300E Fuel Pumps and Filter Leaking

I just finished replacing the fuel injectors and fuel filter on my 89 300E.

As expected, it took more than the usual cranking time to start it after servicing, but it appears to be idling properly.

I left the fuel pump and filter cover off so I could check for leaks, and there appear to be several. The leaking is mostly from the banjo fittings on the end of engine-facing end of the fuel pumps and the new fuel filter. The fitting on the rear-facing side of the filter also has a slight leak.

The lower fuel pump and the plastic housing below it had a bit of residue from fuel and grime prior to changing the filter, so I think there may have been a small fuel leak previously.

Is it that the fittings on either end of the fuel filter just need to be tightened? How tight do they need to be? I was concerned about distorting the fittings if I overtorqued them.

I have a copper seal ring inset on either side of the fuel filter, and I am assuming that is correct.

In reference to the fuel fittings on the end of the fuel pumps, do they just need to be tightened, or are there seal rings, seals, or washers that need replacement?

Apologies for the length of this post. Any and all advice would be welcome. I really need to get this car back on the road (And not as a potential fuel bomb)

[Mike Murrell]

Hopefully you used new copper washers on the end of the filter. I had one begin to leak after replacing it and found that it needed more snugging up. I thought I had it tight enough , but didn't.

[csnow]

There should be a copper washer on each side of those 'banjo bolt' fittings, one on the head side, and one on the other side.

Tightening really should work. The copper washers do all of the sealing here, though they must be flat and clean. This is not a place where you can add sealants, or teflon tape, or the like...

See image at:
http://www.eccentrix.com/computer/csnow/images/MBFP.jpg

An update from this morning..

On closer inspection, the copper seal rings on both fuel pump banjo fittings look old and tired. I am going to remove the entire filter and pump assemblies next week, and replace and retighten all fittings on the workbench. I have had enough of laying under the car with fuel dripping on me.

Speaking of fuel pump and filter removal - Does anyone have a recommendation for disconnenecting the fuel supply hose from the tank before I pull out the fuel pumps?

Unfortunately, I have about 3/4 tank of gas. Do I need to drain the tank before this project?

Thanks guys for the replies so far.

[ronald_m]

This thing happen to me when i tried changing my fuel filter,I need to crowled under the car the gas smell terrible i didn't fix the leak so i had to bring to mechanic to lift the car for better access.It cost me $30.

[Mike Murrell]

You don't need to drain the tank, but you will need to clamp or plug the fuel line(s).

The previous poster mentioned an access problem. Fuel pump work on cars that have a rear-mounted pump is more easily achived if you first back the car up on ramps. You don't have to back up all the way, but enough to give you added crawling space. Afterwards, set the parking brake and block the front wheels. I always pull the ground strap off the battery too. If you create a spark by unintentionnally grounding something, you and the car may be unintentionally gone.

[pmizell]

and was surprised to find that the new filter came with only one copper washer. You can buy these at Fastlane under the category 'tools and hardware'. Washer is what you're looking for for future reference.

Good luck

~Paul

__________________
'91 300E, 213K miles

[csnow]

It's much easier if you can drain the tank.
15 gallons is a lot to contend with.
I was fortunate enough to have an oil extractor that worked fast on the 5 gallons I had in there.
If you got a cheap $10 siphon pump and 3-4 5-gallon gas cans, that would work too.

It may be possible to pinch off the rubber portion of the supply line. They make special hose-pinching tools just for this purpose, though you can use a big pair of visegrips and 2 pencils, chopsticks, or equivalent. The idea is to clamp it off without damaging the hose. Place one chopstick on either side of the hose, and squeeze them together with the visegrips.