Geko Posted January 11, 2016 Report Share Posted January 11, 2016 Never ending story... While restoring my steering wheel I though I would attend a small shaft play. I ended up dismantling the whole steering column only to find out that the lower coupling was gone. After dismantling I noticed that the bore of 2 of the 4 holes in the coupling are larger than the other but only the 1st third through. Is there a reason for it ? cheers Quote Link to post Share on other sites
RogerH Posted January 11, 2016 Report Share Posted January 11, 2016 Hi Stef, the holes look concentric - have they been counterbored? Can't see how they would wear like that. Where the splined clamps doing their job. Quite often there is a little play no matter how tight you do the clamp bolt - there is an answer. Roger Quote Link to post Share on other sites
Geko Posted January 11, 2016 Author Report Share Posted January 11, 2016 Hi Roger, this isn't wear, this is counter bore but no logical justification/use to it as the bolts have the same diameter throughout. The splined clamps were always a bit loose I guess due to the clamping bolt and nut being too thin and not providing enough torque for proper clamping. I'm going to re-bore those a bit and insert larger bolts with locknuts. Quote Link to post Share on other sites
Steve Zodiac Posted January 11, 2016 Report Share Posted January 11, 2016 Hi, Think you will find that the later TR6 had 'cap' heads (allen bolts) that were recessed into the column rubber coupling. I think this coupling has been sold as a retro fit but no mention of the reduced 'land' if the original hex headed bolts are reused. That's been my understanding, but maybe I should get my coat............... Steve Quote Link to post Share on other sites
RogerH Posted January 11, 2016 Report Share Posted January 11, 2016 Hi Stef, the splined clamp joint should not be loose bo matter what bolt is fitted. Have a very close look at the area between where the clamp effect takes action - you may well find that it is not being allowed to clamp I have done a mod on mine and a few other parts - see attached pic. Roger Quote Link to post Share on other sites
TR 2100 Posted January 11, 2016 Report Share Posted January 11, 2016 Hi, Think you will find that the later TR6 had 'cap' heads (allen bolts) that were recessed into the column rubber coupling. I think this coupling has been sold as a retro fit but no mention of the reduced 'land' if the original hex headed bolts are reused. That's been my understanding, but maybe I should get my coat............... Steve Steve, Leave your coat on the peg. AlanR Quote Link to post Share on other sites
Geko Posted January 11, 2016 Author Report Share Posted January 11, 2016 Hi, Think you will find that the later TR6 had 'cap' heads (allen bolts) that were recessed into the column rubber coupling. I think this coupling has been sold as a retro fit but no mention of the reduced 'land' if the original hex headed bolts are reused. That's been my understanding, but maybe I should get my coat............... Steve bingo, I found a pic of the TR6 coupling Quote Link to post Share on other sites
Geko Posted January 11, 2016 Author Report Share Posted January 11, 2016 (edited) Hi Stef, the splined clamp joint should not be loose bo matter what bolt is fitted. Have a very close look at the area between where the clamp effect takes action - you may well find that it is not being allowed to clamp I have done a mod on mine and a few other parts - see attached pic. Roger DSCF0079c.jpg Here are pics of the upper and lower splines. What's your verdict? It does look that the shaft has been worked on to accommodate larger bolts (or is it wear?). I have put the clamp in my enormous vise to test the clamping force. The steel is too thick and there's no way that inserting even larger bolt will provide enough force to clamp down to the shaft- the bolt and nut are only there as a safety to retain the shaft in the clamp and so is your setup I suppose. Larger bolts will reduce the lateral play but will not contribute to tighter clamping on the splines. Or shall I do the horn earth a favor in installing all steel/alloy UJ couplings and delete the rubber ones? Edited January 11, 2016 by Geko Quote Link to post Share on other sites
peejay4A Posted January 11, 2016 Report Share Posted January 11, 2016 (edited) Stef, Roger's modification relieves the slot so that the clamping bolt can actually exert real force on the splines. The standard bolt is well able to clamp it up very firmly indeed. It does look as though one end has been modified but if the slot can't close then as you've found, no size of bolt will tighten it up. The bolt and groove also serves to stop the shaft from fully detaching if it does loosen but I'm not sure if that's really a useful safety measure if the shaft is already turning in the splines. The horn should work fine with the rubber couplings as long as the earthing straps are in place. I've also independently strapped the steering rack to earth. You might consider replacing the lower coupling with a TR6 U/J so you don't have to mess around replacing the one that gets all the muck and oil on it. I've kept the upper one just for a little protection against kick back through the steering. Edited January 11, 2016 by peejay4A Quote Link to post Share on other sites
