My pull-down latch on my 88 seems to move up and down just fine.

The problem is that sometimes it "lets go" during the pull down.

The mechanism clearly engages the "hook" on the hatch, and it pulls it down snug, and just when it reaches the bottom of the movement, I hear "click" sound. When this happens, I can grab the hatch and lift it without any resistance from the pull-down mechanism. Clearly the pull-down is letting go of the hatch right at the bottom of the movement. When I then lift the hatch, the latch is in the open position. Sometimes I have to go through "the routine" of it doing this several times until it finally holds-on to the hatch.

Any ideas what may be going on here?

Maybe the pull-down mechanism just on its way out?

Smart time/money on the notion of just replacing it?

BTW, my hatch struts are pretty kaput - only work (sort of) on hot days. Cool days, the struts won't even hold the hatch up for a moment. So, I don't think the hatch struts are fighting the pull-down motor.

 

im thinking the plastic gear that drives the pull down has a few teeth gone

 

I could see this or maybe the latch isn't engaging enough due to dirt or build-up. My commute used to involve a lot of unpaved roads back when I had my '85 Z28. The dirt would get into the hatch latch and it would take 3-4 times to get it to stay closed. However that car didn't have the automatic hatch pull down though.

 

my standard latch takes a few times to close lol its perfectly clean too

 

Indeed, sounds like the gear is missing a couple teeth.

 

Thanks for the replies.

It seems to pull-down really snug, and then at the very end I hear the click sound.
There is no visual indication that the latch has disengaged, or that the hatch has popped-up. But, if I just grab the hatch, it opens right up if the "click" has happened.

There doesn't seem to be any difference if I "help" the hatch down during the pull-down.

 

Try adjusting the hatch bumpers on each side inwards so it can go down further THEN give it a some additional pressure and it might catch the next tooth.

 

Nope. A few teeth missing on the gear nut would be the cause of the motor running and running, yet the pull-down latch not moving up or down.

Lon

 

I agree with this answer. The latch is either damaged or dirty preventing full engagement. When the unit powers down fully it compresses the hatch seal putting pressure on the hatch hook and latch, so the latch that what was only marginally holding releases. I'd put it in my ultrasonic cleaner to get all the crud out, but you may not have that equipment. You can try cleaning the latch with that geat solvent called WD40 and a toothbrush. Afterward wipe it off and lube it with silicone spray.

Lon

 

Nope. There is no "next tooth" to engage. The latch is either fullly engaged or not. Clean, inspect and lube the latch mechanism. If the problem persists, then replace it.

Lon

 

I have seen a gear that was evenly shaved all the way around evenly. Sure seems like something with that ring gear to me. If a tooth was in fact missing on the ring gear the pinion gear will continue to run in place and the hatch motor will no longer pull down. However, in this case the motor would continue to run if the down cycle was incomplete as the switch would not stop the reversing/pull-down operation. I don't think dirt build-up would be the problem, harrison's experiences was with a manual hatch he said. Maybe, a big maybe, something (a screw) has simply fallen onto the top of the pulldown arm and is blocking it from going down....? Kerosene is a good cleaner. Checkout the second photo in my pictures here and you can get an idea of how these things work. After cleaning lube with white lithium from permatex. Hope this helps.

 

I really appreciate the replies.

The '88 is getting some make-it-pass-inspection work at the moment.

I'm looking forward to doing surgery on the pull-down motor as soon as the more-urgent matters are resolved.

I'll try to do a vid to show what its doing with a little more clarity.