hi all, can anyone tell me if the 48-52 ford f1 axle has a front side or is it symmetrical? The factory shop manual says caster and camber are built into the axle. And the axle is already installed so it isn't easy to check the king pin angle on the axle. Any markings on the axle to indicate the front?
Look at the taper for the king pin pinch bolts and then hope you remember what side the threads of the bolt stuck out . I'm thinking that the larger side of the taper goes to the front and the nut is on the back and serves as the steering stop. I think that was the way the 52 axle I had was when I snagged the front drums and backing plates off it. I don't have a picture one of that chassis as they were on a computer that died a tragic death. Snagging this off Sid's site the shock stud goes to the front and the king pin pinch bolt goes in from the front .
Here is the reason for posting.... Someone else is having issues, they have the pin bolt going in reverse. my immediate thought was they had their axle in backwards because I thought the pin went in only one direction (making the axle directional). So I removed the pin nut on my truck to see if the hole on the nut side was smaller. and it was not. Measured with a caliper, it was same diameter on both sides with a noticeable clearance around the bolt threads. Now I believe the pin can go in either side and does not dictate front of axle. But your right...the ford diagrams show the pin going in from the front. This might be because of the special cap nut that goes on top of the regular nut...and I was told that acts as a stop for the spindle rotation. So anyway, this research has me concerned if the axle has an orientation. The shop manual says caster and camber is built-in which leads me to believe it is not symmetrical. I don't think I paid any attention to this when I put it together some years ago. The alignment shop said it was in specs...but this will nag me til I know for sure if there is an orientation and if I installed it correctly. one more point, I saw the letter R near the pinch bolt on one side. Thinking this might indicate right side, but it is on the left side on my truck...so if R means right side, then mine is backwards. The production casting numbers are on opposite sides so if you flip the axle around, you always have the casting number in the same place.
I believe those axles are the same front and back and can be turned around with no ill effect. You mentioned the king pin retainer holes being drilled straight through, that is correct. The retainer has an angle milled on it and as you draw up the stop nut that will advance the ramp (angle) of the retainer tighter against the notch in the king pin. Camber is machined in, although your axle being 70 + years old could be bent but a good front end shop versed in working on straight axle trucks could correct that. As far as caster goes, I will admit that I’ve never worked on an F1 truck but I doubt they machined caster into the spring pads. I expect the caster will be set by using tapered shims under the leaf springs to tilt the axle back 6-7 degrees. The last thing, and really the only one that might throw my explanation a curve ball would be the shock mount holes. If they are also drilled straight through like the k/p retainer holes then the axle is definitely reversible, and the shocks were originally mounted in front of the axle.
Well my day is good because I learned something and that is that the the hole for the king pin bolt is straight through and not tapered. Now I have to put checking my Chevy axle to see if it is the same way. I'm thinking that on the 52 F-1 axle there was a nut that looked like a mag wheel lug nut on that bolt that served as a steering stop. On my 48 there is supposed to be a tab that bolts under the nut and is bent so the spindle hits it to stop it from turning .
Only help I can give is the confirmation that the king pin lock hole on all Ford passenger axles from 48 and older is drilled straight through. There is no front or back on the passenger axles. I can’t think of why Ford would want to make things more difficult for the trucks.
If you want to know for sure, jack stands under the front axle, wheels/tire removed, place the center of the spindle as close as it was with it sitting on the ground with the tires/wheels on it. The measuring App I have on my phone also has an angle finder. You can set the phone up right, or sideways. Some math and creativity needed for either method of phone orientation. But as mentioned, I’d bet a cold coke it doesn’t matter. I mean think of how many were coming in and spindle assemblies, etc installed and bolted on.