Geko Posted January 11, 2016 Author Report Share Posted January 11, 2016 (edited) Stef, Roger's modification relieves the slot so that the clamping bolt can actually exert real force on the splines. The standard bolt is well able to clamp it up very firmly indeed. Ok, now I get it but needed to have my nose on the clamp Edited January 11, 2016 by Geko Quote Link to post Share on other sites
RogerH Posted January 11, 2016 Report Share Posted January 11, 2016 Hi Stef, have a look at my picture. The arrow points to an area of the clamp that is machined away. This is only required on one side of the clamp. Once this is done the standard 1/4UNF bolt will lock the spline with simple hand turning of a 6" ratchet. Roger Quote Link to post Share on other sites
Geko Posted January 13, 2016 Author Report Share Posted January 13, 2016 Hi Stef, have a look at my picture. The arrow points to an area of the clamp that is machined away. This is only required on one side of the clamp. Once this is done the standard 1/4UNF bolt will lock the spline with simple hand turning of a 6" ratchet. Roger Yes, Roger that. Have you also tried removing material over 5-6 mm in the slot only? How to do that is another question.... Quote Link to post Share on other sites
RogerH Posted January 13, 2016 Report Share Posted January 13, 2016 Hi Stef, by going in from the side, as per my pic, that area of solid metal will be removed and the clamp will work correctly. Roger Quote Link to post Share on other sites
Geko Posted January 13, 2016 Author Report Share Posted January 13, 2016 Indeed, now I can see the light. Thanks for the tip. Quote Link to post Share on other sites
RogerH Posted January 13, 2016 Report Share Posted January 13, 2016 Hi Stef, your photo's say it all. The one on the left will now work. The one on the right never worked Roger Quote Link to post Share on other sites
MikeF Posted January 13, 2016 Report Share Posted January 13, 2016 Not having Roger's talents or facilities I drilled a hole through clamp where he machined to and then hacksawed down to hole. The cut allows a more bendy clamp where needed and the circumference of the drilled hole is classic way of relieving any stress cracking. Not as elegant, but seems effective enough. [i have the Six's coupling on the lower end.] Mike Quote Link to post Share on other sites
dpb Posted January 13, 2016 Report Share Posted January 13, 2016 Stef Those photos explained it for me. I was puzzling over Roger's excellent photo with arrow, and how that was helping, but now I know! Thanks both. Dave ==== Quote Link to post Share on other sites
D Murton Posted January 13, 2016 Report Share Posted January 13, 2016 Roger I understand the reasoning behind this mod but should we really be expected to modify a safety critical item. Is his not a case for the PQI ? Dave Quote Link to post Share on other sites
Geko Posted January 13, 2016 Author Report Share Posted January 13, 2016 Indeed but you'll find that these clamps are NLA with most suppliers and I doubt that remanufacturing proper ones would be economically viable. But maybe another mission for AlanT and RogerH Quote Link to post Share on other sites
Geko Posted January 14, 2016 Author Report Share Posted January 14, 2016 (edited) Edit Edited January 14, 2016 by Geko Quote Link to post Share on other sites
RogerH Posted January 14, 2016 Report Share Posted January 14, 2016 Hi Dave, this is a 50 year old quality issue by ST. Who are you going to complain to - everybody has gone. I had this publish in TRAction back in th elate 90's and the Tech Ed's at the time didn't think much of it - the mind boggles. I have run my mod'd shaft for 170,000+ miles with no problem - and that is with BOTH clamp arms cut through. With only one arm cut through it will last forever and much longer. Using the angle grinder shown above will cut through both. Using a milling machine you can cut through just the one. Roger Quote Link to post Share on other sites
D Murton Posted January 14, 2016 Report Share Posted January 14, 2016 Hi Dave, this is a 50 year old quality issue by ST. Who are you going to complain to - everybody has gone. I had this publish in TRAction back in th elate 90's and the Tech Ed's at the time didn't think much of it - the mind boggles. I have run my mod'd shaft for 170,000+ miles with no problem - and that is with BOTH clamp arms cut through. With only one arm cut through it will last forever and much longer. Using the angle grinder shown above will cut through both. Using a milling machine you can cut through just the one. Roger Sorry. I assumed this was a replacement part. Dave Quote Link to post Share on other sites
RogerH Posted January 14, 2016 Report Share Posted January 14, 2016 Hi Dave, not many ST parts were iffy but this one is a howler. If it was a repro then we would be on the case. There are various ways of relieving the clamp - milling, grinding, drilling, and hacksaw. I prefer Milling. Roger Quote Link to post Share on other sites
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