Superaquarama Posted October 29, 2012 Report Share Posted October 29, 2012 (edited) Hi Guys, Just getting around to the front suspension now, having done the rear. 1) I've somehow contrived to have 2 good left hand vertical links and no right ! Is there any reason not to use a l/h link on the r/h side, as I've got another good l/h trunnion and it would save the hassle of finding another good link ? Other than it may cause confusion if it needs another trunnion somewhere down the line ! 2) Top balljoints - the parallell holes are, to say the least, a generous fit around the bolts with perhaps 1/16" of clearance, yet I think the bolts are correct as anything larger wouldn't fit through the holes on the wishbones. Is this normal, or have I got duff balljoint carriers ? They're actually labelled TR6, but I understand they're the same as the 4A. Thanks, Anthony Edited October 29, 2012 by Superaquarama Quote Link to post Share on other sites
RogerH Posted October 29, 2012 Report Share Posted October 29, 2012 Hi Anthony, the threads for the trunnion at the bottom are handed. With the normal set up when turning, the LH thread and the RH thread cancel each other out and you go round the corner level If you have two LH links then when turning you will get a slight rise (or fall) on one side. However this is a very small amount and wouldn't really be noticed for normal driving. But I'm sure there is a lean on the link making it not quite vertical. The next expert will know. Put your link up for sale on the Buy,Sell, Trade forum and ask if there is a RH out there. Roger Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 29, 2012 Report Share Posted October 29, 2012 (edited) Hi Anthony, You will need a LH and a RH link with its matching trunion to get the suspension correct. The thread on the link is LH on one side and RH on the other so you can not mix up. The trunion is machined for 3 degrees castor. The top wishbones are formed to set the ball joint towards the rear to produce the 3 degree castor. (top of post leans backwards) I have looked at the used top ball joints I have and the bolts are not a very tight fit in them. Are you using bolts with a plain shank, rather than fully threaded ones? The shank of the bolt is 3/8 inch diameter and the thread will be below that size. Cheers Peter W Edit - you got in as I was typing Roger! Where are you Anthony? I have one hand only of a USED TR4A-6 link (I do not know which side at present but 15 mins in the garage would answer). Sorry - The one I have is LH thread and VERY rusty, so of no use to anyone except as a fishing weight. I do have some NOS suspension bushes for the TR4A - No big trunion bolts though. Cheers Peter W Edited October 29, 2012 by BlueTR3A-5EKT Quote Link to post Share on other sites
Superaquarama Posted October 29, 2012 Author Report Share Posted October 29, 2012 Many thanks, Roger and Peter. So it looks as though, whilst it would work, it would be better to get the r/h link and the thing will be correct then. Actually I've got to collect some bits from a spares chap so I'll see if he's got one. Thanks for the info on the balljoint, in the meantime I found an old one and agree that it too has generous clearance, so we should be ok. Regards, Anthony Quote Link to post Share on other sites
AlanT Posted October 29, 2012 Report Share Posted October 29, 2012 This is much more complex than it appears. The WSM describes versions with 0 deg and 3 deg castor. You must have a lefthand and righthand pair if you have 3 deg castor. At some stage, having settled on 0 deg castor it looks as if they may have abandoned handed parts. This means the trunion would be the same both sides. You really need to get a WSM that covers the 4A as well as the 4, Moss do them I think, and then try to work out what you have. The WSM gives all the dimensions to do this. The small amount of rise and fall you get by less than 1/2 turn on the trunion probably wont matter, The castor angle will, because the wheel would "point the wrong way". Twist my arm and I'll tell where to find the WSM on line but it may not cover the 4A like mine does. Al. Quote Link to post Share on other sites
peejay4A Posted October 29, 2012 Report Share Posted October 29, 2012 The 4A has the 3 DEG castor to the best of my knowledge and the vertical links are handed. Quote Link to post Share on other sites
Kiwifrog Posted October 30, 2012 Report Share Posted October 30, 2012 TR4A Vertical links from 4A Parts manual 307215 RH vertical link 307216 LH vertical link The one I have (LHS) has a grease nipple at the bottom of the link that is oriented to the rear of the car Cheers Alan Quote Link to post Share on other sites
Superaquarama Posted October 30, 2012 Author Report Share Posted October 30, 2012 Thanks for the further info. There is -3 deg of caster, Al, but this isn't achieved via the vertical links, according to the WSM (which I do have !). Maybe the upper wishbone mounting points are set back slightly on the 4A, or the lowers set forward ? Only one part no is listed (at least by Moss) for all TR2-4 links, this being 20180, so neither TR4A part no. is the same as this. Thus it seems that TR2-4 links are not handed, so they must suffer from more lean on corners ! Problem then is identifying the correct RH link for a TR4A - maybe the grease nipple is a giveaway, and I need to ensure the RH trunnion will screw onto it. Cheers, Anthony Quote Link to post Share on other sites
peejay4A Posted October 30, 2012 Report Share Posted October 30, 2012 The trunnions usually have R or L stamped on them. Quote Link to post Share on other sites
