a/c hose o-ring
 

I'm changing the a/c hoses on my '85 300D. All of the hose connection 0-rings are of the normal variety, except one. On the high side hose connection to the condenser, the o-ring has a flat contour to it, rather than round. Is it necessary I use an exact replacement, or will a normally shaped round 0-ring suffice?

Are you sure that it is not a round O-ring that has flattened from age and pressure?

Also, if you are preparing the system for changeover to r134a use, be sure to use green o-rings.

Good luck,