My 97 f350 reg cab keeps breaking the steering box sector cap when making a right turn. It's driving me nuts as it makes no sense, i bought the truck used with 103K miles and put about 500 miles on it with no problem even plowed snow with no issues. after plowing it sat for a while then one day my son went to use it and power steering fluid poured out it. after diagnosing it was the box I ordered a re-manufactured one from Ford swamped it out along with new high and low pressure lines. I put maybe 100 miles on it then had a brake line rot out, so it sat for months.
Fixed the brake lines was driving it around the farm made a hard right turn heard a loud pow fluid everywhere, this time I noticed the sector cap was cracked clean in half, i assumed i had gotten a bad one and fortunately it was still under warranty. While waiting for the replacement to come in I became impatient & took the box off a 89 f350 parts truck I had installed it and it worked fine, when the new replacement came in I decided to put it on the shelf. Today made a rolling right turn and pow! fluid all over and broken sector cap again. I never confirmed if the 1st box had cracked the sector cap because it was so grungy I probably didn't notice, but now I would have to think it had also cracked the cap.
any information would be appreciated .

 

Thats an interesting problem to be having. Does the cap break when you have the steering turned all the way to the lock? Any resistance or odd behavior before it breaks? Pump pressure way too high maybe?

 

My 15 year old son was driving (farm truck) every time when it happened and 2 of the 3 times I was standing near by and witnessed once it was locked out to the right, the other 2 times I'm not sure if it was locked out but definitely turning right. Teaching young kids NOT TO turn the wheel all the way to lock out without moving drives me nuts! So considering I'm always yelling at him for it I can't expect to get the truth whether if the other 2 incidents were full lock out.
Nothing odd no resistance it's actually super easy to turn and my son always asks why is it so much easier to turn the wheel on this truck compared to another 97 F350 w/5.8 we have. I'm staring to think maybe it's because there is in fact a problem with the pump building too much pressure and may be the reason for it turning too easy.
I'm not a parts changer mechanic to diagnose problems, but at this point I'm ready to replace the pump in order to rule it out. I can understand the pump building enough pressure to blow a seal I just can't fathom it can crack the steel sector cap.