Rear Suspension Torque Specs Conflicting Info

[SS 310H55A]

I'm going to be swapping on z/28 rear upper control arm bushings, trailing arms, toe links, and solid real cradle bushings. I'm trying to figure out which bolts are TTY and what the torque specs. I've found four different charts (see also pdf attached) and they're not all consistent.

Does anyone know which chart is correct? More specifically, what is the correct torque for the following:

- Upper Control Arm Rear Bolt to Bushing: is it 37lbft 120 degrees or is it 118lbft?
- Upper control arm rear bushing to frame bolts: is it 37lbft 120 degrees or 59lbft 120 degrees?
- rear cradle: is it 74 lbft and 120 degrees or 110 degrees?
- Upper control arm pivot joint: is 59lbft 120 degrees or 44lbft 90 degrees?

[Chris49066SS]

I used the top chart for reference when I did my cradle bushings and everything has been good.

[SS 310H55A]

Originally Posted by Chris49066SS

I used the top chart for reference when I did my cradle bushings and everything has been good.

What’s even more strange, I’m also looking at a pdf of the shop manual and it says on a chart, 118 lb ft for the upper control arm bushing bolt, but then on the install procedure it says torque the bolt to 37lb ft plus 120 degrees. So I guess it’s not 118 lb ft then.

The pdf shop manual also goes on to explain that the trailing arm to knuckle NUT is what needs to be replaced, does not say to replace the bolt. I am so confused. I thought it’s the bolt that stretches due to it being TTY. Does anyone know if the nuts that go to the TTY bolts also need to be replaced?

[Chris49066SS]

It was all so clear cut when I did my stuff because I just went with the specs in the directions (I did BMR toes and TAs) then Pegasus cradle bushings. For my degrees I eyeballed the turns with the breaker bar, and I reused the oem TA and cradle bolts, then have their camber bolts. Its a little dismaying that there are multiple spec sheets out there like that. What are you going to do?

[SS 310H55A]

Originally Posted by Chris49066SS

It was all so clear cut when I did my stuff because I just went with the specs in the directions (I did BMR toes and TAs) then Pegasus cradle bushings. For my degrees I eyeballed the turns with the breaker bar, and I reused the oem TA and cradle bolts, then have their camber bolts. Its a little dismaying that there are multiple spec sheets out there like that. What are you going to do?

It's pretty frustrating to say the least. The excel table I threw together in the last attachment below is what I will be going with. I honestly do not know if the Upper Control Arm Bushing Bolt torque spec should be 118lbft or 37+120 degrees, so I'm just going to to assume it's a TTY bolt and go with the 37lbft + 120 degrees spec.

I think I see why there are so many conflicting torque specs circulating. You'll get a different torque spec depending on the page of the shop manual you are referencing. If the copy of the manual I'm referencing is truly what came from GM, it's pretty upsetting to see so many inconsistencies in what should be an official source of information.

For example:
- Toe Rod to Sub Frame Torque: It says rear adjuster link to frame nuts is 85 lbft in the table on the first attachment, then says 129 lbft in the install procedure on the second attachment
- rear upper control arm bushings: it says 118lbft in the table, then on the install procedure it says 37lbft + 120 degrees.

[Chris49066SS]

Yeah I definitely did 85 ft lbs and not 129 on the cradle to toe. I just did the camber bolts about 2 months ago, so I remember that one.