1969: Steering box removal
8th Gear
Joined: Jan 2020
Posts: 8
Likes: 2
Thanks Mark G and mysixtynine
Here's my situation. Car is '69 350sb, Muncie 4sd, power steer, no power brakes, with 37k miles.
Exactly 4 years ago, early 2016, did complete body-off-frame rebuild. Everything under the f-glass is new or rebuilt, from my 10 year spending spree at Carlisle, Ebay and the usual suspects.
This includes a complete front and rear Performance Plus suspension pkg and power steering replacement valve/kit from Vette Brakes & Products.
The steering box was not done. For 2 years after the frame off, I noticed a quarter sized drop of grease wherever parked coming from bottom of the steering box. This finally stopped - likely meaning it's all leaked out. I tried a few times unsuccesfully to get the top screws out to regrease. Finally decided to replace the box, and have a new rebuilt unit from Corvette America I'm about to put in.
Just checked and there is no play at rag joint or input shaft bearing. However, when I observe the steering box input-to-output action when I rock the steering wheel, there is about 1/8th inch rotation of input shaft before this is transmitted to movement of the pitman arm.
So,.. question now is do I need to do the subject preloading of the input shaft on the new/rebuilt box, or is this procedure just for re-install of old units? Whew - Thanks!
Here's my situation. Car is '69 350sb, Muncie 4sd, power steer, no power brakes, with 37k miles.
Exactly 4 years ago, early 2016, did complete body-off-frame rebuild. Everything under the f-glass is new or rebuilt, from my 10 year spending spree at Carlisle, Ebay and the usual suspects.
This includes a complete front and rear Performance Plus suspension pkg and power steering replacement valve/kit from Vette Brakes & Products.
The steering box was not done. For 2 years after the frame off, I noticed a quarter sized drop of grease wherever parked coming from bottom of the steering box. This finally stopped - likely meaning it's all leaked out. I tried a few times unsuccesfully to get the top screws out to regrease. Finally decided to replace the box, and have a new rebuilt unit from Corvette America I'm about to put in.
Just checked and there is no play at rag joint or input shaft bearing. However, when I observe the steering box input-to-output action when I rock the steering wheel, there is about 1/8th inch rotation of input shaft before this is transmitted to movement of the pitman arm.
So,.. question now is do I need to do the subject preloading of the input shaft on the new/rebuilt box, or is this procedure just for re-install of old units? Whew - Thanks!
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,990
From: Connecticut, USA
That is referring to the bearing preload and 6 in/lb is too much. As mentioned if your box is old and sloppy the bearing preload will be long gone by now and adjusting the lash to call it good is nothing more then a band-aid. The top adjustment is the lash. There is no mention of true center, arm center or high lash so you can try but it most likely won't help much. The box may have 40 year grease which is an acidic sludge many times, then there are those who add STP, Gear oil, mix of greases, etc, they are bad ideas and typically do not resolve issues.
Safety Car
Joined: Jul 2005
Posts: 3,697
Likes: 833
From: WI
1/8 of an INCH ...Is that at the steering wheel or the shaft itself? How are you measuring the rotational action of the pitman arm, with a dial indicator or your by hand?
If it's 1/8" at the steering wheel that's ok, if it's 1/8" at the shaft that will translate to quite a bit at the wheel which would seem to be excessive. I wouldn't screw with any adjustments ..get a replacement. Not worth your screwing around. You don't want to get tied up into a he-said, she-said situation on adjustment.
Mine for instance has no discernable 'free-play'.
.
If it's 1/8" at the steering wheel that's ok, if it's 1/8" at the shaft that will translate to quite a bit at the wheel which would seem to be excessive. I wouldn't screw with any adjustments ..get a replacement. Not worth your screwing around. You don't want to get tied up into a he-said, she-said situation on adjustment.
Mine for instance has no discernable 'free-play'.
.
Last edited by Mark G; Jan 28, 2020 at 05:16 PM.
8th Gear
Joined: Jan 2020
Posts: 8
Likes: 2
Thanks Mark G. I previously posted an update of my status to clear things up.
The suspension, steering links, steering valve and hoses are all new from 4 yr old frame off rebuild.
Only the steering box and column is orig - on '69 C3 with 37k mi and with power steering.
I am putting in a new/rebuiilt steering box from Corvette Am.
The old box is still in the car - 1/8th play is observed at the input shaft, not the steering wheel.
That translating from input shaft to pitman arm delay are by visual observation, while rocking the steering wheel.
So, I'm replacing the old. Just need to know if new/rebuilt unit needs anything other than bolting on.
The suspension, steering links, steering valve and hoses are all new from 4 yr old frame off rebuild.
Only the steering box and column is orig - on '69 C3 with 37k mi and with power steering.
I am putting in a new/rebuiilt steering box from Corvette Am.
The old box is still in the car - 1/8th play is observed at the input shaft, not the steering wheel.
That translating from input shaft to pitman arm delay are by visual observation, while rocking the steering wheel.
So, I'm replacing the old. Just need to know if new/rebuilt unit needs anything other than bolting on.
