Just today, I replaced the glow plugs on my Ford GT75; it uses the same Shibaura E673 engine as several other tractors. Two of the glow plugs are easily accessed for removal and replacement; the third (rearmost, as viewed from the radiator end of the engine), however, is not!
For access to the rearmost glow plug, you have to remove the fuel bleed screw, a couple of banjo fittings, the fuel lines to the injectors, and the return pipe assembly. It's not really that bad; most of my time was wasted doing a little research to make sure I wasn't removing more than I needed to.
In my case, I'm not sure replacing them was really worthwhile; none of the plugs had failed, but I thought it might be helpful preventive maintenance at 1085 hours and I (incorrectly!) assumed the job would be trivial. Although dirty, the old plugs looked pretty good (to my untrained eye).
A few tips and notes on glow plug replacement:
- Disconnect the battery ground before doing this work.
- Close the fuel valve above the fuel filter; this, maybe along with the fact that I hadn't used the tractor for at least a month, resulted in surprisingly little fuel being released when I removed fuel hoses and lines.
- It helps to remove the soft braided fuel line from the banjo fitting under the bleed screw and then remove (two screws) the big bracket that holds the fuel filter; drop it down to gain better access to the front two glow plugs. (There's a hole in that bracket that gives you a good shot at the front glow plug, but you can't quite get a straight shot at the middle glow plug with the bracket in the way). You'll then have a straight shot at those two glow plugs so you can get a torque wrench on the new glow plugs.
- If this is the first time you're removing fuel lines, you'll be breaking a lot of brittle paint. This paint will break into small chips, and if you're not careful (and maybe even if you are!), those chips will drop into open fuel ports/fittings. Be careful, and be prepared to remove some chips that fall into, for example, the tops of the fuel injectors (I used a Q-tips to remove some paint chips that dropped into such places).
- I didn't see any evidence of anti-seize on the threads of the original glow plugs, so I just installed them dry.
- I noted some fine carbon (or similar) powder on the inside of the threaded glow plug holes and vacuumed the holes out before installing the new glow plugs.
- Make darn sure to double check that all fittings are tight and that all hoses and clamps are back in place before reengaging the fuel pumps!
- Since the fuel lines have been opened, you'll need to bleed the fuel system. Open the bleed screw and turn on the ignition (after reconnecting the battery!) and let the pump run enough until you see a little fuel trickling out from around the bleed screw (I placed a small piece of paper towel around it to sop up that little bit of fuel).
- Make sure to check for leaks after you re-pressurize the fuel system (and after you have the engine started for a while). I actually had a very slow leak out of the fuel feed fitting for the middle injector. Loosening the fitting, re-seating it, and re-tightening did the trick.
I used NGK 6628 Y-107V glow plugs; I'm pretty sure they're identical to the New Holland SBA185366190 (supersedes SBA185366092) parts.
The starting point.
The fuel filter bracket dropped out of the way, fuel injector lines removed, the two front glow plugs removed. Ready to lift the fuel return pipe off the injectors.
Fuel return pipe removed and stashed out of the way. Ready to remove the banjo fitting that connects to the braided hose to the fuel filter.
Now there's clear access to the rear glow plug. Make sure to cover up that port on the fuel injection pump first, though, so debris doesn't drop in!
One new and three old glow plugs. Note that the new glow plugs include a new flange nut.
Torque new glow plugs to 15 to 20 N⋅m.
Scrape the paint off the connector bar where it needs to make a good electrical connection. (in my case, the new flange nuts were larger than the original nuts and would have probably sat atop paint rather than making electric contact!)
Done installing the glow plugs, but still need to reconnect fuel lines.
Wondering what the bottom of the fuel return pipe assembly looks like? The ring/washer with the two holes stuck to the return pipe assembly on one of these fittings, but stuck to the top of the injectors on the other two fittings.
Everything back in place.
Another view, looking down from the other side of the tractor.