Installing Gabriel Hijackers onto TB/Envoy

[jdmccright]

This is a thread in progress, so bear with me as I hash this out....

I am in the process of installing some Gabriel Hijackers (#49213) onto my '03 Envoy XL with standard spring rear suspension, which has become more of an adventure than a simple swap when I initially bought them. This is because the AZ site does not differentiate between the old (Jimmy) and new Envoys...I found this out after the purchase. I wanted them because I frequently tow a horse trailer and wanted to be able to compensate for the added tongue load without resorting to retrofitting the air ride option...much cheaper, too, at $76 for the kit.

However, doing some research the suggested replacement rear shocks are very close to the Hijackers in compressed and extended lengths and stroke (have photo for comparison). So, I chose to give it a shot. The major difference needed is to remove the metal bushings from the old OEM Bilsteins and fit them into the new air shocks...so far a PITA since the rubber was molded around the metal inserts and then pressed into the shock ends. The Envoy doesn't use the standard two-bolt shock mount for the top (add photo comparison) and the lower mount has a wide metal insert to keep it centered (add photo comparison). The lower inserts also have a smaller inner diameter than what is provided on the Hijackers, so they have to be swapped out to prevent any slop and maintain compatibility with the OEM bolts.

After removing one shock, I loose fit the new one to see if there was any interference with the frame and the larger diameter shock barrel...so far so good.

Using a 6" bench vise, some silicone spray, and various socket sizes, I was able to press out the metal/rubber bushings from one shock so far as a trial, but the rubber has split some so they likely should not be reused. Thus, I've gone to cutting the rubber away from the metal insert...I used a hacksaw to saw it down without damaging the insert then use a utility knife to get closer. My final step will be to use a propane torch to burn the rest off and scrape it off. (add photo showing removed insert and bare metal insert).

I located a potential site for the air valve on the trailer electrical hook-up bracket (add photo showing marked hole location)

Next steps I see are to clean up the metal inserts (ran out of propane) and round the edges so that they will press into the new shock ends without cutting the rubber but not so much that they are shortened.

Stay tuned....

[jdmccright]

The metal inserts for the upper and lower mounts clean up nicely after heating them with a propane torch and wire brushing off the charred rubber residue, with only a few marks from the hacksaw used to get rid of the bulk rubber. Then I used a utility knife to cut it down close to the metal, then hit it with the torch to char the remaining rubber that was attached. After cooling, I used a file to round down the edges so that pressing them into the new bushings wouldn't cut the rubber.

Unfortunately (and I found this out after unsuccessfully trying over and over), the upper OEM metal insert on the has a much larger OD (3/4") than the rubber bushing's ID (7/16") supplied with the Hijackers shocks. Forcing it in with the vise only served to split the bushing. The Hijacker's bottom rubber mount is just the right size for the OEM lower insert. It fitted right in by hand with a little silicone lube spray...the rubber went into the eye first, then the insert went in.

So, I was left to find new rubber bushings for the top that would fit both the Hijacker's ID as well as the OEM insert's OD. I looked online at Energy Suspension and saw a few possibilities, but didn't want to go to urethane unless I had to.

I searched the auto parts store's HELP! racks, but they are very limited and didn't have the right size. I did notice that the lower bushing would work for the upper mount as well, so I called Gabriel's support line. However, they don't have a separate part number for that bushing. Dead end there.

Back to Energy Suspension, their 9.8140 shock bushing looks to be the closest fit, so I've ordered two sets (they come in pairs) to do all four shock mounts. Hopefully, the ride won't be too harsh...but anything will be an improvement over the rocking chair ride I have now. Should get them in a few days.

We're getting there....

[jdmccright]

Envoy rear shock equivalent
Gabriel Ultra G63842
Ext. Length - 23.33 in
Comp. Length - 14.8 in
Stroke - 8.53 in

Gabriel Hijackers 49213
Ext. Length - 24.17 in
Comp. Length - 14.56 in
Stroke - 9.61 in

Difference
Ext. Length - +0.84 in
Comp. Length - -0.24 in
Stroke - +1.08 in

Hats off to Energysuspensionparts.com! Ordered the bushings early Friday afternoon and got them the next day, Saturday, with normal FedEx ground. Turns out the 9.8140G (black, graphite impregnated to reduce squeaking) bushings fit perfect. They come 2 to a package to do one shock...order 2 for both sides.

To do the pressing, I used a 6" bench vise and various socket sizes (some deep to accommodate the longer lower insert). Spraying them down with silicone spray helps loosen them. The vise was also very useful in holding the bushings and inserts while working on them.

After pressing out the the OEM bushings, the rubber surrounding the metal inserts must be removed in order to reuse the inserts in the new shocks.

Inserts removed from OEM Bilsteins.jpg

I removed the rubber in a series of steps, starting with a hacksaw to cut the bulk away, taking care to not cut into the metal.

Insert after hacksaw.jpg

Then I used a utility knife to cut closer.

Insert after knife.jpg

Finally I used a propane torch for 2-3 minutes to char the remaining rubber...it comes off easily with a wire brush.

Insert after wire brushh.jpg

Here is what you have before pressing in the new bushings.

Exploded shock.jpg

You can press the new bushings into the Hijackers, again using silicone spray on the bushings and inside the shock eyes. Go slow so that they go in straight. I supported the shock upright by hand and adjusted it to coerce it in straight while turning the vise handle.

The urethane bushings can be easily cut, so prior to pressing in the inserts, I used a flat hand file to round the edges of them. After coating the insert and bushing hole with silicone, they pressed in with ease. The inserts for the lower mounts need to be centered, so use a deep enough socket to allow this.

Afterwards, the Hijackers have new bushings and the reused OEM inserts.

Assembled shock.jpg

They install back onto the truck with no trouble and with clearance all around (insert photos of installed shock).

Routing the air lines is up to you. I wanted to mount the valve near the trailer hookup but there's not enough room on the back side. For now, I have the tubing bundled up and tucked in behind the left reverse light. I secured it to the fuel fill hose on the left side and the rear A/C hoses on the right with zip ties, adding a loop to allow for range of motion. For the right side air hose, I also routed it to the left side along a wiring harness and used the existing plastic hold-downs.

Fill the shocks with air slowly so the upper barrels seat. I initially set mine to 35 psi. The truck has a definite nose down stance this way. The ride is firmer but not harsh. Very pleased, but dropping the presure to between 25-30 psi reduces the truck-like stance some (25 psi is the minimum). My guess is about 27-28 psi is good for normal driving and add more when you want to level it out when towing.

All in all, this was a pretty easy swap once I got the replacements figured out. I'll answer any questions if needed.

Good luck to all!

[jdmccright]

As an aside, I accidentally ordered four sets of the shock bushings when I only needed two (I thought I was buying them individually). So, if you're interested in doing this, PM me and I'll sell them for $8 plus $5 shipping via USPS Priority Mail.