'72 250 - Installing rear shoulder seat belts??
 

I have regular lap belts in the rear seat of my '72 250 but I need/want to install a 3 point shoulder belt.

I have found Seat Belts Plus online for generic belts (and I'm sure there are others)...

Has anyone done this? Just a little worried about the shoulder bolt connection.

Thanks, ryan

My 1970 W108 had attach points for seat belts built right into the hat tray. I'll bet W114 models do too.

Hat tray???

there's a flat panel behind the rear seat. He means that. -CTH

I guess we're talking about the flat area under the back window...I have carpet glued down (original), but in trying to to pull it up some I don't see anything underneath that looks like an attachment point???

Look underneath from the trunk side of the shelf. You are looking for welded nuts or heavy threaded inserts or maybe a caged square nut. One each side and toward the outside. Not saying they are there, just what to look for. The threads will be odd, maybe 7/16 fine thread or something like that. Do not force a regular bolt in, these bolts are kind of special.

If you don’t find factory fittings, universal belts come with a couple different ways to add the mount.

I used belts from https://www.wescoperformance.com/3-point-seat-belt-help.html in my ‘74 F250 SuperCab. I can post a link to that install if cross posting from another non Mercedes forum is ok.

Michael

Found them! Thank you gentlemen!

Now it's just a matter of figuring out the thread size - AND how to remove the back seat. Any help?

Thanks.

Never mind on the rear seat removal question...

You just pull up really hard!

Was gonna say pull hard or look for 2 bolts at lower front corners. Seat back should be 2 bolts then lift up off hooks at top.

Try one of the lap belt bolts to see if it fits, it’s easier to take a bolt to the hardware store than the whole car. And do some research on what grade they are if you buy bolts locally. Seat belt vendors will supply the correct grade.

Michael

You were right - 7/16" 20 pitch. Bought 2 at Home Depot and they fit perfect (I bought Grade 5 as I didn't see any Grade 8 at HD).
Trying to figure out how to secure the shoulder belt bolt here and still allow movement at the connection point. I believe seat belt bolts have either a spacer or have some kind of shoulder - so you can tighten the bolt down but still allow the belt to move some.

ryan

Glad to help.

You are correct in thinking that some bolts do have a shoulder to allow for movement. The source you found may have shouldered bolts as might Wesco. Another option is to look here on Pelican parts for bolts or hit row52.com looking for older Mercedes with 3 point belts in the rear. It may turn out that you don’t need more freedom of movement than the belt loop through the mount gives although the shoulder will let the hardware sit above the carpet with the bolt fully tight.

Michael

Yea, I found several online suppliers - Wesco has them for $1.95/ea, but want $15 for shipping. I'll pass...

May just look for something that I can use as a spacer. Found some nylon spacers at Lowes but the ID of the hole was less than 7/16"...

I’d avoid anything soft. You want the bolt to be tight metal to metal. This means either a shouldered bolt, a metal sleeve, a stack of washers or cutting a hole in the carpet to let the fitting sit on the deck.

Michael