Frame rail repair

[SlantSixSullivan]

My left front frame rail is rusted out, right behind the wheel, where the frame becomes straight. I have a solid parts car to rob a clean rail from. I have never done this before. Is it safe to just support the car and cut out the piece I need? Thanks

 

[Oldiron440]

As long as you don't get under the car...

 

[SlantSixSullivan]

As long as you don't get under the car...

Understood. I figured, if I have to ask, the answer is no.

 

[GregG48213]

frame rail is rusted out

From my experience living in the rust belt: by the time the frame was rotten, the rest of the body was so bad that the car was junked. My '88 M-body was better rust-wise, but at over 200,000 miles, I wasn't going to rebuild the engine.

 

[SlantSixSullivan]

From my experience living in the rust belt: by the time the frame was rotten, the rest of the body was so bad that the car was junked. My '88 M-body was better rust-wise, but at over 200,000 miles, I wasn't going to rebuild the engine.

The body actually isnt too bad at all. Not perfect, but as far as I can see, it's really just this one section on the frame.

 

[Aspen500]

My Aspen was relatively rust free fro a Wisconsin car. Most of the worst damage turned out to be from unseen water leaks (like the 1/4 windows), not salt. I mean, there were numerous areas of rot but no huge gaping holes. The left front frame rail was rotted out from the bottom of the firewall area up about half way on the upward part. Not sure what it is about that lf rail, seems to be a very common rust area, even on cars which are otherwise not too bad. Always the left side, not the right. Right side rail on my car is solid as can be. It was only ever in 7 Wisconsin winters so it has to be some reason other than just road salt. Yeah I know, over thinking things again, lol.

As long as the car is supported well, you can do the frame rail. Be sure to take lots of measurements and record them (distance to floor in a few spots, things like that). That way you'll be sure nothing flexed or bent and the new rail is welded in straight and square.

 

[SlantSixSullivan]

My Aspen was relatively rust free fro a Wisconsin car. Most of the worst damage turned out to be from unseen water leaks (like the 1/4 windows), not salt. I mean, there were numerous areas of rot but no huge gaping holes. The left front frame rail was rotted out from the bottom of the firewall area up about half way on the upward part. Not sure what it is about that lf rail, seems to be a very common rust area, even on cars which are otherwise not too bad. Always the left side, not the right. Right side rail on my car is solid as can be. It was only ever in 7 Wisconsin winters so it has to be some reason other than just road salt. Yeah I know, over thinking things again, lol.

As long as the car is supported well, you can do the frame rail. Be sure to take lots of measurements and record them (distance to floor in a few spots, things like that). That way you'll be sure nothing flexed or bent and the new rail is welded in straight and square.

Thanks, Aspen. I just wasn't sure, with it being a unibody, if it would collapse, snap, etc. As I said, and as you stated, it really is just that left front rail. The mind boggles at how the rest of the car can remain so solid after seeing this one area.

 

[M_Body_Coupe]

You will of course need to support the body/shell in the appropriate points in order to make sure that whatever support the rotted out frame-rail supports, when it goes away as you attempt to replace it, does not jeopardize the structural integrity of the rest of the chassis.

For the most part you're going to have to deal with the heavy items, such as engine still in the car, therefore K-from being the heavy part, etc.

Take a look at the attached Alignment Deminsions page out of my 1980 FSM. At the very least it will give you some good reference points as far as distances between a flat floor and various body points.

The 'Side View' in particular would help you make sure no parts of the frame sag or lift in response to you taking out a chunk of the frame.

My thinking though is: as long as you do not take the chunk out and then leave it for some weeks/months, it'll probably be OK. Just do some reference measurements before you start, do them again when you're about to weld-in the replacement stuff in-place, then do them again once it's all done.

 

[SlantSixSullivan]

You will of course need to support the body/shell in the appropriate points in order to make sure that whatever support the rotted out frame-rail supports, when it goes away as you attempt to replace it, does not jeopardize the structural integrity of the rest of the chassis.

For the most part you're going to have to deal with the heavy items, such as engine still in the car, therefore K-from being the heavy part, etc.

Take a look at the attached Alignment Deminsions page out of my 1980 FSM. At the very least it will give you some good reference points as far as distances between a flat floor and various body points.

The 'Side View' in particular would help you make sure no parts of the frame sag or lift in response to you taking out a chunk of the frame.

My thinking though is: as long as you do not take the chunk out and then leave it for some weeks/months, it'll probably be OK. Just do some reference measurements before you start, do them again when you're about to weld-in the replacement stuff in-place, then do them again once it's all done.

View attachment 44184

That should help. Unfortunately I did place the engine and trans in the car, before this repair. Hindsight tells me I should have done this first, but I was way too excited to let the engine sit there. Luckily I decided to leave the driver's side header off for now. I will probably take the piece I need off of the parts car first, cutting down on the amount of time that my project will spend with the frame cut.