front axle

[Tom Endy]

I am of the opinion that a front axle should be perfectly straight and that it can be installed with either side facing forward. I have heard it said that the holes for the kingpins are off-set at a 7 degree angle, so that there is a front and a back to a front axle. What say the experts?

I would think that if there is an angle to them it would be outboard, not fore and aft.

The axle in the photo was removed from a 1930 Tudor and I suspect it is the first time it has ever been removed. Notice the curve to it. This could have occurred if someone ran head long into a curb thinking a driveway was there.

Tom Endy

 

[1931 flamingo]

Is not the angle set by the cross member??
Paul in CT

 

[BRENT in 10-uh-C]

Not according to the print Tom. As you indicated, there is King Pin Inclination however axle can be used in either direction.

 

[Bill G]

Notice the curve to it. This could have occurred if someone ran head long into a curb thinking a driveway was there.

Tom Endy

I am wondering if someone tied a tow rope to the center of the axle and tried to pull the car and bending the axle out from the center.

 

[mcgarrett]

The radius rod/spring perch bolts determine the king pin angle, so can be installed either way.

 

[The Master Cylinder]

I am wondering if someone tied a tow rope to the center of the axle and tried to pull the car and bending the axle out from the center.

I could see that happening, Bill. When I first bought my Sedan I checked the toe-in and found it was actually toe-out! No wonder it handled so nice! After crawling under her it was obvious that at sometime someone tied a rope or chain around the center on the axle AND the tie rod, bending the tie rod. No telling what abuse these Ol' Girls have been subjected to.

Good info to know about the axle, Brent. I wonder, is there anyone around the straightens axles?

Years ago when I had an Econoline Van, with "Twin I-Beam Suspension", they used to bend the axles at the alignment shop for caster/camber adjustment.

 

[jw hash]

if you have a nice flat surface the axle should lay flat either way.

 

[Herb Concord Ca]

What Brent and JW say is true. However let the king pin locking bolts be your guide as they may only go in one way.

 

[V8COOPMAN]

I am of the opinion that a front axle should be perfectly straight and that it can be installed with either side facing forward. I have heard it said that the holes for the kingpins are off-set at a 7 degree angle, so that there is a front and a back to a front axle. What say the experts?

I would think that if there is an angle to them it would be outboard, not fore and aft.
Tom Endy

Of course there is a king pin angle, angled inboard at the top in plane with the centerline of the top of the axle. The enclosed drawing indicates right at 7 degrees from vertical per side. Of course, this king pin angle is to set the designed CAMBER, which is complemented by the designed offset in each spindle's king pin bosses. There is no designed CASTER offset or twist from vertical when axle center line is vertical, or when situated 90 degrees from level. I'm not sure about your Model A axles, but NO '32-'48 axles have tapered king pin lock-bolt holes. The lock bolts' tapered, horizontal extrusion locks itself via an interference-fit with the slot in the king pin. The axle can be used EITHER direction, front to back! DD

 

[KR500]

Tom, Here is what I have found after requesting the front crossmember from Ford Benson. The frame has a 5 degree positive tip back which establishes the 5 degree positive caster. The axle as you say originally constructed is symetrical and can be turned either direction. Now here is where the problems can be brought in, the companies such as Bear, John Bean, Beeline, Weaver and other frame alignment companies reestablish caster numbers on vehicles which have been in wrecks, accidents, or damage by using bending equipment which bends and twists the axle back to the numbers, cold of course. Should you pick up an axle at a swap meet from a vehicle which has had some of these corrections you could, if you didn't check it, install an axle and have negative caster. I have never seen any process where the front crossmember is corrected to reestablish the correct 5 degree tip back originally formed in. I can PM you a print of the front crossmember if you desire.

 

[David R.]

What think ye of this axle? From a double A truck. The one on left is replacement for bent one. I could not find any difference to determine front or back. I always thought locking bolt holes were tapered, but measurements proved otherwise. After installation of replacement I noticed a slight bit of wear where drag link had rubbed top of axle on right side, so I actually installed it reversed from it’s original position.

 

[Joe K]

What Brent and JW say is true. However let the king pin locking bolts be your guide as they may only go in one way.

Not entirely so. Or for reason not stated.

The retaining pins are "cylindrical" as are the holes. The retaining pins can be inserted into the hole and can be made to "fall through" if the hole/pin is clean and slightly lubed.

What makes the retaining pins non-reversible is the "ramp" which wedges against the groove in the kingpin. The groove in the kingpin is made to an orientation relative to the top hood and thus kingpins are usually "right & left" with only one side installation permitted. The retaining pin meanwhile goes in with the nut on the front as this provides the proper orientation of the "ramp" to allow the kingpin top hood proper orientation.

Retaining pins, rather their "acorn nuts" also serve as "stops" to prevent too sharp a turning radius.

I'm reminded of this - a 1970s era king-pin set came not with the proper acorn type retaining pin nut (which acts as a sort of spacer/limit to wheel spindle turning) but rather a pair of common fine thread nuts - and washers.

