K5 Tailgate repair (odd one)

[dyeager535]

I think most of my problems are odd. I also think I create most of them. This one though, not sure how. Maybe.

Tailgate stopped going up. As if the window was physically hitting something. Could see/hear it when it stopped. I recently had the tailgate apart attempting to fix a similar issue. Turned out one of the track rollers was flat-spotted. So I replaced the riveted roller with a bolted in bearing. Along with taking the side window tracks out, shoring those up (they were rusted through in spots) and lubing everything. There is no felt to "guide" the glass anymore inside the gate, but I don't *think* that would be the cause of this. Before and after all this work the window never worked well.

Anyway, long story long, driving the cable with a hand drill, the drivers side regulator arm (the one I put the bearing in) is bent. When it gets to a certain point in it's travel, not much beyond where the window is, the window stops, and the arm bends outward to the point that it hits the tailgate shell. I know everyone likes pics, I didn't take any because my phone sucks. But part in question is the "arm" on the right side of the regulator in this pic:

I noticed the opposite roller is pretty flatspotted as well, so that will be bearing-ed as well when the part comes in. With the window detached from the regulator it moves up and down freely. There was no binding in the roller bushing/bearing track on that side that I could find. No evidence of anything else going wrong there.

Any ideas how to "shore up" that regulator arm? Ideally I'm not keeping this tailgate, so I don't want to invest money in a new one, and I'm not convinced all the problem is in the regulator. But to futz around, I'd like to straighten the arm, then reinforce it, without taking a bunch of time and effort. Because of the tight clearances, any reinforcement is going to have to be fairly thin. I was thinking some 1/8 or 1/4" angle iron on each edge would make straightening easy, while providing additional strength. Except as far as I can find, that's not made. I could cut larger angle iron down, but that would be fairly time consuming.

Any ideas or sources for said angle iron?

And no, I'm not going manual. I get too much use out of the electric.

 

[dyeager535]

This may indeed be a one-off problem, but updating just in case anyone ever comes across this too.

Took a door regulator apart and cut the ribbed (reinforced) section of the arm out of it. Clamped and welded that to the long arm of the tailgate regulator that was bent. Had to grind it down a bit to clear one of the bolt heads that secures the regulator to the tailgate shell, but that was it.

Since the roller is flat spotted, I'm going to bearing that one too.

I have a feeling that part of these problems are a result of the window track felt being gone. I have thought of a fix for that which would be pretty cheap, but can't implement it right now since I need the window together for this weekend. I can't see spending ~$200 on aftermarket window channels, for a tailgate that is in as bad of shape as this one. But it's going to have more time spent working on it than any other one out there! lol

Window glass assembly has "guide ears" that extend out into the window channels, which are what ride on the felt. When the felt is worn/gone, it's metal on metal as the window goes up and down. Thinking of getting round Delrin rod (pretty cheap on ebay) and using that as a guide for the window. Route out a slot in a short piece of Delrin, so that it fits over the ears on the window assembly. Short enough and not so thick that it binds as the window moves up and down since the tracks are curved, but still wide/thick enough to remain captured in the window channel.

I suppose if I can find it for not too much, it may be possible to get Delrin sheet that could be cut to line the window tracks with. Other than figuring out how to attach it to the window tracks, that would seem a pretty non-complex solution.

I took pics, I'll get those up when I get time. Regulator arm bend took a set, even with the repair it's got a slight twist in it still, but there is enough slop in everything so that won't be a real issue.

 

[Blue85]

You can get steel rod in small sizes like 1/4" and weld it to the arm every few inches or whatever. I can usually find some in the garden near the tomato plants , so it's probably available cheap at your local garden center. That, tiny-size rebar or 1/4" flat bar from Home Depot would be better than 1/4" angle iron, which is not very stiff.

 

[dyeager535]

You can get steel rod in small sizes like 1/4" and weld it to the arm every few inches or whatever. I can usually find some in the garden near the tomato plants , so it's probably available cheap at your local garden center. That, tiny-size rebar or 1/4" flat bar from Home Depot would be better than 1/4" angle iron, which is not very stiff.

I think clearance is closer to 1/8", although the only spot it appears there is any interference is over the one screw, nearest the regulator mechanism. The rest of the travel area is mainly where the tailgate is the "thickest". I measured the regulator arm being bent about 1/2" from flat, and that cleared upward and downward movement.

