Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Replacing Cab Supports 73-87 4x4

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by merc359, Aug 26, 2006.

  1. merc359

    merc359 1/2 ton status

    Joined:
    Mar 25, 2005
    Posts:
    103
    Likes Received:
    0
    Location:
    Vancouver, BC. Canada
    Hello,

    I am in the process of replacing my cab supports (front) and mounts on my truck. This is a common problem on chevy trucks as you well know. In order to bolt the cab to the frame, a bolt went up from the bottom, through the mount, and into the cab support. Within the cab support there was a goofy weld-in nut that the bolt mated onto. While taking off the cab, surprise of surprises, the bolt snapped in the mount. After inspection it become clear I had to replace the whole supoort and part of the floor.

    I cut out the relevant sections, and some one in my shop, being far too bloody industrious, tossed out the cut out sections leaving me with nothing to look at. I have since ordered and received new OEM weld-in cab supports, but they seem to have no provision (other than a hole) for the bolt to actually thread into.

    What do I use? Is there an aftermarket part for the bolt to thread into that did not come with the cab support? Do I need to just weld in another ultra-lame nut to the support and go from there? This seems like simply a bad design and doomed for future problems.

    Any suggestions?

    I have attached a picture of the cab support that I have (both a top and bottom shot) for review but am a noob at attaching images and don't know if it'll work.

    Thanks,

    Cab Support Pic.jpg

    Cab Support  2.jpg
     
  2. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

    Joined:
    Dec 24, 2003
    Posts:
    4,395
    Likes Received:
    50
    Location:
    VA
    If I remember correctly from when I did mine, the rear one uses the original nut welded in the old section as the rear ones are usually covers for the original section. The front one I used had a nut on a square plate 'retained' as there is no way to position it.
     
  3. merc359

    merc359 1/2 ton status

    Joined:
    Mar 25, 2005
    Posts:
    103
    Likes Received:
    0
    Location:
    Vancouver, BC. Canada
    Ok, so here is what I did. I took the lift kit bolt and confirmed that the thread is a 1/2" UNC (13). I then went and bought some 3/4" x 2" flat bar thick stock from the metal supply shop. I cut it into 2" x 2" blocks (fit perfectly into the new cab support).

    I then lined up the holes, drilled and tapped the blocks, and welded them into support. There are two nice angles to this:

    First, the 2x2 block fits SNUG into the support. Thus, there is no room for it to turn. Then, the blocks are welded in (not held in with thos ultra-lame tabs GM seems to like to confound us with). I ground down the edges of the blocks, and did multiple passes on the thick stock with a nice bead of weld so that the penetration is dep into the stock and also through the support. In short, those blocks are welded TIGHT. Even if, after years of use and abuse, the welds break loose, the blocks cannot move due to the sides of the support. So, in order for them to spin inside the support, the entire thing would need to be rusted out and I would just re-do the damned thing int he process.

    Tons of Never Sieze, good lock washers, and that thing will remain tight. Maybe I should post pics of the finished supports for other to see?
     
  4. BKinzey

    BKinzey 1/2 ton status

    Joined:
    Jan 13, 2006
    Posts:
    3,145
    Likes Received:
    0
    Location:
    Hollywierd, CA
    Ya Damn well better ya hoser!:bow::bow::D:wink1:
     
  5. merc359

    merc359 1/2 ton status

    Joined:
    Mar 25, 2005
    Posts:
    103
    Likes Received:
    0
    Location:
    Vancouver, BC. Canada
    I have taken some pics and they are trapped in this lame Kodak digital camera that doesn't use standard USB cable hook-ups. (I borrowed it from a friend). Pictures to follow later this week.
     
  6. merc359

    merc359 1/2 ton status

    Joined:
    Mar 25, 2005
    Posts:
    103
    Likes Received:
    0
    Location:
    Vancouver, BC. Canada
  7. GaBnn3

    GaBnn3 Registered Member

    Joined:
    Jan 2, 2005
    Posts:
    90
    Likes Received:
    0
    Location:
    Holyoke, Ma.
    Cab supports

    I put a post after yours, entitiled "88 suburban body bolt roadblock." I then read this post and decided that I've got to replace the cab supports also. Your thread is very helpful. Where did you get those OEM cab supports, and how much? Thanks.
     
