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Fuel strainer inaccessible. Not centered in hole.

2K views 11 replies 8 participants last post by  Fonzi 
#1 ·
I have a 1973 450sl and I'm attempting to remove the fuel strainer from the fuel tank. Unfortunately, I can't access it (see photo). As you can see from the attachment (assuming it uploaded correctly) three of the sides of the 46mm hexagonal fitting are hidden under the car body. I've loosened the fuel tank and moved it around but the strainer is stationary. Any helpful hints? Thanks,

Dan
 

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#2 ·
If you are replacing the strainer, use an ease-out inserted into the fitting... You got unlucky and the fitting came loose. Several who have had this problem had the strainer come loose when removing the line/fitting...

Otherwise, you gotta move the tank enough to clear.
 
#4 ·
Thanks for the suggestion. I thought that might be my next step. Please indulge me in a little hand-holding as I work my way through this: The fuel strainer hole is approximately 0.55 inches wide so approximately how much larger should my ease-out be? What is the success rate by the ease-out method? The fuel hose attached to the strainer came off quite easily with fewer than 20 pounds of torque so I didn't get a chance to apply a lot of force to the fuel strainer nut. If the ease-out method fails I'm definitely pulling the tank, right?

Background: I really don't want to pull the tank; however, the car has only been driven 3000 miles since 1989. It has been garaged during this time and shows no rust. The car ran well before storage, has been well maintained and was stored with a full tank of gas. The fuel I drained was possibly five years old and was clear. The engine has been running great over the past month but I'm experiencing the "hot start issue". Both times I drove the car at highway speeds it would not restart after shutdown (outside air temperature was >75* both days w/ winter grade 89 octane fuel). I assumed the hot start problem was due to poor fuel delivery so I set out to change the fuel filter and a leaking braided fuel line (located between the fuel damper cage and the fuel pump). I've since replaced all fuel hoses at the rear of the car. The fuel pump appears to be in good condition.

Based on the above info would you guys/gals remove the fuel strainer or leave it in? Part of me says, "the leaking hose has been replaced and it has a fresh filter so button her up and drive her."

What do y'all think? Thanks.

Dan
 
#3 · (Edited)
Very common problem. I had to pull the tank - couldn't budge the strainer even with an air wrench. Oh, and do yourself a favor and grind out the hole to give you clearance for next time - BUT NOT WITH THE TANK IN THE CAR.

You might be able to fabricate a custom wrench to grab onto the nut edges not blocked, like below. I tried but the thing was just too stuck.



When you put it back in use a little silicone grease on the threads to prevent dissimilar metal corrosion.
 
#10 ·
I've just been through this on our 85. What am I saying, I'm still in it. The accumulator is only one of many possible causes of not starting when hot. The accumulator is a pretty simple piece really. It's a can with a diaphragm and a big spring behind it. If you can't blow through it, it's probably fine. I replaced mine and took the old one apart. It didn't need changing. I chased this problem all summer and never solved it. This is all irrelevant if the 73 doesn't have an accumulator.
The fuel system should maintain some pressure when you shut down to keep the fuel in liquid form. I keep losing pressure and I imagine you are too. The question is, where are you losing pressure, and like I said there are a lot of possibilities.
 
#11 ·
Thanks everyone for discussing my issue. Yes, my car is a '73 so no accumulator. I've replaced the leaking (and non-leaking) fuel hoses at the fuel pump assembly. I agree with Hounut (and others) that I've got a fuel system pressure issue. Hopefully, it was due to the leaking fuel hose (the 3" hose between the damper cage and the fuel pump). Today I will button her up and drive her. It's 30 degrees F today so I expect she'll perform differently.

Fonzi: I, too, perform the "gas pedal mash" technique when starting; however, the other day the fuel flow (pressure?) never climbed high enough to "clear". This is what has me especially concerned. Even several hours later, after the engine was cool, I was still experiencing the same rough start condition. My neighbor listened to the engine turning over and said, "It sounds like you've got air in it." I think he was right. That short 3" fuel hose is right next to the fuel pump inlet.

After typing that previous paragraph I'm more confident than ever that the pump was simply drawing in excessive amounts of air through the deteriorated hose. I'll button her up and drive her and let you know the results this evening. Thanks again for helping.

Dan
 
#12 ·
If the pump was drawling in air from a hose that is below the fuel tank, and then maybe you are right that the strainer is clogged.

The gravity from the tank should be pushing gas down through that hose with some pressure higher then the atmospheric pressure.

Before I was thinking at all about your tank hoses which should be fairly low pressure (I think), I was thinking you should do a flow test with the hose that feeds the injector rails in the engine compartment. Of coarse a pressure test would also be good.
 
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