Manual Steering questions........

[MBE]

I am the new owner of a 2015 Classic Roadster Cobra.
As I am getting to know this car I have questions about the steering.

The car has manual steering with an IDIDIT steering column and rack and pinion steering box. With the car stopped on the ground it is very hard to turn the wheels. when moving on the road it is better but it wanders side to side a little bit. The steering column has 3 u-joints in it, which is typical for these cars. When turning to the right there is a very noticeable binding in the column about every half turn or so. It is not as noticeable when turning back to the left but the bind is there. With the car on jack stands and the front wheels in the air it does turn easier, but not as easy as I think that it should and I can still feel the binding and then the release of the bind. I did take the friction pad out of the rack but I do not feel that it made any difference in releasing any drag on the column.

I also have about an inch of movement at the steering wheel without any movement on the exit end of the shaft. It appears that there is a disconnect (slop) within the tilt mechanism.

Has anyone experienced these same symptoms? Or do they all feel like the u-joints are binding up? The u-joints and spindles are greased and everything is free moving except for the binding. I am working on the hard steering when standing still, and the wandering could be due to the slop in the tilt part of the steering column. I am new to Club Cobra, this is my first post.
Thanks for your help.

[Gaz64]

A little off topic but it may help you.

I had a customers car a few years back that complained of the steering "locking up solid".

Car came in on a towtruck.

After a bit of testing, could not locate the fault, but sure enough during a roadtest, it went solid.

The intermediate coupling was not on the rack far enough and was forcing a u-joint to go through too much angle.
Vehicle had a rack fitted after accident damage by another repairer.

Took about 15 minutes to sort.

Moral is: check all the u-joints are not going beyond about 30 degrees.

Gary

[CR67rep]

As for trouble turning at a stop, this is to be expected with tires as wide as Cobras have with manual steering. You will get used to it, but double check your tire pressures also. If they are low it will make it more difficult.

[trularin]

So, the Ididit column is fairly reliable. But I have had my issues. When the compartment is hot, the column becomes stiff and hard to turn ( bushing temperature tolerance ). I put in a heat shield that seems to have helped.

Then there is the flaming river rack. There are a few I have heard about that needed the bushings replaced because of sticking.

I do not like the three U joint configuration - seems like to much angle changing. I would look there first.

Just my $.02

Tru

[Morris]

Look at U-Joint Phasing.....especially with three u-joints.....

[MBE]

I agree with what was said about the 3 joint configuration, and I have looked as the steering wheel was being turned to be sure the knuckles were not hitting metal to metal. (that would be too obvious and I would not be posting here)
It must be too much angle even with 3 joints. But why would this be different than any other Cobra? I thought that maybe the eye bolt that the middle shaft goes through was allowing movement that would cause the binding. There is no movement there.
Do other Cobras turn smooth when in motion?
I do not expect it to turn like a car with power steering when it is stopped, but it should be something that I can do with a little effort not a lot of effort when stopped. (I think about the 57 chev with manual steering that I had 40 years ago)
In the builder's manual that came with the car there is an addendum that says to shim the steering rack with a 1/8 inch shim to move the box farther away from the steering column. This could lengthen the distance between the u-joints and straighten out the shaft a little bit. I tried the 1/8 inch shims last night and it seemed to help some, I think it is worth trying 1/4 inch or more until there is no change in the binding feeling.
If that works I will let everyone know here.

The IDIDIT steering column has a bit of free movement at the steering wheel before the steering shaft begins to move. Has anyone had one of these apart to know what could be tightened up in there? It is a tilt wheel so the u-joint in there could be loose at the attaching points I suppose.

I looked around the steering rack to see if I could find a brand name or what the ratio is for it and did not find anything. I suppose if I counted how many turns lock to lock someone would be able to tell me what ratio I have.
It has a chrome tube with a chromed cast mounting boss on each end, held in place with two 5/8 inch bolts.

I am new to this site and new to this car. I bought it already built and "ready to go", but I realize that a hand built car like this is will require continual tweaking and maintenance. I don't mind the work, I like this stuff.
Thanks for your help

[MBE]

If I had four u-joints I can see getting out of phase, with three u-joints there is only one way they can go together, or am I missing something? Two shafts with one joint in between and one joint on each end. I think the yokes are stationary on the shafts and splined yoke on the pinion and IDIDIT. The small shaft that goes through the eye has to be removable, I will look closer at that.
Thanks

[stallion112]

I have spent quite a few years working with automotive OEM’s designing and validating steering systems and driveshaft’s so universal joints, or cardan joints, are a familiar topic.

My Kellison Stallion was built in the mid ‘70’s so the original steering intermediate shaft utilized Pinto / Bobcat components. This included a thick one inch cable that rotated at a slight angle in place of one of the cardan joints (in addition to the one cardan joint that remained). It was used by the OEM primarily to pass relatively new crash requirements since it would easily fold with a high enough impact to the vehicle and minimize the energy transferred to the upper column. Because of the cable the steering in the Stallion was smooth throughout its full rotation but, since the original cardan joints were worn out from age I decided to design a new system from the steering wheel through to the pinion shaft on the rack & pinion.

