| Author | Message | |||
     Jean-Pierre 'JP' Hilbert Frequent User Username: jphilbert Post Number: 60 Registered: 9-2013 |
New issue: Steering feels a bit uneven and rough, I oiled the top and bottom steering column bearings as far as I could access them but issue remains. I then discovered that the lower steering linkage is rotating in a ''wobbly'' manner. I hope the video uploads! Just observe the irregular motion of the shaft! I came to the conclusion that there is too much preload on the lower steering assembly, that is, it hardly fits between the rubber donut and the steering rack spline. I need to pry the top U-joint with a screwdriver into the position below the safety stalk. Hence I think that the preload creates an outward force and makes the U-joint linkage move out-of-center, causing this wobbly movement (and noticeable donut twist) Investigation showed that the U-joint below the donut and the one set onto the steering rack spline are not correctly phased in accordance with U-joint textbook theory. But the flat part on the spline (to insert the tightening bolt) does not allow any other way of assembly. It is 90 degrees off compared to U-joint theory. Furthermore, the workshop manual TSD440074700 Figure N4-5 shows a 90 degree difference in assembly compared to the exploded parts diagram (pictures attached). Strange, but anyway there is only one way to assemble and that is the out-of-phase one, due to the machined flat part for the tightening bolt. Still, that does not explain why I need to pry-in the linkage. I concluded that it is too long. My steering rack was originally a squared-feet mounting, and has been upgraded to the later style, rounded feet together with adaptor. I suspect that whoever did that work, did not change the lower linkage and that's why it is too long. Mine is 19,6mm/7,71in long, overall. I very much feel like grinding the linkage down by a few mm to make it fit. But I have the feeling that I may be masking the real problem. Apologies for writing a book, would rather be painting Easter eggs, but solving this may solve the weird steering that came with the car when I bought it.
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| bob uk Unregistered guest |
If the shaft is too long then the donut will be loaded along the axis. As the shaft turns the donut will deflect side ways. Wobble. Disconnect column from the rack. The steering should feel smooth like turning a push bike wheel. With the entire coupling and shaft removed check ujs for binding or slop. Oil the bearings. Uj theory. Every quarter rev there is a speed change the size lf which depends upon the angle. On slow rpm shafts such as a steering shaft the speed change is not an issue and the driver will not feel it. On a propshaft the angular velocity change will causes viberation. So the angle of the ujs becomes important. The rememdy is to have a uj at each end running at the same angle to cancel out the speed change. Check that shaft length. (Message approved by david_gore) | |||
| Jean-Pierre 'JP' Hilbert Frequent User Username: jphilbert Post Number: 62 Registered: 9-2013 |
Bob, You wrote: If the shaft is too long then the donut will be loaded along the axis. As the shaft turns the donut will deflect side ways. Wobble. My answer: Yepp, that's exactly what happens. But why? i) Either the distance from firewall/toeboard to steering rack spline is smaller than it should, or ii) the shaft is too long or iii) there is an assembly mistake from my side or iv) the donut is too thick. Would be good to have measurements from other cars? I know that there are 2 different metaplastic bonded couplings around, but their bolt pattern is different. You wrote: Disconnect column from the rack. The steering should feel smooth like turning a push bike wheel. With the entire coupling and shaft removed check ujs for binding or slop. Oil the bearings. My answer: No binding, smooth. I turned the steering rack by hand by the spline, with engine running, no issues here either. U-joints greased with Castrol's finest. Shaft length checked and found to be 19,6mm/7,71in long, overall. I really feel like grinding it down! Meanwhile I'm so angry that I wish to be the 'Biter' from James Bond movies and bite one cm off! Grrrr | |||
| bob uk Unregistered guest |
Donut too thick is a possibility. The donut is very alike ones used on other makes. For instance a Austin Metro donut is thd same as a Renault 18. Ask flying spares how thick their donuts are. If smaller than yours then order one from flying bits. Also ask them to measure the shaft. Note if flying spares co operate, then buy the bits from them, it would be rude not too. If its the shaft too long and it is possible to cut down then its tempting to chop it. But should the shaft be correct and the donut wrong, then when a new donut is required the shaft will be wrong Note. If cutting a shaft down is merely hacksawing bit off then fine. But if the middle is cut and welded together to keep the splines, then best way is to fit a sleeve over the joint and then weld the sleeve to the shaft. The sleeve will hold the two havles in alignment while welding. Plus its stronger. But in the long run fit the correct donut or shaft. SZ steering rack guru required for help on this one. The donut is a service item on all cars and pattern parts are readily available, someone could have fitted the wrong one. (Message approved by david_gore) | |||
| Jean-Pierre 'JP' Hilbert Frequent User Username: jphilbert Post Number: 63 Registered: 9-2013 |
The donut IS from Flying S. I grinded down the shaft at the end, removed 6mm and now steering as smooth as a nun's belly. The splines engage fully. Before, the splined part on the shaft was way longer than necessary to sit within the female part, which makes me think that there is a miss-mash of incorrect parts on my car. I'll contact FS today and kindly ask them to measure me their shafts. The U-joint on the shaft has 1mm play on its axis, this is not noticeable on the steering wheel 8yet) but it does click when one wobbles the assembled donut by hand. | |||
| bob uk Unregistered guest |
Not having felt a nun's belly I wouldn't know. The 1 mm play and click are of concern. Suggest if possible the UJ should be replaced. (Message approved by david_gore) | |||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 147 Registered: 9-2003 |
From my webpage: -Rubber Steering Coupler: Rolls part number UR23270 for Shadow II, & Spirit/Spurs through the '90's using rubber isolated columns. Same as used in the Triumph TR4, 4A, 250, & EARLY TR6. Available from Moss Motors, or Little British Car Co. part# 667-390 for $16.11, compared to Rolls at $150+. PIC:  - Larry Rolls & Bentley Substitute Parts} | |||
| Jean-Pierre 'JP' Hilbert Frequent User Username: jphilbert Post Number: 66 Registered: 9-2013 |
Larry, that's good intel! I wanted to replace mine even tough it is only 2 years old, because it must have gotten some beating with that silly shaft discussed above, but I was hesitating at the high price. Now I won't be hesitating at the little price! Many thanks again! | |||
| bob uk Unregistered guest |
I thought there would other cars using this donut. (Message approved by david_gore) | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1267 Registered: 6-2009 |
I've been directing people to Larry's Rolls-Royce and Bentley Substitute Parts Page for years now. It's precisely the sort of information that makes it far quicker, easier, and less expensive for many of us to lay our hands on necessary parts when the occasion presents itself. I've bought plenty from Crewe Original via Bentley Zionsville [AKA Albers], Post Oak Motors, and others. I've also purchased from The Usual Suspects in the UK, before and after some of their mergers and acquisitions. But, it's a real blessing when one finds oneself in need of what has got to be a common part to have a list of those available that you can source at virtually any local auto parts store. I'll also point out my Rolls-Royce and Bentley Parts, Repair, Restoration and Other Resources Compilation has quite a bit of information that does not overlap Larry's. Brian | |||
| Jean-Pierre 'JP' Hilbert Frequent User Username: jphilbert Post Number: 67 Registered: 9-2013 |
Brian, New steering donut from a TR6 on order. Savings: some 60 GBP. Thanks for the tip! | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1281 Registered: 6-2009 |
JP, Larry is the one who deserves the thanks on this one. If he hadn't confirmed and published this particular alternate then very few other than he would know. Brian |
watch that steering shaft wobble!