How To Diagnose Power Steering Problem 2002-07 Subaru WRX - STi

Hi, I’m Mike from 1A Auto. We’ve been selling auto parts for over 30 years!

Start the car up. Vehicle has a power steering noise or a whine. Turning the wheel left to right. It's also difficult to turn the wheel. We're looking at the power steering reservoir, we pull the cap off. It does have plenty of fluid in it, but it's very frothy and has lots of air bubbles in it. That kind of clues me off that there is a leak somewhere in the system, so I'm going to put the cap back on and with the vehicle running, I see there's some power steering fluid around here that may be from somebody filling up this reservoir because it's been leaking, but I don't see any fluids spraying out anywhere, so I'm going to shut it off and then we can look for some leaks.

If your vehicle is making a power steering noise like that and it's coming from the pump, one of the first places you want to look is locate your power steering pump. On this particular car, the power steering pump is right on the top. Some cars, they're down lower. If this was a front wheel drive car, the engine might be facing this way and the power steering pump could be on the back side towards the firewall. It could be up top in the front. You basically just have to locate it and you want to look around the pump. This one looks pretty dry. It is dirty and there's some stuff around here, but I don't see any fresh power steering fluid leaking out of it, so I'm going to guess that this pump is okay. It's somewhere else that we have a problem.

So to tell if your power steering pump would be leaking, just do a visual inspection. You'd look at it. There might be fluid spraying out from the seal on the pump shaft here being driven by the pulley. There could be fluid spraying all over the rest of the engine. There might be fluid on the belt. You might have a belt squeal because the belt is slipping because there's power steering fluid on it. The high pressure line, for example, goes into the pump, at a certain point the Banjo bolt or the washers could be leaking. There could be fluid spilling out of here, the low pressure return, there could be fluid leaking out of here. The clamp could be bad, the hose could be bad. Basically you're just looking in this area for any signs of fresh power steering fluid or leaking, and that will tip you off that the pump could be bad. This one looks okay, so we're going to move onto the next thing.

So some signs you might have a problem with your power steering pump is a difficulty turning the steering wheel. It doesn't feel as easy or as smooth as it once was because you're basically losing the power assist of this pump. The other thing, it could be you will see fluid coming out of it. You'll see fluid coming out of the return. You'll see fluid coming out of the pressure line. This belt could be wet with fluid, it could be worn out. So I'm looking at the reservoir. I do see a lot of power steering fluid leaked out over this. It's all on the inside of the engine compartment here and it's leaking down. It's leaking from these lines it looks like, or maybe it's spilled. That's the other potential thing. Is it somebody that this system was leaking fluid and somebody was topping it off? Because it does have the correct amount of fluid in it and because they were topping it off, they spilled some and that can be throwing me off, so if you suspect that this could be leaking and you're not sure, you want to take some brake parts cleaner and some rags, or take this car to a carwash and just clean this up with soapy water, brake parts cleaner. Any way to get rid of this extra power steering fluid that's here so that you can check for fresh leaks.

I sprayed a little bit of brake parts cleaner on this rag and I'm just going to wipe down this reservoir as best as I can. Wipe around the low pressure return line and then the feed line that's going into the power steering pump.

Typically the reservoir to look for it in your vehicle, it's typically up high. It will be almost the highest point in the system. It's usually on the side of the fender on one side or the other side, and pretty typical, there's a yellow cap on it to help you find it. And on the cap it usually tells you what type of fluid to be used in the system.

Most power steering systems have a specific type of fluid you should use. For example, this one warns us that we should use ATF dexron only as fluid. Other manufacturers may have their own specific fluid for power steering. You should always check your owner's manual or with the vehicle manufacturer before you just dump any type of power steering fluid into your system. You dump the wrong type of fluid into your system, you could potentially damage it.

One thing you can do is trace your lines. So for example, this is the high pressure line on this car. I'm going to follow it back. Since it's a hard line, it goes underneath over here and I can see where the hard line is crimped to this rubber hose, the flexible part that goes down towards the steering rack. I do see some fresh looking fluid around it. So potentially this line is starting to separate from the crimped part and the rubber part and causing a leak. So that's a potential leak area I want to keep investigating. Now below it, we can follow, usually they're pretty close to one another. This is the low pressure return line, so it does not have as much pressure in it. It's after it comes out of the rack and it's going back to the reservoir so I can see where this line is rubber and then it crimps into the steel right here. It's nice and dry. So this one's not leaking. And you follow it down around along here and it goes into the return line for the reservoir. Let me move these lines out of the way real quick. Right here, it's nice and dry. So that's good that up here, that the return line is nice and dry.

Going to raise and support the vehicle and investigate underneath. I'm going to start over here underneath the car. Once you've get it raised in support, you can look for leaks. There's a lot of fluid coming down here, but this is directly under the reservoir, and again, I think this is just from somebody filling it or some of it potentially spilling out because it does have so many air bubbles in it. I don't think that's actually where the leak is, but I'm going to take my rag and just clean it up so it's not dripping on me. And then of course, always just be careful if you're working around the exhaust, especially if you just had the vehicle running, it'll be really hot. And we can see that this fluid is running all the way back. It's all on the sub frame here, on the suspension. It's not too big a deal. It's just basically oil, hydraulic oil and won't really hurt anything. Just wipe up any of the excess.

This is the steering rack. So if you can find your steering rack, it should be under your vehicle. Usually in this area. Sometimes it's above the sub-frame and it's hard to see. We're lucky on this car. It's below the sub-frame. It's pretty easy to see. And there are some lines that run into it, but those look nice and dry. These boots look fairly dry. There's a little bit of oil on them, but I think that's residual from it being sprayed off as the vehicle drives down the road.

We're looking at our high pressure line here. It's this dark rubber hose and it crimps into the steel part that then goes down and it's kind of hard to see. It's just above the sub-frame, it couples into the hard lines that go into the steering rack. So again, I'm looking at this line and I can see that between the soft rubber hose and the hard crimped hose, there's a lot of fluid leaking here, so I'm heavily suspecting that the high pressure line is starting to separate at these crimp connections and leak. And then if we look over here, this is the low pressure line. It has this insulator on it here for the exhaust heat. It's nice and dry. I don't see any fluid leaking out of it. But you can actually see there are some drips of power steering fluid actually dripping off of this. And then it's dripping down here, so it's a pretty good indication that the high pressure line has begun to fail and should be replaced.

If you couldn't find a leak anywhere else, but the power steering fluid was going somewhere, it is entirely possible that there is an internal leak and these boots have begun to fill with power steering fluid, and as soon as you poked a little hole on these poor right out. But typically they're not completely sealed. You would start to see power steering fluid seep out of the tie rods, seep out back here. You'd want to look at these lines for rust damage. If they're rotted, they might leak in the steel part. But I don't see anything coming out of where they go into the rack and I don't see any signs of internal leaking into this. So I think the steering rack's okay on this car and it's probably in that high pressure line. But those are the types of things that you want to look for if you suspect that you have a leak in your power steering system and the pump has begun to get noisy.

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