MTFCA Forum

I was just pushing my '11 back and forth to move it into alignment to exit the shop door. I found that when I cut the wheel to the left hard enough, the pitman arm will go over center. That is to say, it will go from 6 o'clock through 7, 8, 9 and keep on going towards 12:00 until the crankcase pan stops it! The arm will come right back to normal by steering to the right - it does not get stuck when over center.

I'm sure glad I found this out in the shop! Everything in the front suspension is in good shape, new or like new and nice and tight with no slop. The steering column, pitman arm, drag link, and tie rod are rebuilt and likewise in good condition. The wheels are in alignment per the bible. The steering does not do this when turning right.

Any ideas how to correct this, and things to check? Did the later cars' steering linkages have stops to limit this travel?

Thanks for any help, Bill

I should mention that the arm stops very soon after 9:00. Say, a couple of degerees - just enough to let you know it has gone over center. Thanks, Bill

This is common on early T's. Later steering boxes have a slot milled in & 1 longer gear pin to limit this condition.
I dont know of a safety cure . Just be careful to not over steer while driving. I did witness this happen to a guy while driving. Nearly flipped the car over. When you go over center, you want to turn the wheel back which makes the situation worse. The thing to do is stop & turn the wheel opposite to get things back to normal.

Are you sure you have the correct drag link and pitman arm? If it is correct, the pitman arm should point directly down with the wheels straight ahead.
Norm

When you say "This is common on early T's" I always wonder what the cut off is for that problem. Was this problem fixed by 12, 13, 14?
Just asking because I am still new to Model T's and trying to identify any red flag issue I can.

The "fix," the milled slot in the gear box with the longer pin, didn't come about until some time early in 1921. As to Bill's problem, with the steering moving further one way than another, I would be inclined to check out what Norman posted.

My Canadian 1916 has the brass steering box with the pin slot.

Some older threads on the subject:

http://www.mtfca.com/discus/messages/257047/300409.html

http://www.mtfca.com/discus/messages/17 ... 1317650782

http://www.mtfca.com/discus/messages/29/27096.html

The shorter pitman arm will reduce the overall range of steering from lock to lock, which may or may not be enough to prevent an "over center" condition.

Dangerous? YES.

For Frank (Kerry),

You mentioned:

"My Canadian 1916 has the brass steering box with the pin slot."

But as R.V. Anderson noted that pin slot did not come from the factory until 1921.

Ref: https://www.mtfca.com/encyclo/S-T.htm#sgc

10-28-1921 Added 3/32” to under side of cup, added slot for stop pin in bottom. Brought drawing up to date by specifying outside of cup to be machined and nickel plated. Changed distance between lugs which hold throttle and lead rods from 21/64” to 21/64-11/32”.

I would guess (and it is only a guess) that someone took one of the brass steering cases that had the slot and which would have been plated and had the plating removed. Folks used to do that with the 1926-27 nickel headlamp rims so they could have a brass rim for their 1915 etc. cars. And yes, the style with the slot was made in "W" brass as well as bronze and was plated with nickel, zinc depending on the time frame.

And it is also a way to make the later 5 to 1 ratio gear cases (introduced late 1925 when the balloon tires were ordered) so they would look like the older brass gear cases.

I don't know if there is enough thickness of metal on the earlier 1915-16 brass steering gear cases to allow someone to mill that slot into them or not. If it was thick enough that may have been done when the T was restored.

And if others with Canadian built 1915-20 cars know if their steering gear case also has that slot -- then maybe discovered another difference between the US production and the Canadian production? Or maybe someone already knows that and just needs to let us know?

Respectfully submitted,

Hap l9l5 cut off

Bill,

As mentioned above, yes it is dangerous.

And the links also posted above show that "IF" you have all the correct parts and they are in good working order and installed properly they should not allow the steering to go over-center. Although Ford still modified the gear case to include the stop in 1921 -- and he would not have added and additional step if he didn't think it was needed (or if it didn't save him some money).

Respectfully submitted,

Hap l9l5 cut off

Many, many thanks! I will investigate all this and update the thread. At this point I'm pretty sure the tie rod is correct. I will provide a measurement on the drag link and part number on the pitman arm. I remember it being straight down when the wheels are dead ahead. Cheers Bill

In theory, if all parts are correct, tight, properly adjusted etc etc etc? It isn't supposed to happen?
However, the steering snapping over-center is part of model T lore and legend. Stories date clear back to when the brass Ts were daily transportation. So it must have been a problem more than just a little bit.
I have only had one T a speedster with lowered suspension and steering, that even hinted at maybe could pop over center. However, how the brackets were setup, before it could pop over center, the pitman arm hit the frame, and was safely blocked from any hazardous conditions.

I have seen a couple cars that people added small steel brackets onto the engine pan or frame to block the pitman arm from going over center. I don't offhand recall any specific details? But it should be easy to figure out.
Prudence dictates that all parts involved be inspected for any sort of flaw or misalignment that could cause a safety issue. However, if everything checks out okay, and still there is a chance the pitman arm could go over center? I would put some bracket in place to block it.

With a 1911, I would imagine you want to keep the original brass era gear case? Cutting a safety slot in those is not an option. And of course, replacing with a later slotted gear case defeats the 1911 correctness as well. The added brackets require are small, unobtrusive, and usually out of sight. Also, removeable for shows if needed.

Here is the latest per the excellent information you good folks provided: The pitman arm is part # 929, and hangs straight down when the wheels are dead ahead. The tie rod is the correct one with the ball integral to the rod end. The drag link looks original with brazed and pinned ends, and measures 30-3/4" measured from cap mating surface to cap mating surface. (I made this measurement without help, so I might be a smidge off.) All bushings and their associated pins are in very good shape. I put thin aluminum shims from Langs in the tie rod ball socket and in the pitman ball socket. Everything is original, tight, straight, and smooth.

Based on the reading you all have provided, I am reaching the conclusion that this condition may be normal for an early car. Wayne's suggestion of fabricating a stop that can be removed if desired is a good one and I will look into it. I don't show my cars but I try to make them as original as possible consistent with safe driving and increasing reliability & longevity. Until I get a stop installed, I will be mindful of this steering situation as I drive it. The weather is just too nice here in Philadelphia not to take it out!

Of all the automotive forums I am aware of, this one is tops, and you guys make it so. Again, thank you for all your help!

Cheers, Bill

I thought everyone knew this!

My Canadian 1912 has the original steering parts and does not have this over steer problem.

Colin Mavins wrote: ↑

Sat Sep 25, 2021 11:35 am

My Canadian 1912 has the original steering parts and does not have this over steer problem.

My 14wide track did it once in a u turn. No chance of mismatched parts here. For my driving safety & pleasure, I put a larger period accessory steering wheel( the T came full of period accessories anyway. Maintaining the theme.) & 5-1 gears. Handles much better & I dont think its possible to over steer now.
Early T drivers need to be aware of the possibility & not steer to the extreme. I occasionally drive other peoples T's & am aware, especially with the small steering wheel quick steer.

I have seen the over steer on a 1926 with worn out slot, but my 1921 without the slot, 30 or 21" wheels, I never encounter any over steer. Could some of this have to do with the steering arm or axle itself? Such as a notch worn in the axle allowing the steering arm to swing in too far? Wrong toe in or wrong drag link?