Idler Arm Rebuild
In this article I will discuss how to rebuild 1986 - 1996 Toyota truck and 4Runner (non Tacoma) idler arms. The plastic internal bushings wear out over time causing alignment problems and looseness in the steering. When used on the street the idler arm is good for about 100K miles. When used offroad the idler arm requires service or replacement much more often. Fortunately it's easy and cheep to rebuild yourself. If the idler arm is not bent and not too badly worn you can easily rebuild it for $4 in parts and less than two hours time. Removing and reinstalling the unit is the time consuming part. Disassembly, repair, and reassemble only takes about 20 minutes.
Symptoms of a bad idler arm include looseness in the steering wheel, inability to align the front end or alignment does not stay set. To see if your idler arm is bad perform the following test. Without jacking up the truck have someone move the steering wheel back and fourth just a little while you look at the arm itself. The arm should only move left and right, if it goes up and down then the bushings are shot and it needs to be rebuilt or replaced. If your arm is worn then the front end tow setting changes as your drive and will cause increased tire wear and a wandering feeling on the highway.
To remove the idler arm you will need a pickle fork or tie rod end puller to remove the tie rod from the arm. Next unbolt the arm from the frame, now your ready to service it.
Disassemble the idler arm by first removing the metal dust cap, it can be tapped off with a hammer. Next remove the nut under the cap and the flat washer. Then you can pull the arm out from the housing and remove the rubber dust boot. Next remove the two plastic bushings from the housing (see picture above)
Install the new plastic bushings into the housing. Don't forget to grease the bushing inside. I used Toyota bushing part number 90386-19005. It takes two bushings to rebuild the unit, they cost $2 each. I found the rubber dust boot to be in good condition but you can also order a replacement from the dealer if you feel it needs replacing.
Install the lower dust boot, then slide the arm into the housing. Then add the washer, nut and dust cap. It's a good idea to check the nylock nut. If it is loose replace it with a new one. Now you can bolt the idler arm back on the truck and take the truck for a test drive. It may now be necessary to realign the front end or at least set the front toe setting.
Check the arm before reassembling. If the arm is bent you may need to replace the unit. A bent arm will rub on the frame when you turn the steering wheel. Downey and North West Off Road both make an idler arm brace that can prevent the arm from bending. I have used several different idler arms (Napa, NWOR, Downey and two different Toyota Factory arms) and found them to all be about the same strength. It may be advisable to keep a spare arm with you on the trail along with the tools to install it.