those, was scared about the 1/4" socket. But found one in my socket graveyard box :thumbsup:

Nows the hard part..............

Strider

· #4 · Jun 9, 2007

My strap bolts are 7/16 and I use 2 long extensions. I believe they are roughly 12 inch long so 2 of them give me 24 inches and with the 7/16 socket I have no problems removing the strap bolts.

1982VetteGuy

Discussion Starter · #5 · Jun 9, 2007

The bolts at the rear were actually very easy to get to using a 12" extension...if I didn't ask I would have been trying to wedge a 1/4" ratchet in there:crazy:

But after replacing the u-joints I'm still getting that "clunk" when I put it in gear, I noticed a lot of oilish residue all over the rear u-joint. Thinking it may be coming off the rear end. My problem may be the rear end ...

TimAT

· #6 · Jun 10, 2007

WHile it's in the air, grab a halfshaft on each side and try to twist them in opposite directions. See if there's any slop there. Then set the park brake and try and turn the driveshaft, see how much slop is there. Rattle everything around. Push, tug, pull and see where the movement is. You'll find it.

:cheers:

TwinTurbo

· #7 · Jun 10, 2007

The bolts are not 12 pnt, they are inverted torx. They are 7/16 for all 82s and all 80/81 manuals

1982VetteGuy

Discussion Starter · #8 · Jun 10, 2007

big2bird said:
Check the snubber on the diff. Might be the source of your clunk.:thumbsup:

I looked at the snubber and it looks pretty bad .....

Half shafts are nice and tight, I don't think I needed to replace the driveshaft u-joints....aside from being old they still looked good with no wear.

MYBAD79

· #9 · Jun 10, 2007

You have the car up in the air check the rear rubber trans mount as well.

I replaced the differential front cushion with a polyurethane piece, it's taller than the rubber... my rubber piece was torn in pieces so I had nothing to compare it to.... this resulted in my differential pointing downwards and driveshaft vibration. A $8 plastic angle finder from Home Depot is good enough to measure trans output and differential input angles. I cut the poly cushion until the differential was about level. This is really no big deal but they should warn you about this in their intsructions.... "it's direct fit and bolt on replacement part but you have to cut two inches to make it fit right..."

Back on the U-joint topic: the solid "brute force" U-joints seem to be pretty good, avaiable at the local 'zone' for $16 each (no grease nipple)

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TwinTurbo

· #10 · Jun 10, 2007

I don't like the brute force joints, they have sharp edges in the body.

MYBAD79

· #11 · Jun 10, 2007

TwinTurbo said:
I don't like the brute force joints, they have sharp edges in the body.

They're not as good as Spicer joints but way better than the nipple joints. I'll replace my MidAmerica nipple joints soon...

This is one of Gary's pictures, it's in his U-joint sticky.... this scares me:

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TwinTurbo

· #12 · Jun 10, 2007

that one sure is easy to lube

big2bird

· #13 · Jun 11, 2007

TwinTurbo said:
The bolts are not 12 pnt, they are inverted torx. They are 7/16 for all 82s and all 80/81 manuals

Marck. My 81 is an auto, and is 1/4". I bought both the Torx and the 12 point. The 12 point fit, the Torx would not. I am NOT saying your wrong, just:WTF

1982VetteGuy

Discussion Starter · #14 · Dec 1, 2007

Me again

What is the thread pitch and size for the U-Joint strap bolts? I know it's a fine thread and I'm thinking the bolt size is 5/16" maybe??

I keep going back to 1/4-28 in my mind but I don't think that's it :crazy:

big2bird

· #15 · Dec 1, 2007

1982VetteGuy said:
Me again

What is the thread pitch and size for the U-Joint strap bolts? I know it's a fine thread and I'm thinking the bolt size is 5/16" maybe??

I keep going back to 1/4-28 in my mind but I don't think that's it :crazy:

They are specific bolts. The vendors have them, as do driveline shops.

1982VetteGuy

Discussion Starter · #16 · Dec 1, 2007

big2bird said:
They are specific bolts. The vendors have them, as do driveline shops.

I found some nice grade-8 12-point bolts at Mcmaster carrs website, I bought some 3/8-16 x 3/4" for my motor mounts.

I was hoping they were a standard bolt pattern because they would work perfect for the U-joint bolts because of the small heads. :thud:

mrvette

· #17 · Dec 1, 2007

Reminds me of the old football cheer from OSU, when they got a bad call on the field.....'Nuts and bolts, Nuts and bolts, We Been Screwed'......

I have a 45 y/o collection of nutz and bolts in several bins very rughly assorted to size, it saves my ass a million times a year so it seems....

I want to say the universal size clamp bolts are 5/16 with fine thread...the caps on mine are 7/16 hex.....I think I fought that sillieness 12 point crap ONCE, and tossed them out, found some bolts from old Pontiacs, and everhting is fine once again....

told you all aint NUTTIN' stock about my car...not nuttin'.....

:WTF :cheers:

TwinTurbo

· #18 · Dec 1, 2007

big2bird said:
Marck. My 81 is an auto, and is 1/4". I bought both the Torx and the 12 point. The 12 point fit, the Torx would not. I am NOT saying your wrong, just:WTF

Maybe someone replaced them before? They really are inverted torx.

Hard to see but they're these pesky MFers that round off very easily. I replaced mine with NAS 12 bolt wire lockers.

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