Alright, so here's my attempt at capturing what I did to remove the existing injectors on my 1991 HDJ81 (5spd) with 144,000 kms on it. My recommendation is to go slow and steady and not try to set a speed record (no problem for me!), as a broken part or ruined thread will take even longer to fix. Please know that this is the first time I've ever done anything like this, so go easy on me
FYI, the entire process (removal of old injectors and installation of new injectors) took me about 4.5 hours from start to finish. The tools I used can be found in my very first post on this thread. I have updated the first post to reflect what I actually used.
Also, I used the Toyota Factory Service Manual (FSM) for step-by-step guidance, but did not follow it to the letter. My suggestion is to see what the FSM says and see what I did and decide for yourself...I'm always amazed at the tricks that other folks have come up with that can shave time off this process! For me being able to see photos of what the heck is going on is a big step in the right direction.
1. Loosen the turbo intake pipe on one side. The FSM is pretty easy to follow here...however, I did not actually completely remove the turbo intake pipe like the FSM says to do...instead, I disconnected the tiny rubber hose on the side of the intake pipe at the plastic tee portion (see the photo below). I did not want to tear 25+ year old rubber. The tiny rubber hose's connection to the cast intake pipe itself was on VERY tight. The tiny rubber hose's connection to the plastic tee, however, was easily removed, so that's where I disconnected it. After removing the 4 12mm bolts holding the intake pipe on to the rest of the engine (three of the bolts actually hold the intake pipe on, while the fourth secures the accelerator linkage assembly to the intake pipe), make sure that you grab the metal gasket that sits between the intake pipe and the rest of the engine...it's very thin and easy to lose! FYI, I did not remove the accelerator linkage at all either, just unbolted it from the intake pipe. Once the bolts on the intake pipe were removed I was able to move the entire intake pipe about 3-4 inches in any direction, but remember that it is still connected to the larger diameter rubber hose located on the driver's side of the engine, so be gentle. I was able to do the injector removal/reinstall without much trouble with intake pipe resting out of the way with it resting on a block of wood to hold it up away from the injectors.
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2. Loosen the 6 injection pipe union nut connections using the 17mm flare wrench. I used an adjustable wrench that had 4 sides to do this and it wasn't too difficult. It's righty-tighty, lefty-loosey when you're facing the injectors from the passenger side...sometimes it can be confusing when you have threading like this going on
There are no gaskets or anything that will come out...just some diesel fuel (not much). I used a shop rag to dry off some of the diesel after undoing the injection pipes. The injection pipe ends will simply rest up against the injector. You can move the metal injection pipes with your fingers slightly, but you really don't have that much flexibility...they are pretty stiff. However, you can push on the metal injection pipes to remove the injectors when the time comes...until then I just let the injection pipes rest against the injectors.
Here's a photo with the union nut undone (keep in mind that all of step 3 & part of step 4 below were already completed when I took this photo, but the principle is the same here):
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3. Loosen the nozzle leakage pipe (the metal squiggly thing that connects the top of the 6 injectors together) using a 12mm hex. I had to use a small extension on my ratchet to get some of them loose because of clearance issues and my limited ability to reach into the engine bay while standing on the ground beside the vehicle. Below is a picture of what the leakage pipe looks like after the 6 top hollow bolts have been removed. Keep in mind that there are two small copper gaskets for each hollow bolt...one copper gasket is on the top of the nozzle leakage pipe, and one is below it...you will be installing new ones when the time comes, but the old ones are easy to bump off and lose down in the engine...so be careful.
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I completely removed the leakage pipe from the engine bay...to do this you'll want to disconnect the leakage pipe from the fuel...I did this at the more accessible part of the fuel hose (see two photos below...before and after). The connection that the FSM says to remove is very difficult to access, so I decided to remove the connection down lower (see before and after photo). The one drawback to this is that it makes removing the leakage pipe from the engine bay area more difficult because you have to wrangle a 3-4 inch rubber fuel pipe that has a funky bend to it.
