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K5 rear window only rolls down 1/2 (looking for ideas)

brans87

brans87

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On my 87 K5 rear window today (power) started to only roll down 1/2 way and stop. So before tearing it a part later this week I figured maybe pick your brains on what might be going on.

Note: all seals and tracks have been replaced with in last year or less and new GM cable was installed roughly 3 years ago.

Window does go up and down but only 1/2 way.
 
Mine was hooking on the mechanism inside. Do not remember on what specifically. Took the panel off and watched it stop. Pushed on the glass and it continued down. Adjusted and it worked.

One other time the cable was coming apart and would bind.
 
Same deal for me. Quite a few parts sliding past each other with very little clearance...it doesn't take much for something to interfere and stop with window cold.
 
Mine had the same issue. If for some reason you need the regulator assembly let me know, I have a NOS GM one
 
If the inner side of the tailgate shell is pushed inward from setting something heavy on the gate or is bent will cause the track to catch on the gate.
 
Mine acted the same way. The glass was catching on the motor due to a slightly bent in (Not visible) inner shell.

-Rob
 
Still fighting with mine, lots of problems.

Looks like the regulator is worn out, drivers side of the regulator has "slop", which allows the window to get cockeyed going up, which makes the motor work harder. Due to dents in outside of tailgate(?) the metal channel that holds the glass hits one of the lower bolts that holds the regulator in place. It's a definite clunk when it hits the bolt head. I ground the head down a bit, still not enough.

Replaced worn out felt in the window tracks with nylon strips to keep window away from the mechanism, that helped a bit, but was not 100% solution. Also the plastic rollers that are riveted to the regulator arms, which travel in the tracks bolted to the window holding channel were flat spotted.
 
I blew a drive cable one time - no, make that three times --- and I decided it wasn't gonna happen again.

I cut some stiff PVC tubing and using Gorilla Urethane glue, I put several layers of that tubing over the existing cable housing to beef it up.

That worked great.

At the same time I ran the last ply of the PVC tubing I was putting on, up and over the plastic nipples - to hold them into the cable at the motor and regulator gear box. That kept the ends from popping out on heavy loads.

Two tiny screw-type hose clamps went over everything at each end. That made the driveshaft/cable assy absolutely bulletproof.

I added a 4# AWG wire from the battery - through the frame to a starter relay that puts the power to the motor at full battery voltage.

That helped - I used a four-set of FORD starter relays to reverse polarity and allow the window motor to get polarity changes nearer to the motor itself.

OK - then the 'clunk' showed up.

I'm still looking for it and I think it's one the the bolts that holds the track to the sliders for the arms.

BTW: I added some #6 AWG wire to the door regulators and lock relay/motors too. They really are motivated when they get good voltage to them.
 
I'll say that if anyone references my previous thread on rear window problems, with all stock, well-aged components, mine was still able to bend one of the regulator arms. My clunk is the regulator coming to a hard stop (still on one of the regulator to tailgate bolts), if you are hearing that, be wary about forcing the window up against it time and again. I did straighten the regulator arm and weld a reinforcement in, but that only kept it from bending anymore. That is still the only way I can get it to go up all the way (eventually) without climbing out of the truck, yanking up and shaking the glass front to rear, then getting back in and hitting the switch again.

I've got a spare tailgate and I believe regulator, I just don't want to spend the time on this one that I don't intend to keep trying to discover exactly what the issue is. :( I know what is hitting what, and where the slop is in the system, I'm just not going to swap the components necessary to see what the real fix is. I had hoped all the work I did experimenting was going to be the end-all solution for rear window issues, but it wasn't. I really hoped the nylon track linings would end the need for the "felt" linings that get torn up, and be of the right thickness to keep the bolts from interfering with the window.
 
Let me state here that my clunk comes at about the halfway point, both up and down.

If I can get a volunteer to help, gently pushing IN on the upper glass as it goes down seems to let the clunk not happen - or it misses something that is sticking up/out/near the track as it moves down.

UP seems to be a little easier to keep from happening. If I have someone to pull the window UP, it helps - but I think it just goes faster and cannot totally hook into whatever it is.

This gets worse in the colder months and as such, I am not want to open the rear window until late Spring up 'till early Fall.

Again, I'm at a loss here as I thought everything was kosher inside the tailgate. Obviously not.

Just saying.
 
Nope, sounds pretty similar, although on mine "up" is the problem direction.

I can see why people swap to manual guts on these things, but with no AC, and using the rear window a lot in winter, I'm determined to get the power window to work as it should.

The direct drive conversion shown in the other thread is intriguing, but I'd like to know how or why it's any better than the cable drive setup. I've had no issues related to the window/cable assembly as far as I can tell (and I've swapped motors to test), the problem IMO is how strong the motor itself is. Without getting ridiculous and running 4AWG and two relays back there, I'd just like to increase the power to the regulator to force it past that problem.

The window tracks themselves are pretty flimsy, they don't do a good job of holding the window steady as it moves, if anything is acting against it. Realistically the setup is extremely complex, particularly with 80's and 90's GM build quality...the tracks are adjustable, the felt wears, the top can be removed and put back on in not exactly the same spot, the window moves in an arc not straight, etc.
 
The flimsy track or slop I would say allows for the variables you mentioned to allow the window to operate in varying conditions including temperatures.

The problems with the window catching is inherent to worn track felts and miss adjustment due to wear.
As well as bent or pushed in inner tailgate structure which is what I’ve encountered causing catching of the window lower track on.

I cured my issues by adjusting the tracks to fit the window to the top and pulling the inner structure of the tailgate where the regulator attaches out or away from the inner section of the tailgate and replacing worn components.

Every time you sit or l place an object on an open tailgate your pushing in on the structure where the panel goes which is the weakest part and holds the regulator and motor.
 
I had a similar, less severe issue with my manual window.

I cured it this way:

imgp6445-jpg.249214


Probably not what you're looking for, but I thought I'd throw it out there. It was easier than messing with the regulator, and it's much easier to access the back now.
 
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