I tried to check the angles with a small digital level. There is just enough room on the spring pad to get a reference. but there is not a good place near the kingpin without disassembly. The truck is running and driving, I don't want to go as far as taking things apart. I am hoping someone here will know with certainty regarding orientation. I saw somewhere that the early Fords (30's) were symmetrical. My guess is the 48-52 is also symmetrical. But that letter "R" cast in the I beam leaves me to doubt the symmetry. just another thought...I have 2 degree shims, the other guy I mentioned has no shims, but we both are in caster specs....wonder if i have shim because my axle is backwards. (sometimes I over analyze things...note to self..."must stop") It seems the consensus is 4-6 degrees caster is preferred for today's roads, wider tires, radials, speeds, etc. Any disagreement on this? I plan to add 2 degree shims to get me in that range to help with some wandering. Before loosening bolts and adding shims, I want to understand the axle orientation. Please don't suggest for wandering to check the other components for wear or looseness...Everything is new and rebuilt. If I need to discuss wandering, I can start a new post. thanks all!!
The built in caster the shop manual refers to is the shims. Every F1 to F6 that I have worked on has had them. 2 degrees if I recall. You really should not need more caster unless you have a lot of rake. The 7 degree thing might work for a buggy spring setup but is excessive for parallel leafs. My F1 has 2 degree shims and drives great up to 80 mph
^^^^ THIS^^^!!! While the cross leaf Fords from T buckets to mid 30's drive better at highway speeds with between 4 and 8 degrees positive caster these trucks do a lot better with between 1 and 3 degrees. on the lower side if most of the driving is at lower speeds in town up to two or three if most of your driving is on the highway at legit big road speeds. A lot of the time you need a 3 degree shim to get an honest 2 degrees positive though. Positive with the top of the axle leaning back like a bike fork. Factory specs call for around 1 degree positive if that because the trucks didn't drive that fast then and steering ease while turning was a lot more important than tracking down non existent freeways in that time frame. The more caster the more steering effort it takes at low speed.
I had a ‘48 F1 I parted out years back. Pulled and sold the front axle, there were no shims. I guess someone could have removed them in 50 or so years.
thanks everyone for all the replies. The shop manual says to put the shims back in upon re-assembly, therefore I am convinced they were there to start with (mine had 'em). The shop manual says the caster specs are 2.5 to 4.5 degrees. I may need to do another alignment just to know where my caster is before getting more shims. When it was aligned, they simply said it was OK, I dont know if it is on the low or high end of the specs. A lot of F1 folks claim 4-6 degrees is better with wider tires, higher speeds, etc. I thought 2 more degrees was worth a try. However, my main question here is whether or not the axle is symmetrical or directional. It seems the opinions here are that it is symmetrical. The shock bolt and the king pin pinch bolt appears to go in either side. I would agree with Fordors that they probably did not machine caster into the spring pads. The letter "R" on one side of the axle still cast doubts for me that it is symmetrical. The production casting numbers are on both sides but not the letter "R".
I think I can clear this up....I talked to Posies about getting their rear springs...While talking to them, I asked if they knew if the front axle is symmetrical ......drum-roll please.......... he said yes, we can flip it anyway we want to.
As far as being symmetrical I don’t have an absolute, definitive answer, only what I’ve seen over the years. Model A and early V8 axles I’ve run across over the years may have AA, EE or in the case of the Model A axle pictured an F in a triangle on the forging. This photo is an A axle that was dropped, distorting the F. Some say that identifies the steel alloy. Maybe, but AFAIK Ford used a steel alloy that included vanadium for added strength. Could the different letters, and as on your axle the R, signify the forge shop or forging dies used? Also, somewhere over the years someone did a king pin job on your truck, they didn’t reuse the steering stops. That’s not uncommon, they can get beat up and new ones don’t come with the k/p kit. It looks like the retainer has 3* machined into it to tighten the pin in place.
If I had seen an F, I would assume that was the front! These letters meant something at the factory. like you said, maybe forge shop, dies, or even year, month, dwg revision, batch, etc. My stops have been missing since I got the truck in '84. During this research, only now I realize those are stops and they are missing. I was thinking the retainer pin had a slight taper. Thanks for the pics!
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