Before:
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After:
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4. Remove the injectors by removing the bolt, washer, nozzle holder clamp, injection nozzle and the copper seat. This is where
@Sarmajor 's advice came in handy, big time!!! Thanks! You'll want to make some sort of injector remover rig to do the injector removal. The easiest way is to use the nozzle holder clamp (piece of metal that holds the injector in the engine). The brilliant part is realizing that you can turn the nozzle holder clamp upside down, use the existing 14mm bolt and convex washer as a fulcrum, and then make sure you use a metal washer to protect the surface you'll be reacting against when you pound the other end of the clamp (the end with a small dimple) with the light tap of a hammer. See the photo below for my first attempt, which almost ended in catastrophe.
An almost catastrophe...
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You'll see I have the nozzle holder clamp turned upside down with the 14mm bolt head acting as the fulcrum. The mistake I made was that when I went to hit the small, dimple end of the upside down nozzle clamp with a hammer I was actually making an small indentation on the engine block threaded bolt hole. I almost ruined some of the threading on the engine block, but luckily I was able to get the old bolt back in without having to re-thread the hole...yikes! The solution is to put some sacrificial material between the fulcrum (the 14mm bolt head) and the engine block...I chose to use a cheap metal washer that distributed the impact of the small hammer blows to a wide enough area on the engine block that nothing gets nicked or damaged! I figured out that a small ratchet extension (3 inches or so) for a 3/8 ratchet will fit perfectly over this small, dimpled end and allows you to hit the extension with a light blow from the hammer while focusing the impact cleanly on the clamp. See the photo below for an example of the setup I used:
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I was able to get all 6 injectors out WITH their copper seats using this upside-down nozzle holder clamp method. I did not have to use any PB Blaster before or during the removal...so the o-ring AND the copper seat both came out with the injector, which is extremely lucky, or a testament to how well this injector removal method works
On average, to remove any single injector probably took 12-15 relatively light blows of a normal hammer to dislodge the injector. I would have to reposition the washer at times, as each time you hit the injector moves slightly. You will also have to reposition the upside down nozzle clamp after several hammer blows for the same reason. I had another person help me do this, so I could hold the "injector removal rig" in place while the other person hit the ratchet extension squarely with a light tap of the hammer. No twisting or anything else was done to the injector during removal...simply the light hammer blows. It's crazy how well it works. I hope others find the same!
Below is a photo of the old injectors that I removed:
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And here's one of an old injector vs. a new injector:
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And finally here's one of the new injector with the copper seat and the rubber o-ring before being installed:
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Reinstallation is pretty easy if you just do everything in reverse (I know, classic easier said than done). Just remember to put a new copper seat back in, then the new injector with the new o-ring back in. Of course, this depends on whether you're buying new injectors, or having your existing injectors serviced and reconditioned as to what parts you actually need to get or need to install prior to injector installation.
The hardest part about reinstallation was getting the nozzle leakage pipe back into place. It has some weird dimensions and really takes some creative arm movements to get it back in with the short rubber fuel pipe attached. The other part that takes some finesse is the placement of the new copper washers on the nozzle leakage pipe as there is a copper washer (aka gasket) on both the bottom and top of each nozzle leakage pipe connection. Placing the pipe back onto where you have a tiny copper washer sitting in a very small lip holding it on takes some steady hands
Now, be sure to reconnect the turbo intake tiny rubber hose at the plastic tee and don't forget the intake pipe's metal gasket when reattaching!
Once everything was installed again, torqued properly, and seated, you can go and start the truck. I did NOT have to prime anything or use the fuel filter manual pump or anything like that...the truck coughed a bit when we first started it, but it came alive after a second or two! So it started on the first attempt and even then it only took an extra second or two more than normal...amazing!
So far, after driving it for a couple days with the new injectors I've noticed that it is more responsive when accelerating, smoother, and hopefully, more fuel efficient! I hope to report back with fuel usage after we have a chance to go through a couple tanks of diesel.
I will go back and edit this how-to in the future as I hear from others, or decide to add additional detail as necessary. Hopefully this helps others out too!
