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 .

 

I haven't heard of this issue before. Is the truck and steering linkage stock?

I'd venture something external is causing this. Are you adjusting the box at all or just installing it and driving?

 

The truck is all stock no lift, stock wheels & tires. I did not adjust any of the boxes I installed, it's my understanding your not supposed to and I had no reason to as each box worked very good not to loose not to tight. I previously purchase all NOS steering linkage that i haven't put on, so this evening I held each piece up to the matching ones on my truck to rule out if one of them was bent and they are all perfect in shape. I was also researching if there is an axle stop adjustment, thought maybe it was traveling beyond or stopping short and causing the problem but no luck. I have a Dana 60 it has flat stubs cast into the knuckle that match up with flat stubs cast on the axle housing that appear to be stops, however when the wheel is turned all they way right or left they don't make contact a small 1/8"gap remains.

 

This is a puzzling issue for sure.

You might need to ask in the standard 80-96 too. Gearbox is the same for all the trucks so you have more people that may have run into or heard of this issue.

I've never really messed with a gearboxs internals so im not even sure what is attached to the top plate internally that could lead to it cracking.

 

That's a good idea I'll posit there also. The sector shaft runs vertical and up and out the top of the sector shaft cover which is what is breaking. The way the cap is breaking it looks like can only come from a vertical pressure staring at the Pitman arm pushing upward, I think the cap would be too strong to crack from a side pressure. I've read on other post's about the power steering pump generating too much pressure due to a clog and blowing seals but never cracking the cap.