RickS

I have just become the proud owner of a 1988 300E. I finished off a head gasket job, started by the previous owner, but now don't know the engine vacuum connections. As I live in California, which has very strict emission laws, this is a a critical question. Specificaly, the fuel pressure regulator vacuum line appears to go into the "rocker cover to air filter" rubber hose. On all other fuel injection vehicles I have worked on, this line goes to the inlet manifold, so as to keep a constant pressure across the injectors. Anyone know the answer to this, or where I can get a manual, California specific, which covers this question.
Also, I decided to replace the brake fluid, but a little while after the clean fluid came through, air appeared. Checking the reservoir indicated it was at max. To cut a long story short, I found the reservoir is built in such a way the rear brake chamber does not fill unless you keep the level well above 'max'. Does anyone understand the reason for this design?

Thanks in advance.

mhorn

I don't know if this helps, but I broke that little vacuum line that feeds into the Black goose neck "rocker cover to air filter" rubber hose on my 1991 300E. I was trying to get the rocker cover hose off so I could remove the air filter housing and it was stuck. When the rubber piece finally popped off, it broke the little vacum line that was attached to it. Haven't replaced it yet, but it had no noticable effect on idle, starting, or fuel economy. You may be able to get by without it.

RickS

Yes, that sounds like the one. The 'goose neck' has a small hole for a vacuum line, and the only line that appears to reach there is the one from the fuel pressure regulator. Do you remember if yours went from the goose neck to the regulator?

RickS

mhorn

Can't really see where it goes without taking off the air cleaner. It appears to plug into whatever is under the front of the air cleaner (closest to the front of the car) Like I said I've had to problems since it broke so I don't think it's that critical.

RickS

Hey,well thanks for looking. The fuel presure regulator is just a little forward of the fuel distribution unit, so I guess thats where yours is going.

Thanks for the help.

RickS

oliverb

The plastic becomes brittle near the engine because of heat and also probably age. Just replaced the same section on my 300E a few weeks ago while cleaning and lubricating the accelerator linkages. A piece of the brittle plastic hose broke off up inside the "goose neck". Was able to break it up by gently crushing it by squeezing the rubber nipple with a pair of pliers, and then work the pieces out so the new hose would seat fully.
OliverB