Hi all,well its time to change glow plugs.I have an 86 6.9.Plugs have been in for almost two years.Ive never changed them myself so I was just wondering if there was any special tricks or things not to do.really dont want to break one off.Thanks for any help.

 

This is what I recommend as a procedure especially for Autolite GP removal....remove air cleaner if IDI.
To remove/replace gp's get a 3/8" 6 point deep socket and suitable ratchet, 8" piece of gas line hose that will fit on top of gp. Remove gp electrical caps blow or brush clean each area around gp's, loosen gp with socket until it turns freely remove socket and push hose on top, turn out gp. For the one under the injector lines on drivers side you can use a universal joint (hard) or a 3/8 box end wrench then the hose as usual (do not force or bend lines) Test GP's and check tips.
If you have it put (small amount) anti seize on threads of new gp, you can use hose to start plugs then finish with ratchet to 12 ft/lbs or 1/12th of a turn after bottoming( this is not much torque at all)
If I were you, I would remove all gp's to see what kind they are, if they are not "BERU/Motorcraft" pitch them and buy all 8 new, if they are Beru and test good re install. If some are bad get 8 new and save old ones that are good for backups.
NOTE***If any GP's are hard to remove from hole using the hose ...."STOP" call for assistance and wait for instructions.... DO NOT force the GP to turn out as tips can break off..
PS A big old blanket over the rad helps in laying on the engine.

 

I would like to make the following comment regarding Glow Plugs: The glow plugs for the 7.3 IDI engine are a single coil unit that changes resistance very little as it heats up. This means that some sort of control must be used to prevent MELTDOWN. The Autolite 1109 or the AC 12G glow plugs have a second coil in series with the heating coil. They look exactly like the production glow plugs and will interchange perfectly. The beauty of these are that the second coil will limit the current to the heating coil preventing a MELTDOWN. The terminals are different and will have to be changed, but the advantage of NO MELTDOWN far outweighs the trouble to clip off the old terminal and crimp on a new blade type terminal. To prove this to yourselves, tke an old glow plug and hook it up to a 10 amp battery charger. Watch it heat up look at the current draw. Don't let the end get too hot or it may melt the heating coil. Now take a dial coil glow plug and do the same thing. The current will go down as it heats up and you can leave it plugged in for a long time. I used one to thaw out a frozen fauset a couple of years ago.

 

And the AC and Autolite glow plug swell when they burn out.

Sorry I will never install either one in my engine.
Thawing out a faucet....sounds like a perfect place to use them.

Motorcraft/Beru ZD 9 glow plugs only.

 

Before I changed my glowplugs I soaked each plug location with PB Blaster for a day before I removed them. I also blew off the whole area with air to get the excess crud off. the connector covers just crumbled when I removed the wires so I made sure to blow everything clean before removal.

 

Thanks for the info gang. Happy to report that glow plug swap went fine,mechanic that changed them two years ago used antiseize. One wasent even fireing. After replacing all the truck started right up. Is the BERU/motorcraft a better plug than ac delco ? That is what I had and what I put back in. I dont know what was in the truck when I bought it in 1999 but those plugs lasted until spring of 06 and 70000 miles. I have used truck less the last two years and only got 5000 miles out of the last set.

 

Didn't mean to strike a nerve. Just wanted to inform that there is are temperature limited glow plugs available that will not burn out by leaving them on too long. You surprised me with your staunch support of the Motorcraft/Beru ZD 9 glow plugs. Are they dual coil? Can you leave them on iindefinitely without burning out?

 

No they are not dual coil and you can not leave them on for more than about 15 seconds max.

But the others are famous for swelling when they burn out.
The hole into the pre combustion chamber is not much larger than the glow plug tip.
If the tip swells, when you try to remove them, the tip breaks off and falls into the precombustion chamber.
It will eventually wind up on top of the piston.
Since there is almost no clearance between the piston and head at TDC, piston damage is the result.

