HELP! fuel door will not open.
 

420SEL 1990. I went to put gas in it yesterday and the fuel door will not open. Does this operate on vacuum with the door locks? I tried locking and unlocking the doors several times, no luck. Any ideas?

In the trunk there is a lever you can pull to unlock the fuel pump door. It is very close to the door, so look in that area of the trunk

Thanks, I'll give that a try when I get home.

Yes, vacuum does lock/unlock the fuel door.

Yes, the fuel door operates on the same vacuum system as central locking. The pump for the system is located in the trunk next to the spare tire encased in a block of foam.

There are a few things that could cause it. First, the door itself is thin metal and the little hoop that the lock pin goes through can get bent which can cause the lock pin to stick. Dirt or other foreign matter can make it stick.

Try pushing in on the door a bit as you unlock the passenger's door. That might take away the friction caused by a bend in the hasp part of the door.

Use the release in the trunk if you have to.

Once you get it open, leave it open and lock/unlock the system several times. Look in there to see if the little black plastic pin moves in and out.

I'd be willing to bet you have a surplus of friction somewhere in that mechanism. Either that or a vacuum leak, but I bet friction.

Thanks!
 

Just wanted to say thanks to all who responded. A special thanks to tinypanzer, you hit the nail on the head. I went out with a can of compressed air and sprayed it through the crack in the door and it opened right up! Thanks again!