Learn why replacing the boot doesn’t fix a rack and pinion leak

When the high-pressure seals wear out in a rack and pinion steering gear, you’ll see power steering fluid leaking out of the bellows-style boot. The fix requires replacing the steering gear assembly. But many DIYers refuse to believe that, thinking they can fix a rack and pinion leak simply by replacing the boot. Here’s why that won’t fix the leak.

The wet boot is a symptom, not a cause

The boots don’t hold any pressure. Their only job is to keep dirt and grit out of the inner tie rod joint and off the ends of the rack. If you replace an old leaking rack boot with a new boot, you’ll just wind up with a new boot that leaks, because you haven’t fixed the cause of the leak.

Where a rack and pinion leak starts

The power assist is provided by high-pressure fluid from the power steering pump. As you turn the wheel, the spool valve at the top of the rack directs the fluid pressure to the right or left side of the piston seal. The fluid pressure pushes the rack to the left or right. The pressure chamber is sealed by a high-pressure seal on the left and right. It’s those seals that wear and leak. Once fluid escapes the high-pressure chamber, it fills the boots and eventually causes them to split or tear. That’s when you notice the leak.

To fix a leaking rack and pinion, you have to rebuild it with new seals

To do that you have to remove the rack from the vehicle, disassemble it completely, and replace all the worn seals. It’s a big job. You can buy a new seal kit for about $50, but unless you know what you’re doing, I don’t recommend it.

Rack and pinion seal kit

Symptoms of a rack and pinion leak

• Fluid drips on the pavement below the rack and pinion boots
• Wet appearance on the boots
• Low power steering fluid in the reservoir
• Power steering whine

©, 2024 Rick Muscoplat

Posted on February 7, 2024 by Rick Muscoplat