From hill-to-dale or mud-to-boulder, our lifted Jeeps see more stress than the factory ever intended. We twist driveshafts, bend differential covers, mangle sheetmetal, and inflict damage on things that we often don’t even see. One of those things we don’t see or think about until it’s too late is the power steering system. It isn’t until we hear that whine coming from under the hood or can’t steer in some rock garden that we worry about it.
Once it goes bad, many Jeepers overcompensate with upgrades. The truth is that if you are running 35-inch tires you don’t need a hydraulic assist ram, and for most guys running 37-inch tires a ram isn’t needed. Yet we keep running across Jeeps with dual-ended rams and the thing doesn’t have one rock scar on it.
Once you hear that moaning from under the hood, you need to inspect your fluid for metal particles. There is no filter in the system, and driving the Jeep with either the box or the pump in bad shape will kill the other component in no time. On older, V-belt-equipped Jeeps you can just pull the power steering belt. That’s a little harder on a serpentine-equipped Jeep, so replacing the pump and box at the same time is often a good idea.
There are many variables when it comes to selecting a power steering system for a modified Jeep. When the time came to replace the power steering on our ’91 Comanche we contacted the experts at PSC Motorsports for a high-quality replacement pump and box. The company offers many replacement options, so when you call be up-front about what you are putting your Jeep through. The company might suggest a stock-sized box for one guy but a bigger box for another guy, even if they have identical Jeeps. The company suggests its regular replacement box for up to 35-inch tires with light use, the bigger-bore replacement box for 35-inch-and-larger tires with heavy use, and hydraulic ram-assist for 37-inch tires or bigger with heavy use.
So, we ordered the large-piston steering box and direct-replacement pump for our MJ. As we were working our way to one-finger, leak-free steering, we shot some pictures of tips and tricks we’ve learned over the years so that you can do your next power steering system swap like a pro.
Bleed It Out
Properly bleeding the system is very important. The air pockets that are in the system when you first fire up the vehicle can kill the pump. It is a time consuming process, but worth it. Step 2 sometimes only has to be done 10 times, but we’ve had to do it 40 or more times too. Patience is key.
Step 1 - Put the front end up on jack stands with the tires off the ground.
Step 2 - With the engine off, spin the steering wheel from lock-to-lock (the full 3¼ turns) about three times. Five times is okay too, but ten times back and forth is a little excessive.
Step 3 - Using a flashlight, look into the reservoir for air bubbles. If there are no air bubbles increase the number of lock-to-lock turns.
Step 4 - Once the air bubbles disperse, repeat. At the beginning of the process it usually takes around 10 minutes for the bubbles to go away.
Step 5 - When no more bubbles surface but with the front tires still off the ground, fire the Jeep up and look for bubbles.
Step 6 - If there are no bubbles, and with the Jeep running, turn lock-to-lock three times.
Step 7a - If there are bubbles, shut the Jeep off and wait for them to disperse. Go back to Step 2.
Step 7b - If there are no bubbles, put the Jeep on the ground and spin the wheel lock-to-lock a few times while listening for any noises and look for bubbles. If you still have a lot of bubbles or hear noises, start again, you probably didn’t repeat the wait-for-bubbles steps enough times. If there are only a few bubbles, it steers easily, and you hear no bad noises, enjoy your new steering system.