This is for a 72 GMC Sprint, passenger quarter panel

Replacing outer wheel house and quarter panel. This is what it looks like as of now, with rust cut out and enough room provided to install (temporarily with sheet metal screws) the outer wheel house.
http://i944.photobucket.com/albums/ad285/xny1989/th_quartercutline.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=quartercutline.jpg).

First question is how to attach the lower front portion of quarter panel to the rocker panel?

The second question is whether it is recommended to use the full replacement quarter panel by removing all of the existing sheet metal, or setting a cut line and cutting the replacement quarter panel to fit. If I use the entire new panel, how to I take apart the seams in the door and across the rear top of the existing panel without destroying the underlying metal? The horizontal black line in the photo above is the proposed cut line.

The underlying metal in the quarter is in good shape, just surface rust on the inside that I can wire brush and seal. The rear lower metal is all messed up when I removed a patch panel that was installed over the original. Below is a photo of the exiting metal that would be behind the bumper.
http://i944.photobucket.com/albums/ad285/xny1989/th_underbumberdamage-1.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=underbumberdamage-1.jpg)

The third question involves lining up the body lines and stuff. Below is a photo of the new quarter just laid over the existing metal. The wheel arch of the new quarter is about 1 inch lower than the outer wheel house arch, yet the outer wheel house inner arch lines up perfectly with the inner wheel house arch. Is this a problem that needs some massaging?

http://i944.photobucket.com/albums/ad285/xny1989/th_doorlineup.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=doorlineup.jpg)

Also, if the solution to the third question is to raise up the quarter, then what if the body lines to the door don't line up? In looking at the new quarter, it looks as if the body lines are actually a bit higher than those on the door. I would think that the body lines lineup is more important than the outer wheelhouse-quarter panel gap.

http://i944.photobucket.com/albums/ad285/xny1989/th_quarterhaningon-1.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=quarterhaningon-1.jpg)

http://i944.photobucket.com/albums/ad285/xny1989/th_rearlighthousing-2-1.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=rearlighthousing-2-1.jpg)

The pic above relates to my next question.

The tail light opening on the new quarter is a little different than the exiting one, particularly for the piece that holds the tail light in place. I can probably weld an additional piece of sheet metal on that tab to make it longer so that the screws holes would line up. Does that make sense?

Any advice would be useful, and thanks in advance.

T t t

Can you put the tailgate back on before you weld please?

Tailgate is on, it was just open when I took the photo's

T t t

Get some self tap screws and get EVERYTHING lined up before you start welding. It will take some time to get it all lined up.

That's the way I'm going to do it. At this point, since I don't feel its necessary to try and open up the seams in the door and along the tail light area, that I'll do the cut at the line I show in the first pic, then cut the 1/4 with several inches to spare all around and get everything lined up using screws (i'll be using lap joints with a flange cause my welding butt joints is bad). I still don't know how to secure the lower front portion of the quarter to the inside. Any suggestions?

I'd strongly recommend you NOT lap weld the joints. You are asking for trouble down the road. Spend a little time practicing butt welds on the scrap pieces you cut off - you will achieve a much better result. Make sure to move around to avoid heat build up.

-b

First, are these FULL 1/4 panels that include the entire door jamb and the sail panel? If so I would put the entire panel on. If it is a skin I leave the door janb and tail light area alone and splice the panel in about an 1nch from the edge. You cannot fit the new outer wheelhouse until you are ready to fit the 1/4 panel, you fit them together at the same time. Dont overlap anything and butt weld everything.
Ron

If you look at the 4th pic (in the first post), you'll see the quarter panel I'm working with. It does have the door jamb lip, plus a lip on the top. In fact, it's held in place in the pic by the lip on the top. It doesn't have the sail panel though, as you can see in the pic.
I have a tool that creates a flange that I was planning to use to recess into the existing metal and lap weld within the flange. In some practice I've done and in several patches I put in I welded this way, and there was no bulge.

By the way, thanks for answering my post. Also, I do need to know how to attach the front lower end of the quarter.

