Rear Frame Repair 71 K10 Shortbed

[beanious]

Hello all, I am going to be repairing the rear frame of my truck. The damaged section of frame is in the back behind the leaf spring perches, where the bumper mounts attach to the frame. It's a classic case of previous owner damage, finally being repaired. I believe the frame was damaged in an accident and then repaired using junk. Summarization of the issues: welded in trailer hitch, spring perches welded on, rear cross member cracked in half, bottom rear 7" of frame rail missing. I am going to attempt to fix all of these issues and after completed install a Curt 14082 trailer hitch and an Aerotank 40 gallon gas tank. I know this may seem like a lot to do, but I've had classes in welding, completed larger automotive tasks. I am also looking forward to having a functional trailer hitch and much larger gas tank. As I progress through the repairs I will be posting pictures to assist others in the repair process and to ask for advice as one off questions arise. Look forward to hearing from you all!

Bryan B.
1971 K10, SWB, 350, TH350, 8" Lift, 35" tires, Etc...

[beanious]

Well, the welded in tow hitch is now gone. The welded on spring perches have been removed and replaced with another set of factory perches, bolted in where the originals were riveted. The next step is to carefully remove the remaining pieces that have been welded to the frame. After this I plan to start mocking up the the frame repair pieces. I plan to use original frame material pulled off a junk yard truck to replace and then add extra support with frame stiffner sections welded in. I have attached some pics of the remaining damage.

Bryan B.

[57taskforce]

Thats a mess no doubt about it. Looks like you've got the right idea to me.

[lyrikz]

Originally Posted by beanious

Hello all, I am going to be repairing the rear frame of my truck. The damaged section of frame is in the back behind the leaf spring perches, where the bumper mounts attach to the frame. It's a classic case of previous owner damage, finally being repaired. I believe the frame was damaged in an accident and then repaired using junk. Summarization of the issues: welded in trailer hitch, spring perches welded on, rear cross member cracked in half, bottom rear 7" of frame rail missing. I am going to attempt to fix all of these issues and after completed install a Curt 14082 trailer hitch and an Aerotank 40 gallon gas tank. I know this may seem like a lot to do, but I've had classes in welding, completed larger automotive tasks. I am also looking forward to having a functional trailer hitch and much larger gas tank. As I progress through the repairs I will be posting pictures to assist others in the repair process and to ask for advice as one off questions arise. Look forward to hearing from you all!

Bryan B.
1971 K10, SWB, 350, TH350, 8" Lift, 35" tires, Etc...

Sounds like my blazer. Im doing this now.

[beanious]

Ok, so here is a pic of how bad the rear crossmember is in it's current state. It was previously cut out and then actually cracked in half. I looked over my entire frame after seeing this, thank goodness no cracks.

[beanious]

Pic of new crossmember from ECE...

[beanious]

So, I removed all the welding with an angle grinder on the driver's side frame rail. It took a good deal of time, trying to remove old cross member by grinding out rivets...

[68 TT]

Originally Posted by beanious

So, I removed all the welding with an angle grinder on the driver's side frame rail. It took a good deal of time, trying to remove old cross member by grinding out rivets...

Try drilling through the rivets with a 5/16" drill bit first then you can knock the heads off with a chisel. After that you can knock out what is left below the head with a punch. Makes getting them out much easier than all that time with the grinder and doesn't damage the frame as much.

I made some drill centering fixtures of varying sizes on the lathe that I could put over the head of the rivet no matter what the crushed diameter was and get the drill hole close to the center of the rivet. Made things much easier and quicker.

[57taskforce]

I always just grind the head off one side and let the air hammer do the rest. If your good with the grinder there is no frame damage.

[beanious]

Grinder and air hammer is my current method. That air hammer is a beast of a tool!

[beanious]

Update, the rear passenger frame was previously welded by someone that did not do a very good job, at all. I spend a few hours grinding down the welds. When I got to real metal I found at least two cracks in the last 6" of the drivers side frame, turns out the cracks are from misc plates being welded in as repairs. My current plan is to remove the last 6" section of frame and replace it with a piece out from a donor truck. It will be painful cutting out the damaged section and replacement piece, but worth it for piece of mind. After the two pieces are ready I'm going to have them TIG welded together (by a professional) and then I will grind down the excess and paint to match. Please see the attached for pics of what it looks like after the last work performed. Thanks for following...

Bryan B.

[beanious]

Hello all, please see the below for pic updates for the frame job. I cut out the damaged section and replacement piece. I used a dremel for the cutting and a rasp to do final fitting, it actually fits really really well! Thanks for tuning in.

[beanious]

All, the welding job has been completed. I took two pics of the frame so that I could post them and the fantastic results. It looks almost perfectly stock, although I still have to clean up the welds on the inside tomorrow. I am really stoked, now to install the trailer hitch and bumper. More to follow...

[57taskforce]

Very nice!!!

[hugger6933]

I just did the same basic thing to a 12 Silverado crew cab Z71.
On the rivet thing also a good method is to take a die grinder and make a huge X in the rivet, then you can pop the head off easier. Then as with the method posted above you can take the air hammer and drive out the offending little rivet.
In my shop I have on occasion needed to replace a frame spring hanger or something similar, I've bolted on a replacement with grade 8 bolts a little long and double nutted them then tacked the out side nut to the bolt. Out of the ones that I have done that way never a problem