Hi all,
Have a small problem with my 1989 560SL, a leak at the EHA. Thought it was o-rings, but replaced with new and still a leak. Leaks as soon as the key is turned on. Gas comes out around the mounting surface and from the little holes in the black plastic housing, basically from all sides it seems like. The mounting surface is flat except that the mount screw sleeves are roughly 0.010" higher than the o-ring surface. When I loosen the mount screws after a few minutes of the ignition being off, there is still some residual fuel pressure, so must be relieving the pressure down to a certain PSI and then stops leaking.
Has anybody else had this problem? Are the screw sleeves supposed to be slightly higher than the o-ring surface, or do they have a tendency to slip in the housing? Do the EHA's go bad and leak from the inside out? Don't know if the leaking from the housing holes is due to an internal leak or gas seeping inside the case from around the o-ring mount surface. Short of replacing the EHA, are there any fixes?