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.

A new Place to look for frame cracks

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BowtieBlazer, Apr 10, 2006.

  1. BowtieBlazer

    BowtieBlazer 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,462
    Likes Received:
    0
    Location:
    Baton Rouge, Louisiana
    SO, I was unbolting the last two bolts on my tranny x-member and bang, it hits the ground. What the hell?
    [​IMG]
    I looked up at the frame:eek1:
    [​IMG]

    Yup, its cracked. I found this discovery very strange being that this was and has been a stock truck with the 305 and OD tranny with 31" tires its whole life. And very rarely offroad at that....this is on a 1986 Blazer
    Looks like I have some welding to do....
     
  2. shawnboy

    shawnboy 1/2 ton status

    Joined:
    Jun 22, 2001
    Posts:
    468
    Likes Received:
    0
    Location:
    Toronto, Canada, eh.
    Great post. A lot of us out here probably wouldn't think to check there for cracks. I had that happen on a previous K5. I just made up my own repair like you are gonna do. I wonder if boxing the frame would be a good idea? Good luck in your repair.
     
  3. koldsimer

    koldsimer 1/2 ton status GMOTM Winner

    Joined:
    Jan 10, 2005
    Posts:
    1,480
    Likes Received:
    0
    Location:
    texas
    Was anything else wrong that could have contributed to it?
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    Obviously not a common problem, but I wonder if that didn't/doesn't happen because the later truck crossmembers moved the bolts so close to each other compared to all previous.

    You can see on the crossmember the "outboard" bolts, that's about how far the earlier crossmembers spaced them.
     
  5. koldsimer

    koldsimer 1/2 ton status GMOTM Winner

    Joined:
    Jan 10, 2005
    Posts:
    1,480
    Likes Received:
    0
    Location:
    texas
    That would make sense huh? I didn't even notice how close the holes are until you mentioned it.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    As an aside, it was a stock truck, so were those metal spacers on the bolts as well? (still no idea why GM started using them)

    Any evidence that the bolts had been loose previous to you taking it apart, and had been allowed to hammer the frame constantly?
     
  7. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

    Joined:
    Dec 28, 2001
    Posts:
    4,987
    Likes Received:
    38
    Location:
    The Rustbelt
    The metal spacers are to enable use of a longer bolt. Short bolts don't hold troque very well. The longer the bolt, the more it will strectch during torquing and hold that torque better. This is vastly more important on 'critical' bolts, like the ones holding the steering box to the frame. Those have long metal bushings on them as well.
     
  8. mouse

    mouse 1/2 ton status

    Joined:
    Nov 10, 2003
    Posts:
    1,448
    Likes Received:
    0
    Location:
    Great Falls Mt
    I've seen a couple cracked around the trans crossmember. Also, if you want to look for more cracks, I've seen more cracks around the rear shock mounts than the trans crossmember. In the past couple of months I have seen probably 4 trucks with either a crack, or a repaired crack on the rear shock mounts on the frame.
     
  9. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

    Joined:
    Dec 28, 2001
    Posts:
    4,987
    Likes Received:
    38
    Location:
    The Rustbelt
    I had to repair my frame back there.
     
    Last edited: Apr 12, 2006
  10. BowtieBlazer

    BowtieBlazer 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,462
    Likes Received:
    0
    Location:
    Baton Rouge, Louisiana
    Nope, the bolts I bet had never been loosened, the previous owner drove this truck as a work truck from 86(new) to 88 then bought it from his company and I have a file folder 4" thick with routine maint from 88-04 when I bought it. The guy didnt hunt and had maybe taken it offroad a handful of times, with 120K on it....drove like a caddy...my theory is the same as:

    I plan on using my old crossmember anyway. I really think the close spacing and a bad tranny mount could do that.

    Just a little suprise...:rolleyes:
     
  11. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

    Joined:
    Dec 28, 2001
    Posts:
    4,987
    Likes Received:
    38
    Location:
    The Rustbelt
    Do you have the cross member that ties to the upper and lower c sections of the frame. I've seen some that just bolt up to the bottom. If yours' just ties to the the lower section, I would probably go to the junkyard and get the other type that has a branch to tie into the upper frame section as well.
     
  12. BowtieBlazer

    BowtieBlazer 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,462
    Likes Received:
    0
    Location:
    Baton Rouge, Louisiana
    I've seen that type but only on older trucks. I will more than likely box the frame in that area either way
     
  13. steve_kibbe

    steve_kibbe 1/2 ton status

    Joined:
    Feb 4, 2004
    Posts:
    2,895
    Likes Received:
    2
    Location:
    Spartanburg, SC
    Might wanna drill a hole at the end of that crack too:D
     
  14. RaisedK5

    RaisedK5 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    932
    Likes Received:
    0
    Location:
    Long Beach, CA
    Correct me if i'm wrong but it looks like you did the old drop teh t-case by putting the spacer between the crossmember and frame trick. Right? I've seen this in several trucks in our club, The spacers localize the stress around the bolt hole leading to the cracking that you have, you shouldn't need to totally box the frame, do a good repair. Maybe even plate that area, but when you put it back together use square tube or a solid block of steel or even a stack of 1/4 plate instead of the spacers to spread the load out over a large portion of the framerail.
     
  15. steve_kibbe

    steve_kibbe 1/2 ton status

    Joined:
    Feb 4, 2004
    Posts:
    2,895
    Likes Received:
    2
    Location:
    Spartanburg, SC
    He said it was a stock k5 on 31's.
     
  16. RaisedK5

    RaisedK5 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    932
    Likes Received:
    0
    Location:
    Long Beach, CA
    Now that i look at it again, i guess my eyes were playing tricks on me i thought it looked like the spacer was between the frame chunk and the crossmember.
     
  17. steve_kibbe

    steve_kibbe 1/2 ton status

    Joined:
    Feb 4, 2004
    Posts:
    2,895
    Likes Received:
    2
    Location:
    Spartanburg, SC
    I had to look twice too:doah: :D
     
  18. BowtieBlazer

    BowtieBlazer 1/2 ton status

    Joined:
    Jul 15, 2001
    Posts:
    2,462
    Likes Received:
    0
    Location:
    Baton Rouge, Louisiana
    nope, the spacers were on bottom
     
  19. SkulzNBonz

    SkulzNBonz 1/2 ton status

    Joined:
    Feb 20, 2002
    Posts:
    4,522
    Likes Received:
    0
    Location:
    OKC, Oklahoma
    My 86 cracked there too. After I repaired it. I used some large flat washers to spread the load.

    John
     
  20. uglytruk

    uglytruk 1/2 ton status

    Joined:
    Oct 24, 2004
    Posts:
    1,329
    Likes Received:
    0
    Location:
    IN A JUNKYARD, UNDER A TRUCK*N E Rust Belt
    Just looked at a neighbors '86 3/4T 4x4 Burb. One owner little old lady from Florida, so no rust. LR shock mount broken right off! Client has a '90 1/2 V6 5 speed 4x4, LR shock mount rotted off, and cracked, but rest of frame not too bad...
     

Share This Page