Early Ford Spindle Identification
This article will cover Ford spindles from 1928-48 passenger cars & pickups. Keep in mind, this is for Ford cars & pickups only. Trucks and other makes such as Lincoln do not apply.
Model A (1928-1931) Spindles
Model A spindles are easily identified by the bolt on steering arm. This is the only early Ford spindle that features the bolt on arms. All others are forged into the spindle. Backing plate holes are 3/8" diameter. Kingpin diameter is 0.812"
1932-1934 Spindles
1932-34 Ford spindles are the first of the forged steering arms. The drivers side features an upper arm for the drag link. Later models do not have a drag link arm forged on. Backing plate holes are 3/8" diameter. Kingpin diameter is 0.812"
1935 Spindles
1935 Ford spindles are a one year only. They are the first to feature no upper steering arm. This is due to 1935 being the first year of the cross-steer steering box design. Because of that, the 1935 passenger spindle will have two holes in the steering arm (one for the drag link and the other for the tie rod). The snout will measure 5-5/8" and backing plate holes are 3/8" diameter. Kingpin diameter is 0.812"
1936 Spindles
1936 is also a one year only design. Very similar to the 1935, the only difference in 1936 is the snout length which is 5-3/8" long. Beware when matching up your brake drum/hubs as the 1936 wide 5 hubs are different than the 1937-39 and they cannot be interchanged.
1937-1941 Spindles
Commonly reffered to as "round back" spindles, these are a top choice for many traditional hot rodders. They feature 1/2" holes and use the same bolt pattern for early juice (hydraulic) brake backing plates. They also accept 1937-48 hubs & drums with no modifications needed. Kingpin diameter remained the same at 0.812" and they feature the same cross-steer setup with two holes in the passenger steering arm.
1942-1948 Spindles
Known as "Square back" spindles due to the shape. Very similar to the 1937-41 spindles, the 1942-48's will accept the juice brake backing plates, hubs and brakes. They have the same 0.812 kingpin diameter but require longer kingpins due to the larger bushing bosses.
Questions & Answers
Q: Can I install 1939-48 "juice" brakes on an early (1928-36) spindle?
A: Yes, there is a kit available to adapt 1939-48 juice brake to early spindles. It consists of spacers for the rear bearings and spacer rings for the backing plates. The holes in the backing plates must be filled and redrilled to the early spindle pattern.
Q: Can I use 1937-48 kingpins in earlier spindles?
A: No. Although the kingpin hole is the same diameter, in 1937 Ford redesigned where the thrust bearing is located, from on top of the spindle to the bottom of the axle in between the spindle and axle. This in turn puts the kingpin retainer groove in the wrong place. Over the years people have ground a new groove into later kingpins to make it work but it is not suggested. Futhermore, if you wanted to retain stock brakes, the 1928-36 kingpins have a cup on top to receive the brake actuator. 1937-48 kingpins have a flat top.
Q: I have a dropped axle. Can I safely bend my steering arms so my tie rod will clear the wishbone?
A: Yes, early Ford spindles are forged and the steering arms, just like your axle, can be heated and dropped for clearance. It is advised to have the spindles crack-checked after dropping. If you do not feel comfortable dropping them, usually the professional who dropped your axle can also drop your steering arms.
Q: Are the holes in the steering arms tapered?
A: Yes, the holes are a 7 degree taper to receive an early Ford tie rod end or tie rod end ball (1932-34)
Q: My Model A steering arms have non-replaceable ball ends. Can I repair worn out oblonged ball ends?
A: Model A steering arm ball ends can be repaired by cutting off the old ball, drilling out the end and welding in new replacement ball studs which are available at most Model A parts vendors.
Q: Are the large spindle castle nuts all the same?
A: No. There is two different nuts for the early Ford spindles. 1928-35 Have a larger (taller) nut. In 1936, Ford went to a shorter castle nut. All threads are the same (3/4-16)