I am replacing a diesel injector on my 84 300 CD. I know I should do all of them at once, but I'm only doing this at all because one is weeping badly and it must be removed.

I have a rebuilt bosch injector and acces to a garage with plenty of tools.

I have a 27mm deep well socket to get the injector out, but what aobut the 17mm special tool used to remove the fuel lines? is this really neccessary or can I just use my 17mm open end wrench to get it done?

I'm guessing this has something to do with applying the exact amount of torque to the fuel lines, something you can't do accurately with a box wrench. Still, I'd rather not have to invest in another special tool if I can help myself.

My only concern with getting the injector out is that I may loosen the entire socket and not just the injector. What then?

What about the little washer that goes inside, or the condition of the ball socket itself? Anything I ought to look for while I'm in there?

Any thoughts on the task are welcome, and thanks

Gil

There are kits to do this.
If you are going OEM.

And they replace the fuel lines completely.

You may want to consider a variable pattern injector and not a fixed pattern type.

They are used on performance diesel motors ... Like the Ford PowerStoke.

I am not sure if they sell them for the Mercedes, think so.

You will need to adjust the injector timing as well.
This is very important.

Diesels are sloppy when the injector timing is concerned.
Not like gas type injector systems.

Having it tuned, will give you the most noticable power gain overall ... even if you just use the old ones for that matter.

And you should replace them all.

What happens is the spring inside the injector gets worn, and eventually does not perform correctly.

Thanks

All you really need is the 27mm socket, torque wrench, a 17mm open end, pair of 8mm wrenches to take loose the line clamp, and maybe some new cloth fuel return hose. Loosen the line ends , then take the clamps off then remove the steel line. Remove the return lines from the injector. Remove the injector with the big socket. Remove the heat shield (the funny little washer below the injector-note which way it was put in). Install the new injector and use a new heat shield-you remember which way it goes-right? Torque the injector to 70-80 nm. Redo the steel line. I like to tighten both ends, then back off the injector end one flat. Put the cloth covered return lines back on. Sometimes you can just cut off the last 10mm of the line and push it back on the injector, sometimes you just have to replace the line. They can leak pretty easy (that isn't the real source of the leak is it?). Reclamp the steel line. Have soemone start the car and as soon as fuel starts to come out of the slightly loose nut at the injector, tighten it down the rest of the way. I like to do it this way to get the air out of the lines in hurry. Officially, the line nuts should be torqued down to 25 nm with the proper tool and a torque wrench, but I have yet to have a problem this way.
Now if we could just set the timing as easily with a dial indicator on the Benz as I can on a vw diesel.

Setting the IP timing on an MB diesel is pretty easy, IF you have a 1982 or newer engine (except the 240D). There is a "lock" tool that you insert in the side of the IP, it will fit in place when the IP is at 15 ATDC. Fiddle with the pump rotation & the crank at 15 until it all lines up, tighten down, rotate a few times to check, and you're done. The OM60x engines are even easier because there is a turnbuckle to rotate the pump exactly where you want it. The lock tool costs ~$25 from the dealer. There is a different tool that allows you to move the pump & engine with the tool in place (which you CAN'T do with the lock), but it costs ~$250...

Both are much easier than dinking with a dial gauge like the VW though!

Regards,

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Before reoplacing the injector, replace your cross over lines...
I thought I had a leaking injector and in fact it was the cross over that leaked just enough fuel that it settled at the bottom of the injector and made me think that it was the injector.
Replaced the hoses and voila, no more leak.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

I've yet to begin, but I am fairly certain of one thing, that the fuel is coming from the center of the injector, between two threaded parts. The injector itself has sprung a leak between two major components. I'll double check the lines to be sure, though.

What needs to be adjusted on the injector itself? Something about timing? I understand the bit about loosening the fuel lines and starting the motor to clear out the air (good trick!) but I'm not clear on what needs to happen as far as timing adjustments.

I don't know nor have I ever heard of any kit involving variable pattern injectors for this engine, but I'm interested for sometime later on. Where do I look for these?

Meanwhile, I'm not going to get overly anal about micro adjusting anything, if possible. I really just want to get the fuel leak solved. Do I really need to fuss with timing at all?

Seems to me this shouldn't be much more than an advanced spark plug change, task wise.


Feel free to correct me if I'm dangerously oversimplifying this job.



Gil

Just replacing an injector will not affect your IP timing.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

Forget variable injectors, they are not available for MB's. Injectors do not affect IP timing, only the timing chain & IP placement do that. However, inejctors have a spring inside with a precision spacer that sets the "pop" pressure of the injector. Each of your 5 (or 6?) injectors need to have the same "pop" pressure, within about 3 bar preferably (spec for turbo engines is 135 bar I believe). If you install an injector with a significantly different setting than the others, you will have a rough idle. You can't do this yourself, a diesel shop with an injector tester & shim assortment is required. Or you can buy a used pop tester for ~$200. You might get lucky and get one that bolts in & works fine out of the box, you never know. It's still VERY strange to have a leak between injector sections, there is bascially no "seal" between them, you would have to have a damaged or severely worn body to cause this. I still think your problem is something else, like the return lines, or the two sections not being tightened together...

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Gil,

My number 4 injector is leaking in the same spot that you indicated. I replaced the return line and tightened the fuel feed fitting but it continues to leak. It almost seeems as if the return line barb at the base is possibly at fault also.

I am going to take a closer look at it tonight to see what is up.

I've heard of problems caused when people used a knife to cut off the return hose. This "nicked" the hose barb and caused leaks. Not sure what the cure is, but the preventive method of removal is to use needle nose pliers to pull (or pinch off) the hose.


Good luck,

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sniezur

Have had that problem myself. Found it to be the small barbed part on the injector was bent and leaking. I figured there was little fuel pressure there, so I removed the injector and straightened that part and tapped it back into the injector body.
Seems to work ok. Has not been leaking now for several months.
Give it a good look, although usually the leak is at the return line.

Old Deis:

What small barbed part are we all talking about? On the line or on the injector?

Gil

Gil,

The barbs are on the injector body. The 6 mm cloth covered return lines push onto them. Each injector has two barbs so the return lines can daisey chain to each injector then to the spin-on filter mounting bracket.

OK, I know now. The little spouts on each injector are the "barbs".

Well, come to find out, it IS odd that an injector should be leaking from the middle of the injector body.

In fact, those lines were looking a little old, and yes, I found that it was a leaky cloth line, and NOT a bad injector (thanks,gsxr!)

What's the best way to plug off the last injector in the series? Currently, I have a little bit of cloth hose coming off the last barb that is crudely blocked off with a bolt or something. It doesn't look like a factory fix. Any proper way of blocking the final barb, or is it supposed to lead somewhere else.

Any thoughts?

Gil

If the last one is not leaking with the bolt I would leave it alone. There is a "plug" that is used at that location but all it is going to do is "not leak" - just like the bolt if it ain't.

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Jim