I need a seat back locking vacuum element for a 300cd
 

I pulled the passenger seat today and one of the two seat back vacuum locking elements doesn't hold vacuum...therefore that side doesn't lock.
A. How do I get it out...screws are facing the bottom of the seat.
B. Anybody have one they are willing to part with?
C. Am I crazy for trying to fix this? Any suggestions on how to remove the actuator?

Thanks

Continuation of above post
 

So after work today i took the passenger seat out and took off the upholstery on the bottom. I removed the faulty seat back locking vacuum element. I was surprised to find that the membrane looks like bicycle inner tube when it was cleaned with soapy water. It has a small hole, like a flat tire on it. Question is, could I use a bicycle tire repair kit to repair the membrane? Is there anything i could spray on the rubber to reinforce the entire membrane? Silicone maybe? Rubber glue? Any suggestions?

Thanks for any input.

This pdf may help. Sounds like the fix you suggested, inner tube repair, should work.
Click on the buy parts tab on top of the page, and ask Phil.

Thanks Bob
 

I'm going to try an inner tube repair kit first before purchasing new element. This car needs so much, and I have to save in my yearly budget in case something really really expensive needs fixing. Worst case scenary I'll take some wire and wire the seat back hook permanently locked if I can't get it to work with the vacuum.

Have you used Diesel Giant and his videos? Thinking about getting the valve adjustment and cover gasket repair DVD.

George Murphy sells replacement diaphragms. I don't know if they fit that particular module. Search on his name on the forum and his phone number will come up. He doesn't have a website. He could tell you if the diaphragms fit. They are not expensive.
I'd be inclined to use a small glob of Goop to repair the existing one, rather than a tube repair kit.

Thanks Kerry. Wish I'd gotten your reply before i bought the rubber repair kit and patched the hole...I'll know soon enough if it holds...worse case scenario is it holds, I put the seat back together and in the car, and it fails a month from now.

Inner tube repair failed. It held seal until I reattached the element to the seat and locking mechanism. I'll have to go find some goop tomorrow and see if that will hold. If that doesn't work I'll seek out George Murphy.

katchung,

i have one from a 1991 W124 donor car from my rust repair project. would that work with your car?

bob

Sorry to hear!
Good luck.

forgive my ignorance but what exactly is the purpose of locking the seat back with vacuum? is this a way to trap passengers?

http://mindbo.fatcow.com/Mercedes.html without the seatback lock the driver and passenger seat backs are not locked in place...in an accident you would be thrown forward into the dash strapped in or not.
http://www.peachparts.com/shopforum/...c/progress.gif Here's a picture of it. http://mindbo.fatcow.com/Mercedes.html

Thanks

seat back lock purpose
 

without the seatback lock the driver and passenger seat backs are not locked in place...in an accident you would be thrown forward into the dash strapped in or not.

ok, but why with vacuum? they have a release button, why not a lever like everyone else?, why complicate a seat back with a vacuum actuator? just wondering if there is some other thing it accomplishes

Gotta keep the engineers busy!
I don't know, redundant, I assume.

Neither of the vacuum seat locks work on my coupe either. Eventually I'll have to pull the seats and fix them somehow. This was a "luxury" car, and who would want to press a button to unlock seats when vacuum can do the job for you in 1977?