I just replaced my injectors and both fuel filters. I filled up the large spin-on filter with diesel and installed it. I cracked loose the banjo bolt on the housing at the line that goes to the injection pump and pumped the primer pump until fuel was flowing out of it, then I tightened the banjo bolt.

Then I cracked loose the injector lines and cranked several times at wide open throttle until they were all soaked with fuel, then tightened up the lines.

The car then started right up and ran fine. But, I noticed that the large top bolt on the fuel filter housing was seeping. So, I cranked it down snug and it stopped. But, am I going to have to bleed the fuel system again since there was fuel leaking out of the top bolt? I hate bleeding the system and getting biodiesel all over my engine, which I have to immediately wash off with our hard Phoenix hose water.

If there is air in the system, will it bleed itself out over time, or will it always be there causing problems?

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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Yes, pull the bolt, change the o-rings, and enjoy a working, leak free fuel filter

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I was just thinking of you when I saw this thread of a 300SD being parted out:

You might need something:

http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/357873-parting-out-w116-1980-300sd.html

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Upgrade the fuel filter housing and bolt to the new style which uses two o-rings on the bolt to seal as opposed to the copper washer under the head of the original bolt.

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Regards,
Aaron

I say that would be more likely for fuel to leak out at that spot than for air to leak in. That spot is downstream from the lift pump. So, it should be under positive fuel pressure after everything is primed up and pumping. A leak there may cause the pump to loose prime after it sits tho.

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

If you have a leaky copper washer on the fuel filter bolt, it will most definitely let air into the system- when the engine is off (via siphon action). If you install a clear hose at the filter tee going back to the tank (highest point of the system), and if you see an air bubble there in the morning before starting engine, air has gotten in. It should be full at all times.

A little bit of air in the filter should not result in a no start and that air will bleed out after a few minutes after engine start, until air get in again when the engine is off. If the filter is empty and full of air (possible by siphon drain back from a low fuel tank with the car nose up), it could stall after a start and may not start again until the system is primed.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yeah, you probably have the early style filter head, it has an 01, with an "O" ring and crush washer, whereas the newer style with two "O" rings has an 02.

Once you have the issue resolved, you shouldn't have to bleed the system, but crank until it starts.

Attached Thumbnails

       

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83 SD

84 CD

Is dimensions in pic #2 for the 01 filter head? What is in package of pic#3 and which filter head is it for?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

The first pic is of the newer (02) style.

The others are of and for the old (01) style.

The second pic has dimensions, the third has what I picked up from my local hardware store, works fine. However, I've noticed the composite washer in the package, #30 CAP THREAD GASKET, is now plastic.

I don't have any cars with the old style anymore, so haven't checked lately.

I don't know if you need the 02 head for the new style bolt to fit or not.

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83 SD

84 CD

I guess I'll have to bleed the fuel system again, though the vehicle runs fine, but might run better if there is some air in the system now.

Suginami, thanks for the link. That is some interesting pinstriping.

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DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Oh, I may not have to bleed the system, then? The filter is not leaking at the crush washer anymore. But I am debating as whether to bleed the fuel system again, just in case there may be trapped air that will never find its way out and will cause the fuel going from the pump to the injectors to compress and not put out enough pressure?

__________________
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DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Like I mentioned already, if there is air, it will bleed itself out a minute after engine starts, by design of the banjo bolt on the top of the filter tee. Like I mentioned already, a clear hose at the exit of the 5/16" barb on the filter tee, will tell you whether you have air in the system or not. There is no easier way.

If you have air, you must find where it is coming from and fix it, rather than try to bleed it out which is a waste of time until the air intrusion point is fixed

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

It's good to hear that the leaking crush washer at the filter wasn't leaking air into the system, and even if it did, the system is self-bleeding as long as there aren't leaks.

But with that said, my rebuilt injectors are pouring fuel out between the halves. I am not happy. It looks like they need to come out again. So, I might as well replace the crush washer and O-ring at the filter and vent it again.

__________________
Stop paying for animal enslavement, cruelty, and slaughter. Save your health and the planet. Go vegan! I did 18 years ago. https://challenge22.com/

DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

It's easy to to think the leak is occurring at the halves, and may be.

Make sure the jumper lines are not producing the issue.

If you determine the halves are the problem, sounds like they weren't lapped properly.

Perhaps you can tighten down on the injectors, but that may not work.

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83 SD

84 CD

If you're not leaking and it is running correctly no need to bleed....

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.