A rule of thumb for a slow speed, low torque steering application is for the cardan joint to not exceed 30 degrees of operating angle. Even then, the entire system has to be properly phased. Phasing refers to the relationship of one set of yoke “ears” (the section of the yokes that support the bearings) with respect to the opposing set of yoke ears.

At first glance, a series of shafts that are connected by cardan joints appear to all be rotating at the same velocity. However, a closer look reveals that they are not. Imaging two shafts that are joined together in the middle by a cardan joint. Now hold it up to eye level and in the horizontal position. The set of yoke ears connected to the shaft in the right hand are “Plane A”. The set of yoke ears connected to the shaft in the left hand are “Plane B”. Now rotate the shaft assembly. The instantaneous velocity of the set from “Plane A” is the same as the instantaneous velocity of the set from “Plane B”. Now keep the shaft in your right hand horizontal and tilt the shaft in your left hand at an angle. When you rotate the shaft assembly now you can see that the set in “Plane A” or your right hand still rotates in the vertical plane, but the set in “Plane B” or your left hand rotates in a sinusoidal motion relative to “Plane A”. For every one full rotation the speed and velocity of the shaft in the right hand equals that of the shaft in the left hand. However, during each rotation the instantaneous velocity of “Plane B” both accelerates and decelerates relative to “Plane A”. In addition, due to the sinusoidal motion there is an axial load being generated through the system. The higher the operating angle the higher the axial load that is generated.

I know this sounds complicated but the bottom line is that each cardan joint needs to be cancelled out or balanced (phased) with another cardan joint operating in an equal and opposite motion. This is especially important with high speed, high torque applications like a drive shaft.

One way to help balance out the system is by using a double-cardan joint. This is simple a back-to-back cardan joint assembly. Input equals output at all points throughout rotation. My Stallion uses a three joint system, two cardan joints at each end with a double-cardan in the middle.

I would recommend using Heim type joints on one side of the cardan joints to help support the shaft and keep it rotating about its intended axis. Otherwise they can move around when the system is rotated and make the steering feel “lumpy”. This is especially true when using a double-cardan joint. Make sure that the bearings in the column are properly supporting the shaft as well since they perform the same function as the Heim joints.

Another thing I suggest doing is setting up the system by using wooden dowels or broom sticks along with the cardan joints to determine the length, angle, and phasing of the steering intermediate shaft between the lower column and rack & pinion. It is much easier than cutting DD or splined steel shafts.

Lastly, some type of a rubber isolator should be used to dampen vibration from the chassis. I prefer the older style donut shaped isolators but the ones that are incorporated into tube shaped yokes provide for a slightly stiffer feel. The isolator should be located next to the pinion shaft from the rack & pinion to minimize vibration.

[MBE]

I will look at the phasing of the u-joints. Maybe I am looking at them wrong.
Thanks for the help.

[MBE]

I have made some discoveries in the last week.
I have an IDIDIT horn cover.
The column is not from IDIDIT or Flaming River.
It is suggested that it is a Chinese knock off that does not hold up under the strain put through it on the manual rack and pinion in this car. I do not see a brand name on the steering rack either, so I assume that it is a knock off too.
I shimmed the rack away from the cross member that it is bolted onto, that helped some with the binding that seemed to be timed with the u-joint binding, but it still was very hard to turn the wheels without moving the car. My next step is to pull the column and see how much effort it takes just to turn the pinion with out weight on the tires.
It takes about 4 1/8 turns lock to lock, which seems like a lower geared steering rack compared to some of the other manual racks that I have read about on this site that are in the 3 1/2 turn range.
The spindles and tie rod ends all look to be lubricated and not part of the hard turning issue.
It has become obvious to me that I am going to have to replace the rack and pinion or the steering column or both rack and column. I am leaning towards power steering and have been searching for something that will work with the engine and available space in my car. I appreciate any suggestions from someone that has done this before. My car is the Classic Roadster with the DOHC all aluminum Ford V-8, very light weight compared to other engines. The big heads and valve covers on the engine make the steering shaft a tight fit around the left front to get to the pinion on the rack, and I am sure that finding the brackets and belt for the engine mounted hydraulic pump can be difficult. Or can I go to a junk yard and buy the whole setup, rack and pinion, pump, brackets and belts from a wrecked Mustang or other same sized car?
Thanks for your continued input here.

[CR67rep]

I believe there is a power steering system on the market that has variable rates--more assistance at low speed than at highway speed. I think DV may have the info on this if memory serves right.

[MBE]

Who is DV?

[CR67rep]

Double Venom. In my short time here so far he seems to be the resident Classic Roadsters guru. Has built hundreds of them and is actively involved in helping the Canadian company that is bringing them back to the market

[Dwight]

Double Venom = Ed Combs

[MBE]

OH, OK
I am a new Cobra owner on this site. Have to learn how to post questions and pictures on here. Have to learn about the idiosyncrasies of these cars too. I have all sorts of issues that will keep me busy for some time.