80 Series on Air Bags
by Herb Peyerl
Your dream rig is never really quite finished. You make a modification,
try it out, are either happy with it or not, then you go back and
either fix it or discover something else that needs to be done....
I bought a 1993 FZJ80 from the Eastern U.S. and brought it up to Canada. It came with a 2.5" OME lift, snorkel, ARB front bumper and about $30 in U.S. coins in the seats, under the carpet and just about every other place possible. Over time, I've done the diesel/5-speed swap, added a 4x4 Labs rear bumper and tire carrier, and put some 5" coils on that I inherited from a friend. I knew the coils were worn out but I added them anyway. I was impressed with the improved capabilities of the truck but over time, the truck began to lean to the driver's side to the point where I couldn't walk away from the truck without someone pointing it out to me. The front coils were bending in a curved fashion. I needed to either buy new springs or do something else.
It occurred to me that what I actually wanted was a sub-2" lift for towing the family travel trailer or for squeezing the truck into parking garages; and a 10" lift for wheeling in deep mud holes. I wanted extreme lean for driving off-camber. I also wanted to be able to sag the tailgate down to ground level for ease of loading and unloading. I scoured the Internet looking for springs that would meet these needs but couldn't find anything—imagine that.
So I decided air bags were the way to go. One of my chapter-mates, Cody Chatfield, has a similar setup on his Cummins-powered 80. I did some measuring and examining and started to put my plan into action.
After some research, I decided I wanted to be able to individually control each corner of the truck. In show-car circles, this is known as Front/Back/Side-to-Side (FBSS) and there are a myriad of kits available to do this. I examined many of the kits and determined that they either had substandard parts or were from disreputable dealers—or were far overpriced.
After toying with some cheap air valves, I learned a few lessons. First and foremost, the pressure rating of a solenoid valve tells you how much pressure there can be on either side of the valve that the spring will overcome. If you have a 100-psi valve and there is more than 100-psi of pressure on either side of the valve, then the valve will open just fine but it will not close. So you need to choose valves that are rated higher than any pressure you intend to run in your bag.
Based on reports from Cody, he typically runs his bags at about 70-psi but if he goes over a bump or occasionally while wheeling, it's not uncommon to see the pressure go up to 120-psi. I elected to go with industrial valves with removable electrical connectors, replaceable coils and replaceable valve assemblies from Mac Valves. Most importantly, the case of this valve is not grounded to one side of the coil. This was important due to my selection of control panel.
I lived in anguish for weeks over how to set up my airbag control panel. Get some DPDT switches and mount them in a box near the dash? The obvious answer came to me as I was driving to work one day and happened to look at my window control panel on the drivers side door handle. It had 4 switches that could each make a single window go up and down. It was perfect. So off to the wrecker I went and came back with a couple of these switch panels from a 1990s era Toyota Camry for $6.00 each. Identical to the 80 series switch panel, they came with a rocker switch for the door lock, which I planned to use to override my compressor.
Next I needed to build an onboard air setup. I researched compressors and finally wound up buying a Viair 480C. I wanted something that could run up to at least 150-psi and at 100% duty cycle. I wasn't overly concerned with flow rate but it did need to be reasonable. I chose the 480C because a local tool supplier had previously broken up a dual-480C pack for another customer and I got the extra 480C from that kit for $300 Canadian. The Viair compressors also come with a check valve so air can't leak back through the compressor.
After removing the old OEM jack mount and discarding the plastic interior panel, I mounted the compressor in the rear driver's side quarter panel. I had an extra 11-gallon air brake tank, which was more than I'd need but I had it, so I mounted it under the truck where the spare tire used to live. I screwed a pressure switch into it (145-psi) and plumbed the tank to the compressor through a 1/2" ball valve so I could isolate the inside air system from whatever happens outside. This way I can still have air even if I tear the tank off on the outside.
There's more to this story, but there's only one place you can read it: Toyota Trails. Get your very own copy by joining TLCA now!
Air suspension control panel from a 1992 Toyota Camry—4 bags up/down plus compressor override.
The Land Cruiser at maximum height (top) and minimum height (bottom).
BUDGET
Air Bags: 4 at $130 Canadian each ($125 US)
Solenoid Valves: 8 at $32 Canadian each ($25 US)
Compressor: $300 Canadian ($280 US)
Brass Fittings: $100 Canadian ($95 US)
Control Panel: $6 Canadian ($5.50 US)
Brake Hose: 2 at $12 Canadian each ($11 US)
Photos by Herb Peyerl
