D25C: Steering box assessment question

[bamfordsgarage]

Hello all, good to browse a bit and see some familiar names. It's been too long since I visited regularly.

 

I'm replacing the steering box in my well-travelled D25 sedan. The original box seems worn past the limits of adjustment. I've found a replacement box from a D25 coupe and to my amazement it seems nearly perfect as is. That rarely happens in my world, and I'd like comments from those more knowledgeable before making assumptions.

 

There is no discernible end play in the steering shaft or cross shaft, nor can I sense any looseness in the bushings. The shaft turns easily and the pitman arm spins the shaft with reasonable effort. There was no particular indication of chronic leakage and the box contained plenty of heavy oil.

 

With the steering centred, there is no discernible play/lost motion between the steering shaft and the cross shaft. This holds true for the first 1/2 turn of the shaft in either direction. From that point, in either direction, there is increasing play between the worm and roller. At full lock, which is two column rotations in either direction, the play translates to about 8" at the steering wheel rim (the end of my wooden spoke).

 

The box is 4-1/2 turns lock-to-lock on the bench with no components attached. My car's lock-to-lock is about 3 turns — on that basis, when the replacement steering box is rotated 1-1/2 turns in either direction (3X L2L), the free play is about 4" at the wheel rim.

 

I don't think I should go tighter on the cross-shaft adjustment because it turns easily and there's no play to be felt.  With the cap off the box it appears that increasing play at the extremities of travel is a function of the design — the arc of the worm — and not something I can address. The factory and Chilton manuals call for lash adjustment to be made when steering is centred.

 

Finally my question: If the gear lash is correct with the steering centred, is the increasing play as the wheel is turned considered normal or cause for concern?

 

Photos: 1 Box cleaned up; 2 Steering wheel centred, extremes of travel, & no-free-play zone in red; 3 Steering centred; 4 Steering left lock; 5 Steering right lock; Donor D25 Coupe

[Young Ed]

1 hour ago, bamfordsgarage said:

Hello all, good to browse a bit and see some familiar names. It's been too long since I visited regularly.

 

I'm replacing the steering box in my well-travelled D25 sedan. The original box seems worn past the limits of adjustment. I've found a replacement box from a D25 coupe and to my amazement it seems nearly perfect as is. That rarely happens in my world, and I'd like comments from those more knowledgeable before making assumptions.

 

There is no discernible end play in the steering shaft or cross shaft, nor can I sense any looseness in the bushings. The shaft turns easily and the pitman arm spins the shaft with reasonable effort. There was no particular indication of chronic leakage and the box contained plenty of heavy oil.

 

With the steering centred, there is no discernible play/lost motion between the steering shaft and the cross shaft. This holds true for the first 1/2 turn of the shaft in either direction. From that point, in either direction, there is increasing play between the worm and roller. At full lock, which is two column rotations in either direction, the play translates to about 8" at the steering wheel rim (the end of my wooden spoke).

 

The box is 4-1/2 turns lock-to-lock on the bench with no components attached. My car's lock-to-lock is about 3 turns — on that basis, when the replacement steering box is rotated 1-1/2 turns in either direction (3X L2L), the free play is about 4" at the wheel rim.

 

I don't think I should go tighter on the cross-shaft adjustment because it turns easily and there's no play to be felt.  With the cap off the box it appears that increasing play at the extremities of travel is a function of the design — the arc of the worm — and not something I can address. The factory and Chilton manuals call for lash adjustment to be made when steering is centred.

 

Finally my question: If the gear lash is correct with the steering centred, is the increasing play as the wheel is turned considered normal or cause for concern?

 

Photos: 1 Box cleaned up; 2 Steering wheel centred, extremes of travel, & no-free-play zone in red; 3 Steering centred; 4 Steering left lock; 5 Steering right lock; Donor D25 Coupe

Wow you should grab the cowl trim off that beast!

[Plymouthy Adams]

not to mention the windshield trim and connector clips..the antenna mounts are nice and heavy duty...the aerial seems not to have survived as well  anybody see a snake in this picture...?

[bamfordsgarage]

" ...anybody see a snake in this picture...?"

 

I hope you're not referring to friend Jerry ?

 

" ...you should grab the cowl trim off that beast!"

 

Would those be the short pieces ahead of the doors?

 

If I do go back to recover more bits it won't be until spring — winter landed here today:

 

[Young Ed]

1 hour ago, bamfordsgarage said:

" ...anybody see a snake in this picture...?"

 

I hope you're not referring to friend Jerry ?

 

" ...you should grab the cowl trim off that beast!"

 

Would those be the short pieces ahead of the doors?

 

 

Correct they like to have the clips rust and then fall off and get lost.

