ok ive searched and searched. the glowplug element keeps braking on #4
and the pre chamber has been replaced so my mom tell's me. it looks like someone hit it with a hammer until it broke. what could be the problem? i'll get a pic of it when i can . all the plugs are new bosch . she had brout it to a mechanic when i couldn't figure it out "my computer was down" and we thought i was fixed . nope . she's about to buy a nothere car ! i want to fix it ! she kepping
the MB thank god . i know this thing can be reliable uhg . the mechanic was talking about a rebuil for 2000-3000$ the mechanic was the 1st owner the secont was a ministor and then my mom

1977 240d
thank you tangent

Ball pin in the prechamber is most likely broken and bouncing around. This will beat the filament to death.

Check by removing the injector -- ball pin should be visible as a sphere held in place by two small extensions on the sides sitting directly under the hole in the prechamber.

If broken, it needs to be replaced, and this means pulling the prechamber. You MUST use some special tools to do this, so I'd suggest finding a shop so equiped, it will be cheaper than the tools.

If the prechamber is badly beaten up, it and possibly the injector nozzle will need to be replaced.

If the ball pin is OK, have the injector checked, a bad one can burn the filament off, too.

In either case, you will have noticable injector knock on that cylinder.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Is there any "trick" to seeing the visible ball pin through the hole left after the injector is removed? Or, is it a matter of having a top quality flashlight and 20/20 vision, and I didn't

My experience from about a month ago was that I couldn't tell much of anything when I looked for the ball pin. I

Also, when you say the small extension from the sides holding the ball pin, is that talking a left-right orientation, or an up and down orientation?

Just a flashlight. It is just below the hole were the injector nozzle goes, and should be obvious.

The pins are on the sides, more or less right to left.

You might want to crank the engine briefly with the glow plug or injector out to glow out any fragements of old glow plug stuck in there, or fish a small magnet into the glow plug hole.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

some pics

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another

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can a short cosed by the injector some how lead to a phisical breaking of the glowplug the only other thing i can think to do now is pull the head and have a look

tangent:

A short will definitely cause the filament to break as it will be overheated.

Check the next glow plug (#3) for a short to ground. If that one is grounded, it will burn out #4.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Ok, if you think this is being broken going in.... you need to check the thickness of the spacer .... if a head is milled then different thickness spacers are required.... then a REAMER must be used to realign the hole and the precombustion chamber....

thanks for giveing me something to work with other than having to pull the head

I should have been more specific with the possibilities... since the prechamber has been replaced there is also the chance that the spacer was forgotten when replacing it..... or two were put in .... that sort of mechanical misfit... not just if the head had been milled...

they didn't pull the head when the replaced the prechamber . i was thinking about pulling the head becuse i thought i was out of options i'm still learning

The head does not need to have ever been off the car for them to pull the precombustion chambers and mess up the shims.... this is done from the top.. just as the ' check' and ' cure' are being suggested for your actions....

one i'm swaping the injector with the broken glowplug element
with one that i know works to let us know if it's the injector


two is there any threads relating to the proper asimbly of the precombustion chambers or any good links or pics
my manual is crap

Yes there are... but the PCC's are really simple... and I am sure I have posted the ' cutaway' side diagram of them from the manual....
If you can't find it email me and I will email it to you ...