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Discussion Starter · #121 ·
Are you using a 0-30 in/lb dial torque wrench for setup?

Preload should be a smooth steady reading and set at 5 in/lb
Any jumping on the needle when using new end bearings indicates a bad ball screw and the only option is to replace the worm assembly. If the reading is steady then you can move on to installing the pitman shaft (sector) and checking the high center and set it to 12 in/lb.

If you can't get to that point you might have an issue with the gear mesh. The center tooth on the pitman shaft is machined larger to hold it steady on center. If you have 3 thread showing I would recheck things. Make sure you have the worm centered when installing the pitman shaft.
 

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Thanks Gary

I more or less followed the same steps as when you helped me with my own box a couple years back there (except the bushings fit this time)

I'm using an (older) snap-on 0-30 in-lb dial torque wrench (actually was certified but out of date now)

Preload came in no problems and seems smooth or at least smooth to me.
Shimmed the stud to .005

Found and marked the center and installed the sector shaft and set it to 12 in-lb right at the center point.

Everything seems ok but after installing the pitman, if I hold onto it to apply a little drag, I have several degrees of backlash on the sector shaft before the pitman starts to move.

I can't really tell if it's tight right on the dead center and then worn as soon as it goes either way a tiny bit but since I'm getting the 12 perfectly on center I can only guess that's what going on???

M

Oh and I had another look and really it's probably 2 turns (minor dia, 3 major) showing above the chamfer on the nut
 

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Discussion Starter · #123 ·
Thanks Gary

I more or less followed the same steps as when you helped me with my own box a couple years back there (except the bushings fit this time)

I'm using an (older) snap-on 0-30 in-lb dial torque wrench (actually was certified but out of date now)

Preload came in no problems and seems smooth or at least smooth to me.
Shimmed the stud to .005

Found and marked the center and installed the sector shaft and set it to 12 in-lb right at the center point.

Everything seems ok but after installing the pitman, if I hold onto it to apply a little drag, I have several degrees of backlash on the sector shaft before the pitman starts to move.

I can't really tell if it's tight right on the dead center and then worn as soon as it goes either way a tiny bit but since I'm getting the 12 perfectly on center I can only guess that's what going on???

M

Oh and I had another look and really it's probably 2 turns (minor dia, 3 major) showing above the chamfer on the nut


The Snap- On TW is good. Some have tell-tails which is nice to see the high point but with the dial you should clearly see the needle movement. Slight jumping, say under 1 in/lb is ok. Jumping 2+ in/lbs I don't like and would install a new worm. ( I have complete stock of new gears- unlike vendors)

Sounds like you have gone through the process. Now if it's tight on center and looser off center that is how it should be. That is why the box should go from 5 -12- 5 not 12 lock to lock. On center there should be no play in the box. Moving the input, the output should respond.

The lash bolt should be set to 002"
 

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It's giving me the light-tight-light but there is no movment of the pitman as it goes across the center.


I'll check again tomorrow but i think it going to be something where theres a really worn area just off center and then normal after that.
Weird
 

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Well went through everything again (shimmed the stud down to .002) and it's the same thing. 12 in-lb on the input shaft is leaving a bunch of slop in the gear at mid-point.

M
 

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What about this

If something is out of line (shaft bent or ????) and it's getting 12 just on the shaft in that position and the gear isn't actually touching properly?

I know, pretty sketchy.

I'm going to dial the adjustment way out so the gear isn't even close and see if the torque on the input shaft changes from lock to lock type of idea
M
 

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Discussion Starter · #127 ·
It doesn't make sense if you have 12 on high center there should be no play. I would have to check the box to see. Sometimes there are odd ball boxes. I had a 72 box in recently that was rebuilt by a well known vendor. I couldn't get a good preload on the new bearings, with either the original worm or a new one. I found the issue to be in the casting and once I corrected that it dialed in perfectly with the original worm. It was like that since new and the vendor never bothered to try and figure it out, just build it and ship it.

Is there any pitting on the teeth of the worm nut ( ball screw nut) or the pitman teeth? If your preload on the new bearings is steady at 5 in/lbs then the issue is with the mesh. I have never seen a pitman shaft bent
 

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I think I'll blow the whole thing completely apart again later this week and start from scratch again. Obviously there is something I've overlooked or put back together upsidedown.

Maybe before I take it apart I'll bring the adjustment in until the slop goes away and see what the torque on the input looks like on center and off

BTW, when I checked Ecklers for a rebuild kit it looked like they are selling new gears???? Didn't think anyone even made them anymore.

Thanks again Gary
M
 

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Discussion Starter · #129 ·
I would be very cautious with new gears. I have fit them for years and some dial in others do not. I don't know whose those are but they are not made by the vendor. I have not used that particular kit so I can't say one way or the other but I do know that there were a couple of manufacturers of steering gears about 15 years ago and both went belly up due to poor QC. The new gears I have are from Corvette Steering. The bushings in that kit are most likely not as tight as the ones I have made and final fit.
 

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I'm really not wanting to getting that deep with this box. Still hoping it's just something I missed or ???.

I'm not sure where the gears came from as it's the first time I've even seen them at one of the suppliers, that's why I mentioned it to you.

I haven't had a chance to get back to this one as I've been trying to get a little work on my own car for a change.

Maybe I'll put in a borgenson and sell him my box :laughing:

I'll post some details once I get the problem child on the bench again.
M
 

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OK so finally back to this box today and I think I've found something that was probably the issue.

