No Fuel Delivery and Best Repair Manual for 1974 M-B 240D ?
 

It looks like I've found the right place. Can anyone suggest a good Repair Manual for a 1974 Mercedes 240D?

I'm having a problem with fuel delivery. I bought this car from a friend who kept it in storage for about 6 years in an outside lot. He drove it very little for the 3 years prior to storing it and before that, it was in storage for another 7 years indoors. It's pretty low mileage for a 1974.

Anyway, it's run well for me since I bought it in 2005, however, it was leaking brake fluid from the reservoir on the side that affected the clutch. At first it was a slow leak, required filling every couple weeks and developed to needing fluid every day. That's when I scheduled it to be checked. Turned out, I needed a master and slave cylinder.

The problem is, it was starting fine until the day before I was to take it to the shop for the brake/clutch fluid leak. So they replace master/slave cylinders and then tell me that when they went to start it, diesel fuel was running out from behind the injector pump. They don't normally work on diesels so ended up towing the car back home. This was 8 months ago now. I've cranked the engine and I can't see any sign of leakage from the injector pump but I do notice that a new in-line filter just adjacent and slightly forward of the injector pump is empty of any fuel. I was just wondering if perhaps the problem is not the injector pump at all but the regular fuel pump. Would this account for no fuel being in the in-line fuel filter after cranking the engine? I'm not the best mechanic but can usually do the basics if I have a manual. Right now, I don't even know where the regular fuel pump is. I wanted to see if it is pumping fuel. Is there an electric fuel pump on this thing or is there a mechanical pump?? And where the heck is it?

Thanks in advance. The car was starting and running fine then just suddenly didn't start the day I was to take it in for the fluid leak. Is it possilbe for the injector pump to be working fine one day and not at all, the next?

Thanks for any help or suggestions.

Capt. Mike

This is where to get the Factory Service Manul CDs that covers the complete car with the exception of rebuilding the transmission. $19.99+$7 shipping
http://www.classictechlit.mbusa.com/MB/product.asp?catalog%5Fname=Retail&category%5Fname=1009%28ClassicTechLit%29&product%5Fid=QL%2D6516%2D 0507%2D02%28ClassicTechLit%29
If you are not in the US perhaps you can use the Service Manual Part Number and see if you can get it from the local Dealer.

You need to do a visual inspection of the Fuel Inlet and Outlet hoses to make sure they did not crack or break any of the tubing under the hood (Bonnet).

The Blue Arrow in the pic below points to the Fuel Supply Pump.
The Red Arrow in the pic points to the Hand Primer Pump. This is the Newest Style Hand Primer; to pump fuel you just push down and up on it.

If your Hand Primer Pump has a hard plastic Knob and an shiny Aluminum Body; that is the Old Style one. With the Old style on you need to turn the Know like you were unscrewing a Light Bulb and pull the Knob up and down to pump. When you are finished you need to push the Knob all the way down and screw it in as if you were tightening a Light Bulb.

Pumping on the Hand Primer bleeds the air out of the low pressure section of the Fuel Injection Pump.
After you have bleed the air out of the low pressure section you need to loosen all of the steel fuel injection tubing nuts up at the Fuel Injectors with a 17mm Wrench; loosen about 1 turn.
You will crank the Engine until you see fuel comming out from under the Injector Tubing Nuts; afterwhich tighten them.
And, try to start your car.
(If you run out of fuel; after putting fuel in the tank you will need to go through the same bleeding process or you will likely deaden your Battery trying to get the air out by Cranking the Enigne.)

Thank you, Diesel911
 

Thanks very much. It gives me somewhere to start and I do appreciate it. I just don't understand how/why the fuel problem developed overnight. It was starting one day, not the next and hasn't run since. Hard to believe that the pump just suddenly went bad overnight, but then, what do I know.

I'll try priming the pump and see what happens. I have a full tank of diesel.

Thanks again and I'll report back.

Capt. Mike

Well, I really do need to get some metric tools. I managed to get just one (1) of the fuel tubes loosened. After pumping the hand pump (I have the white plastic cap type) which did mostly fill the in-line filter, I cranked the engine and did see pulses of fuel at the forward-most injector coming from the loosened fuel tube. But the engine didn't even give a hint of trying to start.

One thing, on top of the injector pump aft of the low pressure pump, there is a red cap that says Oel on it. I opened it and had to stick a screwdriver in to check the level....there wasn't any. I have a feeling this should be full.....of something. Oel as in "Oil"?

I recently decided to bring this 240 back to life so I'm not very prepared with the proper tools or the manual or the basic understanding of this engine...yet, but I'll get them soon.

Any idea of how to proceed until I can pick up a set of metric wrenches hopefully tomorrow? That empty reservoir under the red 'Oel" cap is troubling.

Capt. Mike

I do not think it just died overnight.
I believe those people who worked on your car busted a fuel inlet hose causing the leak. When they tried to start the car it sucked in a lot of air.

If air gets between the Fuel Injection Pump and the Injectors in those Steel Tubings it compresses and does not want to move. Cranking the Engine to get the air out of this area takes a tole on the Battery and the Starter.

Another possibility is that after starting a car that sat a long time is that it loosened a lot of stuff in your Fuel Tank that has now plugged up your Fuel Tank Strainer (at the bottom inside of your Fuel Tank) or 1 or both of the Fuel Filters.

I am hope that you can give the Car a rest somewhere while you get a hold of some manuals so you will understand before you start tinkering.

Go up to the top of the page and put the cursor on the Resourses Button; you will see DIY Articles and DIY Links.
Click on either but read through both of them. Your 240D is similar enough to a 617 Engine as far as the Fuel System goes that you can use that information. Just disreguard the info concerning the Stuff that would go with a turboed engine.

