Non-functioning lumbar - fixed with my own 3d printed parts

[goldata81]

My lumbar has not worked in my 07 Yukon Denali for the past few years and I had pulled the seat to investigate a fwd/aft binding issue. The lumbar would move up and down but not in and out. I could hear a clicking in the rear of the seat when attempting to operate the lumbar motor but there was never any movement. While I had the seat out I figured I'd investigate, although access to the lumbar function does not require removing the seat. When removing the rear seat cover I found the right side motor cable had a large amount of slack to it. I removed the right side lumbar motor and removed the 3 squared head screws that held the cover on the gear box to find this.... 2 broken gears and the planetary carrier broken.



The ring gear was also warped a bit due to pieces of the broken gear getting wedged underneath and sitting for the past few years.



I found that https://www.gruvenparts.com/ makes replacement brass gears but didn't see that they made the planetary carrier. Had only the gears broke, I probably would have just bought the upgraded brass gears from them.

After a couple test prints with adjustments, I think I have something that may work. I added a 4th planetary gear from the original design since there was room. Seems to be working so far. We'll see how it holds up again being made from plastic. I just used the PLA I had on hand.

 

[exp500]

Do any contract work? Nice to know somebody that "can do"when one of the crazy things arrives. I'm impressed!

 

[iamdub]

My lumbar quit recently. Same thing- moves up and down, but not in or out. Also, ever since I've had it, I could adjust it out (more pressure on the back), but if I leaned back on it too hard, it would pop backward. I don't know if that's related.

I really like these types of repairs and am digging the "4-pinion planetary" upgrade. If I find mine has the same failure, I may hit you up for a gear set!

 

[Joseph Garcia]

VERY impressive!

 

[10Thoe]

My lumbar has not worked in my 07 Yukon Denali for the past few years and I had pulled the seat to investigate a fwd/aft binding issue. The lumbar would move up and down but not in and out. I could hear a clicking in the rear of the seat when attempting to operate the lumbar motor but there was never any movement. While I had the seat out I figured I'd investigate, although access to the lumbar function does not require removing the seat. When removing the rear seat cover I found the right side motor cable had a large amount of slack to it. I removed the right side lumbar motor and removed the 3 squared head screws that held the cover on the gear box to find this.... 2 broken gears and the planetary carrier broken.
View attachment 277326


The ring gear was also warped a bit due to pieces of the broken gear getting wedged underneath and sitting for the past few years.
View attachment 277327


I found that https://www.gruvenparts.com/ makes replacement brass gears but didn't see that they made the planetary carrier. Had only the gears broke, I probably would have just bought the upgraded brass gears from them.

After a couple test prints with adjustments, I think I have something that may work. I added a 4th planetary gear from the original design since there was room. Seems to be working so far. We'll see how it holds up again being made from plastic. I just used the PLA I had on hand.
View attachment 277338 View attachment 277339 View attachment 277341

VERY impressive!

I have the same problem with broken disc. Do you sell them?

 

[goldata81]

I figured I'd post an update.

Unfortunately after about 3 weeks, the lumbar seemed to not function again. Opened up the gearbox to find broken parts. I'm thinking it could be a combination of things. I printed these with PLA which has a low melting point of most(if not all) the 3d printing filaments. A hot summer interior and running the gear set up to the physical stop may have been enough to break these plus the fact PLA absorbs moisture and will get brittle. This isn't the best solution but I'd thought I give it a try.

I've printed another set(PLA again) with the stop removed(the thing in the white box). I installed those mid August and so far are holding up. A note of caution that without that stop, one runs the risk of over running the position sensor's physical range that sits in the gear housing cap and could potentially break the position sensor. I am willing to risk a broken position sensor as long drives with no lumbar support is not fun.