[Plymouthy Adams]

good to see Jerry out and about scrounging up parts....so no, he is not the snake in the picture, in truth I saw no snake but was only trying to get folks to start looking for one....I was looking at some cars buried beneath stuff in a shed yesterday and the man said he DID see a snake the day before.....today is start of retrieval of said cars.

[Dan Hiebert]

Extreme left to right with the steering box on the bench will be different than on the car with everything attached.  On the bench, the roller tooth gear can be rotated past where it is intended to stop on the worm gear, creating that free play you mention.  There is no free play measurement at the extremes, either on the car or off.  The only free play measurement is as you noted, with the steering wheel centered, but that is with the box on the car, and that is in-out free play of the steering wheel shaft.  Supposed to be "0", but no more than 1/32nd of an inch.  The bench test only specifies the effort needed to turn the wheel, no more than 3/4 pound without the roller tooth shaft installed, no more than 2 1/4 lbs. with it installed.  I was wondering where' you'd been, I really enjoyed your adventures with "the Heap" and hadn't seen a post for quite some time.   

Edited November 9, 2020 by Dan Hiebert
typo

[bamfordsgarage]

1 hour ago, Dan Hiebert said:

Extreme left to right with the steering box on the bench will be different than on the car with everything attached.  On the bench, the roller tooth gear can be rotated past where it is intended to stop on the worm gear, creating that free play you mention.  There is no free play measurement at the extremes, either on the car or off.  The only free play measurement is as you noted, with the steering wheel centered, but that is with the box on the car, and that is in-out free play of the steering wheel shaft.  Supposed to be "0", but no more than 1/32nd of an inch.  The bench test only specifies the effort needed to turn the wheel, no more than 3/4 pound without the roller tooth shaft installed, no more than 2 1/4 lbs. with it installed.  That's adjusted with shims at the end of the steering box.  I was wondering where' you'd been, I really enjoyed your adventures with "the Heap" and hadn't seen a post for quite some time.   

Hi Dan, thanks for your comments.

 

To clarify, I did realize that the lock-to-lock on the bench is greater than in the car with steering components attached. By my figuring it was  4-1/2 turns on the bench and 3 in the car. Having said that, even at 3 turns lock-to-lock on the bench, there is the equivalent of 4" play at the steering wheel rim even though there is no rim play when centred (the steering seems play-free until about 1/2 turn either way from centred). Also, there is none of the in-out play of the steering shaft that you mentioned. Although the bench test is for wheel effort, that probably doesn't preclude rim play from being measured on the bench as well.

 

I've been PM-ing with forum member RobertKB and he mentioned his vintage Mopars also have more free play towards the extremes than in the centre. A local friend is going to jack up his '47 D25 Coupe today and measure the total turns lock-to-lock and the steering wheel play at various points and let me know. I'll post his findings here.

 

Finally, I did read a random comment on line (so it pretty much has to be true) to the effect that the lack of worm/roller play when centred is intended to help the vehicle straighten out after making a turn. Anybody here familiar with that concept?

[Dan Hiebert]

I think the caster and camber angles of the front suspension have more to do with a car's return to center than the steering mechanism.  Our D24's steering wheel has some play when it's pegged out either left or right, too, but I've never worried about it to measure it because the other two checks are where they're supposed to be.  I don't know if it's so much free play, or just so easy to move that it seems like free play.  The "end play" checks for both D24s and P15s are with everything on the car and the steering between center and lock, where there should be "none".  Meaning there's probably an engineering reason for the play at the extremes, but that's above my pay grade.  As you note, its a function of the design.  I'll shorten the story and offer an answer to your question - nothing to be concerned about, I don't think there is anything amiss with your "new" steering box.      

[Sniper]

Three things come to mind.

 

1. with the wheels on the ground you will likely not see as much free play.

 

2. you are only going to be turning at those extreme angles at low speed, where any free play will likely be a non-issue.

 

3. you may be overthinking this

[bamfordsgarage]

Thank you Dan and Sniper. 
 

I agree that castor and maybe camber are bigger factors in steering return. In Model Ts the only steering adjustment is toe-in (the others are built in) and that affects it as well. Good to hear Dan that yours has play near the extremes as well. 
 

Also agree that free play near the extremes is not a big deal during low-speed - ie parking - operation. 
 

This much thought about a steering box is new for me. Dunno about “over thinking”, just trying to fully understand. A big hurdle for me was the notion that this critical component, subject to wear and requiring adjustments, would in fact be ready to go as pulled straight from that wreck. 
 

I appreciate everyone’s comments and input... off to the workshop!

[Plymouthy Adams]

starting digging the cars out of the shed....its quite the job to be truthful....mentioning this just to say....3 snakes spotted in the process.....end of the window we had to work, two 4 cars moved....mine are setting in position to load next trip up