73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Topic started by: 4x4orbust on May 27, 2009, 12:56:03 pm
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This relates to my 82 K10, SWB, 355/th350/np208.
I was in the process of removing the bed yesterday afternoon, to gain access to the frame for scraping/sanding/painting and came across a couple rather thin spots on the frame. both are on the drivers side, behind the spring hanger for the rear axle (one closest to the cab). i am pretty sure that i could punch a nail through it with a hammer (although i haven't tried it yet). i know that one of the croossmembers is rotted out and needs to be replaced, basically in the same area as this. i have not found any other areas (yet) that have this much rot, but they may be there...
so this is throwing a wrench in the gears of my rebuild. i figure i have a few options, but looking for others input.
option 1: repair the frame by welding new metal on top of the rotted area, but it's so close to the spring hanger, i'm not sure if it's possible without interfering.
option 2: remove rotted portion of frame, replace with good section of frame from a similar truck in a junkyard. (i have never done anything to this extent, and somewhat nervous of it. i could do a lot of work and realize it's way out of whack because of inexperience)
option 3: remove the motor/transmission/cab/frontend and place them on my 1973 k2500 chassis, then restore that back to roadworthy stature. (this is the way i am leaning right now, the 73 rolling chassis is in perfect condition, with the exception of some steering components)
looking for some advice on any or all of the options i have, or if there are some that i didn't mention. or even if i am worrying about nothing and should continue my rebuild.
picture of affected area for reference: (i measured the frame at the holes nearby, and the thickest was just under 1/8", thinnest was about 1/16")
(http://i301.photobucket.com/albums/nn77/prfakaharry/IMG_0797.jpg)
edit: a link to pictures of the 73 frame: http://s301.photobucket.com/albums/nn77/prfakaharry/1973%20gmc%202500/
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I went thru this same scenario with my 1st 80 c10.
Since i was originally from RI originally the c10 was originally a new england truck.When it came time to restore the truck i took the bed off and found that the rear crossmember was so rotted i figured i replace it and the rear bumper frame horns and it be OK.Well digging deeper into it i took a ball peen hammer and hammered on top of the frame and big and i mean BIG chunks came off.I looked a little bit closer and right behind the cab i seen a section where it was rotting bad.I said no way is this safe.I showed my folks they said yank the drivetrain and junk the rest.Well i stripped the truck of all its parts.I cut up the cab, stripped the frame of its drivetrian and suspension in the front.I couldn't undo the leaf spring bolts and just left them.I sawzaw`d the frame and scrapped it.Me and my father travelled 900 miles in 1 day to pick up a 77 frame and it was in alot better shape and needed no replacing of metal.So i would say change the frame cause if that other truck`s frame is good you can strip it down to a bare frame, coat it with por 15 and then rebuild the suspension, drop in your drivetrain and then your body and your good to go..
thanks
pat
p.s. you start taking a body hammer with a point to the end of it you`ll definately start blowing more holes in the frame and then you`ll realize it s better to replace then repair..
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this is just my opinion, but if you are rebuilding the truck and you have pulled the body off the frame or plan to, I would take this opportunity to swap to a better frame,
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If the rest of the frame is decent you can certainly patch it up and even do it so it's unnoticeable.
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Me and my dad have done a lot of frame patches on these old chevy trucks, That doesnt look absolutely horrible. You can definetly patch it I would patch it if the rest of the frame is in good shape. another thing you can look at, is finding a junk or going to a junkyard and cutting the back half of another truck and welding that on if its just the rear frame thats bad, i can't even count how many times weve done that here, due to the high salt and sang usage during the winter months. But before you make any hasty decisions check the rest of the frame, if its all uniformly bad replace the whole frame, if its just the whole back half chop it and find a new rear half or if its just that little part, i would just patch it. Goodluck with whatever you do.
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I would swap the frames. I'm guessing that if your frame on the 82 is rotted than the truck is ready other work as well such as body bushings and brake lines etc. If you will be pulling the truck apart anyway why not start off with a clean frame?
I would strip the frame of the 73 and have it sandblasted (should run about $300 to have done). Pick and choose the best drivetrain/suspension parts from both trucks and swap the cabs. I think in the long run it will be worth the time and effort.
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thanks for the replies, your opinions are greatly valued in my book...
the body on the 82 needs some work, but it is definitely salvageable (rockers, cab corners, door bottoms, about 3 inches of drivers side floor, new hood)
the rest of the frame on the 82 is in somewhat ok shape. it was a plow truck in new england for a few years, and the salt did a number on the frame. (it was originally from arizona, and showed up here as a perfectly clean truck) i have pulled flakes of rust off the frame that are huge. two crossmembers are rotted out, the part of the frame that is in question, and who knows what else. from the cab forward seems ok.
when you patch these frames, do you cut out the old section and weld in a new peice? or do you weld over the rotted section? (again, i have never done this) what gauge metal would you use?
i am still kinda leaning towards swapping onto the 73 frame, and if i go this route, can i keep the radiator support and headlights from the 73 era? or do i have to use the 82 radiator support and headlights? (i know the fenders from the 73 would not work with the 82 cab, but would like to have the round headlights) the 73 frame has the stout drivetrain (np205, 14b FF, D44) and would get the engine and tranny from the 82 (built 355, th350)
also, would the plow mount from the 82 fit on the 73? one is a 1/2 ton, the other a 3/4 ton, are the frames different in any way that would not allow it?
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You can use the 73 front end on the 83 cab BUT your going to want to do some modifications to the cab 1st.like the corners noted in the pic below your gonna need these from the 73 cab to work on the 82 for the hood adjustments and also for your fender mounting areas. Also it isnt a worry but i did it the windshield washer nozzle jets on the 82 have a small divit in the cowl as the 73-80 didnt as they were on the hood, you may want to weld 2 sections from the 73 cab to the 82 cab.I did these mods as the cab i have was from a 85 and modified the cab to 73-80 specs..But it can be done if you take your time and do it little by little..
If you got anymore questions i can help you out as well as others here i`m sure..
thanks
pat
p.s. the only problem i see is that it looks like heck when you weld a steel patch over a area of the frame thats bad.. Iam 1 to just swap parts to a better frame.
(http://i205.photobucket.com/albums/bb112/ramsportguy/firewall5.jpg)
(http://i205.photobucket.com/albums/bb112/ramsportguy/corner1-1.jpg)
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i was thinking more along the lines of using the 82 fenders and hood, and wasn't sure if i could swap the grilles, but keep the round headlights. (or swap/cut/whatever to keep the round headlights)
i have come to the decision that i am going to attempt to repair the frame and keep on with the project. when i repair it, should i cut out the rotted section and weld new in it's place? or plate on both sides of the frame to encase the rotted section?
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Where its rotted badly your going to have to go beyond the area cause if you try n weld to it your going to blow thr the metal and your never going to penetrate the welds solidly. I/E if you got a 12 inch section thats weak your going to need at least a 16 inch patch panel to give you 2 inches on each side for strength and weld durability.Not to mention you said 2 of your crossmembers are shot that too means busting the factory spot rivets and replacing them with another pair from another frame.Unless you plan on making your own..
thanks
pat
p.s. changing the front end on your 73 to your 82 fenders wont work due to the bolt holes being different and it wont line up properly...Your goingto have to swap everything from fenders and so forth to make it work...