I've read quite a few threads on the topic but most of them deal with the after-math of what went wrong during the fuel filter replacement process. I've gathered bits and pieces from that but wanted to be sure on the steps - sorry, don't have the FSM yet - so plz, can someone outline the proper procedure for replacing the main spin-on filter and the secondary in-line filter on the '87 300SDL? The process seems a bit more difficult on this car since it has no primer pump like my 300D...

Many thanks -
James

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

James, I'm stepping out a bit here since I am not really familiar with your system. However on my 123 and 126 I don't even use the primer. I just fill the new filter up with fuel and put it back on (main filter). On pre filter, I just have the new filter ready and don't let a lot of fuel leak out of the lines when changing. I do have the backup of a primer pump, but never have to use it.

__________________
John Schroader
bio burnin' 83 300D, '83 300 SD, '79 240D
"I've never met a man who was good at making excuses who was good at anything else" Ben Franklin
"You cannot permanently help a man by doing for him what he could and should do for himself" Abraham Lincoln

Ok - thx, but I'm still waiting for the FSM steps for doing this, otherwise I'll be one of those "Help me - my car won't start" threads... for sure...

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

Hello and welcome.
The canister is the secondary and the plastic clear is the primary. I know it sounds confusing, its just the way it is.
Changing Secondary fuel filter:
http://w124performance.com/service/w124CD1/Program/Maintenance/My81/0780.pdf
Changing Primary Fuel Filter:
http://w124performance.com/service/w124CD1/Program/Maintenance/My81/0781.pdf

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92 300D 2.5L OM602 OBK #59

Here's what I did with mine when I replaced them (very recently):

I did the primary (clear filter first).

1. Note the orientation, pinched off the lines with vicegrips and softjaws.
2. Loosened hose clamps, drained the filter into the new secondary filter canister (didn't want to waste any diesel).
3. Put a new filter in the same orientation, tightened the hose clamps.

Next, the larger secondary filter.

1. Survey the area, figure out how you're going to get it out. Mine's obstructed by the upper radiator hose and a large vacuum hose.
2. With a plan of attack, loosen the bolt at the top of the housing, and slowly extract it from the bottom. If it's like the 300D, the only way out is the front. It'll be extremely full, so, it's worth your time to cover things up with rags, so diesel doesn't get everywhere.
3. Carefully remove the filter, and put it some place it won't spill.
4. Put new o-rings on the banjo bolt. There are two.
5. I put my new filter in place and slightly offset to fill it. If you don't fill it manually, it will take a very long time to fill it by cranking (also, it's hard on the battery and starter). I used a tube and filled mine with powerservice, as full as possible.
6. Hold the filter firmly against the housing and replace the bolt. Tighten by hand, and then snug with a wrench.
7. Remove tools from engine compartment.
8. Crank car. I did about two 10-second intervals. After that point, it started to catch, and I was golden.
9. Check for leaks.
10. Test drive for good measure.

Attached Thumbnails

 

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1982 240D, sold 9/17/2008
1987 300D TurboW124.133 - 603.960, 722.317 - Smoke Silver Metallic / Medium Red (702/177), acquired 8/15/2009
262,715 and counting

Thank you much -

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

The FSM procedure is trivial -- remove old filter, install new filter. It's pretty much the same as your old 300D. The secondary filter is perhaps a little harder to get off and on.

The only "tricks" I've learned from this forum, other fora, and personal experience are:
(1) A warm engine will start more easily after filter changes;
(2) A freshly-charged battery is nice if the engine happens to need more than average cranking;
(3) If you use hose clamps (Vice-grips(R) will work if you're gentle), you can minimize the fuel that will leak out of the lines while changing the primary;
(4) The fuel tank should be at least half full and it helps to have the car in a nose-down position so fuel will flow from the tank w/o help;
(5) It's very difficult to get a secondary filter into place while it is completely full of fuel without spilling. Fill it mostly full, then wiggle it into place and put a wedge underneath to keep the filter pressed up against the housing. Now use a funnel to fill the filter the rest of the way and put the central bolt back in place. Tighten the bolt with a wrench, don't turn the filter. Make sure the one or two sealing o-rings on the bolt are in good shape and don't over-tighten the bolt, it's only threading into the filter.

