Front axle question

Robbie Horn

Robbie Horn

Member
How can you tell how to install the front axle? Which side faces the front?
 

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There is no front to the A axle.The kingpin lock bolt holes are straight,and if they look tapered,then they are wallowed out and need to be fixed.
 
Take a look at the tapered holes for the spindle bolt locking pins fit. Those hole are tapered to fit the pin front to back for the nuts to attach on the back of the axle.
That tapering is the way to tell the front from the back of the axle.
 
The holes are not tapered. Here is a print Brent posted, they are reamed .561-.563.
 

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Look at the Ford print.No taper.Straight drilled hole,the locking pin has the taper machined onto it to squeeze against the notch in the kingpin.If you have a taper the axle is screwed up from somebody driving the pins in too tight.
 
My experience says that the holes in the axle for the cotter pins is parallel . It is the pin itself that has the taper cut into it. The taper slides in a groove in the king pin to lock it in place.
 
As Syncro99 and others say, the pin is straight. Without the king-pin in place it will slip right through its hole.

The King pin has a cut "Key-area" which the pin engages. The king pins are made so the "cut" matches the orientation of the top hood. You can put it together wrong but the hoods will be misaligned to the brake actuators.

The usual issue with a front axle is one of "straightness." Almost all axles "out there" (or you're likely to find) are bent in some fashion, the usual bend being the passenger side outside of the spring perch being bent "backwards" - from hitting objects along the side of the road.

The best solution for this is to "demount" the axle from the wishbone and then "straighten" in a press using the KRW "Indicator rods" (Shown below applied to a Model T axle but the application/correction identical. )
430604.jpg

To straighten a Model A axle with the wishbone attached CAN be done, but you'll need a correspondingly "taller" press and various not normally seen "anvils" for the press. Some have reported success by bringing the axle/wishbone to a frame straightening or truck shop who have a "straightening table" which has dogs and moveable cylinders. Note that in doing a straighten without removal of the wishbone one "overlooks" the introduced inaccuracy of a bend in the wish-bone - although this bend is usually visible on a more basic level.

It is possible to "make" the straightening indicators if you have a lathe. Mine was made in my "pre-metal lathe" period using wooden tapered spools done on my father's woodworking lathe.

Joe K
 
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The A axle mandrels are similar to the T axle but the photo illustrates the checks needed. There were four mandrels in the set plus a gauge to indicate angle alignment. I believe the angle was 14 degrees between sides and 7 degrees from vertical center on each side on the model A.

The axle can go either way but some put the forging marks forward as a matter of reference in case the axle is ever readjusted in place.
 
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I recommend that if you do not have the axle alignment rods pictured above that you use a long straight edge. The center lines of the holes should all line up. In my experience it is common for the axles to be bent reward some at the perch holes. Even minor bending becomes obvious.

They can be straightened with a 10 ton press a little at a time. If the axle moves easy and had little bounce back then it was heated and is not good for a car you plan on driving a lot.
 
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