OK, you dont have a full panel. I cut the old panel off about an inch from the door jamb and tail light area and butt weld the new one to that. At the front lower I also leave a little of the old panel there to weld to and trim the new panel to fit that. If you have already cut off too much of the old one its easy to fab a piece to attach there.
If you wrap the new 1/4 around the door jamb it closes up the door gap.
I have one of those flangers too, I wouldnt use it here in this case, you are always better off butt welding.
Ron

If you are replacing into the door jamb area make sure you check/replace the pins and bushings in your door first. Make sure you have a good quarter to door gap and fender to door gap before you starting cutting anything on the quarter. It is nice to start of knowing that you do have the proper gaps.

If you are replacing into the door jamb area make sure you check/replace the pins and bushings in your door first. Make sure you have a good quarter to door gap and fender to door gap before you starting cutting anything on the quarter. It is nice to start of knowing that you do have the proper gaps.
Alex is correct, remove the door striker and make sure the door fits the rocker and 1/4 without the striker and the bushings and pins are good in the hinges. Dont worry about the fender fit.

This is where I've cut thus far. The panel by the rocker was too far gone to save, except for the last several inches by the door. The replacement quarter shape around the tail light is not quite the same and the area under the tail light was also too far gone to save. So, I've got some complex cuts to make to get the quarter to fit, but is doable. Looks like I'll fab up a piece to connect the the front part of the quarter to the rocker area too.

http://i944.photobucket.com/albums/ad285/xny1989/th_quartermostlyremoved.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=quartermostlyremoved.jpg)

I also have to fab in the part that wraps around below the tail light, as that was messed up when I took off the patch panel that had been installed.

Several of the reply's indicated that the quarter and outer wheel house get installed together. I take that to mean that they need to be lined up together by temporarily attaching the wheel house to the quarter, getting the quarter to line up with the body lines, marking where the wheelhouse would be installed, then separate them, install the wheelhouse temporarily, the quarter temporariy (using sheet metal screws), making sure that all lines up correctly, make any needed adjustments, then fire up the ol' welder and start burning holes, er, um I mean welding the panels in place.

Thanks for all the advice. I'll post some pics as I get the work done.

Sounds like you have the idea, good luck.
Ron

thanks

will practice butt welding over the next several days with scrap sheet metal. I am concerned about how perfect the cut panel seam needs to be. I don't know that I have the expertise to get the quarter cut exactly to perfectly match up to the existing metal. Any suggestions?

That's the way I'm going to do it. At this point, since I don't feel its necessary to try and open up the seams in the door and along the tail light area, that I'll do the cut at the line I show in the first pic, then cut the 1/4 with several inches to spare all around and get everything lined up using screws (i'll be using lap joints with a flange cause my welding butt joints is bad). I still don't know how to secure the lower front portion of the quarter to the inside. Any suggestions?

to secure the lower front of the quarter I did it by removing the smuggler cover at the front(warning you might find more rust) and then there is an inspection cover that you remove.

It's not a very big hole but your can get hand in to weld..

If you have an arc welder, forget bout it. get a mig

Also when weld in a panel like that i like to drill some holes on the flange to fill in and weld.

thanks

will practice butt welding over the next several days with scrap sheet metal. I am concerned about how perfect the cut panel seam needs to be. I don't know that I have the expertise to get the quarter cut exactly to perfectly match up to the existing metal. Any suggestions?

I like to use a small air body saw to make my cuts. A cut off wheel leaves to much of a gap between the 2 metals and you will have hell welding them together for the butt weld.

You can have the metal over lap the old quarter. Maybe have a few screws holding it. Then take the air saw and cut across the lip of the new quarter. The saw blade is 1/16" and leaves a small gap to weld. When welding the gap might close on you so I use the saw to reopen the gap between the spot welds.

I actually like to wrap the quarter around the lip in the door jamb like the picture you have. But I cut in the middle of the 2 panels ( the 3/4" area ) of the door jamb and butt weld them. That way I dont have to do all the body work on the outside of the quarter panel,,, just the small lip in the door jamb. If you cut both panels and then butt weld them the door gap will be fine.

