Torq Specs

[phxraptor]

I will be installing a new VB&P 330# rear composite mono spring soon and need to know the torq specs for attaching it to the diff houseing. Will use all new spring bolts and spring plate. Any help would be appreciated

 

[Yoda]

Hey Dean,

From the Shop Manual
Rear Spring Plate to Carrier = 45 ft/lbs

As a caveat to this I was told by an old Corvette Mech. buddy NOT to torq to the full 45lbs while the wheels are off the ground, but torq to 35lbs then lower the car and finish torq to 45lbs. (Or load the spring using a pair of jacks then torq to 45lbs.)

His concern is over torq and busting the aluminum housing and having the carrier being normally stressed when finishing the torq process.

These torq specs are from the GM Shop Manual ST-364-81 and refer to the STEEL SPRING PLATE.. I don't have a clue if this would be the same for the composite spring, Maybe a call to VB&P is in order, unless someone here has specs.

Bud

 

[1BAD80]

I just done my car yesturday with VB&P's complete kit.
I have an 80' but in my shop book it has 70# tq. & that's what I put mine at. There are no spec's on the instruction sheet from VB&P. You will like the ride.
Did you get the shocks to match the fiberglass spring?

 

[phxraptor]

Hi Bud, We had talked about the torq specs when you were in Phoenix for the Corvettes against Cancer show. I forgot what you had told me though. If the specs you quoted are out of the 81 book wouldn't they apply to the composite mono spring as that is what was standard equipment on an 81 unless the Gymkhana suspension was ordered then is was steel. Any one else who has done this repair/swap and knows the answer for a VB&P spring? Thanks, Dean

 

[phxraptor]

I just done my car yesturday with VB&P's complete kit.
I have an 80' but in my shop book it has 70# tq. & that's what I put mine at. There are no spec's on the instruction sheet from VB&P. You will like the ride.
Did you get the shocks to match the fiberglass spring?

:cool Also going on at the same time are 4 Bilstein shocks and a set of 460# GT front springs.

 

[Yoda]

..... .. If the specs you quoted are out of the 81 book wouldn't they apply to the composite mono spring as that is what was standard equipment on an 81 unless the Gymkhana suspension was ordered then is was steel. Any one else who has done this repair/swap and knows the answer for a VB&P spring? Thanks, Dean

Dean,
The mono spring was only installed in the Automatic Transmission L81's (without the FE option) and NOT all Automatics got the mono spring. I've found some early and late production St. Louis cars with the mono spring and some with the steel one in the Automatics. I haven't run across a Bowling Green Automatic with standard suspension and a Steel spring.

To me 45 ft/lbs doesn't seem like enough BUT.. one must remember the carrier IS Aluminum :eek

Bud

 

[phxraptor]

Dean,
The mono spring was only installed in the Automatic Transmission L81's (without the FE option) and NOT all Automatics got the mono spring. I've found some early and late production St. Louis cars with the mono spring and some with the steel one in the Automatics. I haven't run across a Bowling Green Automatic with standard suspension and a Steel spring.

To me 45 ft/lbs doesn't seem like enough BUT.. one must remember the carrier IS Aluminum :eek

Bud

:cool Bud, you are a walking book of wisdom! No wonder Skywalker always goes to you for advice.:BOW My 81 is out of StLouis,1G1AY8761BS409128. Maybe that would help. I thought the composite mono spring was part of the Corvette hype for 81? I knew the FE package did not use it but did not know that all others possibly also did not. Thanks again, Dean

 

[Yoda]

Born on Date would be November 5, 1980 which makes it a fairly old L81 or early production number.

Black Book documents 31,611 built at St. Louis and 8,995 built at Bowling Green for the 1981 production year.

I usually look at '81's to see if they have the mono spring, then ask if it is original or not. As I recall you had the steel spring. The other two (excuding Rare, Rare is a 4-speed steel spring) also had the steel spring, one was an automatic and the other was a 4-speed

Bud

 

[clar2001]

the manual for my 75 said 55-70 lbs so when I installed my 330 composit spring torked the bolts to 65 off the ground was to much bent the plate thats the new vpb plate that was supose to be stamped out of heavier steel ,I would start at 40 then 50 on the ground

 

[1BAD80]

Your probably correct clar2001 , on the 80 they changed the rearend carrier and made it a lot stronger.