Window lift drive cushion

[Injuhneer]

My truck did a cool trick. The window (driver front) will go down but not up.

Pulled the panel to find the rubber cushion in the window lift motor shredded.

The rest of the entire assembly is fine. Just drive cushion is shot.

Is there anyplace that sells these internal bits? Or is this going to require the completely unnecessary purchase of a motor or whole lift?

 

[pinkytoe69]

Same thing happened on my D1.

If the regulator is fine you just need a new (or in my case, junkyard) motor.

 

[Injuhneer]

I thought that might be the case. I saw that some enterprising person on ebay is moulding new cushions to do the repair. The drive cushion looks very different. After some study it looks like this cushion is something that could be whipped up out of urethane on a mill. I may take a shot at it just for fun.

Or buy one of these ebay units and give it a go.

 

[discostew]

I thought that might be the case. I the gear only on ebay (used). The drive cushion looks very different. After some study it looks like this cushion is something that could be whipped up out of urethane on a mill. I may take a shot at it just for fun.

What is a drive cushion ? I have a parts truck I could get whatever that is out of it for you . I'm guessing it sits between the motors gear and the regulator ?

 

[pdxrovermech]

yeah i've only been doing this 20 years and i have no idea what he's talking about.

 

[discostew]

yeah i've only been doing this 20 years and i have no idea what he's talking about.

Down stop ?

 

[pinkytoe69]

If you pop the metal cover off the motor, you will see that the gear that moves the regulator is connected to the motor drive via a rubber "doughnut" thingy.

With age, the rubber cracks and eventually breaks.

I dont know why it still has enough resistance to hold the window up, but not actually move it up.

 

[discostew]

If you pop the metal cover off the motor, you will see that the gear that moves the regulator is connected to the motor drive via a rubber "doughnut" thingy.

With age, the rubber cracks and eventually breaks.

I dont know why it still has enough resistance to hold the window up, but not actually move it up.

Got it

 

[Injuhneer]

pinkytoe69 nailed it.

It is the rubber cushion inside the gear reducer on each window lift motor. It is what prevents the nylon gear from cracking due to stress.

 

[discostew]

pinkytoe69 nailed it.

It is the rubber cushion inside the gear reducer on each window lift motor. It is what prevents the nylon gear from cracking due to stress.

Well if you want I can more than likely pull one out of my parts truck for you . I'm on vacation for 2 weeks after today , so if you want me to dig it out of my old truck and mail it to you I can do it .

 

[jafir]

Are they all the same? I think I've still got a stripped out front right motor from my 2003 I can open up and see if it's got it.

 

[Injuhneer]

I don't know if they are the same but I studied the cushion a bit and came up with a replacement to test. Whipped this up on the mill:

And it looks like this:

Basically it is a MDS nylon cog with tygon cushions.

The hub to drive it is in the works. It will fit over the center with 4 drive lugs to engage the cog and a slotted hole to engage the gear shaft. Here is the tool path.

The tygon cushions may not even be necessary but the slots they occupy make the nylon fingers flexible to spare the gears from shock.

I'll run it a while and see how it works. If it looks like it is stressing the nylon gear the cushions will be removed to give it a bit more flex. The fatigue point of stress relieved nylon is high. The window would have to be cycled several thousand times to see any weakening of the fingers.

I suspect this will outlast the truck.

 

[discostew]

What is the Mill ? How long did it take you to do that ? I like your granite work surface

 

[Injuhneer]

It is just "mill"; short for milling machine. I have a CNC mill. The CAM file took about 30 minutes to draw. The code took about 30 minutes to run. Lots of small cuts with a small tool.

 

[Injuhneer]

6 month update.

This repaired lift has been getting daily use for 6 months now. It is smooth and quiet as well as the motor sound is linear. No varying motor speed due to the damaged cushion.