FZJ80 F&R Airbag Install Procedure (long)

Joined
Jun 1, 2005
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1,836
Location
Chicago
Folks:
After doing some research on suspension options for my recently acquired '94 80 I decided to go with the front and rear airbag (spring insert type). The rears were a standard Air Lift Spring application (www.airliftcompany.com rear kit 60728). The fronts turned out to be a bit more of a challenge, but highly desired: especially after installing the rears, then hanging the TJM on the front. Although I saw a front kit listed by somebody somewhere (AUS?), I decided to try going with a stock Air Lift Spring application. After a couple calls and faxes to Air Lift technical, it would appear that they had something pretty close in the 60702 kit (late model ford van app).

INSTALL REAR (AIR LIFT KIT 60728):
For the rear Air Springs, I had some helpers, and took the long route in my shop. Removed the bump stop first (13mm long ext). Disconnected the shock, diff vent, rear prop valve, then pried the spring out while levering down on the respective wheels. Installed airbags fitting down (hole already there) and routed lines to a bracket at the LR bumper.

INSTALL FRONT (AIR LIFT KIT 60702):
DISCLAIMER: This procedure is not for the faint of heart, nor is it recommended as a bolt in kit. It *allows* one to put front airbags from a US vendor onto a '94 FZJ80.

For this install, I decided to try compressing the spring instead of removing all the goodies attached to the axle, or dropping the control arms as I had read someone had to do. Jacked up the front end, set floor jacks, and removed the front wheels and the lower rubber bump stop. I used a clamshell type spring compressor to remove the springs with *everything* else in situ, including shocks, etc. I suspect that the dual wrench type spring compressors would work as well.

Spring perch prep... There is a upper bracket mounted to the top of the spring perch on the drivers side that needs to be drilled if using the top air line fitting method. This bracket is not found on the passengers side. I drilled out to the Air Lift recommended 3/4 in hole.

Bump stop modification: The rubber bump stop is removed and discarded. Remove the 2 bump stop retaining nuts (12mm socket) from the top of the upper spring perch. The 6in upper metal section now needs to be modified with a hack saw. I marked down about 3/4in from the top, and cut the upper perch. This allows the spring to stay located, *and* convenienty allows you to use the plastic spacer included in 60702 kit for each side. In fact, they center perfectly in the upper perch. Hard to visualize (no pics up yet), but basically you have a cut upper perch now hollow, that the spacer fits inside of the modified bump stop/locator, to give the airbag a flat resting point. Before installing, sand/grind the cut metal bump stop/locator, to get rid of bag puncturing sharp edges.

Attach airlines to air bags and install bags into spring. Feed lines thru spacer and thru installed spring locator and upper perch hole. Put spring back in place and remove tension from spring compressors. Do not lower vehicle until lines are installed completely. I routed the PS line thru the frame rail (to avoid radiator hose and exhaust heat), then over to DS and made a air fitting bracket attached to a TJM mounting tab. I routed the DS under the battery tray and out one of the front body holes.

Final touches
Before adding air to bags, use something to prop both bags up to the upper perch, this allows the spring to trap the spacer in the modified upper spring locator bump stop. Add 15psi or so, install wheels, and lower to ground.

Intial Impressions (800mile trip immediately following install). Much tighter front end and less dive on heavy braking. I'm probably going to add an additional 1in spacer to allow more height adjustability with less pressure. Right now max pressure give just a hair above stock ride height.

Comparative Impressions (to 2in lifted RN61 4Runner). Much more versatile in ride height and ride quality. The ability to control front end dive and finitely adjust to heavier loads with just air pressure is great. Using a bicycle pump to fine tune the low airbag pressures (5psi min-35psi max) is great.

Mods 2B. That slick Air Lift electronic dual air controller looks like the ultimate ticket, and I plan on adding this toy in the next couple months. Overall: Good choice and alternative to full time stiff/raised suspension options.

HTH

Scott Justusson
QSHIPQ Performance Tuning
Chicago IL
'94 FZJ 80 (TJM, Airlift F&R, Momo, running board delete)
'87 RN61 (SR5 Turbo A/T, TJM, 2in suspension lift, skid armor, F/R axle truss, 3in turbo back exhaust)
 
Joined
Jan 13, 2004
Messages
496
so you are running the rear bags fitting down, and the front fitting up?

I assume the airbags are not crosslinked?

another pic request - esp of the airbags when suspension is flexed
 

e9999

You want to do what...?
Moderator
 
 
Joined
Sep 21, 2003
Messages
16,614
Location
US
and this was with OEM springs and shocks, I gather?

if so, you did put them in front to avoid having to retrofit HD springs there cuz of the TJM weight, is that right?
 
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