I put the front end together using the "new" parts entirely. My rationale being then "this is a kit with a purpose and they must know what they are providing."

Maybe not so much? (retrospect) I was pleased to find the Model A could be turned entirely around within the confines of my Dad's two car garage - a total turning diameter of only 24 feet?

However, not so pleased later when I hit a bump and found the car suddenly thrown into a 90 degree turn as the wheel was jerked from my hands. Fortunately I was not going too fast and kept the car upright. I imagine today skidding to a stop SIDEWAYS with two wheels on the ground - almost a Laurel & Hardy moment. It was a tenuous trip home that day.

Anyway, the front axle is USUALLY installed with the FORD script to the front. Many axles are corroded a bit, or overpainted a bit and this detail is missing. It may not have been too distinct to begin with.

And the damage to the front axle of the wheels being "curled" to the rear around the wishbone, particularly on the passenger side is typical. I have about five axles here and ALL show the damage to greater or lesser extent.

I have advocated MANY times use of the "alignment rods" according to method given first by Victor Page in his book "The Model A Ford" and most recently in Restorer Magazine July/August 2018 (Kudos to Grady/Janke) p.12

Victor Page "recycled" a pix from his Model T book into his Model A book - but the principle is the same.

Lot of work to demount and straighten an axle though. Gives you an excuse to have a "spare axle" around - or five of them.

Joe K

 

[BRENT in 10-uh-C]

Brent. I wonder, is there anyone around the straightens axles?

While I cannot speak for your locale when you say "around", but in my area, we do. We have made aluminum mandrels that fit into each of the boss holes which allows us to use a straight edge to check for straightness. We cold bend in a hydraulic press, but I am sure there are other means too. We do weld on axles as often there is metal wear from worn perches or spring hangers that needs to be repaired.

Tom, Here is what I have found after requesting the front crossmember from Ford Benson. The frame has a 5 degree positive tip back which establishes the 5 degree positive caster. The axle as you say originally constructed is symetrical and can be turned either direction. Now here is where the problems can be brought in, the companies such as Bear, John Bean, Beeline, Weaver and other frame alignment companies reestablish caster numbers on vehicles which have been in wrecks, accidents, or damage by using bending equipment which bends and twists the axle back to the numbers, cold of course. Should you pick up an axle at a swap meet from a vehicle which has had some of these corrections you could, if you didn't check it, install an axle and have negative caster. I have never seen any process where the front crossmember is corrected to reestablish the correct 5 degree tip back originally formed in. I can PM you a print of the front crossmember if you desire.

I do agree the crossmember does have draft in the area directly below the crank bearing however it is my opinion this does not set the castor angle. I believe it is the A-3405-* Front Radius Rod Assy. that establishes the castor angle for the front axle. Because of the parabolic arc of the axle travel, the crossmember angle allows for the spring to align better but I don't think that is what sets the castor angle. Maybe I am wrong but on a fully assembled front suspension, if the front spring were removed from axle and the castor angle was checked, I believe it would remain within the same specs. even if the frame was raised or lowered slightly.

.

 

[katy]

The retaining pin meanwhile goes in with the nut on the front

I disagree, the elongated nut should be on the back. See: Judging standards, page 4-1,

 

[abachman3]

We have cold straightened axles using a 30 ton press. Generally you set the high side up and apply pressure where it is up. Press slightly lower than desired, as when the pressure is released, it rebounds slightly. A 20 ton press is generally not sufficient.

 

[Joe K]

I disagree, the elongated nut should be on the back. See: Judging standards, page 4-1,

Thank you. I wrote that without checking. The rest of the essay applies.

Some thought on that though, putting the acorn nut on the front causes the kingpins to "reverse" left to right - this to keep the kingpin top hood orientation "up tight" against the brake shaft housing.

So yes, it is possible to entirely "reverse" the front assembly and make it work. It may take reversing the brake shaft housings left to right too.

Curiously, a little half moon cutout on the steering spindles appears on both front and back of the yokes both left and right. This half moon cutout is the "touch point" for the acorn nut limiter. Thus the steering spindles CAN be reversed left to right.

Possibly done this way for RHD car production?

Joe K

 

[nomadpsd]

Thank you. I wrote that without checking. The rest of the essay applies.

Some thought on that though, putting the acorn nut on the front causes the kingpins to "reverse" left to right - this to keep the kingpin top hood orientation "up tight" against the brake shaft housing.

So yes, it is possible to entirely "reverse" the front assembly and make it work. It may take reversing the brake shaft housings left to right too.

Curiously, a little half moon cutout on the steering spindles appears on both front and back of the yokes both left and right. This half moon cutout is the "touch point" for the acorn nut limiter. Thus the steering spindles CAN be reversed left to right.

Possibly done this way for RHD car production?

Joe K

The King Pins can't be swapped side for side. If you did, the brake levers would push instead of pull.

 

[Purdy Swoft]

Most of the model A front axles that I have worked on was found to be bent . I have had good luck using a heavy chain and a bottle jack to straighten axles . A press often works better . I always straighten front axles cold .