W124 power seat track broke! - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 09-20-2016, 07:07 PM

Had a rather large passenger in the front passenger seat the other day (1995 E300D); when he drove the power seat back something must have snapped because the forward-back motion no longer works. All of the other motions work correctly. I can hear the motor running when I press the switch (either way) and can feel the cable turning inside its housing. I suspect the cable broke or rounded off its square end (similar to a speedo cable). The seat is out of the car and on the garage floor. None of my manuals talk about taking the seat tracks apart and most of the German manuals assume non-power seats. Anyone have experience repairing W124 power seat tracks? If necessary I can get a replacement seat from Pick-n-Pull but I'd prefer to repair what I've already got.

Jeremy

sixto · #2 09-20-2016, 09:46 PM

Are you sure it isn't just a matter of reseating the cable? It seems it's something of a fuse in that it disengages rather than causes gear cogs to shear off.

Sixto
83 300SD

jay_bob · #3 09-21-2016, 06:55 AM

That's what I think, may be a shear pin (mechanical equivalent of a fuse).

Jeremy5848 · #4 09-21-2016, 03:26 PM

I was able to pull the cable out of its sheath enough to get it into the worm gear that drives the track. How long it will work is yet to be seen. I've ordered a new cable (dealer, 422 with MBCA 15% discount) in case it fails again.

Some have suggested shortening the cable outside by 1/4 inch or so to let the center stick out more. I may try that.

Jeremy

Jeremy5848 · #5 09-21-2016, 04:27 PM

I was able to pull the cable out of its sheath enough to get it into the worm gear that drives the track. How long it will work is yet to be seen. I've ordered a new cable (dealer, 422 with MBCA 15% discount) in case it fails again.

Some have suggested shortening the cable outside by 1/4 inch or so to let the center stick out more. I may try that. Here are some pictures.

Jeremy

(1) This shows the seat out of the car and upside down, with a red oval around the worm gear casing and cable.

(2) View of the mechanism from the other side.

(3) Removing the cable from the worm drive requires removing these two Torx screws (red arrows). Unfortunately, the cover is trapped by the seat frame member, making it difficult to access.

(4) The best access is by partially removing the frame from the seat. Unfortunately, one screw (red arrow) is hidden by the track assembly. If your seat is most of the way backwards, like mine was, the screw is hidden. Since I couldn't do that, I had to remove as many frame screws as possible, then with a screwdriver wedge the worm drive open just enough to get the cable out.

(5) Another view of the worm drive and cable. It would be much easier with the cover off but the frame interferes.

Jeremy5848 · #6 09-21-2016, 09:36 PM

The seat is back in the car and working. I wanted to post two additional pictures showing my new Skil driver with its optional 90-degree head tightening the miserable-to-get-at bolts that attach the seat to the floor of the car. The tool makes the job easy and it has enough torque that you don't have to follow up with a wrench.

Jeremy

Phillytwotank · #7 09-22-2016, 10:56 AM

Cool Tool!

Jeremy5848 · #8 09-22-2016, 11:25 AM

Quote:

Originally Posted by Phillytwotank

Cool Tool!

And not expensive—about US$40 for a refurb (Amazon). The refurb is not currently available but I'm sure others will appear and in the meantime the new ones are about $10 more. The 90-degree attachment snaps on w/o tools and adjusts to many angles relative to the driver. Takes 1/4-inch bits and the battery is long lasting and the motor high torque. Single speed, forward or reverse.

"Factory-Reconditioned Skil 2354-02-RT 4V Max Cordless Lithium-Ion iXO Palm-Sized Driver with Right Angle Attachment and 10-Piece Bit Set"