C2 Steering box Lash

[William G.]

Greetings,

I'm attempting to resolve a little issue with my manual C2 steering which concerns the fact that it is a little twitchy when negotiating corners/curves. Best way I can describe it is to say that if the car is set up properly for the curve all seems well but if a slight mid-curve correction is attempted the car seems a mite unstable/twitchy. Now, given that the car is not driven often this MIGHT be due to the fact that in comparison with modern rack and pinion steering, these old Corvettes are not as predictable by a fair margin. However, at present, my steering seems to suffer more than I recall these cars doing.

Presently I'm in the process of replacing the ball and socket link between the pitman arm and relay rod with a kit from Zip. Additionally, recently I've replaced lower ball joints and all four lower control arm bushings (and upper bushings). My question concerns lash in the gears and races in the box. With the pitman arm disconnected from the relay rod there is a perceptible amount of play in that the pitman arm can be moved about 1/16 inch before the slack is taken up. Stated another way, given that the pitman arm is about 5 3/4 inches long between attachment points at the pitman shaft and the ball socket at the relay rod, this approximate slackness amounts to about 0.5 degrees. I'm eye balling the 1/16 inch and thus possibly the angular movement could be a little more than 30 minutes (1/2 degree). Is this normal or should there be No slack (lash) whatsoever? I've read instructions on the use of a small (inch/pounds) torque wrench to measure the force necessary to move the steering wheel/shaft but have yet to locate that small a torque wrench. Again, is a little looseness between input and output shaft indicative of a a problem in the steering box or is this normal?

What else might be causing my concern as to the loose feeling I have [there is nothing to compare with rack and pinion steering and I salute the English for coming up with it--first used, I believe, on MGs in the '50s]? I know it could be tie rod ends but they certainly "feel" tight. My alignment is about 1 1/4 degrees positive caster and 1/2 to 3/4 degree positive camber. Toe about 3/16 inch total. As to the rear, the right side could stand to be toed in by moving 1/32" of shim from inside to outside of trailing arm. Rear camber is about 1/4 to 1/2 degree negative. (I believe on the right side moving 1/16" of shims would likely be too much toe-in.) I say "about" because this is my using a caster/camber gauge and a string line for toe. I'm hoping to replace all worn components myself before paying for alignment and/or not being satisfied with what I can do myself.

Thanks,
Bill

[Owen L.]

Re: C2 Steering box Lash

Check the front upper/lower A-arm bushings for their integrity. If you are not feeling sloppiness in the steering input, then look to the rear.
Degraded rear trailing arm bushings can contribute to a Jello-y, rear-end-steering-the-car feeling as can lost rear shims at the trailing arm(s).

[William G.]

Re: C2 Steering box Lash

Owen,
I've replaced the rear trailing arm bushings, the shim packs are tight with new stainless shims. On the front, I've replaced the upper and lower control arm bushings (what you refer to as A-arm bushings........same thing).

I can't say that the steering feels "sloppy"................only as compared to rack and pinion steering would the front be described as "sloppy" but given that most of my driving is in rack and pinion vehicles (as we all are) could the recirculating ball system be described as "sloppy". However, it doesn't exude much confidence in the curves......for sure. At my age I certainly pay close attention to the speed limit and I've never had the back end try to swap ends with the front. With a well handling vehicle and when a little younger I'd often take corners at approximately ten miles over the limit but presently with the '66 I'd not attempt anything over what is posted and even then on a narrow road, well best be very careful.

Bill

[Duke W.]

Re: C2 Steering box Lash

Owen,
I've replaced the rear trailing arm bushings, the shim packs are tight with new stainless shims.
Bill

These cars are extremely sensitive to rear toe. About 1/32" toe-in per side is correct for radials and is also at the lower end of the range for bias ply tires. Any amount of rear toe-out will make these cars feel like they're possessed by the Devil.

It's easy to measure total rear toe, but very tedious and difficult to determine if it's equally split between both sides, which is critically important. A modern laser alignment rack will get the numbers, so maybe you can find a shop that will set it up, give you the numbers maybe just for rear toe, but not spend time to adjust for a reasonable price.

That's what I helped one owner to do. Once we got the rear toe off the machine we went back to his place and swapped shims on his drive on lift (using a pole jack to relieve the spring load) as required to dial it in as explained in the following thread.

https://www.corvetteforum.com/forums...-distance.html

There's no way to "adjust" the steering gear while it's in the car, but attempting to do so is a great way to screw it up. It may be time for an overhaul if it's never been done. The procedure is in the 1963 Corvette Shop Manual and later COMs. Check it out.

