I got around to installing the CPP power steering box in my 55 F100 and have run into what I consider a major problem. The pitman arm will not press onto the shaft far enough to get the lock washer and nut onto the shaft. The other part of the problem is the spline part of the shaft is larger than the threaded part which leaves a gap that is almost as big as the washer. The gap is big enough that the washer will not seat against the pitman arm. It actually starts to suck into the gap when the nut is tightened. I called Mid Fifty to see if the box, the sector shaft or the PA needed to be replaced. I told them the nut would not even go flush with the shaft. Mid fifty said the nut only needs to be flush. CPP tech support said it was OK and I could use Locktite if I wanted. Since they have know about this problem for many years I cant believe they are willing to accept the liability. I can't imagine any tech inspection would pass a vehicle with no threads showing above a nut. That's not the only problem. Money is a problem and I'm not going to throw the POS in the trash like I would have a few years ago. I am planning on machining a spacer that will eliminate the dead space and then removing enough of the outer surface of the PA to allow for a flat plate or washer to make full contact with the PA. I would think torquing the nut to 200 pounds with red Locktite would keep it all together. I'm worried about the lack of lock washer but if I can get a few threads showing I can try to stake it. I'm interested in how others have remedied this. The shiny part around the hole is the only contact the lock washer makes with the PA. The lock washer wants to slide into the hole.
I'm thinking that you are correct, You can see the gap between the teeth of the sector shaft and the pitman arm. Or it is the wrong pitman arm that is intended for a larger box. The box should be the CP50006F 1953-56, 400 Series™ You did buy the 5356PA-T Pitman arm? A Ford pitman arm isn't going to work on that Toyota (style) box. A bit of a gap between the end of the splines on the sector shaft and the surface of the pitman arm where the nut and lockwasher hit is required, there is a good chance that the pitman arm won't fully seat on the sector shaft if it doesn't have that bit of space.
Absolutely not. If the PA was reversed it would not connect to the drag link. Of course there is a possibility the Chinese machinists ran the taper the wrong way but then there would be another problem. CPP and Mid Fifty have known about this problem for years. I'm ashamed I didn't research this before I bought the kit. I have done two previous F100's with the old ram system that worked fine. I made the mistake of thinking this was better. At least I didn't put a Mustang II or Crown Vic clip on it. I'm just too old and feeble to turn the stock steering without some power assist. This is going to be my daily driver and I need to be able to comfortably drive it up to the time I go underground. FWIW I did turn the PA around to see if it fit and it didn't so I put it on the right way and tried to press it on with pressure from the nut. Bottom line its a POS piece of bad machining that we are supposed to just live with.
Its either a wrong pitman arm or a wrong box. CPP and Mid Fifty say it OK, just run the nut down as far as you can and don't worry about it. That's wrong and I won"t do it.
Apparently not. Tech support at Mid Fifty and CPP said the PA isn't supposed to go all the way on the splines. They both said the nut doesn't need any threads showing past the nut. This isn't rocket science, its bad machining plain and simple. I posted this because nobody should just run the nut down and live with it. Its dangerous and its wrong.
Do you have a pitman are puller? If so tighten the nut up then see how hard it is to remove the pitman arm. Can you find a pitman arm the shape you need and the correct taper?
Yes, I have a pitman arm puller. I have tightened up the nut. I will need heat to remove the pitman arm. The stock pitman arm won't work. CPP claims I need to use their PA. They claim both the shaft and the PA have a taper. A Google search will show this is an ongoing problem since at least 2016. Shame on me for trusting an aftermarket company to provide a product that worked. The point of this post is two fold: 1. What have others done to remedy the problem 2. Warn others this is not a simple bolt in modification
Mr. 48 Chevy: This is a kit from CPP that comes with the pitman arm. The Ford pitman arm is entirely different. Different radius and a different attachment. The gap is 0.364, as I recall. Something is really wrong here and there have evidently been a lot of wrong kits sent out in the past. Both Mid Fifty and CPP have simply told people to tighten the nut down and live with it. In all actuality it would probably last for a long time even without a nut if you just jammed it down as tight as you could and threw the nut away. But that's not right on something as important as the steering. Its a real simple thing for CPP to send the parts back to China and have them machine the parts to fit properly. I'm still looking for someone who has dealt with this situation in the past and what they did to correct it. That is the point of this post.
Tapered splines require a space between the small end of the splines and the nut. If the nut is bottomed against the splines there is a possibility that the pitman arm will not be pulled down tight in the taper and could get loose from impacts such as driving through pot holes. Do not put a spacer in there to fill the gap because you may not get the nut tight enough to lock the arm to the splines. Throw the lock washer in the trash. Just use a heavy hard washer and the nut. Caterpillar stopped using lock washers in the 80's. Lock washers are hard and prone to breaking, then falling out. When that happens, your nut (or bolt) is loose. Your Caterpillar dealer is an excellent source of hard washers. How thick is your nut? There is no reason to have a nut more than about 3/8 thick. Perhaps you can find a pinion nut of the proper thread count with a flange built on instead of using a washer. I am well aware that my 2 cents worth won't buy much of anything.
