I have just acquired a 1930 A chassis with 29 closed cab P/U installed. I am hanging a So Cal dropped axle (4") kit with hairpins. I have the chassis setup at future ride height. The directions say to lean axle back a little and weld hairpin brackets to frame. How far back should the axle lean? What angle should the king pins be at? Thanks for help.
6-8 degrees of kingpin inclination as I recall, one thing for sure not enuff and it won't wanna go straight, to much and it will only like going straight, You should have some adjustment on the hairpins too. Von Doc
At ride height with motor installed the kingpins should be between 4-6 degrees positive caster. Bottom of kingpin forward, top of kingpin leaning back in other words. Double check and make sure the the axle is 90degrees to the frame rails, cross measure checking the wheelbase. Dad always reccomended about 1/8" toe in with belted, your mileage may vary. Hope this helps
So cal directions say , "a little bit " ? Really!?! Hopefully your hairpins are adjustable at the axle , yes?
Maybe the directions said slightly. Either way there was no numerical value given. The haipins are adjustable at batwings. Thank you all for info!
Why dont'cha just clamp hairpin brackets to the frame until you have eng/trans,radiator, Body, etc. mounted in the frame, then determine what caster will be set at..one of the last things, before ya drive it. 4-6 degrees, and bolt them, don't weld the brackets, use 3or4 bolts.. ya don't want brackets to low or to high.
X2 with Mr. verde742- don't finish weld anything till you've got it ALL set up. Frame set up is very time consuming- measure everything over and over ( gremlins move things around when you go in the house).Run a center line front to back, and take diagonal measurements to check squareness. Work, check, work, check etc.And once you do start to weld things up, take your time- slow and steady so you'll avoid overheating and distortion. Good luck with the project- pictures are mandatory! Mike from Mass.
Don't forgot get the effect "rubber rake" will have on caster. Do you have your intended wheel and tire combo already? "Listen Mr... It ain't broke if I can't fix it"
"King pin inclination" is viewed and measure from the front and refers to the angle towards center of the axle. It is forged into the axle and spindle and not adjustable. View attachment 2699846
Just kinda funny and it fits with a conversation I had with "SoCal's so called" tech department. Just make sure that your adjustment isn't locked in, you could center it if you like. Make sure the car is at ride height and rake, then weld your stuff up centered, square and at 4* In relation to the ground. You can adjust more or less if you need after road tests. You may find you want or need to shim/adjust/change the crossmember spring mounting pad to eliminate some spring bind if you get it. Its completely adjustable during fabrication. You can get the frame mounts in the pavement or in the windshield. Neither would be correct but you can get the frame mount to go anywhere you might need it.
I havent gotten the front wheels/tires yet but I have mocked frame at correct height. I have loaded front end with weight to simulate engine installed so as to load front spring and help locate upper shock mounts. I like the idea of temp mounting until actual road test. Thanks to all, I appreciate your detailed instructions. Pics will come with a build thread as time allows.
Yeah well I'm sure not talking about what can't be changed, but rather the rotation fore and aft. lord knows I've installed plenty. Von Doc
The SoCal instructions seem like they give the impression this is all a piece of cake. That's too bad because any of us that have done this know better, as was stated. You can simulate engine weight, guess at the ride height etc etc and according to "the numbers" it should all be close. Who here hasn't done the exact same thing and had to re-do most of it once everything is together? You can simulate all you want but there's no substitute for having all your parts together. That's hard to do when you're on a budget I know. But things just change when ALL the weight is on a car. Little shit like fan belts, plug wires, coolant, the cool valve covers you found half way through the build. Doesn't seem like much weight individually but put em all together in a pile and it adds up. Then you stand back and say to yourself, "that's not the rake I had in the shop". The springs will settle after a while too, my front spring is about 1/8" away from the axle right now! It's hitting the axle on hard bumps. Wasn't like that when I put it together. I've been driving my AV8 pickup since May. I've had to tweak the caster twice and pulled the rear spring 3 times screwing with the ride height and softening up the ride. Front and rear shock mounts were the last thing I did. So as has been said, don't nail anything down permanently right away. There WILL be changes.
When you go to finalize the rear mounting; be sure that the hairpins are parallel to the ground or a little uphill to the rear. To me, it always seems to look wrong if the wishbones or hairpins run downhill to the rear mount. Easy to do with the clevises on hairpins; but a little more work to pie-cut wishbones; but in either case well worth the effort.
No caster adjustments with bones. That's a different animal there, if you need or want tweaking it takes heating&bending or cutting&welding. That's one of the reasons Henry's "within" specs on caster is so W I D E on the stock chassis.
So are we supposed to ask you what you're talking about or for a copy of your personal dictionary? Because if you told me you wanted your car set with 8* king pin inclination, I'm bending your axle. It seems as though you took offense to a complete proper definition and explanation of a term used incorrectly. Maybe its a typo, maybe its something else
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