leaking fuel expansion tank

[Markus]

After leaving an unsecured tool box in the trunk, when making a sharp turn it crushed/broke one of the small vent pipes that fit into the bottom of the fuel expansion tank. Has anyone had any similar problem, or successful repair method?(MEK/permatex) The plastic pipe is cracked 3/4 inch below the receiving boss, on the reinforced serrated section. This is the large expansion tank on a late 70 280sl.

[Markus]

Well I have never answered my own thread before, but this is what I did. (see if it works)  Blew lots of compressed air through the tank after leaving it in the sun to purge out all fuel vapors. Snipped off remainder of broken pipe (about 3/4 inch) Drilled out receiving boss on tank to accomodate the piece that broke, inserted plastic pipe, and bonded with JB Weld epoxy composite. So far, so good.

[hands_aus]

was the plastic pipe designed for petrol use?

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Markus]

The 3/4" was snipped off the original black vent line, and inserted into the drilled out boss at the expansion tank, so now its just about 1" shorter, and compensated for with a longer rubber fuel hose connection at the fuel tank. Confusing isn't it?

[tuultyme]

I also had a leak in the line going to the expansion tank.  But I also had gas in this line; which do to the leak I was getting gas into the tunk.  Temperarily I sliced a translucent line in to stop the leak.  My question is; should there be any gas in this line or in the expansion tank; late 70 model? I have ordered another expansion tank valve to see if that makes any difference.

Bruce; 268Blaugrun(green) 1970 280SL; IL

[Markus]

I would say "Yes"  There is on occasion fuel in both the expansion tank and the line, or at least there was in mine. Most common after a fill up, cornering with a full tank, and temperature decreases which cause fuel vapors to condense in the expansion tank.