69 Rear Shock Install
Thread Starter
Racer
Joined: Sep 2017
Posts: 337
Likes: 56
69 Rear Shock Install
Hello. I have a 69 that I'm putting new shocks on. I've done shocks on many cars before, usually a case of off they go, new ones on and tighten everything up. This one has me wondering about something. I looked at the A.I.M. out of curiosity. Great amount of info in there. The AIM (page J183) says to tighten the lower nut 30-40 ft. lbs. with the vehicle at "D" height specified for rear geometry setting. What does the "D" height etc. part mean?
Should I torque it with the weight of the car on the ground, jacked up or am I over thinking this. Thanks and take care.
Should I torque it with the weight of the car on the ground, jacked up or am I over thinking this. Thanks and take care.
Pro
Joined: Apr 2012
Posts: 696
Likes: 193
From: USA
Hello. I have a 69 that I'm putting new shocks on. I've done shocks on many cars before, usually a case of off they go, new ones on and tighten everything up. This one has me wondering about something. I looked at the A.I.M. out of curiosity. Great amount of info in there. The AIM (page J183) says to tighten the lower nut 30-40 ft. lbs. with the vehicle at "D" height specified for rear geometry setting. What does the "D" height etc. part mean?
Should I torque it with the weight of the car on the ground, jacked up or am I over thinking this. Thanks and take care.
Should I torque it with the weight of the car on the ground, jacked up or am I over thinking this. Thanks and take care.
Melting Slicks
Joined: Nov 2006
Posts: 3,409
Likes: 1,821
From: Apple Valley, MN
For the rears, I would simply make sure that you jack as necessary to make sure: 1) you are safe, 2) you have good access to apply the torque properly, 3) the shock slips easily over the mount before installing the washer and nut. I've just done a body off on my 69 and am waiting until the car is fully assembled before I attach the rears as the suspension is too far extended to allow the shock to be attached.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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in answer to gg521. it's all about torqueing the rubber bushing in the shock eye in a "Neutral" position.
Melting Slicks
Joined: Jan 2000
Posts: 3,326
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From: home
The "D" height is GM's term for the rear ride height. There is a procedure in the shop manual on how to measure it. I don't have one in front of me but it may say tire pressures set to spec, 1/2 or full tank of fuel, with or without driver weight. "Z" height is the front.
Racer
Joined: Jul 2005
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From: GA
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Race Director
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From: Sunshine Coast, Queensland, Australia
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jacking the trailing arm until the half shaft is level should be just fine. those bushings really don't move much. I am certain that will be close enough.
Racer
Joined: Jan 2008
Posts: 295
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From: Arvada Colorado
The rear shock is mounted on a "pin" that is supported by the rear wheel bearing support. This "pin" also holds the strut rod in place, This pin is securely mounted and there is no more pressure on the shock if it is in the air or if it is on the ground. It does not matter if the shock is on a Corvette or a pickup truck as far a mounting the thing, wheel in the air or on the ground.
Race Director
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your missing the point gg. as that "Pin" moves from the very bottom of it's total travel, to the very top. (hitting the bump stop). it rotates or twists. the idea is to torque down that rubber bushing in approximately the center of it's rotation. so the bushing twists a little one way on the way up, and the other way on the way down with no deflection or neutral at normal ride height.
Last edited by 4-vettes; Nov 26, 2020 at 03:08 AM.
Racer
Joined: Jan 2008
Posts: 295
Likes: 58
From: Arvada Colorado
your missing the point gg. as that "Pin" moves from the very bottom of it's total travel, to the very top. (hitting the bump stop). it rotates or twists. the idea is to torque down that rubber bushing in approximately the center of it's rotation. so the bushing twists a little one way on the way up, and the other way on the way down with no deflection or neutral at normal ride height.
Racer
Joined: Jan 2008
Posts: 295
Likes: 58
From: Arvada Colorado
Thank You, Thank You. Its very comforting and reassuring to know that we have your permission to do what we already know is the ok thing to do. It may not follow the strict GM guidelines but I think they will cut us some slack. Thanks again.
Racer
Joined: Jan 2008
Posts: 295
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From: Arvada Colorado
As I see it, this forum is comprised of a few groups. One group has a couple of experts in their field. Then there is a small group who have good general knowledge. The largest group is just stating their opinion, which is ok. Then there is a small group of people making gratuitous comments. Not hard to figure in which group you fall.
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Get your dander up pretty easy...eh, youngster? Someone wants the OP to 'cut corners' on how to do a job, I'll share my 2 cents...which I did. I don't recall you being elected as 'policeman' for this thread. I didn't insult you or anyone else. On the other hand, you are just an a@@h0le.
Last edited by 7T1vette; Nov 28, 2020 at 04:49 PM.