Started again from scratch, backed the lash way off and checked the preload, getting about 6-7 across the entire rotation, pretty consistent all the way and in either direction.
But I could see some linear movement in the shaft. Clamping a spare rag-joint on so I can get a hold of it I can move the shaft in and out slightly but enough to see it actually moving (should have put an indicator on it for a number but visible movement)

I re-tightened the adjuster plug to remove any movement, backed it off 1/4 turn (following the chassis manual) and reset to 6-7 in/lbs again, this time can't see any linear shaft movement.

So I'm guessing when I initially tightened the plug and then backed it off the 1/4 turn it didn't fully set everything. The play I was getting in the box wasn't sector shaft and ballnut it was the ballscrew moving up/down before moving the ballnut.

Set the lash, getting about 8 across the range and goes up to 13-14 as it goes across center (13 in one dir, 14 in the other)

Lightly clamped locking pliers on the input and output shafts, put a indicator on the output pliers and applied a little load by hand and gently moved the input pliers back and forth at the center position, hard to tell for sure but looks like virtually no backlash, not sure what that will be at the steering wheel....

Now, is there a way of making sure the preload is fully set? Tap on the shaft end with rubber mallet?
Tighten it to get 10-15 in/lbs and then back off and reset?
Tighten the crap out of the plug (and distort everything)?
What's your procedure on setting the plug before adjustment?

Thanks again Gary
M
 

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Discussion Starter · #132 ·
The end bearing preload should be set without the pitman shaft,(sector), in the box. These bearings are not high precision machine bearings so you don't want to overload them and could damage them. The preload should be smooth, the needle on the TW should not move much at all, certainly less then 1 in/lb. I do not back off on adjustment. I read stuff like that on CF and it's wrong. Set the preload to 5 in/lb, lock the ring and recheck to make sure it's still at 5.

Install the sector, center and check the high center. 13 -14 is too much. Keep it to 12- 12.5 total.

There should be -0- play in the worm ( input) or in the high center gear mesh. There should be no lateral play in the sector to bushings.

DO NOT adjust the lash screw and back it off, as mentioned before that is incorrect.

I do not install the seals until I know the gears and preload is correct. Otherwise you risk damaging the seals.
 

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Thanks Gary
(The tighten / backoff and set torque for the plug I got from the manual via J. Shea's pages, most of the useful box stuff I've found on CF is still your old posts from way back when, other than that it's tighten the lash or buy a new box :laughing:)

Keeping in mind these torque values are now with the box sealed and full of grease.

I'll pop the sector out and re-set the preload for 5, maybe it was the sector that was the extra drag. Hard to say how much variation on the TW is the box and how much is me.

But anyway, that seemed to be the issue (the linear movement) no measurable backlash that I can see with the indicator over center, might even be better than my own box but I got that one set right the first time (following this thread of course) better luck than management no doubt.

Thanks again.
M


Oh, forgot, lash screw adjustment was always CW, when I over tightened I'd back it off too far and come at it again. I did re-shim the stud to somewhere under a .001 feeler. :thumbsup:
 

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Pulled it back apart again, got the preload to 5+ (with seals, sector removed and most of the grease out) consistent across the range (5 one way and about 5-1/2 the other)

Set the lash (with grease etc) at 12-1/2 (12+ one way, 12-1/2+ the other) as if goes across center.

Can't feel any play on center, hopefully when the guys car moves in a couple of years it'll be good.

Thanks for the push to give it another go Gary, much appreciated.
M
 

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Another guy who wants a quality steering box

Hey Gary - I just signed up to see if you're still rebuilding C3 steering boxes. I've got a '77 with some seriously sloppy play in the steering box. Power steering is also leaking like a sieve so I'm about to overhaul the whole lot.


I'm interested in your price to rebuild my current core or just ship me one you've already done. Please PM me with info.


Thanks!
 

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Discussion Starter · #137 · (Edited)
Hi guys,
I wanted to post these pictures for those of you who are looking to buy a used vette box. One thing I stress in my Carlisle seminars with boxes is the condition of the gears. If the gears are shot there is not a lot of value because they have to replaced. Most rebuilders do not have new gears, I have the complete stock of Corvette Steerings new gears that were supplied to the rebuilders, only a few purchased them so what is being used??

When I look at boxes whether in person or online I look at the lash bolt and nut. I want to see where the lash screw is and if I don't see any threads, it is a very good bet that the gears are bad and will need replacement. Now you will get all kinds of stories on how the box was great in the car but then it was removed for another box or system- why? Because it was sloppy and who knows if it was worked on. If you see -0- threads beware. Now the real con men out there will back off the screw to show threads and when the box is checked and adjusted it is found they are no good.

Here is what happens when the screw is deep- the sector bottoms out on the casting.






 

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Hello Gary,

I’m very impressed with the workmanship and attention to details of your repair. I wonder if you’re still interested in doing any work? I got a 64 C2 steering box with a lot of plays. If so please give me your contacts to my email [email protected]
I appreciate it and thanks in advance!

Oliver
 

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Pittman Arm Puller

I'm a little late to this party, but I did rebuild my steering box about a year and a half ago using the GM service manual and this thread. I know my way around precision measurement (my career field for 33 years) but I am in NO WAY an expert or authority on a steering box overhaul.


Based on my experience in rebuilding this box I can say gtr1999 is spot on. Thank you for sharing your expertise!


Anyway, I thought I'd share a good pittman arm puller that works quite well on the C3 box. It is made by OTC, part number OTC-8150. On Amazon, around $45.
 

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Discussion Starter · #140 ·
That is the best puller to use, I have broken a couple of the common 2 jaw pullers with some very seized pitman arms but that puller never failed yet.
 
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