Alright guys, having a issue her I could use some advice on.

I have a 1992 Chevy K3500 four-wheel drive dully, flatbed with the pre-vortec 350 in it for one of the company trucks.

The problem.

Since the snow has hit, it blows out the power steering pressure line about every three hundred miles of so.

I tried having a line made out of more heavy duty hydraulic lines, and it did the same thing.

So here is my theory.

Its starting to get colder, and the truck is getting idled about 12-16 hours a day in 0F and colder weather, with about maybe 15 miles a day of driving time.

So, is the fluid perhaps getting thicker and causing higher pressure that is blowing out the lines? Could I change out the fluid with something thinner, like Marvels Mystery Oil, or maybe perhaps put a bigger pulley on the pump so it doesn't turn as fast? (the truck has v-belts, so finding a new belt wouldn't be too hard)

Or, and otherr idea's? It's starting to get very annoying and expansive. The truck only has about 29,000 miles on it.

 

I would give that a try.... change out the fluid for something thinner. I would guess with all the idleing Moisture is a accumulating and causing the pressure to rise. (just my guess)
I've never seen this problem B4

 

Does it run into a PS cooler in the radiator? Maybe the cooler's plugged. That or the return line is restricted or being pinched off by something? Maybe the steering gear has a restriction. One thing I do know is that maxing out the steering to one side or the other and holding it there definitely isn't good for the PS lines. Maybe the rubber can't handle that cold temperature. Can you get a braided steel line for it like a brake line?

 

It doesn't have a cooler. Iv'e tried flushing the systom, and it all came out clean. steering hasnt been maxed out. I would try to get a solid steel like made for it, but im 580 miles from anywhere, so getting parts made is difficult.

 

Oh right, Alaska lol

Well if you had a steel hard line, you could flare ends for it and make it out of steel brake line/fuel line. I don't remember what style ends are on those saginaw pumps so maybe a brake flaring tool can't make the flare, but that hydraulic place should be able to make the ends onto your steel line. I think that there's supposed to be give in the line, so who knows what will happen if you use that solid steel line.

Well according to the MSDS for Amsoil PS fluid, the freezing point is -60F(-50C). Maybe your truck is experiencing around those temperatures?
https://docs.google.com/viewer?url=h...eringfluid.pdf

Try some synthetic PS fluid maybe? Googling looks like some guys say their pumps moan in really cold weather. Maybe the lines for these pumps can't handle the higher pressure from the oil being thick.

 

The only thing I can think of is either a blockage (or partial blockage somewhere) or...


Because it is so damn cold up there, the fluid you are using is generally much thicker at the temps in that area, causing the system to work harder, and build more pressure. It's possible it's so thick that the pressure just exceeds what the hoses can handle, but I would think if it was running that high all the time, either the engine would run rough from such a load at idle, or the pump would be complaining about it.

Although, power steering fluid is generally warm/hot when it is circulating through the system after it is run through it a bit, even at idle.

Try this, run the truck like you normally do, but once or twice during your next working day, pull the dipstick out, and feel the fluid on the end. Is it warm? Check the engine when cold, where is the fluid on the dipstick? Is it now higher than that area?


If the fluid is getting warm/hot, then the pump should be running at less line pressure than when it is cold.

It's possible the pump could be going bad, the truck only has 29K, but how many years of service has it been run for 12-16 hours a day?

The chassis may have 29K on it, but an engine idling for that long for a long period of time has a LOT of "miles" on it. Including all the accessories.

 

its only been around -20 at the coldest, holding at about 0.

And we bought the truck about a year ago, with about 8000 on the truck and engine. it came from out out of state. I'm going to try making a steel line for it, and seeing how it turns out.

 

Yeah, if it's hovering around 0 the fluid should not be anywhere near thick enough to increase the operating pressure to the point a line blows.

I'd lean towards the pump itself being the culprit here. If there was a blockage, it wouldn't take several hundred miles to blow the line, and if there was a partial blockage, enough to wear it increased pressure to the point of the pump blowing the lines every few hundred miles, the pump ought to be making some noise.

 

Yea, it seems fine, but im gonna go with a steel line, and try robbing the pump off of the othere truck and see if it helps.

 

I lived in Calgary and had similar problems. Perhaps you could find a Power steering cooler and place it in the path of the fan after sucking warm air through the radiator. If you buy a hose long enough you could bundle it with one of the radiator hoses. But if you keep buying stronger lines, something else is gonna break...like your pump housing or something even more expensive.

You said that the rig came in from Out Of State. Did you have the fluids changed for "Artic Conditions?" If not, that is the very first theng I would do....there really is a difference as I'm sure you know.