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  #1  
Old 04-16-2008, 11:00 PM
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Leaky injectors (return line nipples?)

A couple of my injectors are wet. A couple of return line nipple barbs are a bit scratched and dented, so I think this is the problem. Is there any way of fixing the nipples, or is getting some "new" used injectors the way to go?

There are bubbles at the bottom of these injectors, looking as if they are not torqued down tight enough, but they're tight and the crush heat shields were new. Could there be some other common problem that I may have overlooked?
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  #2  
Old 04-16-2008, 11:27 PM
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when you pulled your injectors, did you jerk the wrench, or pull steady on it?
if you pulled steady, you most likely loosened some of the PC rings... only way to tighten them up is to buy a PC ring tool, and tighten them down... you may be able to build a tool to fit in the notch and get them tight, but others (including me...) have tried and failed...
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Old 04-17-2008, 02:16 AM
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If the nipples are truly damaged or loose there is no way that I have heard of to fix them. If they are leaking from being loose about all you can do is us an aluminum or brass drift a hit them enough to stop the leak.
If there is a big deep scratch on the nipple It might be possible to degrease it with brake cleaner and work a tiny amount of JB weld Epoxy into the crack and after it is good and hard sand the excess of with 400 grit wet and dry sand paper.
Other ideas if the nipples are scored: Degrease as above apply silicone sealant around out side of nipple and put a NEW hose over it and let it sit for several hours on a warm day before you use it, try using return lines of a different material such as Weed Whacker fuel line or 3/16" silicone vacuum line (I had some on my Volvo diesel for a little more than a year; it works but it gets so hard that you cannot use it ounce it pulled off), or how about some Viton return line.
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Old 04-17-2008, 07:31 AM
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I think I may actually have both problems because I not only have wet injectors, but bubbles around their seats. So, it looks like new return lines again, and a PC tool for $85.

Samstag sales:
Threaded pin wrench socket. for the proper R&R of threaded ring which secures prechamber in cylinder head. It is applicable on engine - OM 615, OM 616, OM 617.91 / 93/ 95.

"Pin wrench socket"?
Am I going to need a "pin wrench"? Or, is this THE pin wrench?
It's just a spanner? Or is it a socket?
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  #5  
Old 04-17-2008, 07:38 AM
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Put on new return lines, get them down as far as possible, then use zip-strips on return line just past the nipple. Fix this leak first, then don't worry about the other 'leak'. Almost always when an inexperienced person suffers from return line leakage, they think that the wet fuel bubbling at injector base is combustion gasses escaping from around injector or pre-chamber. I'll wager that if you spill diesel fuel on all of your injector bases, they will all appear to be leaking combustion gasses past the injector or pre-chamber.
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  #6  
Old 04-17-2008, 08:21 AM
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I will try that first, but I'm not that optimistic because I just changed the injectors, and I didn't "jerk" the wrench at all.

But, I cranked them down probably over torque spec. Any problem there? If anything, I would think that might tighten the PC's if they could have been loosened by removal.
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  #7  
Old 04-17-2008, 01:16 PM
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Quote:
Originally Posted by 1983/300CD View Post
I think I may actually have both problems because I not only have wet injectors, but bubbles around their seats. So, it looks like new return lines again, and a PC tool for $85.

Samstag sales:
Threaded pin wrench socket. for the proper R&R of threaded ring which secures prechamber in cylinder head. It is applicable on engine - OM 615, OM 616, OM 617.91 / 93/ 95.

"Pin wrench socket"?
Am I going to need a "pin wrench"? Or, is this THE pin wrench?
It's just a spanner? Or is it a socket?
I would look at Ebay for the tool first. Zdmak and El Paso tool sells mercedes tools there.
Change the return lines first. Maybe the fuel is leaking down there and the bubbling is caused by the diesel fuel evaporating due to the precombustion chamber heat. I bet if you stop the leak and run the car long enough the bubbling will dissapear.
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  #8  
Old 04-17-2008, 01:23 PM
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Quote:
Originally Posted by 1983/300CD View Post
I will try that first, but I'm not that optimistic because I just changed the injectors, and I didn't "jerk" the wrench at all.

But, I cranked them down probably over torque spec. Any problem there? If anything, I would think that might tighten the PC's if they could have been loosened by removal.
You did not say if the injectors were rebuilt or not or if rebuilt who did the job. If the injectors were taken apart and re-assembled it is possible for the injector to leak between the injector nut and the upper injector body. This can happen due to a cracked injector nut (the part that threads into the precombustion chamber), the injector inside surfaces were not lapped before re-assembly, injector nut not torqued correctly to the upper body, or dirt got between some of the inside parts.
Often leaks in this area do nut show up until the injectors are good and hot.
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