Sub frame alignment? - Page 2 - Lateral-g Forums

jlwdvm · #11 10-03-2015, 05:50 PM

If your wheel base is the same on each side, wouldn't the rear end have to be square with the front subframe (since the wheels are attached to it)? The 4 corners made up of the tire patches would be square...right? I have the sub centered side-to-side according the the pinch welds. Currently I have the wheel base within an 1/8" when comparing drivers side to passenger. I am using wheel studs on the rear with the car at ride height and a level placed on 2 studs and then measuring to a stud on the front rotor after doing the same and also making sure the rotor is the same distance from the frame so toe isn't a factor.

snappytravis · #12 10-03-2015, 07:05 PM

Ditto on the laser level I measured out the center of my front crossmember under engine. Then I set the level on the crossmember below radiator, shot towards rear of car with it line up on next crossmember back and could see exactly where the rear end was sitting. If this makes sense, I also used a digital tram guage set it up on 2 jack stands one by the front hub and one on the rear axle center line. Then was able to measure wheelbase of both sides.. Same theory as plum bob. Specs call plus or minus 1/4 inch. I would think if you were this close the rest could be adjusted in suspension. I do agree with Weld, How close where these from the factory? I used seat belt bolt holes, Drain plug holes, anything that is stamped from the factory for a reference.. Measure from rear subframe mounting holes across to radiator support mounting holes. Measure, measure, measure. Then cross your fingers and start welding!

**GregWeld** · #13 10-03-2015, 07:52 PM

Quote:

Originally Posted by jlwdvm

If your wheel base is the same on each side, wouldn't the rear end have to be square with the front subframe (since the wheels are attached to it)? The 4 corners made up of the tire patches would be square...right? I have the sub centered side-to-side according the the pinch welds. Currently I have the wheel base within an 1/8" when comparing drivers side to passenger. I am using wheel studs on the rear with the car at ride height and a level placed on 2 studs and then measuring to a stud on the front rotor after doing the same and also making sure the rotor is the same distance from the frame so toe isn't a factor.

Sounds like it's in pretty good shape then!! Try to get the wheelbase a little closer if at all possible. If not - it probably didn't leave the factory anywhere near an 1/8th.

Drop a point of measure off all four corners and measure on the diagonal... that's how you check for square. If that checks out - you're golden.

bsharpe · #14 10-04-2015, 07:20 AM

I spent a lot of time trying to align the subframe on my firebird. It is not easy with these cars especially on jackstands. I understood that my unibody was not perfect (the pinch welds are destroyed and she has been hit), the ford 9" and 4 link isn't perfect (I didn't measure enough when I installed it) and my subframe has some issues but I didn't expect to run into major problems and spend as much time as I did.

I used a laser level and old vinyl tiles under the jackstands to level the car. I then plumb bobbed from everything that was symmetrical on the car like holes in the frame and the pinch welds. I used a chalk line to find the center line of the car. I then squared the rear axle to the body by taking cross measurements and wheelbase measurements. I then tried to square the subframe to the rear axle. I was unsuccessful and found major issues with my subframe. I am now evaluating my options.

**GregWeld** · #15 10-04-2015, 08:03 AM

Quote:

Originally Posted by bsharpe

I spent a lot of time trying to align the subframe on my firebird. It is not easy with these cars especially on jackstands. I understood that my unibody was not perfect (the pinch welds are destroyed and she has been hit), the ford 9" and 4 link isn't perfect (I didn't measure enough when I installed it) and my subframe has some issues but I didn't expect to run into major problems and spend as much time as I did.

I used a laser level and old vinyl tiles under the jackstands to level the car. I then plumb bobbed from everything that was symmetrical on the car like holes in the frame and the pinch welds. I used a chalk line to find the center line of the car. I then squared the rear axle to the body by taking cross measurements and wheelbase measurements. I then tried to square the subframe to the rear axle. I was unsuccessful and found major issues with my subframe. I am now evaluating my options.

These cars have "issues" -- they're not exactly spring chickens... they've had a rough life... The point is - that you either have to get the body back to where it should be - or you have to modify things to get all of this to line up and be square and the wheelbase to be right. Whatever course that takes is a matter of skill and pocketbook... etc.

When I did my brother in laws Camaro - it had taken a hit on the driver side... so much so that I had to pie cut the area where the steering wheel goes thru the firewall... and I had to make a "spacer" to take up the area under the floor between the floor and the sub mount. We didn't have another way to fix this "alignment" issue. We made it work and the car drives perfectly. And his gaps are perfect. The key is to have accurate measurements so that you can "fix" the issue and know what you're doing. You can fix anything if you know where you need to be when you're finished.

Check out this "spacer" I had to make for the driver side! I milled it to the .001 of an inch... just because... there was really no reason to get that close other than I just like using some of my tools. HAHAHAHAHAHAHAHA

It worked out just fine!

snappytravis · #16 10-04-2015, 11:27 AM

Quote:

Originally Posted by GregWeld

These cars have "issues" -- they're not exactly spring chickens... they've had a rough life... The point is - that you either have to get the body back to where it should be - or you have to modify things to get all of this to line up and be square and the wheelbase to be right. Whatever course that takes is a matter of skill and pocketbook... etc.

When I did my brother in laws Camaro - it had taken a hit on the driver side... so much so that I had to pie cut the area where the steering wheel goes thru the firewall... and I had to make a "spacer" to take up the area under the floor between the floor and the sub mount. We didn't have another way to fix this "alignment" issue. We made it work and the car drives perfectly. And his gaps are perfect. The key is to have accurate measurements so that you can "fix" the issue and know what you're doing. You can fix anything if you know where you need to be when you're finished.

Check out this "spacer" I had to make for the driver side! I milled it to the .001 of an inch... just because... there was really no reason to get that close other than I just like using some of my tools. HAHAHAHAHAHAHAHA

It worked out just fine!

To much Dukes of Hazards in the old Days!

bsharpe · #17 10-04-2015, 04:12 PM

Quote:

Originally Posted by GregWeld

The point is - that you either have to get the body back to where it should be - or you have to modify things to get all of this to line up and be square and the wheelbase to be right. Whatever course that takes is a matter of skill and pocketbook... etc.

That is why I spent so much time measuring. I know now that the Scott Mock subframe is the problem. I wanted it to be the body but the real and major issue is the subframe.

**GregWeld** · #18 10-04-2015, 04:13 PM

Quote:

Originally Posted by bsharpe

That is why I spent so much time measuring. I know now that the Scott Mock subframe is the problem. I wanted it to be the body but the real and major issue is the subframe.

Wow.... never heard that before.... LOL

Sorry. Yeah -- that sub has more than a few issues.

bsharpe · #19 10-04-2015, 05:28 PM

Quote:

Originally Posted by GregWeld

Wow.... never heard that before.... LOL

Sorry. Yeah -- that sub has more than a few issues.

I hoped for the best because I have one of his original subframes which was built before he had any issues and everybody loved his subframes but that was before Ron Sutton taught everybody to measure and tune their suspension.

**GregWeld** · #20 10-04-2015, 05:34 PM

Quote:

Originally Posted by bsharpe

I hoped for the best because I have one of his original subframes which was built before he had any issues and everybody loved his subframes but that was before Ron Sutton taught everybody to measure and tune their suspension.

It's such a shame -- I really liked Scott.... and he was a good contributor here. Sometimes - like Jeb Bush said - Stuff happens. For whatever reason his quality control took a giant dump. Sad.