Glow Plug Removal

[crashz]

While my 87 is laid up for some frame repairs and I have the nose torn off, I've decided to replace the glow plugs. The first one on the passenger side front, unscrewed just fine, but began to resist as I progressed. I unscrewed it out until the threads of the glow plug were clear of the head, but it would not pull out with light force. Fearing that the glow plug is swollen, I screwed it back in.

Does that sound to you guys like a typical swollen GP? Whats my next move if so? I'd like to get the truck back up and running well, but my time frame is not critical. The only probelm is that if I have to remove the heads, it will sit "headless" for some time.

BTW - all this started by chasing a simple air leak in the fuel system... :D

[DmaxMaverick]

That's a swelled plug, but you aren't in bad shape. Ideal, actually. No need to pull the head.

You could spend hours (or forever) trying to get it out, but the risk of it breaking off remains. There are methods of pulling it past the swelled tip, but it's a 50/50 chance at best it will come out in one piece. With the front sheet metal off, it will never be as easy as it is right now. Pull the injector, plug the pre-cup flash hole (foam rubber works well, and won't hurt anything if you don't get it back), break the plug off clean, a quick blast of shop air into the GP hole and the tip will blow out the injector hole. Remove the flash-hole plug, replace the injector and GP. Done. Repeat as necessary for any others.

When I replace glow plugs, I clean the hole and threads with some WD40 and a bore brush (.40-.44 caliber IIRC, nylon or phosphor-bronze, NOT stainless steel) attached to a drill. Some slow in/out passes and they are clean as a whistle.

[Subzilla]

Swollen? Not necessarily. Usually they are heavily carboned up and I found that if you keep turning them and pulling on them, they will eventually pop out.

I've heard of others unscrewing them, then cranking the engine and let the cylinder compression blow them out. Never done it so I don't know what happens when they bullet into your wheel well.

Another trick I've never done, is to unscrew them as you did, then vice grip 2 pieces of metal on each side of the GP threads. Then unscrew them some more. In theory, the GP threads will cut into the metal and pull themselves out of the head.

But, if they are swollen, you can go ahead and bend/break off the tip, then remove the injectors and fish out the broken piece out of the injectore hole with the old grease on the finger trick. Make sure you get all of the pieces out - match them up with what's left of the GP.

[DmaxMaverick]

You could. However, the ONLY way to absolutely guarantee you won't have to pull the head is as I described. You could work it out, use a puller/device (split nut, aluminum tubing, brute force, etc.) but the risk of breaking it is always present. Break it off and it may fall through the flash hole and sit on top of the piston until you do something about it.

Do yourself a favor. Invest a little time and do it right while you can. Cleaning up a mistake later is option #2.

[Subzilla]

Yup, like your method. Never heard of blasting with the air - sounds proper.

[crashz]

Thanks Dmax and Subzilla!

I didn't realize that I would be able to work through the injector hole, but it does make sense. The GP and injector are on the inside of the pre-cup, so assuming I can block that pre-cup hole, I should be able to clean all of the broken bits out with nothing falling into the cylinder.

Some other folks have mentioned that the GPs could be just carboned up and that I need to keep unscrewing them to get them out. But either way it seems like a pile of debris to fall into the cylinder. I'll pull the injectors and follow DMax's instructions.