If you can tighten the nut enough to have to use a puller to get the arm off then what is the worry? You actually think it will come loose? I have always busted my nuts to get a PA off and most times I have to use a lot of heat; never see one loosen up. That nut is like 3/4-16 thread, should be able to put at least 70 ft lbs torque to it. Leave the loc washer out, use loc tite if your nervous and check it when you change the oil.
Fabber McGee: Yes the spacer would have to allow for some space. Right now the space is .364 and that is enough for the PA to rock back and forth. I do have a John Deere dealer nearby and will try for a flange nut. seb fontana: Yes I worry about it coming loose. I also worry that the only part of the nut that would contact the PA would be the points of the nut if the washer was left out. Take note of that shiny part around the edge of the hole. That is the contact area. Someone who sits on a tech inspection committee should weigh in here and tell me its OK to have that little contact with the nut/washer and not have a single thread showing. Really??
I put a CPP disc brake kit in my car last spriñg. After several go arounds with CPP Tech Support for the wrong parts in the kit or incorrectly manufactured parts in the kit, I learned my lesson and won't buy CPP again if I can help it. My proportioning valve had one hole that was tapped off-center of the pre-drilled hole so it had no threads on one side of the hole. It takes effort to screw up a part like that.
I'm just thinking, I'd pop the pitman arm off and check the spots where it actually shows to have made contadt with the sector shaft splines and look for burrs or risings. It might be prudent to gently dress the splines with a small three corner file to clean up any rough spots.
If the pitman arm actually rocks on the shan't the taper(s) are wrong . I would not fee! Comfortable running it , once the face of the PA wears as well as the faced of the but ,the arm will be loose ( not seated) on the splines .
If you would "need heat" to get it off as you mentioned in post 10 and you are still able to rock the arm back and forth; seems to me there is something much more seriously wrong with the fit between the external and internal splines than just the depth of engagement.
The first thing to do is check the fit of the splines in both parts. As @Mr48chev pointed out, a clean up may help. I can't tell from the photo, but how far does the thread on the shaft extend? You could get a heavy nut turned down to make a 'shoulder nut' which would give you more thread engagement, then use Loctite. Good luck!
I had a chassis customer that wanted a CPP Vega style power box on a 32 chassis I was doing for him. After struggling with the various fitment items and having conversations with CPP tech the customer and I decided a manual Vega box would be fine. Was supposed to be a direct replacement for the manual Vega box?
I have a Vega box. I needed a pitman arm. There are 57 flavors of arms for Vega boxes. Everything from punched out of plate to ones that must be made of unobtanium by the price. I looked at pictures and read 100's of reviews. Exactly what you describe happens with half of them too. "Can't get enough nut on it". They are just wrong. I'd find another pitman arm, like an OEM Toyota (or whatever it actually is). Or find an aftermarket one that is a different forging (different source). Try it and see if you still have the problem. All arms are not created equal. I got one from an online rod shop that actual customers had reviewed as working (or really bright AI). It was forged and yellow chromate plated (that I don't want). The rod hole is tapered from both sides. It fits. Nut and washer. Threads will show when I tighten it good. It came in a Helix box (Hoffman). Who knew ? I'd try another, just to see. Mike
I pulled the PA off this morning and did my best to accurately measure what is going on. The problem is the relative size of the shaft and the arm. The splines are clean and it is a correct fit with no rocking motion when pushed together by hand. The problem is caused because the hole in the arm is not large enough for the splines to be fully engaged for their entire length. Because of this misfit there is insufficient room for the nut to properly seat. I am waiting to hear back from CPP to see what they offer for a solution. I find it hard to believe that anyone would accept this kind of crap. I would like to try a different PA to see if I can gain a bit there. I found a 7/8 Grade 8 washer at John Deere and I have ordered a lock nut from Honda that might work. Worse case scenario will be to mill .050 off the front of the PA, install the flat washer and them Locktite the Honda nut in place. I have tried to find a flange nut that would work but they all require way more thread then I could ever get. That will do until I find something better. I will never like it but I will have to live with it. I'm open to suggestions for an OEM solution that would work. This is going to be a daily driver and at my age I just cant live without PS. I never thought it would come to this but old age ain't what its cracked up to be.
On aircraft, two threads at least must protrude past the nut to guarantee enough thread purchase. The inspectors won't buy your work if at least two threads don't protrude. If it's good enough for aircraft, it's plenty good for automotive use. I worked flight test for many years with the major manufacturers and it became second nature to follow the same rules when I built hot rods or race cars.
If you could show the shape and measure the pitman shaft and give spline count and taper we may be able to help.
Noticed your thread on FTE also. I agree with the suggestion of attempting to get a OEM Toyota (or whatever it is ) pitman arm and see how far it goes on... Might not be possible... But if so you would know for sure... Yeah I hate this aftermarket crap also....I am following cuz I want PS on my truck someday. Good Luck!
It seems almost too simple to ask, because you must have checked, but are there any missing splines on either piece to only allow the arm to go on in one location. I have had to grind away a few unsplined areas in the past when a pitman arm wasn't aimed where I wanted it on a custom installation.
And then there is the other side of the story. I put that same CPP Vega power box in my '26 T. My only problem was trying to stuff 10# in a 5# sack under the T hood. It's been in there over 10K miles now and works just great. But no, it is not exactly a bolt on.
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