Thank you. I ordered the Manual on CD that you suggested today. And I'll go through those threads you mention.

I didn't give enough detail in my first post though. I'm sure the guys that worked on the brake fluid leak problem in early 2009 didn't cause it not to run, though. The car is very low mileage for a 1974 having spent approximately 15 years in storage.

Here's the breakdown:

1974 Purchased new by original owner, driven until he passed in 1983.

1983-1991 Stored in original owner's garage.

1991-1998 Driven lightly by a friend who actually bought the car retail from a Mercedes dealership. Good shape to sell 17 yo car retail.

1998-2005 Stored again by my friend, outdoors this time.

2005 I purchased the car. Tank was nearly empty, put 5 gallons of diesel in it and a new battery and she started up after a few minutes combined cranking. Changed the oil/filter after I got it home.

She passed inspection after having the breaks done.

I ran the car pretty regularly from its purchase in 2005 up until I was ready to get that brake fluid leak addressed. The thing is, by then, if the car sat for even 2 days, I had to fill the brake fluid reservoir and pump the clutch pedal to eventually pump the pressure up enough to disengage the clutch.

But the engine started every time, every couple days, right up until the day, actually it was the evening prior, to me driving it to the shop for the fluid leak. I was just going to fill the reservoir as usual and drive it in to the shop. But for the first time ever, it just kept cranking and cranking with no hint of starting.

So, I had to get them to tow it to their shop and explained the starting situation to them before they started working. When I went in to pick the car up, they said after they did they replaced the master/slave cylinders and went to start it, that fuel was "pouring" out from underneath the car. The put it up on the lift and said they could see the fuel was coming from the Injection Pump.

I just found it hard to understand how something that started and ran fine a couple days earlier, was now "pouring" fuel from the Injection Pump. There is one thing, they let it sit for almost 2 months before they got to the car, but still can't see how that would cause a sudden leak like they described.

Also, so far, I can't get any fuel to leak from the pump when I crank the engine. Even after using the priming pump like you suggested earlier.

I feel like I'm in over my head, but it's difficult finding anyone who is willing to work on it around here (eastern WV) and usually, in the past, if I've had a manual or good instructions, troubleshooting, etc., I've managed to be able to fix this sort of thing. But I am by no means a master mechanic....or even close. :(

Oh well. I really appreciate you taking the time to respond, Diesel911. Thank you.

Forgot to tell ya, my IP has the red cap and I read that later models used engine oil but mine apparently needs to have oil added. I opened the red cap and it seemed bone dry in there. Someone mentioned using 15w-40. Do you agree with that? Should I fill that thing up or will the manual I ordered explain that? No telling how long that's been low on oil.

REALLY looking forward to that Manual.

Thanks again.

I would use 30wt Oil in the IP.
The IPs that you have to fill with oil vary somewhat as to how you know how much to fill them. (There shold be a pipe plug somewhere towards the bottom of the IP the drain the old oil out.)

Some of the IPs actuall have a Dip Stick on the side. Others have an upper and lower Pipe Plug. Lower to drain the oil out and an upper one you open before you fill the IP until oil comes out of that upper plug hole.

Another type has the lower pipe plug as a drain but somewhere on the IP has a short piece of bent tubing; you fill it until oil comes out of that tubine.
All of them need to be checked ounce in a while as over time Diesel Fuel gets mixed with the Oil. How, much mixes depends on how worn you IP is.

I have also read on this forum where some of th IPs do not have a drain plug and the old oil needs to be sucke out through the upper oil level plug.

One of the ways to trouble shoot a fuel system is to get a separate container with clean Diesel Fuel and hook up a longer fuel inlet hose into that container; making it a small fuel tank so to speak. This will bypass anything from there back to the fuel tank.

Thanks again Diesel911...you are a very helpful guy. Still waiting on the manual. I'm not giving up on this thing. It was running fine before. And now, I'll be able to familiarize myself with the systems and take better care of it.

Man.....I'm getting discouraged and my manual hasn't even arrived yet. Whenever I pump the hand pump, a lot of fuel squirts up around the outside of the plunger. I don't imagine that is supposed to happen.

I added oil to the reservoir under the red cap, and cranked the engine a bit, and the oil i put in seemed to disappear. Thinking that it may have circulated somewhere, I topped it off again and cranked the engine a bit more. Again, the oil seems to have dropped to near the bottom. Can this be normal?

To make matters worse, when I had these guys put on a new master/slave cylinder to stop the leaking brake fluid, before I realized I likely had a major fuel problem, I told them to put in 5 new glow plugs. Well, they never put the 5th one in the dash which never glowed before. Here's the thing, whenever I pull the starter button to the point where the glow plugs should be heating up, the red oil light on the dash always dimmed noticeably letting me know the 4 glow plugs in the engine were working. But now that 4 new plugs were put in, I notice that the red oil light in the dash does NOT dim at all when the plugs should be glowing. I don't know where to begin troubleshooting the glow plugs. Sheesh.

I'm going to do a lot of reading of that repair manual when it gets here, but I have to admit, I'm getting discouraged. Damn.

It sounds like your having a few issues here. First youhave 4 glowplugs,the little thing on the dash is just a piece of metal, not a glowplug.

As for the glow plugs youneed to check and make sure they're hooked up properly. Take some pictures and we'll tell you if they installed correctly.

You need to replace the fuel primer pump, this is probably leaking air into the fuel system. After that you need to loosen all 4 injector lines and crank the engine until fuel shoots out of each line, then tighten the lines back down, and then try to start it.