Get the suspension, including alignment and steering linkage squared away and then decide if the steering gear needs an overhaul. It's actually not a hard job for the average DIYer (but you do need a 50 in-lb or preferably a 25 in-lb torque wrench) as long as the housing bushings are okay, and if not, there are pros that can do the job.

Duke

[Gary R.]

Re: C2 Steering box Lash

A correctly aligned vette, 63-82, with dialed in steering box, good rag joint, tires, suspension will not have any play in it. There has been a myth around a long time that old vettes were sloppy with steering. That is not correct and most times it is caused by worn parts or people who should not be touching parts without the proper understanding.

With a 60-year box, possibly with 60-year-old sludge that was once grease in it, the ball screw radius and other metal parts get acidic etched, wrecking them. When I install new bearings in a box and retest the worm there should be no chop in the preload. A 2-3 in/lb chop is no good. When I install a new worm, one from my stock- not a vendors, the same bearings used, the preload is dead smooth and steady.

There are several areas to check within the box, some are outlined in the manual, some are my own that I don't share anymore.

While the lash can be adjusted on the car, the preload can't. It is best to have the box out of the car and check it before breaking it down. The only way to accurately check it is with a 0-30 in/lb dial TW. No clicker, beams are close but not good enough, no fish scales.

Comparison of true center, high lash, & arm position need to be made before you can address issues. This is not in the manuals. This is real world, hands on experience with these boxes. Few of them were ever textbook.

The common kits sold today are not impressive. At best you will get an ok build, better than what you have, but it won't be the true potential of the box with the common bushings sold and without some internal tweaks. The kits don't even come with cover bushings anymore. The bearings and seals are ok. I used to machine my own bushings, to my own spec, but now have them made to my spec and I final size them to each sector.

All said and done, in the correct driving location, there should be -0- play in the box. I apply only hand pressure to the input and have a dial indicator on the arm and hand pressure along is moving the arm. If there is play in the system after that, it's not in the box.

Good luck. If done correctly it will compete with the Jeep box and rack systems for less money, fits better, and is correct for the car.

[James W.]

Re: C2 Steering box Lash

IF you decide to go the route of a rebuild, I recommend you contact NCRS Member Gary Ramedai. He is the person you want to overhaul you steering gear.

James

[William G.]

Re: C2 Steering box Lash

Thanks go out to Duke and Gary, as well as others, for their replies.

Gary, I realize that you have to see the box before you can give an exact rebuild price. However, how about a range which would be applicable to 90% of the boxes you see?

Duke, as well as others, perhaps. In looking at the original ball and socket joint between the pitman arm and relay rod, mine looks pretty good with just a little normal wear and corrosion. It looks like a toss up whether I install the Chinese parts and take a chance as the quality is likely not very comparable to the original (no offense intended but in some minds it might be "its just for the Americans, so how important is it whether we employ the use of the original type steel, heat treating, etc", even if the Chinese have access to those specs after all these years, which is somewhat unlikely) or reuse the original parts.

As to the rear toe-in I'm thinking that moving a 1/32" shim inside to outside on the right side is likely not quite enough and a 1/16" shim likely too much. I think I'm going to move a 1/32" as this will bring me very close to the left side and thus be equal. I've done the trailing arm shimming process enough to know that it is a royal pain and if I had a worst enemy I'd be reluctant to demand he/she do it for me even if I was confident it would be done correctly. Its not the worst job but its right up there near the top of the list as to what I can tackle. At the risk of offending some people (and it is not my intention to do so) I'll still say that the only time I want to go against what the factory did is if it truly is an improvement to do so. And of course here I'm referring to drilling the frame pocket and using the slotted shims and huge cotter pin (huge by any standard other than that for a Caterpillar Tractor!). Many if not most of us can recall the time when all sorts of indignities were heaped on these cars by supposed well meaning folks. Therefore, today we (at least I do) lean more towards going a little overboard on originality. And I'm well aware of the fact that the factory used the huge cotter pins on latter C3s. Then again, as I said earlier, doing it the way it was originally is a huge pain. However, it has always bugged me when I purchase a car and have to undo what some "kid" did who likely had trouble with high school math but was convinced he knew better than Detroit engineers. Just my opinion.

Finally, if I get a pro to finalize the alignment I'll have him measure the rear toe and I'll take that part of it from there and fight the shim changes. Duke, since on rear toe we're talking about toe measurements on the order of 1/32" to perhaps 1/16" (for total), I'm not sure I would have, myself, an easier time measuring total toe than each side individually. My string lines are close to dead on but a .030" dimension is pretty fine for me to get down to. At close to 82 years (young), some mornings I have to screw myself up pretty tight to want to go out to the garage and practice my Navy days type cussing on trailing arm shims and pivot bolts, etc.

Thanks again,
Bill