Friday, July 28, 2017

Retro Post: Astro Van Lift-Kit Installation

I've been guilty, multiple times during the life of the Astrolander project, of letting my detailed blog posts get out of sync with the current state of affairs.  My build threads on ExpeditionPortal and the AstroSafariVans.org forums have been maintained somewhat more diligently, but I realize not everyone follows there.  To help remedy that, I'm undertaking some "Retro" posts to re-document some of the work that I've done but not covered here.

Here's the first installment:  Installing the Overland Vans 4" Lift Kit.

Part of the reason that I didn't document this initially is that this is well-trod ground for Astro/Safari owners.  I didn't add anything new versus the dozens (maybe hundreds) of other owners who have installed this or similar lifts onto the van.  For those coming from outside that community, though, there are some basics worth reviewing:

  • The Astro/Safari platform is a "semi-unibody" design.  The front includes a roughly half-body subframe that mounts the engine/transmission, front suspension, and in the case of the AWD models, the transfer-case and front differential.
  • You can get ~2" of "body lift" by installing pucks between this subframe and the unibody.
  • Additional front lift can be had by increasing the preload on the torsion-bar springs.  This is accomplished via the pre-load adjuster on the torsion-spring "key", or (if more lift is needed), via re-indexed torsion bar keys that increase the preload beyond the range of the adjustment screw.  
  • Rear Lift is accomplished by fitting re-arched leaf-springs.  As it happens, GM's S-10 Light Truck uses a spring pack that is the same eye-to-eye length and load rating, but with ~3" more arch.  (Thanks, General!)
  • The remaining lift can be had via "lift" spring hangers.
With all of that, let's begin:


 This is essentially two separate jobs.  The front lift begins by removing the front facia/grill and bumper pieces.

Here we can see one of the rubber "donuts" that sandwiches between the subframe and body.  We remove the six long bolts that goes through each of these.  Just below (and in front) of the donut is the OEM bumper mount.  (Soon to be replaced).

The rod hanging down is a support for the bumper cover/fascia.  More on this at the end.
 Now that the body is just resting on the subframe, we can very slowly and carefully raise one corner of the body at a time.  The aim here is to  create enough space to insert the 2" lift pucks, but not to damage any of the many connections between the body and subframe.  There are numerous hoses and wiring looms that must be carefully re-positioned.  In some cases, some of the hard-lines like heater and brake lines might need to be gently (and carefully) bent downwards slightly.

Lots of cribbing and good jacks and stands are useful here.  Once the pucks are inserted, replace the long bolts with even longer ones supplied in the kit, and torque in a cross-pattern to the specified values.




Here you can see the puck above the rubber donut as well as the new bumper mount.  Note that it's the length of the bolts through these pucks that's one of the limits to how much "body lift" you can safely achieve.  Beyond 2-3", the bolts are subject to a lot of side-force, so you're better off welding steel perches to the subframe.  The other limit is hose lengths and the steering shaft, and that happens just after 2".  As I replace hoses due to aging, I'll try to ensure I use longer kit for everything and I may someday swap to 3" pucks.


Because the bumper mounts via the subframe, after you lift the body with the pucks, there would normally be a significant gap between it and the front grill/body work.  These new hangers have a range of re-indexed holes allowing you to position the bumper higher on the subframe so that it meshes with the grill.

Since I was working alone and it was hard to hold the bumper in position and fit bolts and backing nuts with only two hands, I tack-welded the nuts onto the back of the hangers (in the same way the OEM hangers are built), making it much easier to hang the bumper later.

 The Overland Vans kit includes a replacement parking brake cable bracket with a new hole drilled higher up.  Thifty DIY-lifters can also just re-drill the stock bracket.  I wasn't sure why exactly I needed this until I saw how the path of the cable would interfere on the triangular "ear" on the subframe.


Another piece that requires adjustment is the radiator fan shroud.  The radiator fan is mechanical-clutch type, so it's mounted on the engine/subframe.  The shroud attaches to the body, which has just gone up 2", so you need to trim the bottom portion of the shroud where the fan will interfere.  You can see where I've cleaned and marked a line on the shroud.  This HarborFreight air body saw really sucks, though.  I switched to my 60+ year old Craftsman electric jigsaw and zipped right through this plastic.