I hate to say it but the full quarter would have been the easiest and less body work.

hey Ron, I noticed you said not to install outer wheel house til you get 1/4 set. I welded rear inner rocker first, then inner wheel house and yes I welded in outer wheel house. I took pictures of everything before I remove all metal and referance them to reinstall. I trial fit 1/4 a few times everytime i welded in new panel. today i rough fit 1/4 w/ wheel house already welded (did not clamp anything) and everything looks like its gonna fit good.(you really got me worried) I,ve never did this much extensive sheet metal replacement and never heard about fitting outer wheel house until 1/4 was set until you mentioned it. I even asked forum before I attempted this work and nothing was said. tommorrow I have to replace tail light panel i have it off now and new one ready but I think i am gonna fit 1/4 first. Man I hope i do not have to move outer wheel house and drill out all those spot welds. nervous in arkansas

hey Ron, I noticed you said not to install outer wheel house til you get 1/4 set. I welded rear inner rocker first, then inner wheel house and yes I welded in outer wheel house. I took pictures of everything before I remove all metal and referance them to reinstall. I trial fit 1/4 a few times everytime i welded in new panel. today i rough fit 1/4 w/ wheel house already welded (did not clamp anything) and everything looks like its gonna fit good.(you really got me worried) I,ve never did this much extensive sheet metal replacement and never heard about fitting outer wheel house until 1/4 was set until you mentioned it. I even asked forum before I attempted this work and nothing was said. tommorrow I have to replace tail light panel i have it off now and new one ready but I think i am gonna fit 1/4 first. Man I hope i do not have to move outer wheel house and drill out all those spot welds. nervous in arkansasWell, I have replaced a lot of 1/4s and wheelhouses with repro parts and I have never had an outer wheelhouse line up exactly with the factory inner where the original was after fitting the 1/4 panel.
Good luck to you

Bill, you were right as rain, I had to remove outer wheel house to get 1/4 on (clamped only) then I was able to put in outer wheel house from underneath. the only problem now is that flanged area where you weld the two halfs together don,t line up. Its only an area of about 20 inches so i am thinking some massaging of outer wheel house is gonna be necessary to line up seam. so i made a pie cut to close up gap staying away from lip that aligns with 1/4 lip Tacked it and put it back in. Its pretty close but I can see another area that's pushing on 1/4 but i think a little heat and body hammer and dolly should take care of that. Man and you have done a few of these. At lease when I do drivers side 1/4 I'll be aware. Out of the 5 panels i have installed on car so far only this outer wheel house did not fit right correctly. I would not get so crazy w/ alignment but I plan on painting the whole floor and wheel housings of car the same color as top coat. anyway thanks for help, Tony

Great advice from everyone. Been kind of gun shy in proceeding because I wasn't sure I could cut the metal to do the butt weld, but prostreet69camaro gave me a technique I'll consider (and I get to buy a new tool too!).
I've attached several photo's of the wheelhouse to rocker gap. I presume I need to get that gap to be smaller. I've also attached photo's of my butt welding results - lots of blow through on my first several attempts. After doing some research on this, it appears that I'm moving the welding tip too slowly (I have a Firepower 120 volt mig, and have been practicing with flux cored - .035 wire, but can do gas too). Will practice some more over the next several days.

http://i944.photobucket.com/albums/ad285/xny1989/th_wheelhouserockergap1.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=wheelhouserockergap1.jpg)

http://i944.photobucket.com/albums/ad285/xny1989/th_buttweld1.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=buttweld1.jpg)

http://i944.photobucket.com/albums/ad285/xny1989/th_buttweld2.jpg (http://s944.photobucket.com/albums/ad285/xny1989/?action=view&current=buttweld2.jpg)

I would get away from the flux core wire. I would use gas and solid wire. It will give you a cleaner weld and you wont have to worry about the slag effecting the paint later.

I would get away from the flux core wire. I would use gas and solid wire. It will give you a cleaner weld and you wont have to worry about the slag effecting the paint later.In the past I have installed probably twenty 1/4 panels with the flux core wire in a cheap mig welder, I never had any problem with the flux. Yes, the gas makes a cleaner looking weld but I grind and wire brush all the welds anyway so it doesnt matter. The only reason I went to gas is because I bought a bigger welder to use on heavier material.
Remember, practice, practice, practice.
Ron

I've been using the flux cored for practice so I don't use up the gas. For my next practice (I feel like I'm doing homework!) I'll switch over to gas. I know that I have to change polarity of the leads. Does wire thickness make a difference? The flux cored I've been using is .035, and I think the regular wire I have is .025.