[pancho400cid]

All right... it's not the first time I've been accused of guilding the lilly.... I said from the get-go that the damage, if any, is slight. I just want to do all I can to keep from having suspension alignment issues and body alignment issues going forward.

More back story - The car was in decent original shape. Pretty un-molested by the standards of what you usually see in a 40 yr old un-restored Trans Am. That said, the front fenders were beat up, and it has been re-painted at least once I think and I cant say how it looked or whether it in a fender-bender before that. No signs of a major accident.

The four subframe bolts were difficult to get out, but I would expect them to be as I doubt they had been turned since leaving the factory. At least one cage nut broke loose, but that is not at all uncommon.

By the measurements I have it looks like one frame horn ahead of the crossmember is tweaked outward slightly. This weekend I plan to try working it back into place with sledgehammer and/or maybe a harbor freight ram as I posted (I'd have to buy it first). The trick obviously is restraining the subframe in a way that you bend it how you want it to go and NOT bend it any other way. Curious myself to see what I end up doing...

have a look at what we do Down Under with our Holden Kingswood subframes

Found some interesting info. Thanks!

[pancho400cid]

OK... I could not get any outside help with my subframe so decided to see what I could do to get it as close to spec as I could. The first thing I needed was better measurements so I bought a piece of 1" square aluminum tubing and some 5/16" dia steel rod. Lowe's had it in stock. I checked them for straightness against a long level I have. Nice material. I sawed the rod in two pieces and ground points, making sure the points ran out as little as possible - not "machined" but runout is about 1/32" max. Used with the square tube, the accuracy was surprisingly good - very pleased with the set up.



I then did an experiment to se what could be achieved with a sledgehammer. Bottom line is I got no movement at all and I quickly saw that the risk of pointlessly beating up / damaging the subframe was too great. I needed more force. I just couldn't make myself pull the trigger on the $140.00 Harbor Freight hydraulic puller without having good reason to believe it would help. Instead I opted to try their biggest (4 ton) come-a-long. Got it home and tried it. It would definitely move stuff in the way I wanted, but it would relax when the tension was released. I could move it but could not yield it. As you can see, the connection near the cross-member is much stronger/stiffer than the one at the outboard end of the opposite rail. The point being to move the outboard end of that rail toward the centerline of the subframe.



That gave me enough confidence to go back to HF and plunk down $140 for the hyd kit plus $50 for a "pulling" actuator (kit came with a "pusher" ram). Here is basically how I set it up (shown loose with tension removed):



The hydraulics AND come-a-long used together making enough force to be "scary" was enough to move the frame horn permanently. By late Sunday PM I had moved the frame horn I believe was bent to be much closer to spec. Measurement "A" is now right at 37-3/4" where spec is 37-11/16. Everything else is very close to spec.

I did make one mistake. G Should be 33-7/16 and is now about 33-11/16. When I started it was about 33-1/8. I actually let the "long" legs move out too far. I should have tried chaining them together once they got "right". I am less worried about this than the dimensions nearer the suspension/steering. Hopefully it will all go together and work well. I agree the whole exercise "may" not have been necessary, but I feel better now....

One last thing... I've definitely been guilty of Harbor Freight bashing in the past, but that kit is very useful and nice and worked like a champ out of the box with zero fiddling... I started pumping... it started moving.....

[Chief of the 60's]

Oh this should be good.

[rohrt]

Subscribed.

I like the Trammel idea for measuring. I just bought some for the sub frame I'm working on, so thanks for the idea

Here is my .02 cents on this and it just my opinion.

You seem to have 1 of the measurements that is pretty far off "A" with 9/16th. Your "B" and "G" measurements are just a little off IMO and not much to worry about. I just can't see the Horizontal measurement effecting the panel fitment. Vertical measurements yeah I could see that.

IMO what I would do is test fit the radiator support and bumper to the frame if it good then stop messing with it. I have a feeling with your "B" measurement is only off by 3/16th then by pulling in you frame horns isnt going to do much for your "A" measurement. Also with pulling in your frame horns you are most likely going to pull only one side in and that might be an issue.

For panel adjustment I would be more concerned with the Vertical measurements.

[pancho400cid]

If all my dims had been within 1/4" of the spec I would have left it alone. Using the "A" and "D" measurements (crossing dim taken "both ways"), I could see that only one frame horn was out of place - by about 9/16". I intentionally set up the ram to move only the one horn. After using the puller, my "A" dim is almost exactly right now (off by 1/16") and the "D" dimension both ways is almost exact to the 57-1/4 spec.

[rohrt]

I guess I missed that D measurement explanation.

Nice work!