 Double check all your bolt-torques, re-attach the bumper, cover, grill, and front fascia, and you're done with the front body lift.

You can drive around like this for a while, if you don't mind the "pre-runner" look and have short working-windows on the Weekends, like me.

Note: As of this moment, I waited to do the torsion-spring pre-load adjustments until I had the rear lift complete, so I could "level" to that.
 On to the rear lift.  Here I'm comparing the original leaf springs (bottom), to the S-10 leaf-springs (top).  You can see there's significantly more arch, despite the overall spring-rate being the same.  The part# for these springs is 22-687-ME (medium duty), 1,450lb rating.  You sometimes see them listed only as 22-687.  It's important to know what you're looking at because there's also a part# 22-687-HD which fits the same application but is rated to 1,750lbs.  Good if you're hauling a lot of extra weight, but would ride like crap on a lightly-loaded passenger van.
 This job has a lot going on.  Lift the rear of the van.  In this case, though it looks like the weight is on the bumper, it's actually on my Class III hitch, which is tied heavily into the unibody but out of the way of the rear-spring hangers, which I'll be working on.  After the van is raised, remove the wheels  and support the rear axle so you can unload the springs and start un-bolting things.  Be VERY careful here about the brake lines, emergency-brake line, and differential-vent line.  Everything needs to be disconnected so that you don't stretch anything when you drop the axle.
 The new spring pack came with this massive locating pin.  On mine, it was a bit too tall and interfered with the clamshell that sandwiches the spring back to the perch on the axle.  I had to knock it down with a cut-off wheel.
 Once that adjustment was made, you can attach the spring to the perch via the clamshell.  Yes, this photo is upside down, but it's easier to read part#s this way!
For some reason I don't have pictures of the replacement spring hangers.  They attach at the rear and include a set of indexed holes allowing you to add a little extra lift in 1" increments.  When my replacement leaf springs were new, I actually kept using the OEM hangers for a while.  After the springs settled, I swapped back to the replacement hangers at the 1" additional-lift setting.

 The Overland Vans kit also includes a bracket to drop the hanger for the Parking Brake cable.  The angles looked wrong on mine and I ended up not using it.  I think this is partly due to the fact that I have a snapped mount at the axle, allowing things to move a bit more.  If/when I get that repaired, I might need to revisit that as I suspect the cable would be stretched more.
The last optional bit of the Overland Vans kit is a set of tabs to relocate the shock mounts up higher on the axle.  In my case we fabbed up a spacer the same width as the lower shock-eye and used it to help hold the tabs in place for welding to the axle.  
The idea is that these let you continue using stock-length shocks and to remove the mounts that hang below the axle (and I suppose could be prone to snagging while off-roading).  The problem with this design is that there's no provision for changing the bump-stop geometry.  So you're using stock (short) shocks on a raised suspension, with theoretically more up-travel, but without offering any mechanical limit on that up-travel beyond the original stop.  I'm still working on solving this issue, but I finally have something in mind.  I also have to say that the tabs looked like something off-the-shelf, as the curve on the "axle side" didn't match the diameter of the axle-tube very well. Overall, I'm not sure this was a worthwhile add-on.  Instead, I'd skip this bit and find a replacement shock with a 4" longer stroke and just use the OEM mounts...

This was never going to be a good look with the stock-sized tires, but this shows how much the rear was lifted with the new leaf-springs and the 1" lift via the spring hanger.  

In this photo, the front torsion-spring preload has been adjusted to "max".  I have re-indexed keys from the kit, but didn't want to raise the front any more than necessary (since more extreme angles cause issues with wear on the CVs and idler-arms.)

This was why I swapped back to the OEM spring hangers until the springs settled.  New 247/70-16" (30") tires went on right away, too.

Additional items:
  • After fitting the larger tires, some trimming of body work is still needed at the front. Moving the steering through its sweep shows the interference spots, most of the areas are trim plastic, though most owners also end up needing to cut and/or hammer back one portion of a pinch-weld seam right at the bottom/rear of the wheel arch near the doors.
  • The bumper fascia will also need to be trimmed at the bottom/front, and the support rod mentioned above will need to be bent slightly to facilitate a new mounting hole in the fascia. (You trim the old hole away, as its right at the bottom/rear where it interferes with the tire.)
  • Obviously the vehicle should receive a full alignment check after any suspension adjustments/modifications.

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