Street News

How to Properly Replace A Rack and Pinion Unit

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While most of us take it for granted, the power steering system is a critical component of your vehicle. Eventually, the parts that make up the steering system will wear out. External components, such as the tie rod ends and links wear out much faster than the internal components, so you will experience servicing those parts regularly. The internal components, which include the hydraulics and rack and pinion unit, last much longer, so servicing those items is a fairly rare occurrence.

When you do have to service the internal system, it must be done right. The most common failure is a broken line. This is easily replaced at no detriment to the rest of the system. If the pump fails, however, the likelihood of further damage is very good. When a power steering pump fails, there is usually a good amount of metal shavings sent though the lines. The shavings wreak havoc on the valves and seals, which means that the power assist function will quickly die, and possibly take out the new pump as well if it is not replaced at the same time.

Replacing the rack is not physically difficult, but there are a few steps that you need to take in order to ensure that it is done correctly so the repair will last. Cleanliness is the key to a rack replacement, so you need a couple of cans of non-chlorinated brake cleaner on hand.

Begin by setting the wheels in the centered position. This is important, as you want to ensure that the steering wheel stays centered. The wheels can stay on, but we removed them for photography purposes. Measure the distance from tie rod to tie rod and make a note of it. This is so you can set the new rack at the same position, minimizing the adjustment required at the alignment shop.

Measure tie rod to tie rod before taking anything apart and make note of this measurement.

Measure tie rod to tie rod before taking anything apart and make note of this measurement.

The tie rods can often be separated with just a few blows of a hammer on the steering arm (never on the tie rod threads!), and if it works, the tie rod will simply fall out. If it does not work, then you will need a tie rod separator. If you are planning on reusing the tie rod ends (only if they are relatively new and in good shape), a tie rod separator will not damage the boot, unlike a pickle-fork.

Yes, banging on the steering arm does actually work.

Yes, banging on the steering arm does actually work.

Moving up to the steering linkage, the universal joint is typically secured with a single bolt. Loosen the bolt and separate the u-joint.

Loosen the clamp on the U-joint at the top of the rack and separate the linkage.

Loosen the clamp on the U-joint at the top of the rack and separate the linkage.

The lines need to be removed as well. A line wrench is best, but a regular open-end wrench will suffice. Just be careful not to round off the nut.

Next, the hydraulic lines are removed. Some fluid will pour out, be prepared for that, it is quite slippery.

Next, the hydraulic lines are removed. Some fluid will pour out, be prepared for that, it is quite slippery.

At this point, the rack is ready for removal. Locate the rack mount bolts and remove them. This should allow the rack to come out of the vehicle. There are two types of rack mounts: bushed lugs or clamps. This rack on a 2009 Challenger uses the bushed lug style.

Removing the rack is as simple as pulling the two bolts.

Removing the rack is as simple as pulling the two bolts.

Here is the rack itself. Note the two large lug bosses just to the inside of the bellows. These are the rack mounts. This is an end-steer rack, where the steering arms come out of the ends. The other style of rack is center steer, where the steering arms are mounted to a tie rod bar.

Comparing the new rack to the old rack, they must be exactly the same.

The top rack is the new unit. This car only has 28k miles on it, but the pump went out, and sent shrapnel through the lines, killing the rack.

The top rack is the new unit. This car only has 28k miles on it, but the pump went out, and sent shrapnel through the lines, killing the rack.

Using a wrench, the rack was centered by turning the rack to the lock position on one side, then to the other lock, counting the number of turns. That number is divided and the rack is turned to that number, setting it at the center.

Each side is measured and noted for the placement of the tie rod end. The tie rods were removed from the old rack, as they are in excellent shape. The number of threads required to remove them were noted.

Then the tie rods were reinstalled using the same number of turns.

The tie rod ends were reinstalled using the same number of turns as they came off the old rack.

The tie rod ends were reinstalled using the same number of turns as they came off the old rack.

The installation is a reverse of the removal, in the same order, with the exception of the hydraulics. Those need to be cleaned up first. Don’t forget to check the torque specs on all of the fasteners.

Each line must be thoroughly flushed with brake cleaner if they are to be reused. Unless they are cracked or cut, the lines can be reused.

We used 3M brake clean to clean out the lines.

We used 3M brake clean to clean out the lines.

 

Then the lines were blown out with compressed air.

Then the lines were blown out with compressed air.

For external reservoir systems, like this one, the reservoir must be cleaned out as well. We sprayed this with brake cleaner, blowing it out with compressed air and then repeated several times.

We picked up a magnetic inline filter for the return line of the system. The filter goes in the return line from the rack to the reservoir. This works for both external and internal reservoir pumps.

To ensure a long life, we installed a line filter on the return line.

To ensure a long life, we installed an  inline filter on the return line.

 

The filter installs between the reservoir and the pump, or between the rack and the pump on the return side.

The filter installs between the reservoir and the pump, or between the rack and the pump on the return side.

Next, the reservoir was reinstalled, and the lines hooked up to the rack.

We filled the reservoir with new power steering fluid and turned the steering wheels 15-20 times lock to lock to purge the air from the lines. This is done with the engine off. If you do this with the wheels off the ground, it is much easier to complete this task.

Using new power steering fluid, the system was filled up and purged or air.

Using new power steering fluid, the system was filled up and purged or air.

At this point, the engine was started and the system was working properly. Within the next few miles, some additional air pockets will likely be dislodged, lowering the fluid level in the reservoir, so it should be checked for several days and additional fluid added as needed. By taking the proper steps, your new rack will last many years with regular service.

Sources:

3M

About Jefferson Bryant (223 Articles)
A life-long gearhead, Street Tech Magazine founder and editor Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 5 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced. You can follow Jefferson on Facebook (Jefferson Bryant), Twitter (71Buickfreak), and YouTube (RedDirtRodz).

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