8th Gear
Joined: Jan 2020
Posts: 8
Likes: 2
You put the steering box in your vise. First rotate the input shaft with a 12-pt socket or pliers ..and check that top input bearing for roughness. They often rust and the bearing and race can get really boogered up b/c people wash off their proud engine compartments and put their car in the garage. Well, water runs down the input shaft and sits there at the lip of the seal. Eventually over time and many washes, corrosion occurs and water gets *under* the seal ...and into the top bearing. The bearing is not robust ...about like a bicycle crank bearing. If your steering box's bearing feels smooth, the proceed. If not, replace it (they're cheap). The better approach would be to wash the engine compartment off first and THEN drive the car to wherever ...the heat will evaporate the water. But nobody's going to do it that way so why even suggest it?? Ha ha.
Then loosen the top screw and the preload adjuster and rotate the shaft. At this point it would be advisable to check the bottom bronze bushing for side-to-side lash (a micro amt of lash goes a long way in the world of steering play).
Once you've confirmed all is good, it's time to tighten the pre-load adjustment. What that does is put's pressure on the shaft bearings (pre load) and removes the 'play' on the main shaft. Tighten to spec and you're looking for a certain amount of rotating 'resistance' as you turn the input shaft *over-center*. So if they say you need 8 in/lbs ...thats the resistance you need while rotating the steering box input shaft ..advisably at the over-center location. Adjust the screw so you have the specified pre-load amt. Re check it after you tighten the lock nut as it may have changed. Remember, the spec is fairly wide and on some other steering boxes it's almost a factor of 2 (e.g. 8-16 in/lbs). Then adjust the top screw accordingly and it's lock nut. I don't remember the spec for that off the top of my head. Get it snug.
BTW, since many people don't have an in/lbs wrench here's a warm tip: If you take a chrome deep-well 9/16" socket (3/8" drive), and attach a standard 3/8" ratchet to it (not long handle ...just regular), hold the socket as tight as you can in one hand (no greasy hands) ....turn the ratchet with the other and that's the torque you need for the pre-load torque ...as you rotate the shaft. I've measured it. The spec they typically give on steering box torques is really wide. A guy would need to be a bozo to over-tighten one (but we all know Bozo's exist!!).
Also another note for the future (doesn't pertain to C3's manual steering) on a power steering box [changing the topic now] you'd never expect to get all the 'lash' out of the input shaft. The input shaft is two shafts (on most power steering boxes) and a little back/fourth is required b/c that 'play' is the valving needed to port 'assist fluid' one direction or the other. I only bring this up b/c many folks mistakenly believe they need to tighten out all the 'play' on a typical saginaw-style p/s box like they would on a manual steering box. Not true. Just a little nugget to keep in the back of the mind for other classic cars guys may own. The beauty of the C3 steering design intent was incorporating the responsiveness of a manual steering box (with no 'lash') ....but also having power assist (the ram) needed most at low speeds, esp with a big block. See Zora had an idea....
Good luck!
.
Then loosen the top screw and the preload adjuster and rotate the shaft. At this point it would be advisable to check the bottom bronze bushing for side-to-side lash (a micro amt of lash goes a long way in the world of steering play).
Once you've confirmed all is good, it's time to tighten the pre-load adjustment. What that does is put's pressure on the shaft bearings (pre load) and removes the 'play' on the main shaft. Tighten to spec and you're looking for a certain amount of rotating 'resistance' as you turn the input shaft *over-center*. So if they say you need 8 in/lbs ...thats the resistance you need while rotating the steering box input shaft ..advisably at the over-center location. Adjust the screw so you have the specified pre-load amt. Re check it after you tighten the lock nut as it may have changed. Remember, the spec is fairly wide and on some other steering boxes it's almost a factor of 2 (e.g. 8-16 in/lbs). Then adjust the top screw accordingly and it's lock nut. I don't remember the spec for that off the top of my head. Get it snug.
BTW, since many people don't have an in/lbs wrench here's a warm tip: If you take a chrome deep-well 9/16" socket (3/8" drive), and attach a standard 3/8" ratchet to it (not long handle ...just regular), hold the socket as tight as you can in one hand (no greasy hands) ....turn the ratchet with the other and that's the torque you need for the pre-load torque ...as you rotate the shaft. I've measured it. The spec they typically give on steering box torques is really wide. A guy would need to be a bozo to over-tighten one (but we all know Bozo's exist!!).
Also another note for the future (doesn't pertain to C3's manual steering) on a power steering box [changing the topic now] you'd never expect to get all the 'lash' out of the input shaft. The input shaft is two shafts (on most power steering boxes) and a little back/fourth is required b/c that 'play' is the valving needed to port 'assist fluid' one direction or the other. I only bring this up b/c many folks mistakenly believe they need to tighten out all the 'play' on a typical saginaw-style p/s box like they would on a manual steering box. Not true. Just a little nugget to keep in the back of the mind for other classic cars guys may own. The beauty of the C3 steering design intent was incorporating the responsiveness of a manual steering box (with no 'lash') ....but also having power assist (the ram) needed most at low speeds, esp with a big block. See Zora had an idea....
Good luck!
.
I posted a reply descibing my car and situation. I am installing a new/rebuilt steering box.
Do I need to do the setup procedures you descibed for the rebuilt box, or are they maintenance for re-install of old box.
