Power steering blow off

[simonsteve]

95 IH 3600 thomas vista, hydro brakes with booster. Drive from WI to CO over the course of 3 days, on third day in Boulder CO, the Powersteering fluid had blown off out the filler/dipstick tube. Cool down and clean up, dip stick reads full. Figured it was altitude change, because I topped off resevoir before trip in 0degF WI. Drive another 30 miles and stop for night, blows off again and now is below dipstick. Refill to bottom of stick when cold, drive back to Boulder. At first brakes were really stiff, then softened a little, 4 miles in brake harder and the electric booster pump and brake pressure light and alarm kick on. Only come on when braking hard, but does every time. Finish trip back and the fluid is blown off again. Power steering was for the most part fine, but briefly absent thriugh some sharper corners. Looking at the hoses, one is slightly kinked running from bottom of PSF resevoir to hydrobooster. Am I correct in thinking its sucking air somewhere, foaming and overflowing until its low, where it then can't assist with brake pressure? If so is it a fluid flush and replace that hose? Is there a way of checking for vacuum leaks in case it's not the kinked hose?
Thanks for the help!

[Danjo]

Just taking a swing at it, did your brakes get hot, like a dragging shoe or stuck caliper? My thought is that you boiled the fluid, it expanded and overflowed?

[simonsteve]

The hydro booster keeps power steering and brake fluid separate from each other, so I don't think that would be it. I did brake more often in town cs highway when it first blew off, but I don't think brakes were abnormally hot. I did have a short in a tail light but that has been fixed.

[bluebird90]

I have encountered this before. The shaft seal on the pump is drawing air while running and aerating the fluid. Replace the pump or at least the shaft seal. That should solve it.

[simonsteve]

Does that require removing the serpentine belt? Or can you pull the pump without pulling the belt?

[banman]

Originally Posted by simonsteve

Does that require removing the serpentine belt? Or can you pull the pump without pulling the belt?

If your pump is belt driven you'll don't need to remove the belt or at least relieve tension on the belt.

But I'm not familiar with your specific engine -- On my CAT, the p/s pump is gear driven...

Also, usually there is a high pressure relief valve on your p/s. If this is faulty that could cause similar problem. The valve will be part of the pump body, so it will be replaced if you choose to replace the pump.

[simonsteve]

Does anyone know anywhere near boulder/denver where I park and work on my bus?

[brokedown]

Autozone parking lot?

[simonsteve]

Replaced the PS pump, good to go. Old one had 1/8th inch of play parallel to the shaft. Thanks!

[Brad_SwiftFur]

Sort of unrelated - i have a power steering pump intermittent "whine" in an 06 Town & Country, mostly when it's cold (goes away when it warms up).

[banman]

Originally Posted by Brad_SwiftFur

Sort of unrelated - i have a power steering pump intermittent "whine" in an 06 Town & Country, mostly when it's cold (goes away when it warms up).

The cold oil is thicker creating more resistance to the pump...

Pull the belt off and feel for play on the shaft. There should be minimal axial play and no radial play.

Rebuild, or replace the pump.

[Booyah45828]

Or flush the fluid. Most people ignore and neglect it, and it's condition plays a big factor in system performance. Plus, if you're changing the pump anyways, you should flush the fluid regardless.