'98 E300 TD with glow plugs stuck in head - Page 3 - PeachParts Mercedes-Benz Forum

Todd Miller · #31 02-20-2009, 11:51 PM

Well, here's how royally screwed I currently am. While drilling out more of the center of the glow plug, the drill suddenly moved inward about 1/2". Right after that, the outer shaft of the glow plug started to spin in the head and just came right out when I removed the drill bit.

However, the center element had actually come loose and had moved forward.......the sudden movement I got in the drill.....and that 1" or so of electrode tip is now down in the head, inside that last bit of oriface that it would normally protrude through.

It's not attracted to a magnet enough for my pencil magnet to drag it out. I duct taped some 1/4" diameter fuel hose into my shop vac, but couldn't suck it out. Did a test of putting a drop of super glue on back end of a 4" long drill bit and tried to glue that to the electrode of another glow plug....it wouldn't stick.

Anyone have some advice? I thought about cranking the engine over and maybe compression would force it out. But I'm worried that it might fall into the engine. I've pushed gently on it, and it appears to have bottomed out on whatever there is of the pre-combustion chamber. I also thought about removing the injector and using compressed air to blast it out. But the injectors are about 8" long (or look that way) and so it looks like that'll take a special deep socket.

This is so f

cked.

Here's a shot of how far off I got with the drill. I should have been inside the center of that bullseye, instead, you can see how I was off at about 1 o'clock. @#$%!!!!

Todd Miller · #32 02-21-2009, 12:00 AM

Broken glow plug

Cutting the electrode off. I'd already slid the broken nut off of this one.

Electrode cut off

Drilling out the threaded area begins

Picking out the threaded remains of the glow plug

Getting down into the threaded area of the head

Center of glow plug drilled with 17/64" bit and tapped for 5/16x18

Grade two 5/16"x18 rod threaded in, and the glow plug is starting to come out. Note: Not shown is the step where I had 2 sockets slid down over the rod, 3 grade 8 washers stacked up, and a grade 8 nut being tightened against the washers

Glow plug removed. Note: I had to switch to a 13mm deep well socket so that the glow plug could be sucked all the way out of the head.

Re-tapping the head 12mmx1.25pitch

turbobenz · #33 02-21-2009, 02:48 AM

I would try the glue method again but with something gooey. Something that can just grab into it like putty or something. What about a surgical hemostat?

Has anyone ever tried taking a welder or a welding torch to one of these? Ive removed amny seized and broken off bolts with my mig welder. For example, bolt holding the shot to the LCA snapped right off. Took the welder, tack welded an allen key to it and it came out with zero force. The extreme heat of getting red hot seems to break all threads completely loose. I did the same thing on a bellhousing bolt and a motor mount. I bet if you took a welding torch and heated the end of that glow plug to orange hot really quick you may be able to break the bond. That or get liquid nitrogen and super cool the GP to shrink it. Yes, you can buy LN at some gas suppliers.

nhdoc · #34 02-21-2009, 07:21 AM

while you do need a special socket to remove the injectors it is not that hard to do it and it might be the best next step. The socket only costs about $25 from a dealer and they are also available aftermarket. I'm not 100% sure but I think the hole from the injector is a little larger and goes right into the same chamber where the tip of the GP sits so you might have more of a chance of getting it out from there - or blowing it out through there with compressed air. Others with more experience with the pre-chambers on these engines might chime in...

aklim · #35 02-21-2009, 08:14 AM

IF the glowplug is in the prechamber, maybe you can remove the prechamber and the tip that is in the prechamber? Just throwing out an idea.

nhdoc · #36 02-21-2009, 08:16 AM

Update...I looked in the EPC and it definitely looks like the part you broke off is in the prechamber. This is accessible from the top through the injector hole so I would first try and remove the injector and then you can see if you can get it out through the hole in the top of the prechamber. In the worst case scenario you can remove the prechamber itself. It is still a lot less work than pulling the entire cylinder head but I think you will need a special tool to do it with.

If you want to borrow the socket for the injector you can PM me or someone else here probably has one you could borrow as well.

aklim · #37 02-21-2009, 08:30 AM

Quote:

Originally Posted by nhdoc

If you want to borrow the socket for the injector you can PM me or someone else here probably has one you could borrow as well.

