About a week or so ago I finally got our Mile Marker 12k hydraulic winch mounted on my pickup. All went well the power steering has been working just fine since, aside from a small leak from the high pressure fitting on the steering box. Yesterday, I started it up and let it run for a bit before heading to work just like I always do. Temp was in the single digits. Went to back out of the driveway and there was NO power steering! It was dark so I stuck my finger into the ps pump and there was fluid in there. I proceeded to work, about 2 miles, with little improvement on the ps. I shut it off at work and immediately heard that nice squiring, running sound of fluid. I looked underneath and seen fluid running from the pump area. I left it, drove a company vehicle home last night since I was on call, and went back to figure it out this morning. The fluid was still pretty much good but the pump is doing nothing for pumping fluid. After letting it run for a few mins the fluid started to get foamy then foamed up and ran out the top again. Did the fluid level possibly get to low and suck in air causing a bigger problem? Again, the fluid didn't look that low this morning, I've seen it lower in other vehicles and not cause any problems. Is this something easily fixable or did the pump go south? I read this at Geno's Garage, "Pump Failure in cold weather is more common than it should be."

 

I have seen this twice, once to me personally and once to a friend, both in cold weather. Although I dont know what caused your problem, here is what I did for mine and my friends.

We took a turkey baster and sucked out all the fluid from the resivoir, and installed new fluid. Second, we had to jack up the front end (both wheels off the ground) started the truck and turned the wheels both left and right, but not going all the way to both right and left. We did this 3-5 times, before going all the way R&L.

I believe somewhere/how, air gets in the line and causes the problem. The first time it did this, I took it to the dealer, fearing the worst. I asked them what they did to fix it and they told me. We have done it since twice now to different trucks and havent had any problems with it since.

 

im havin the same prob with mine, its a 91 non ic so i think our pump are a lil diff. but anyway i took the vacum/ steering pump off and took it apart didnt see anything wrong only the power steering pump had a lil play in the shaft so i went ahead and put a new pump on it and put it back on the truck. same prob. a few people said that it could be a charge line going bad letting it suck air so i took teh o rings off the lines going into the pump and into the box and it seem to help. so maybe give that a look.

 

Sounds like there is a serious amount of air in the system preventing everything from bleeding properly. Did you saw the steering wheel slowly from lock to lock a few times to bleed the system? I used to have a MM10,500 hydraulic and it killed my ps pump in less than a month. I know that MM says you can run the winch off of a ps pump but I think the way they were meant to be run was from a pto.

 

Well I went ahead and replaced the pump but nothing has changed There's absolutely no power assist. Before removing the old pump I started it with the high pressure line removed and no fluid squirted out, should it? I didn't think to make sure the p/s pump drive on the vacuum pump spins before putting the new pump back on. I removed the pump by taking the 3 nuts off the pump then turning the studs out of the pump so I could twist it to clear that sensor in the block. I didn't wanna break the seal on the vacuum pump.
I did purchase a suction pump for sucking the fluid out of the pump but just kinda skipped over that option.
Any ideas? We're kinda dumbfounded at this point. The next thing I'll probably try is put the original high pressure line back on, eliminating the winch, to make sure that something didn't happen in the winch to stop the flow of fluid.