86 K5 Blazer tailgate windowframe crake repair advice needed

[86_M1009]

View attachment 190441 I come in search of help.

I have an 86 k5 blazer rescently bought in excelnt runing condition and with only minor issues.

One of these isues is the tailgate window ferame being cracked at both ends. This is a manual tailgate and the cracks were discobered while rebuilding the inside due to tje rollers wearing out and the felt and seals being 30 years old. The cracke radiate from bothe ends of the window opening. I want to stop drill and weld the cracks but it seems like this might be a waste of time and it will just keep happening due to a flawed design. I do know that this tailgate was a junk yard replacement for the original but I do not know if it was damaged or not before the transplant. It does loom like some pulling has been done on the rear lip of the opening becaause both ends are slightly higher than the center qs if they had been beat down by someone loadi g crap into the back and someone else tried to pull it back up to the original lines but went a little to far, resulting in lifti g of the metalat the ends wher the rear lip is welded to the sides. This is where the cracks are, the pint where the sheetmetal that is rolled over at the top of the gate and welded to the side frames just above the latches.

I see my options as:
1. Sand, hammer, welp, prime and paint.
2. All of 1 but cuting the tailgate open to add bracing strips to strengthen the ends where the cracking is happening.
3. Buy an electric gate and salvage a factory set of window controlls from the junk yard?
4. Find out if there is a custom flip up rear window and instal a c/k gate.
5. Any and all advice and outside the box solutions will be entertained. Especially if you have delt with rhis issue.View attachment 190440 View attachment 190440

 

[86_M1009]

 

[dyeager535]

The electric ones crack the same way, there are probably a BUNCH of factors at play...slop in the window mechanism (the tracks/felt being worn) misalignment of the topper track to the tailgate/tailgate latch misalignment, bad design right there, and finally frame movement. I will say that mine isn't cracked on the forward (front of vehicle) edge but it also isn't QUITE that bad on the back side. I was getting enough movement though that the screws that hold the hard plastic pieces at the ends ripped out, so I had to weld those holes up a bit so the screws had something to grip again.

I don't care about the tailgate on the truck now, so I cleaned up the metal surrounding the cracks, beat the metal into submission, then made quick welds with the MIG along the crack. One side I obviously didn't get good penetration, and the weld pulled within two driving trips (I don't wheel, we're talking asphalt and some logging roads). The other side obviously got better penetration and so far hasn't cracked again/yet. I made no effort to blend them, I just welded over the crack and didn't grind it flush.

 

[86_M1009]

The electric ones crack the same way

Yea, but it might be nice to roll the window up and down while driving and I bet the manual mechanism wears badly.

there are probably a BUNCH of factors at play...slop in the window mechanism (the tracks/felt being worn) misalignment of the topper track to the tailgate/tailgate latch misalignment, bad design right there, and finally frame movement.

I think you nailed the cause. The wondow was bound up prety good due to one of the rollers being more square than round. The sash was pretty bent up from the forcing the window up and down. That probably acounts for some toque being disipated alomg the entire face of the exterior face. Then there is one body mount bushing that is almost flat at the rear passenger location causing some sag on the body at that location. Finally,there is some misaligment of the gate itself so that it sits higher on the passenger side and lowe on the driver side with so much gap hir right that someone has stacked washers under the latch on the bedside mount location and it is still pulling hard on that side when latched. I habe not figured out if this is due to one or both hinges being bent or if it is just installed crooked. I am tempted to just bend the hjnge down on the pasenger side and be done with that so it will latch up better. I know it will affect the repair of the cracks.

 

[86_M1009]

Ok, so I go out and mull over my tailgate for a while every few days. I want to put the guts back in but should probably fix the cracks first right.......

So I monkeyed around this morning and measured many points afainst many other. Of significance is the sides being a quarter inch farther apart at the top of the garte than at the botom, hench the latch misalignment. Add to this that despite the top of the gate being a quarter inch higher from the frame on the left, the gate sits a lot higer in relation to the top of the bed on the right. I have put it all together and the flatened out body mount rubber on the left rear is causing the body to sag at that poi t qnd also inducing the wider gapmat the top. Fix the rubber issues and get the bed side back square and most of thengate problems will be foxed and I cqn weld it up and fix the latch misalignment all at once. I just ned to decide on poly vs rubber qnd order it up. Gonna mqke a seperate post regarding end user experience with poly.

 

[86_M1009]

It was nothing to do with the bushings. Chqnging them made zero impact on the misalignment of the gate. However, instaling washers on the pasenger side hinge between the hinge and frame on the two fwd bolts lowered the gate on that side. Now I just need a second set of hands to help adjust the inset o the hinges so it is flish top and bottom.