Crank the engine; it should catch immediately; keep the engine at 1000-1500 RPM while any remaining air bubbles are pushed through the system. Check for leaks immediately and after a day or two of driving.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I say what others in this thread have said (replace hollow screw o-ring, etc) - plus the following:

First get the radiator hose out of the way by loosening the hose clamps and disconnecting it from the engine side only - at that point I turn it up perpendicular to keep from losing much coolant. Then get the brake booster vacuum hose out of the way (I just disconnect it from the vacuum pump)

Throw a couple of shop rags in the space under the canister housing, remove the old canister (grip it with one hand and and turn out the hollow screw at the top) and then carefully maneuver the full fresh canister into place threading the hollow screw into the canister until snug - the torque spec is 25 Nm. Reattach everything in place. Before cranking, crack each injector line, stuff rags around the injector line nuts, disconnect the glow plug relay (black box on the driver side fender well) get in the car, press the accelerator to the floor, and turn the engine over for 10 seconds, stop for twenty seconds, repeat for a total of 3 or 4 cycles of turning it over. Collect the rags, torque the injector line nuts to spec, and reconnect the glow plug relay. Crank the engine and enjoy a smooth idling, airless fuel supply circuit.

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327K on 1986 W201, 602.911, 722.414 2.5 190D ("The Red Baron")
139K on 1993 W124, 104.942, 722.433 2.8 300E ("Queen")

http://farm5.static.flickr.com/4081/...0bb92d3c_m.jpg http://i370.photobucket.com/albums/o...g?t=1325284354

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
- Albert Einstein

take a walk down memory lane...

Many thanks - great tips... I feel well equipped now...

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

An old trick to getting the air out. If you disconnect the return line from the filter and CAREFULLY apply low pressure air to the return line to the tank. You can apply a little pressure to the tank and this will push the fuel up through both filters and if you have a piece of clear hose on the filter return line connection into a container you can see when the air bubbles stop and only fuel is in the system. when you disconnect the air, be careful as fuel may come back up the return line. I have done this many times to avoid using the old style manual primer.
BE CAREFUL and don't just use air line pressure, I saw a guy blow the filler cap off the gas tank once.

Ok - now that I'm all done with the tank cleaning and hose replacement process I need to slightly modify the steps for restarting the car knowing I've got some air in the fuel lines....

I've replaced both main (clear) filter and the spin-on filter with brand new ones. I filled the spin-on with PowerService to the brim and then I snugged the bolt on top - should be good and full, but the clear filter has plenty of air in it, so here's the steps I'm planning to follow. Note that the car's rear end is still elevated high on the ramps, which should help somewhat with gravity-fed fuel flow from the tank:

1) Press the STOP lever and wire it in place temporarily so I don't fuel feeding into the cylinders.

2) Disconnect the glow plug relay

3) Fill the tank with clean diesel (I plan on putting about 10 gallons in)

4) Loosen one of the Banjo bolts on the filter to allow the air to escape out of the top. Put some rags there to avoid fuel spillage.

5) Disconnect the return line and use some type of pump (bicycle pump or the Mighty Vac pump) to produce slight pressure in the tank thus forcing the fuel thorught the clear filter, lift pump, spin on filter and out through the gap I create by loosening up the banjo bolt on the spin-on...

6) Pedal to the floor and start cranking in 10 second intervals with 5 second brakes in between and hope it starts eventually...

The things that I'll have working against me will be:
a) The car will be cold since it has not been running for a week
b) The battery may not be the freshest - I may hook up a battery charger accross it for extra starting power.

Anything I'm forgetting that I should do (like pray... )

James

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

Plug the bock heater in for a couple hours before you try to start it!!!!!

Firstly, I don't believe you can pressurize the tank and force fuel back toward the primary filter. The tank is vented to atmosphere.

Secondly, I don't believe you need to bother with all of the above. If the secondary is full, the engine will immediately start............might hesitate a bit and possibly stall once.

If the tank has about 10 gallons in it, the fuel level is higher than the primary and the system will self prime right to the fuel pump. The fact that you see air in the primary is irrelevant. That bit of air will go right on through the secondary and out the return line.

Just start it and mash your foot if it begins to falter. It'll run.

Yes, you were were right on both counts - I couldn't pressurize the tank that much because the pressure kept going out the vent tube, so I gave up on it - turns out I probably didn't need it. I just topped off the spin-on fuel filter to make sure it's got a good drink right off the start.

Tonight I hooked up a freshly charged battery. I plugged in my block heater about 3 hrs beforehand, so the engine was nice and warm. I ran through the full glow cycle, I cranked it, and it started right up... it hesitated a bit and then when I mashed the pedal it took off and was just fine... whew! Thanks very much - I was worried about this - was preparing for an hour of cussing and cranking, but luckily I was wrong. So glad I got it started, thank you all -

Regards,
James

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

I wouldn't want to tell you how many times I've dropped the secondary and topped it off during my little escapade with the primary............two separate trips both with full stalls due to no fuel getting to the engine.


SDL fuel issues..........the trip from hell........

Always started in about 5-7 seconds without a stall.