Seat Belt Won't Retract, 2000 ML 320 (middle rear/2nd row seat)

My middle rear seatbelt would not retract, and with the seat in its down position, that meant the seat wouldn't go up. I brought it in to the dealer, and they wanted $550 to fix it. They said that the seatbelt was "broken" and would have to be replaced. I couldn't believe it, so I declined the repair and went home to have a look at it myself.

I pried the back off of the seat and removed three Phillips screws from the bottom of the felt covered back. That popped off easily.

Then, the seat belt mechanism was in plain view. You need a torque wrench with bit to get it off. I borrowed one from a neighbor, but will buy a set next time I'm at the hardware store.
I unscrewed the seat belt, and gently pried off the plastic cover on the right side. This exposes a smaller plastic cover with two white gears in the middle. This cover pops off easily as well, but be careful since it is small and thin.

Now the gears are exposed, along with the ball-bearing which senses the fast movement and locks the belt. The ball bearing rests on a tiny blue piece of plastic that locks above the white gear shift. The white gear has a small piece of "v" shaped plastic that is flexible. These pieces (the white v-shape and the blue piece) were in the wrong position, hence the locked seatbelt. I toyed around with them for a few minutes to find the right position, and it was fixed, simple as that.

Time to complete: 30 minutes (including a run over to the neighbor's to get the right sized bit).

$550? Unbelievable. I imagine they all work the same way, so give it a try if yours is locked.

Also, a word of warning: This happened after I loaded some heavy stuff in the back with the seats down. The seat belt mechanism rests under the bulge at the top of the seat, and I am sure that it got knocked heavily by the load, which moved the two tiny pieces of plastic out of position. I'll be more careful next time.

 

Hi,

Just read your thread. I have an 02 ML 55 with the same problem. How do you pry off the felt covered back? Are there clips holding it in place? I have more than 3 screws, perhaps because of the cargo floor plates on the ML 55. I tried removing some screws but was afraid of using any leverage to get the back off. Thanks Joe

 

Hey Joe: I remember prying it out after removing the screws--was snug, but it popped out and nothing broke. I don't remember exactly, but there must be clips locking it in place. I'd say try prying two spots around a corner and see if it opens, but use something wider than a screwdriver (I think I used paint stirring sticks).

Hope that helps--good luck and keep us posted.

 

Hello, sorry I know this was years ago, but I'm having the same issue with my 00 ML320 and I have no idea how to take off the felt covered back, do you have a picture of what screws to take off and what to pry open, Thank you in advance!

 

You are on the wrong forum.

https://mbworld.org/forums/m-class-w163-10/