  8. merc359

    merc359 1/2 ton status

    Joined:
    Mar 25, 2005
    Posts:
    103
    Likes Received:
    0
    Location:
    Vancouver, BC. Canada
    There are a number of companies that offer the cab supports. The suburband ones are a slight bit different, but pretty damned close if I am not mistaken. I have seem them available at www.chevyduty.com and LMC Truck. There is also a supplier called something like "AccPac" or "AtPac" or something along those lines. I think www.classicparts.com also has a line on them. You may want to try those to start unless someone else has a better suggestion. I remember hunting around on the net about 3 months ago and found lots of suburban cab support OEM mounts available. I would go with the all-new ones instead of the weld-over type that just hide the problem.
     
  9. GaBnn3

    GaBnn3 Registered Member

    Joined:
    Jan 2, 2005
    Posts:
    90
    Likes Received:
    0
    Location:
    Holyoke, Ma.
    Your tutorial is great. I just bought a MiG welder, that I don't know how to use yet, and will be learning to use the welder, while doing a cab support replacement on my suburban. I will be doing mine with the cab still on the frame, though lifted on the side I am working on, as I replace the body bushings at the same time. I'm curious about your welding technique. I see that you drilled holes around the outside of the cab support before you welded it in. Did you do the spot welds with a MiG welder, and did you need any special equipment? Thanks.
     
  10. merc359

    merc359 1/2 ton status

    Joined:
    Mar 25, 2005
    Posts:
    103
    Likes Received:
    0
    Location:
    Vancouver, BC. Canada
    I didn't really need any special equipment other than the mig welder. The only proviso for this is whether or not you are going to need to cut a hole in the floor to replace the floor piece as well as the actual cab support. If you do NOT have to replace any floor material, then you won't need any other equipment aside from the welder and something to hold the bracket in position while you tack it in. If you need to weld in a patch panel, you can use some large magnets to hold it in, but they don't work that great for this stuff. I would recommend the patch panel clamps from Eastwood. However, if you don't need them, don't worry about it.

    As a side note, this was my first effort at welding sheet metal. I have never done it before either (done lots of tubing and plate through). As for the drilling of the holes, I did that to mimick a spot weld, but it ends up being stronger after I did a bit of testing with it. When you start to weld, weld THROUGH the hole you have drilled on the support and start on the cab floor. In other words, start the weld through the drilled hole by contacting the metal underneath (the cab). As you start to get a pool of weld, fill in the hole with the weld pool using circular motions (very small circles as it is a very small hole - it will happen quickly). Make sure your heat setting is getting you good penetration of the floor metal (verifiable by dark "bluing" when you look at the other side of the metal being welded - in this case the floor. Once the hole is filled in with weld, do another circle or 2 just slightly larger in diameter than the hole. Make sure you see the sheet metal melting AROUND the hole. You will then be sure you have solid penetration of the floor metal as well as the new cab support.

    My only warning using this technique is the one thing my tutorial does NOT show (tee hee I didn't want to show too many screw ups). If you screw up the weld on one of the makeshift spot welds (welding through the drilled holes) it is a beeotch to take back apart as you have to drill etc.... I spent some time (thankfully) practicing on some 18 and 20 gauge sheet steel by cutting off small pieces, tacking them together, cutting them apart, etc... before I went onto the main project. It was time well spent. It lets you dial in the welder appropriately for the material thickness. I have a lot more experience with plate welding and it is pretty easy compared to sheet metal.

    I find that sheet metal requires the SLOWEST wire feed setting and a heat setting of 2-4 depending on how hot the welder you are using is. I am using a Millermatic 251 that we recently acquired and I love it nearly as much as my wife (let's not pass this info around, ok?).

    Anyways, there is my 2 cents...
     

Share This Page