so it took me a while to gather enough information for this in order to do it myself.
i knew the basics, which is that you need '720 4x4 leaf springs,' but i was unsure of
which bushings to use, and later heard that some people use different rear shackles.
-good bushings (see notes)
-jack stands (at least 2)
-13/16 drill bit, drill (to drill out 720 front bushing)
-park the vehicle on a flat, level surface. turn off engine, put in gear or park, and apply hand/emergency brake.
-break torque on lugnut
-chock the front wheels
-place jack under differential, jack up vehicle.
-place jack stands under the rear frame, rest vehicle on jack stands.
-remove [14mm] nuts from shock(s,) disconnect shock(s)
-remove nuts from u-bolts
-remove (2) 22mm nuts from rear shackle.
-remove 24mm nut from front bolt.
-remove leaf springs.
-reverse of removal.
-install good bushings in 720 leaf springs.
-install front bolt.
-install rear shackle.
NOTE: vehicle weight must be on the rear wheels when tightening front pin (bolt,) shackle and shock absorber in order to clamp rubber
bushings in neutral or unloaded position.
-spring front pin (bolt) nut: 37-50 ft lb
-spring shackle nut: 37-50 ft lb
-u bolt nut: 65-72 ft lb
-wheel nut: 87-108 ft lb
for energy suspension bushing install:
-remove the sleeves from the i.d. of the front 620 bushings
(you can cut them out, burn them out, etc. i drilled small holes in the 620 bushing until i could wack out the sleeve.)
-enlarge hole of 720/d21 front bushing to accept 620 sleeve (13/16 drill bit is just about perfect.)
-ensure leaf spring holes are clean of dirt, rust.
-lubricate bushings, shackles & bolts (except for threads,) and any surface where metal and bushings come in contact with each other.
bushings: the i.d. of the bare 620 and 720 leaf spring holes are the same. pretty much the only difference is in the design of the bushings.
the 620 front bushings use both a thin metal sleeve on the outside of the front bushing, as well as a metal sleeve/tube (that the bolt goes through) on the inside
of the bushing.
-energy suspension 720/d21 part number:
-stock 620 bushings part numbers:
REAR ES bushing (top) vs nissan bushing (bottom)
Rear oem bushing (top) vs ES bushing (bottom) you can see the ES bushing has more of a head, which is a good thing.
oem 720 bushing fitment on 720 shackle
front ES bushing (top) vs oem bushing (bottom) different outer design, same function
worn oem bushing on 720/d21 front bolt (Not used on this install)
ES bushing on front bolt
rear oem 620 bushing
as you can see it has a rounded head that would only work with the 620 shackles (which could be used.)
it also has an inner sleeve/tube
shackles: the 620 shackles have a peculiar design. however, after looking at them at the junkyard, i believe the 720 and d21/hardbody have
the exact same front bolt and shackles. the 720/d21 front bolt cannot be used on the 620.
(disregard how i have 2 'shackle end pieces' installed on this one.
720 shackle (same as d21 shackles)
very simple. you could almost make one. ensure you clean these up before installing new bushings.
front bolt: i think i have read (or misread) that some people are running the d21 front bolt. impossiburu! youll have to run the 620 front bolt
620 front bolt
as you can see it has a 'cut' head design that allows it to be captive once installed so that it may be torqued.
720 front bolt (same as d21 front bolt)
the head is completely different and will not work on this install. the small screw in photo is to keep bolt captive.
side by side comparison
2" height difference at 'rest' !
leaf bolt: bought my 720 leafs from someone and they did not come with the bolt that keeps them together installed.
i couldnt get the bolts out of the my old (620) springs... but replacement springs are available! i found a pair at pepboys.
kinda long, but they did the job.
ES front 720 bushings: as discussed, the front 720 bushings have to be drilled out in order to receive the inner sleeve from the old 620
front bushings. you need a 13/16 drill bit. well neither of my sets had anything above 1/2"... and 13/16 is just a weird size, you can probably
get it online but home depot didnt have it. well they did, but in a wood drill bit. well it was only $4 and i was desperate so i went with that.
3 out of the 4 bushings came out find (i clamped them in a vice) but the 4th one:
its a little bit out of round but itll work