For the price he can get it for, I would say he is better buying it. A few bucks in shipping, time and a few bucks more to ship it back and what do you have? Nothing to show for it.

Besides, I always recommend taking out the injectors every 100K for testing. That is why I bought mine.

Edit: Hell, I'd lend him mine but the cost of shipping vs buying his own and it is small enough is discouraging. Now, the prechamber tool is a different story.

nhdoc · #38 02-21-2009, 08:39 AM

Quote:

Originally Posted by turbobenz

I would try the glue method again but with something gooey. Something that can just grab into it like putty or something. What about a surgical hemostat?...

I think the challenge will be getting the piece which broke off to line up with the hole. If it was still lined up then getting something to stick in it would not be bad but I suspect it is not lined up and has fallen into the pre-chamber which means it would be tough to even get it to blow out that hole...that's why I suggested trying going in through the injector's opening which I think it larger than the GP hole.

Also, in looking at the photo again it looks like the hole which is off-center is the hole in the side of the pre-chamber...whether that will cause a problem or not I cannot answer but it might. Still, if you can get the broken part out without removing the prechamber I would do that and see what happens once you get it all put back together, but, if you do land up removing the prechamber it probably makes sense to replace it too if it is damaged.

Todd Miller · #39 02-21-2009, 12:59 PM

Thanks for the advice guys.

I was able to re-drill, right down the center, from what you see in that photo. The center electrode was still inside the GP body, so I think it's so long that it may still be inside the oriface, and not just fallen down into the prechamber.......but I'm not sure. Looking inside with a mirror and really bright light, I think I can see the back end of the electrode, still in the oriface, and using a 5" long 1/8" drill bit, I can plush against it and it doesn't move any further into the head. So I think it's just sitting there.

So here's what I'm going to try. I've got some rare-earth magnets out of a computer hard drive. I'm going to trim one to fit down in the GP hole, let it stick to end of my 5" long 1/8" drill bit and see if it will "suck" the electrode out.

If that doesn't work, I'll try to make a socket today by welding together a couple of deepwell sockets.

So if anyone knows; what size socket fits the injectors? 27mm like on most other diesel stuff?

TMAllison · #40 02-21-2009, 01:02 PM

The inj socket is 22mm, has a cut out on the side to slip past the return line barbs. Youll need a new heat sheild if you pull the inj.

http://www.peachparts.com/diy/mb_tools/mb_tools.php?page=19

From memory, its about 4.5" long. Its also thin walled.

Todd Miller · #41 02-21-2009, 01:39 PM

I'm climbing in off the ledge.

I was able to remove the electrode tip.

Setting a 150w halogen work light in next to the head and lifting up the thick weathersthrip seal that's on the inner fender, I was able to get a better look into the hole. I could see a shoulder of the electrode sticking back. The magnetic tricks still didn't work. But the idea to use something sticky did (HUGE thanks to "turbobenz"). I wadded up some 3M strip caulk (dumb-dumb) onto the end of my long drill bit and simply dragged the electrode right out. It was as if I knew what I was doing

.

But I'm not out of the woods yet. The threads in the head or so wallowed out, that even though I've recut them, they are too large a diameter to hold the GP tight. NAPA can get a heli-coil kit by Tuesday for $68, so I'll have to wait until then.

You guys have no idea....actually, what am I saying, of course you do....how much you've helped me. Thanks a million times over.

TMAllison · #42 02-21-2009, 01:53 PM

Kartek used a time-zert(sp). Was very neat and clean.

Todd Miller · #43 02-21-2009, 04:08 PM

I like Timeserts also.

Just found the local machine shop that I use was open today, and they just loaned me their Heli-Coil set, their 31/64th drill bit and a drill big enough to spin it. Going out now to do the repair and then I'll report back.

KarTek · #44 02-21-2009, 08:03 PM

Nice job! Be ULTRA carefull how you align the drill and insert. Proper seal of the GP depends on it going straight into the hole and this is dependent on the porper installation of the coil/insert.

mikemass1221 · #45 02-21-2009, 08:50 PM

Ok... here's my story. I snapped off the #1 glow plug (one closest to the front of car). Followed all the steps for removing broken plug. But when I got to the step to tap a 5/16" thread in the body of the plug, I snapped off the tap inside the plug... YUP! the tap broke while wedged in the body of the plug. Now what? Guess the head is coming off. any other way?