Posted by Kevin Shoemaker on September 15, 2009
We’ve got a 2002 Chevy Tahoe that we’ll probably keep forever since 1) it’s paid for and 2) it hasn’t given us any real problems yet. We don’t do much beyond the recommended maintenance, so when it passed 85k miles in August we took it to our mechanic to check out a few squeaks and rattles. It turned out those squeaks and rattles were nothing major so we were out the door for $212.50, excluding the $700+ they wanted to replace the Autoride compressor.
Autoride is a suspension feature on GM SUVs (Suburban, Avalanche, Yukon and Escalade) that keeps the vehicle level under load and varies the amount of shock damping on a real-time basis according to road surfaces, speed, steering, and load conditions. Well, at least that’s what the 2002 Tahoe brochure says it does. The ride control system checked out electrically but the compressor wouldn’t run. If that had failed due to leaking shocks we were looking at another chunk of change on top of the $700 to replace those. Ou-freaking-ch. Since we’d already been driving it sans leveling system for a while I decided to continue using it like that while I weighed my options.
After a few weeks I finally crawled under the truck and found a part number (15070878 in my case) on the compressor. With a few well crafted Google searches I found a thread in this forum which pointed to the OEM parts manufacturer where I nabbed the compressor and aftermarket shocks for $538 shipped. With the non-GM shocks we lost the variable damping but picked up a lifetime warranty – a fair trade in my book. Now all I had to do was install this stuff.
I borrowed Pat’s floor jack, impact tools, and jack stand for the job, though you don’t need the car in the air if you’re replacing only the compressor unit. The pump cage is on the outside frame rail behind the driver’s side rear tire and mounts with 3 bolts in keyhole slots. I loosened the bolts and bashed it a couple times with a BFH to break the corrosion. After disconnecting the barrel shaped electrical plug, high pressure line, and a hose that pulls fresh air hose from near the fuel lid the whole thing dropped right out. The 3 Torx screws holding the pump on the vibration mounts took a little extra persuasion in the form of penetrating oil and an impact driver before I could disassemble the old unit. I cut the wires on the plug leaving plenty of pigtail to connect to the new compressor, reassembled all the new parts back in the mounting cage, then mated the new electrical connections with the old plug.
The shock replacement was straightforward enough, just make sure the suspension is at full extension to take out the old and install the new shocks. I used a second jack to compress the springs slightly, relieving tension from the shock mount bolts so they could be removed. The new shocks lack the electronically controlled damping feature like the stockers, so Arnott provides emulators to trick the computer into thinking it has OEM shocks. This eliminates possible error messages on the dash. I cut the old plug from the stock wire leads, connected the devices using the supplied crimp-style butt connectors, and mounted the computer-fooling device on the frame rail behind the compressor.
With the truck back on the ground I fired up the engine to test the new setup. Jen and I climbed in the back but the compressor didn’t kick on. I added a couple bags of sand and 8,000 Adventure Guides flyers but was still stuck in an oh shit moment. I crawled back underneath to to find the electrical plug just dangling there – duh. The pump turned on this time, but I could hear air escaping from the system. Since I’d left the mounting bolts loose, I pulled the cage out for another look. Upon close inspection of the old system I spotted a small red O ring between the air dryer and the compressor and remembered seeing a similar one in the replacement kit. Once that was in place the system worked like a champ.
During the checkup our mechanic said the back rotors were pitted and the pads were almost shot so I ordered those parts as well. They didn’t arrive in time to save my labor, but at least I’ll have something else to write about in a few weeks.