 

[JoshHefnerX]

I scraped all of the old felt out and replaced w/ some 'wicking felt' used for bearings, so far it's held up well.

 

[dyeager535]

I saw that was available if you wanted to replace with felt.

I'm curious if they use the same setup on more modern vehicles, or if they went to something else. Could be something that could be adapted, at least in the way it works.

Did you have any problem with the window binding when the felt was in bad shape? How did you attach it to the channels?

 

[JoshHefnerX]

Modern vehicles use that 'flocked' rubber..

Mine was bouncing around in there and would catch on the arms on the way up. Sometimes on the way down. There wasn't much left in there. I cut that wicking felt down, used some weatherstrip glue and stuffed it into the channel again. After it was dried I worked in some silicone spray and so far it's held up...

 

[dyeager535]

Got it put back together, while it goes up and down now, it needs help as it apparently catches on the mechanism since the tracks aren't "tight enough" without the felt.

Didn't have the pieces to fix the flat spotted roller either, so that isn't helping, but I can hear it hit the mechanism as it's rolling up so I don't think my bearing mod would fix that.

Ordered some 3MM nylon sheet, I'm going to see if I can't just cut and line the tracks with it. I'm going to attempt to leave tabs on one side of the nylon strips I cut, bend it with heat, and rivet the nylon to the "back" of the channel.

 

[blazer74]

Those channels are available if u wanted to go that route$.

 

[dyeager535]

Those channels are available if u wanted to go that route$.

Yes, I actually have a pair of NOS ones, but this tailgate is one that I didn't want to put "good" parts in, as it's not one I plan to keep. i just need to have it work until I can finish the other truck. And you are right, they are spendy.

I like projects, I think the roller bearing modification will definitely hold value going forward, if the nylon works really well, I may just swap that over to the "good" tailgate instead of using the NOS parts. If it doesn't work, I've learned what won't.

 

[blazer74]

Ive got set stashed also.

 

[Metrodps]

These may help or they may not....


CHEVROLET NUMBER:87-T-51
SECTION:10 - Body Section
DATE:January, 1987
SUBJECT:TAILGATE WINDOW ALIGNMENT
MODELS:1984-1987 C/K-R/V JIMMY/BLAZER

Some 1984-1987 C/K - R/V Jimmy/Blazer models equipped with a power tailgate window may experience a tailgate window that operates slowly or does not fully return to its upward or closed position. This condition can be caused by misalignment of the rear tailgate window, cable, guide pins, sash assembly, regulator assembly or the tailgate. The following checks and adjustments should be used to correct this condition.

1.Battery Condition - Check the charge of the battery while the engine is running and also when the engine is stopped. A low battery charge can cause the window to move slowly.

2.Rubber Wedge - Some models have a rubber wedge (5" long) installed at the base of the roof housing between the window track and the glass run seal. If equipped with the wedge, remove it and glue the glass run seal to the roof using weather strip adhesive (P/N 12345097) or equivalent (see Figure No. 1).

3.Cable Assembly - The cable assembly should not interfere with the movement of the window. The cable should run below the lower window stop and through the holding tab (clip) mounted on the tailgate (see Figures No. 2 and 3). Any tight bends in the cable will reduce the power transferred to the regulator assembly.

4.Window Regulator - Check window regulator and left regulator arm for any binding (see Figure No. 4). Marks will be visible where the regulator arm and sash have contacted. If left regulator arm is catching on the window sash, carefully bend regulator arm as required. Check the meshing of the regulator teeth. An overly tight meshing will cause unnecessary binding and the regulator assembly should be replaced.

5.Window and Sash Assembly - Remove glass and sash assembly for inspection. This can be accomplished by removing the four bolts that connect the sash assembly to the regulator arms.

-If sash is not centered on glass, remove the sash and center it on the glass assembly (see Figure No. 5).
-Remove any excess sash filler at the ends of the sash assembly.

-Check the angle of the sash channel guides to ensure they follow the curvature of the glass and sash channel (see Figure No. 6). If adjustment is required, carefully bend the guides to the same curvature as the glass and sash channel. Ensure that the guides travel through the channel smoothly.