A few guys have vacuumed the tip out of the injector hole, a couple guys ran the engine and the broken tip has blown out.

If the vacuum trick or the run the engine till it blows out do not work, you are looking at pulling the head to retrieve the broken glow plug tip.

I have never seen a Motorcraft/Beru swell.
So now you know exactly why I am so brand loyal.

Even pulling the injectors gets you into disturbing the return line, so now you are changing the return tees and O rings.
Much more work and expense than using a good proven product when you change the glow plugs.

Cheap is rarely the least expensive way to do something.

 

I just changed all mine as part of a much larger project. About half of them I had to keep my 3/8" deep socket and racket on them all the way out. I was scared (after reading the horror stories here). The first one came out tight all the way, but it did come out. When I got it in my hand and it had BERU stamped on it, I stopped and thanked God for my luck!! I only know what I read on this site, but I have NEVER read a post about a BERU breaking off. Only one of mine read open with my ohm meter (Fluke 787), the others tested to be good, but looked bent and somewhat deformed. I got a full set off EBAY (Motorcraft Beru ZD-9) for 49 bucks delivered. If you guys don't buy them all, I am going to get another set, because I plan on keeping this ole girl till I die.

Marianna, I only know what I read here. If I read here that the glow plugs you are talking about are as good or better than the BERU's, I will buy them. Parts for these great old trucks are getting harder to find, so new parts are welcomed by me.

I gotta admit, I laughed out loud at Dave's post. That's funny, I don't care who ya are. Too bad the faucets never freeze here in Apollo Beach!!!

 

I just tried to tell you guys that the ones I mentioned are temperature limiting and therefore will not burn out no matter how heavy fingered you get. They get cherry red and stay there as you hold the power button. If you don't beleive me try hooking one up to a 12V battery charger. They don't overheat and swell up like yhe stock ones do. I bought a set of Autolite 1109's and before I installed them, I heated them up to verify that them. 7 out of eight blew up before they got red hot. They warranteed them and the next set was OK. Point being: new plugs that have set around can absorb moisture into the alumina insulation between the sheath and the heating coil. Upon heating suerheated steam is created and will cause the sheath to expand and allow the coil to burn out leaving you without much choice on how to remove the plug. I ALWAYS heat my plugs up before I install them to prevent a major catastrophy. Don't take my word for it. Try it!

 

Interesting information Marianna. Guess i'll have to try that!!

 

Those aren't stock numbers, what is the application?
I just did my glow plugs, and had an interesting find. I had 5 AC 8G's, and 3 Champions. None swelled, although some were burned out. One of the AC's blew the end of the tip off, but that was it. No trouble getting any to come out.

 

Just to confirm that I checked mine correctly, using a test light connected to the positive terminal of the battery and the other end to each glow plug momentarily to see if it will light up should confirm each glow plug without having to pull any of them if they all light up???

 

This is correct but the bulb must be almost as bright if you touched it to ground. A dim light is a sign of a bad glow plug as well.

 

I need a set of the ZD9, who was the seller?

When I first got the 6.9L it wouldn't start without help, I found that only 2 of the GPs were working. I went to pepboys and they sold me a set of the 1107 Autolite.. she fired right up first try that night. The next morning I went out the start her and simply cranked until I smelled fuel. They were all dead. I did a little reaserch on them and found that the 1109 were 11.5V rated and traded the 1107 for a set of 1109, I used a set of heavy jumper cables... clamped the ground on the threads and hot to the spade and they heated right up! no problems. They are still working fine. Now I need a set with the pin connector, and after reading this site I was looking for the ZD9 this time. I have a new set of the ZD1A thinking that I might swap the 1109s out but I decided against it. Now I have a set of new ZD1A when I need ZD9! Or would you say I just need to install the ZD1A in the 6.9L and use the 1109 in the 7.3L with a set of electrical connection adapters? (spade to pin)