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Installing On Board Air on a Toyota Land Cruiser FZJ80

After years of wheeling and building our 1994 FZJ Land Cruiser and using the Master Flow MV50 compressor for each end of trail air up, I decided to go a different route. The electric compressor had worked flawlessly for a long time, but the fact that I now wanted to air up quicker, as well as wanting to run air tools forced me into the decision of installing a York A/C compressor.

The first thing I had to do was round up all the parts needed to do the install. I kept my eyes open for a compressor, and finally found a coworker that was deleting the A/C components off of his AMC car that had a straight six 258 in it. The clutch was in great shape and the compressor turned over easily by hand.

Next I needed to find an air pressure switch, a tank, a gauge, and a check valve. After a few months I came across another coworker that had one of the small twin tank electric compressors. The electric motor on it was fried, so he was just going to throw it away, and since it solved the rest of my major needed components, I scooped it up!

The next step was actually getting the Toyota in the shop to start the onboard air setup. I finally popped the hood one Friday night and dove into to making this setup work. Because this 1994 FJ80 had the emission AIR system in it, it added a little complexity to the install. The later years didn’t have the system, the install on them is bit easier. I believe the only the 1993 and some 1994 models have this system.

The first step was removing the AIR system and related components. This consisted of removing the valve, air filter housing, hoses, and capping off the vacuum line that went to it, as well as removing the two downpipes to the exhaust manifolds. I built two 3/16” steel block off plates to finish the removal.

Now there is a commercially available bracket to mount a York in an FZJ80, but I didn’t really care for the design of it since I wanted to add an extra battery some day, and didn’t like the idea of adding another belt and driving the compressor only from a small diameter custom water pump pulley. The bracket kit would be a quicker way for sure, but I was able to mount it using existing drive components with a little fabrication.

The next step was relocating the heater hose outlet from the thermostat housing. Since the hose and pipe went right through where I wanted to mount the compressor, I had to come up with another plan. So I made another steel flange exactly like the exhaust block off plates since the coolant outlet just happened to be the same size. I drilled a hole in the center and use a 3/8” NPT pipe tap to thread the hole. I used a brass 3/8” street 90 and threaded the fitting unitl it was flush with the plate. I then ground off the excess threads sticking through and filed the flange smooth to ensure a good seal. I used a 3/8” 4” steel pipe nipple and threaded it into the fitting. I was able to reuse the existing factory hose by loosening it and repositioning it. This finished the prep work needed to start making the compressor mount.

To start with I made a rectangular plate with four slotted holes to match the mounting bolts on the side of the York compressor. I then made a couple of plates to mount to the block. All three of these were made from 3/16” plate and cut out with a plasma cutter, but they could have easily been cut out with an angle grinder with a good cutoff wheel if you don’t have access to a plasma. I bolted the plates to the block and compressor and set it up to eye ball the rest of the mounts. I was mounting the compressor to use the belt drive from the factory A/C compressor. Originally the belt went from the crankshaft straight to the A/C compressor with a tensioner pulley on the bottom side. In order to adjust or replace the belt you had to lay under the truck and remove the sheet metal shield, which is a PITA. I was hoping to eliminate the idler pulley, and use the York compressor to tension a new longer belt.

After finishing the bracket build, compensating for hood clearance, exhaust clearance, and verifying proper alignment, it was on to the rest of the intstall. The compressor bolted up and the belt was easily adjusted from the top side now with only a 9/16” wrench now!

Next up was plumbing and wiring the system. I gutted the twin tank donor parts and mounted the check valve, gauge, and pressure switch under the hood on a custom bracket made to hang from the preexisting bracket on the air filter housing. Only the Cruisers that had the AIR system will have this bracket. I used a piece of stainless steel Teflon lined hose to connect the outlet from the compressor to the check valve. I then installed the small canister air filter assembly from the twin tank setup onto the inlet side of the York compressor. I then ran ½ DOT plastic air brake hose from the switch assembly to the rear of the truck. For the air tank, I cut apart the twin tank setup and tapped two ¼” ports in the original transfer pipes. I mounted it to the spare tire crossmember. From there I ran one 3/8” DOT plastic air brake line to just behind the rear bumper with a universal air hose coupler to finish the plumbing of the system. The air tank also already had a 150 PSI safety valve in it as well as a tank drain on it. For the electrical, I simply ran the clutch wire into the switch, and a 12v power supply the other side. The switch has an Auto and Off positions on it, so all that is needed is to pop the hood to turn the system on.

The compressor system works absolutely great. It will pump up to 125 PSI and shutoff, then reengage at 95 PSI. This is completely adjustable, but it was the factory switch settings, so I left it alone. Being able to have steady air to run air tools and quickly fill tires on the trail is awesome, and I would recommend this system to anyone that wheels!

Cost of system:

York compressor: Free
Old Twin Tank 110v Air Compressor: Free
This gave me the tank, pressure switch, safety valve, check valve, gauge, drain valve, air filter, and Teflon hose.
9580 gates belt, quick coupler, DOT hose and related fittings: $40
Some scrap steel for making the brackets: Free
For more discussion on this article, visit: Tech: Installing On Board Air on a Toyota Land Cruiser FZJ80

Planet 4x4
Article by Lumpdog

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