If I run across one before anyone answers, I'll post up...

edit - Borgeson's site... http://ww2.borgeson.com/index.html
Not up to wading thru their catalog just now, tho.

 

This is really about the only thing that I really did not like about my Vette! I HATE the slop in the steering its awful! I've never owned a car with steering so sloppy.
In general, does all of the slop in the steering come from the rag joint, or do you also need to rebuild or replace the box too?
I have never messed with steering before, is this mod pretty easy to do?

 

The joint I showed in my post above works with a completely stock setup in a 74.

 

I got the U-joint last night,(They sent the wrong one.)and was eye balling the gearbox on the bench. I clamped a wire to the output shaft of the gear box,and plotted an arc going lock to lock with the input shaft. Once I determined the center of the arc.......you guessed right. The flat on the input shaft points straight up,which matches the flat on the steering wheel shaft when centered.

Me thinks that not just coincidental.

 

You might be interested in this paper on steering system centering. It provides all of the design issues relative to making sure that your gear is centered as well as making sure that your flex coupling, steering column, and steering wheel end up centered as well.

http://jimshea.corvettefaq.com/wp-co...Rev18MY061.doc

Jim

 

Nice write up Jim. I will use it as reference for sure.

 

Yup, I used Jims paper when i did mine.

 

Doh! Missed that, having not gone all the way back to the OP...



And, thanks Jim. You're the man.

 

Jim,

Obviously, we respect your opinion in this area (no suckin' up here, just fact!) but you've not weighed in on the pro's and con's of using something like this as opposed to the correct rag joint. Care to give your thoughts?

Paul

 

Its a U-joint so there are failures usually associated with rack installs b/c of the angles needed.
As with any u-joint it requires the driver to keep an eye on it as the miles go on the car, its a small u-joint at that so the angles must be checked for binding.
The rag joint was probably chosen by the General for a reason over a u-joint type product. I would imagine the rag would have less failures and aid in decreasing vibration transmitted to the steering column. I don't feel much vibration using the u-joint but then again I have a stiff suspension and poly bushings all around so I really feel the road. I wouldn't recognize any small vibration thru the u-joint.

 

There is a paper by Jim Shea that directly addresses this issue. Go to http://jimshea.corvettefaq.com. click on "Steering papers" and scroll down to the paper titled "Flex Coupling Versus a single Universal Joint". After reading that I stayed with an OEM coupler.

 

Thanks....I had read several of his other papers, but didn't see this one.

From what I can tell, as long as I properly align the steering column to the shaft, then on a vette with a collapsible column (mine is a '68 and so is collapsible) there should be no issues with using a U-joint coupling. The major concern is side loading the lower bearing but he notes that with a collapsible colum, axial adjustment is not as critical. I guess there was some additional play built into collapsible columns.

Jim...If I've misstated anything, let me know. It's not that I have a problem using a flexible coupling, but it seems as if OEM couplings for my '68 are near impossible to find and none of our guru's advocate using aftermarket parts here.

 

For the record a new or "good" rag joint has NO lost motion.

Both stock and Jeep type power steering introduce some lost motion into the steering.

On the stock system it is obvious that when the pitman arm moves the valve in the cross link moves a little to provide the power for the slave cylinder.

On a Jeep type box, there is a rotary valve that also has to move slightly to provide signal to the power steering which acts on the driven gear within the steering box.

With stock manual steering there is NO lost motion if all is as it was when new.

 

WHY DID GENERAL MOTORS USE FLEXIBLE COUPLING ASSEMBLIES?

These are the reasons why General Motors vehicles use a flexible coupling assembly with a laminated rubber disc and stop pins, etc and do not directly couple the steering column to the steering gear by means of a single universal joint.

The flexible coupling serves a couple purposes:
One, because you are steering through a laminated rubber disc, there is a degree of isolation from steering system and engine compartment noise.

Two, the rubber disc also provides tactile vibration isolation from harsh tire and road feedback.

Third, the flexible coupling is used to accommodate the small design angle of the steering column meeting the steering gear input shaft.

Fourth, it can take up a minor amount of misalignment of the steering column shaft to the steering gear input shaft. This misalignment can be from the steering column installation; movement of the body relative to the frame under driving conditions, settling of the body relative to the frame over time and miles.

Fifth, it can take up a minor amount of axial displacement between the steering column and the steering gear input shaft. This axial displacement can be from the same conditions as the number four.

Sixth, provide an electrical grounding path from the steering column shaft to the steering gear (and frame) for the horn ground.

The first two reasons probably are not a great concern for a Corvette owner (i.e. engine noise and road feel).

As I remember the actual design angle between the steering column shaft and the steering gear input shaft is about 1 or 2 degrees. The flexible coupling was designed for 5 degrees. Universal joints easily take up 10 degrees or more of angle.

Being able to accept a minor amount of misalignment and/or axial displacement is important. The AIM sheets and the Chevrolet shop manual have a very specific installation and assembly method called out to align the column to the gear. They called it a Mandatory Assembly Sequence. (The OEM type flexible coupling assembly has orange plastic alignment spacers to assist in the procedure. The spacers are discarded after every thing is assembled and checked.) After completing the column installation, you can inspect the flexible coupling and note if the stop pins are central in the steering column flange slots to determine proper alignment.

Also there is a "flatness" called out in the installation sheets for the flexible coupling disc and stop pins to determine axial alignment.

A single universal joint has no provisions to take up any misalignment or axial displacement. If the steering column and the gear are not closely aligned, a very large side load can be placed on the column lower steering shaft bearing. Note, on steering systems with an intermediate steering shaft there are no alignment concerns - (such as the C4 and later Vettes.)

On vehicles with energy absorbing steering columns, (1967 and later) axial location is probably not of extreme importance.

Overall, we were most concerned about long term durability of the steering column lower bearing from side loading.

JIML82
FlexCplgVsUniversalJoints26AP2006.doc

 

I just bought a rag joint for my Jeep Box conversion from Corvette Steering Srevice there was some vibration with the Borgson joint in my installation but, the Vette is a roadster your coupe may be stiffer than my 70 chassis. I plan on using the Borgson joint on my 72 LT-1 that I autocross.

 

I got the right part last night,and test fit the joint to the gear box. I'm thinking the flat of the box needs to be straight up (12 o'clock) for the steering gear to be centered when the box is installed back on the frame,so I determined that if I offset the gear box set screw 90 degrees,then the set screw for the steering shaft will land on the flat of the steering shaft. The gear box spline is grooved 360,so the set screw for that side will land in the groove, and the steering wheel looks to be centered with the flat on the steering shaft also at 12 o'clock.

Why wouldn't they have put the set screws in synch?

 

Mine should be here tomorrow. Moneypit keep me informed on your install.

 

ok. never knew about this. I gotta do this. My rag joint is sloppy and ratty

 

The thought just occurred to me that the installation of a u-joint likely increases the need to follow the Chevy Power book Corvette Chassis section recommendation to stiffen the area of the chassis near the steering box. Food for thought, especially in a high-perf application such as auto-X'er and/or road racer.

Jim, am I on the right track here?

 

That and solid, rigid body mounts to the frame.
Jim