6.Tailgate Glass - Check curvature of the tailgate window. Lay straight edge on glass and observe the clearance between straight edge and glass at center of window (see Figure No. 7). If clearance exceeds 1/4 of an inch replace the glass.
7.Ground Strap - Install a ground strap (12 gauge wire) from the tailgate to the frame. Attachment can be made from one of the tailgate hinge bolts to one of the holes in the rear frame crossmember. Use a star washer with each bolt to provide good metal to metal contact. Make sure the ground strap does not become kinked when the tailgate is closed. Ensure that the motor is grounded properly to the tailgate. This can be accomplished by replacing one of the window regulator motor bolts with a zinc chromate coated bolt, P/N 9419004.8.Tailgate Fit To Body - Check flushness and height of tailgate to the rear quarter panels. If the top of the tailgate is misaligned (in or out), loosen the strikers on the inside of the rear quarter panels and adjust accordingly. If alignment (in or out) is off on the bottom of the tailgate, loosen hinges and adjust as required.

9.Window Centering - Loosen the two channel adjusting bolts on each side of the tailgate (see Figure No. 8). Close tailgate and run window up and down. Open tailgate enough to access the adjustment bolts and tighten.

 

[wazzabie]

Is this a GM service bulletin? Interesting information.

These may help or they may not....


CHEVROLET NUMBER:87-T-51
SECTION:10 - Body Section
DATE:January, 1987
SUBJECT:TAILGATE WINDOW ALIGNMENT
MODELS:1984-1987 C/K-R/V JIMMY/BLAZER

Some 1984-1987 C/K - R/V Jimmy/Blazer models equipped with a power tailgate window may experience a tailgate window that operates slowly or does not fully return to its upward or closed position. This condition can be caused by misalignment of the rear tailgate window, cable, guide pins, sash assembly, regulator assembly or the tailgate. The following checks and adjustments should be used to correct this condition.

1.Battery Condition - Check the charge of the battery while the engine is running and also when the engine is stopped. A low battery charge can cause the window to move slowly.

2.Rubber Wedge - Some models have a rubber wedge (5" long) installed at the base of the roof housing between the window track and the glass run seal. If equipped with the wedge, remove it and glue the glass run seal to the roof using weather strip adhesive (P/N 12345097) or equivalent (see Figure No. 1).

3.Cable Assembly - The cable assembly should not interfere with the movement of the window. The cable should run below the lower window stop and through the holding tab (clip) mounted on the tailgate (see Figures No. 2 and 3). Any tight bends in the cable will reduce the power transferred to the regulator assembly.

4.Window Regulator - Check window regulator and left regulator arm for any binding (see Figure No. 4). Marks will be visible where the regulator arm and sash have contacted. If left regulator arm is catching on the window sash, carefully bend regulator arm as required. Check the meshing of the regulator teeth. An overly tight meshing will cause unnecessary binding and the regulator assembly should be replaced.

5.Window and Sash Assembly - Remove glass and sash assembly for inspection. This can be accomplished by removing the four bolts that connect the sash assembly to the regulator arms.

-If sash is not centered on glass, remove the sash and center it on the glass assembly (see Figure No. 5).
-Remove any excess sash filler at the ends of the sash assembly.

-Check the angle of the sash channel guides to ensure they follow the curvature of the glass and sash channel (see Figure No. 6). If adjustment is required, carefully bend the guides to the same curvature as the glass and sash channel. Ensure that the guides travel through the channel smoothly.

6.Tailgate Glass - Check curvature of the tailgate window. Lay straight edge on glass and observe the clearance between straight edge and glass at center of window (see Figure No. 7). If clearance exceeds 1/4 of an inch replace the glass.
7.Ground Strap - Install a ground strap (12 gauge wire) from the tailgate to the frame. Attachment can be made from one of the tailgate hinge bolts to one of the holes in the rear frame crossmember. Use a star washer with each bolt to provide good metal to metal contact. Make sure the ground strap does not become kinked when the tailgate is closed. Ensure that the motor is grounded properly to the tailgate. This can be accomplished by replacing one of the window regulator motor bolts with a zinc chromate coated bolt, P/N 9419004.8.Tailgate Fit To Body - Check flushness and height of tailgate to the rear quarter panels. If the top of the tailgate is misaligned (in or out), loosen the strikers on the inside of the rear quarter panels and adjust accordingly. If alignment (in or out) is off on the bottom of the tailgate, loosen hinges and adjust as required.

9.Window Centering - Loosen the two channel adjusting bolts on each side of the tailgate (see Figure No. 8). Close tailgate and run window up and down. Open tailgate enough to access the adjustment bolts and tighten.

View attachment 232032

View attachment 232033

 

[JoshHefnerX]

Good info!

 

[Metrodps]

Alldata was where I got it off of.