Front brake actuating lever sleeve not seating properly in kingpin

[mcoomey]

I took the front brake apart for service and adjustment. While apart I decided to paint some pieces to pretty it up a bit. I masked off the end of the brake actuating lever and when I put it back together it became obvious that it is not seating properly in the kingpin. I think it must have been this way when I started since I don't see any adjustment that I could have inadvertently changed. Also, I don't notice any play in the kingpin.

Does anyone have any idea how to correct this -- or is it even necessary? The brake is working, but the action on the lever is not very smooth. I'm new to working on Model A's, so I'm not too sure how the lever action is supposed to feel.

[rotorwrench]

I've seen where folks put a pill into the upper actuator socket in order to make up for worn push rods or lower wedge roller tracks. Make sure that the socket is empty and that all the actuator components are in good functional condition. Folks were suposed to limit the amount of pills on the bottom but they didn't always follow the recommendations. Some likely have more than they should.

[mcoomey]

Thanks for the reply @rotorwrench. I replaced the wedge and push rod as part of my brake servicing and added just one pill to the wedge to achieve 15° on the actuator lever.

The only way I see of getting the sleeve to sit deeper in the kingpin housing is to move the mounting hole on the leaf spring bracket closer, but that doesn't seem possible without grinding the hole oblong and truing it up with some weld. I don't really want to go that route and I'm open to suggestions.

[Gene F]

Doesn't the backing plate have a nut, or nuts around the axle that will give you enough area of motion if losened to get a difference in play?

Once you cut or grind it's done...

[Kurt in NJ]

Model B kingpin set everything is the same except for the kingpin itself, it has the notch cut at a little different angle, I don’t remember which way it is off ,possibly you have that problem

[mcoomey]

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Originally Posted by Gene F

Doesn't the backing plate have a nut, or nuts around the axle that will give you enough area of motion if losened to get a difference in play?

Thanks @Gene_F. Yes, the backing plate is held onto the axle support with 4 bolts, but that is independent of the kingpin, so moving it would not change the gap.

Originally Posted by Kurt in NJ

Model B kingpin set everything is the same except for the kingpin itself, it has the notch cut at a little different angle, I don’t remember which way it is off ,possibly you have that problem

Interesting suggestion, @Kurt_in_NJ. That seems like a possibility because the misalignment that I'm seeing is more pronounced toward the front than toward the rear. If the kingpin were rotated slightly it's exactly what I'd expect to see. I'm going to take the other side apart tomorrow to see what is different between the two. Thanks for the reply.

[Gene F]

A lot of work, but trade the pins from side to side and see if the problem moves. Thta will tell you something.

[john charlton]

For this to occur the kingpin is misaligned in the axle . Knock the kingpin securing bolt out and inspect witness marks to see how it has seated in the axle end . Remove the actuator and try to revolve the kingpin so it looks like the other side . Reinstall the actuator and knock in the securing bolt and hopefully the kingpin does not revolve to the previous wrong position , I do not think it will .

John in hot sunny Chandler AZ

[bobbader]

The problem is most likely a worn spring perch and/or the perch hole in the axle. If the perch was ever loose and driven that way for a long period, the inward force of the spring arch will start pulling the perch toward the center of the axle. Since the brake actuating shaft is attached to the perch, it moves inward as well, maybe causing the gap you have. As the car moves, with the forces on the spring of steering maneuvers, suspension, and the weight of the engine on the front end, the top of the perch wants to move inward and the bottom wants to move outward. after some time, the perch shaft gets worn and the perch hole in the axle is oblong at top and bottom. In the picture, note the offset between the top of the wishbone yolk and the perch hole boss. While these are not precision fits, there is quite a misalignment in the picture. When this happens, the brake operating pin inside the king pin gets cocked at an angle such that it rubs against the top and bottom bore of the king pin. This can be the reason your brake mechanism moves with some resistance. Tightening the perch nut will not fix the situation. A new perch and having the perch hole bushed may be in your future.

[mcoomey]

Thanks everyone for the additional suggestions. I'll investigate them and report back.

[rotorwrench]

When I first purchased my 29 Sport Coupe, the front axle was bent pretty badly. If you can't find any other discrepancy, the front axle alignment should be checked. Ford had steel alignment rods that fit into the king pin and perch bores to check them with.

7 degrees off center line per side with lateral alignment of all four rods. They bend a lot easier than most folks think they would.

[jrelliott]

Check to see if the front brake operating pin slipped out of the grove in the brake operating shaft. The sloop you have there on the housing appears to be about the same as not having the pin in the grove of the operating shaft.

[updraught]

Originally Posted by Kurt in NJ

Model B kingpin set everything is the same except for the kingpin itself, it has the notch cut at a little different angle, I don’t remember which way it is off ,possibly you have that problem

Some pictures
https://www.fordbarn.com/forum/showthread.php?p=785613

[Phil Brown]

Here is another pic showing the difference between the "A" and the "B" kingpins. The "B" is on the left and you can see the notch for the locking pin is rotated a bit more.

[Joe K]

Originally Posted by Phil Brown

Herae is another pic showing the difference between the "A" and the "B" kingpins. The "B" is on the left and you can see the notch for the locking pin is rotated a bit more.

Elsewhere I have described "quality issues" with kingpins - one being the groove not being correctly cut.

I didn't think about this then (didn't know actually) but this may have been a substitution by manufacturer/supplier with a Model B kingpin. They are very close in construction and a mistake would be easy.

And this may be the issue in this case where the "hood" portion of the kingpin doesn't align with the brake shaft actuator housing.

A bent axle MIGHT cause this. Almost all Model A front axles of use are bent somewhat, with the bend occurring most frequently on the "passenger side" of the axle - something about those road-edge potholes, I imagine.

And the correction for a bent axle is usually a complete de-mounting, pressing the axle beam straight, proving out the "correlation" of the kingpin holes and spring perch holes, and re-assembly. Some have had their axle "straightened" at a Truck repair shop many of which seem to have portable equipment of capability designed EXACTLY for this sort of repair - and done while on the car assembled.

Model T below but the principle is the same.


Joe K

[nkaminar]

At least the Model A axle if more robust than a Model T axle. My Model T axle was twisted so that one side had a very different caster than the other. I straightened the axle with a 6-foot pipe wrench and a floor jack. I used aluminum to protect the axle from the jaws of the pipe wrench. I still have the pipe wrench that has come in handy a couple of times.

[ModelA29]

Originally Posted by nkaminar

I straightened the axle with a 6-foot pipe wrench and a floor jack.

A similar trick I used on the ill conceived Twin I Beam Ford pickups to try and cure odd tire wear patterns.

[jw hash]

bottom line it is the king pin not the axle. my guess is either it is a later pin or a reproduction. the groove is located at the angle.

[mcoomey]

Thanks to all for your continued suggestions. I was busy with other things lately, but managed to pull the kingpin out today. Thanks, Phil Brown. From your reference photos I can conclude that I do have the correct kingpin for a Model A. I'm turning my attention now to the locking pin. It's hard to see from the photo, but it is really beat up and I'm wondering if it could be the source of the misalignment of the king pin. I think I'll order a new one to see if it makes any difference.

[nkaminar]

From the photo, a new pin seems like a good idea. Line up the king pin before putting in the locking pin.