Hydraulic pump failure or a collapsed hose?

Dear Car Talk

Dear Car Talk | Nov 01, 1995

Dear Tom and Ray:

I have a 20 foot motor home mounted on a 1984 Chevy G-30 chassis with a 350 V-8. Both power steering and power brake systems are hydraulic, activated from the belt-driven power steering pump. Lose the pump, you lose them both. Recently, after I exited the interstate after several hours of driving, I lost both steering and brake assist on the exit ramp with its curve and stop sign. Fortunately, I was able to muscle the rig to a safe stop. I limped into town, let the rig cool, had a cup of coffee, and tried again. Still no power assist. The belt was in good shape, and the fluid level was normal. I drove two miles to a Chevrolet garage using muscle power all the way, shut it down and sought service. Yes, you guessed it. When the mechanic started it up, everything worked fine. No one had any idea what could have caused the problem. Since then I have driven the vehicle several thousand miles and there has not been the slightest hint of trouble. Twice a year I take this vehicle on vacations through the Smokey Mountains. But I dread losing the steering and brakes. Do you have an answer for me?

TOM: Maybe that's why they call them Smokey Mountains? All those smoldering motor homes at the bottoms of all those ravines. You're a braver man than I, Stuart. I wouldn't keep driving this thing.

RAY: If I had to guess, I'd say you probably had a collapsed hose, Stuart. And it could collapse again.

TOM: There are hoses that run to and from the pump that carry the hydraulic fluid. If one of those hoses collapses internally, you'd lose pressure and lose the power to your steering and brakes. And that's the kind of thing that could correct itself after a while, although it is likely to recur.

RAY: The other possibility is that the pump is going bad. But usually, when those pumps start to go, they make noise. But I'd have the pump tested to make sure it's putting out the correct amount of pressure just to be safe.

TOM: Then I'd go ahead and replace all the hoses. I wouldn't even bother checking them and trying to figure out which one may have collapsed. On a 12 year old vehicle, if they're not bad already, they're probably getting ready to break soon. And if one of them breaks, that'll also take out your power steering and power brakes.

RAY: And while it might be thrilling to find a new, short cut down the mountain and get a new mountain "pass" named after you, it's not a course of action I'd prescribe. So change those hoses pronto, Stuart.

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