Armstrong Steering
 

My PS works occasionally, but never when I need it to help back my trailer for example. I replaced the O-ring to the Vac Pump but no change. Now whereas I appreciate the upper body developement I'd rather work on that when nobody's watching. Fluid's up, did the lock-to-lock "bleed" procedure, serpentine belt's good and no noise (well at least none from there! [laugh]). Any theories?

If you are real lucky you might get by with draining the fluid, flushing the box, and installing an external filter in the return line. If not it's pump time and don't forget to add the filter in the return line. I replaced my pump twice because I thought I could get away without adding the filter.[duhhh] There are suspended metallic contaminates circulating in your fluid that will wreck your new pump when you install it.

Something Else To Worry About/have Fun Fixing
 

Use a Cardone 20-FLT2 power steering filter. It can be purchased online from www.rockauto.com if nothing is available at your local auto parts store. It's about 2 inches in diameter x 3 inches in length. It looks similar to an inline gasoline filter. Pictures and more info at: http://www.magnefine.com/
Cardone is the distributor for the US.

[nonono] I will NEVER replace another power steering pump without adding this filter. Also note that the instruction sheet that comes with every Cardone pump recommends installing a filter in the return line. [nonono]

Considering the age of our trucks, it's a good idea to go ahead and replace all the rubber lines while you're in there.

Most new/reman pumps included instruction strongly recommend such. :)

Many thanks guys, I was kinda afraid of that. And nice link to the filter info. Guess you know where I'll be the next while ... [duhhh]

No Part Found ???
 

It won't sort using the dashes. Here is the link directly to it:
https://www.rockauto.com/dbphp/prt,1,20FLT2

Thank You, Kind Sir
 

This filter looks like it was designed as an automatic transmission filter and Cardone recommends using it as a heavy duty power steering filter.

From the Magnefine website:

When to change?
Recommended change is every 12 months. It is also advisable to renew your transmission fluid at this time. In fleet applications a test by the Ford motor company demonstrated fluid and filter could be 30,000 miles. (Each transmission runs differently and may require different fluid service intervals.) At change interval you simply evacuate (or drain) the fluid from the system, change the in-line filter and refill. OEM¹s acknowledge it is not necessary to touch the pan up to 100,000 miles, unless for mechanical concerns. This also avoids troublesome pan related problems.

Will it clog?
Magnefine double filtration is so efficient it removes 99% of all wear metal contaminants. It¹s design holds the majority of contaminants on the uniquely positioned magnet. Even if the filter element becomes full, it¹s safety bypass opens for full flow and the magnet still cleans metal from the system

Thank You Again
 

Replacing the old hoses is a must...cheaper than a pump...could be collapsing or fraying off inside...Mark