AlfredHitchcock Posted October 30, 2012 Report Share Posted October 30, 2012 (edited) OK. My 2p worth. I have a 4 NOT a 4A and the 3 degree backwards camber (-ve?) is given by the trunions not by the vertical links. The threads on the bottom for the trunions are both the same so you can use either side. I believe this correct for my car. The front top wishbones are swept back to match this camber. I found out that my right side had a left sided trunion fitted so it was leaning forwards!! I couldnt understand how this could have fitted until I found that the chassis and brackets had been slightly bent as a result of a knock and someone had fitted them to compensate for the alignment issues. This must have been done in its previous USA life because of the state of the rest of the suspension. I dont know for sure whether 4 vertical links would fit a 4A but I'd stake money that they would? Edited October 30, 2012 by AlfredHitchcock Quote Link to post Share on other sites
Superaquarama Posted October 30, 2012 Author Report Share Posted October 30, 2012 The trunnions usually have R or L stamped on them. Yes, so if I take along my R trunnion I can offer it up to a RH link to ensure it fits. Although this may not preclude it fitting a TR2-4 link, depends which way they're threaded ? Ah, so it's the trunnion that gives the -3 deg. - thanks. So if a LH link & trunnion were fitted on the RH side we'd presumably have +3 deg ! This is what I was contemplating doing per my original posting, so clearly not a good idea ! So I'd better find a RH link, even if it means £100 at David Manners. But I agree that any link will surely physically fit any TR, but there must be differences apart from the threads or why different part nos. ? Quote Link to post Share on other sites
Alec Pringle Posted October 31, 2012 Report Share Posted October 31, 2012 TR4 and 4A utilise different vertical links and different trunnions. They are not interchangeable. TR2/3/4 utilise the same vertical link both sides throughout, not handed, and nor is the 0 degree trunnion handed. In contrast, the later TR4 (post CT63?? whatever it is) 3 degree trunnions are handed. TR4A employs handed vertical links, and similarly handed trunnions, neither links nor trunnions being interchangeable with TR2/3/4 suspension, and vice versa . . . . OK, I know it is possible to engineer exceptions to that rule, but not in terms of road cars - and I assume we aren't talking competition specials here. Cheers Alec Quote Link to post Share on other sites
Kiwifrog Posted October 31, 2012 Report Share Posted October 31, 2012 The 3° rearward lean on a 4 is caused by the trunnion at the bottom and uneven length wishbones at the top. If you have a very clean pair of upper front TR4 wishbones they have R stamped on one side and L stamped on the other. When mounted on the Left the L is uppermost and when mounted on the right the R is uppermost. According to the moss catalogue the top arms are the same for the later TR4 with 3° castor as those listed for the TR4A. The new TR4 3° trunions do not have L or R stamped on them but it is easy to tell which is which by putting them on a flat surface and looking which way the bottom suspension pivots lean, 3° appears quite small but it is very noticable. TR4 trunions have the pivot pressed into the trunnion. If you order some from the usual suppliers before you do anything check that you have one for each side, it is not unknown for them to send 2 of the same side and a few years ago one of the big suppliers made an error in their catalogue and listed the 2 trunions under the same part number. TR4A Trunions have a seperate pivot bolt which makes rebuilding the suspension and replacing the trunnion easier. You will easily be able to tell the difference between a 4a and a 4 trunion. I Believe the 4A vertical links and trunnions are common to all the IRS chassis cars ie 4a,5 & 6. Most of this information was given to me by Alec and Stuart (and others on the forum) many moons ago when I wanted to know if I could convert my 3A to a 3° castor and what parts I needed. Cheers Alan Quote Link to post Share on other sites
AlanT Posted October 31, 2012 Report Share Posted October 31, 2012 Oh its the opposite to what I remembered. They started unhanded and moved to handed ones. Its a few years since I went through all this and had bits that didnt seem to fit. Al. Quote Link to post Share on other sites
Superaquarama Posted October 31, 2012 Author Report Share Posted October 31, 2012 Thanks again, Alec and Kiwi. My new trunnions are actually marked L & R so it would be nice to think they're NOS items. Thus it seems that the R one will only fit a TR4A/5/6 RH link and nothing else, which should make it simple to check I've got the correct item. And thanks for that titbit about the L and R on the top wishbones, I was wondering about that and have thus managed to get it wrong on the side I've done, but fortunately only loosely assembled so only moments to correct ! Quote Link to post Share on other sites
Kiwifrog Posted October 31, 2012 Report Share Posted October 31, 2012 Here is a photo of my Front Left hand taken from the Front. The arm marked L is at the front on the LH side of the car. It is the longer of the 2 top arms. Cheers Alan Quote Link to post Share on other sites
Superaquarama Posted October 31, 2012 Author Report Share Posted October 31, 2012 Great, thanks for going to the trouble Kiwi ! That's what mine looks like now, just corrected it this evening and of course it now lines up better with the bottom trunnion. Interestingly, though, your top fulcrum pin seems to be the wrong way round, at least according to Roger Wms 'How to Restore...' book, the bow should be outwards on the 4A/5/6. But maybe the pic is of your 3A with suspension upgrade ? Quote Link to post Share on other sites
Kiwifrog Posted November 1, 2012 Report Share Posted November 1, 2012 (edited) Anthony The fulcrum top pins in my photo are correct for TR2, 3 and 4. For the TR4a to the TR6 the top pin was reversed, ie with the curve towards the damper hole. So we are both correct and yep its a 3A with late TR4 front suspension setup with 3° castor to hopefully give self centering steering Cheers Alan Edited November 1, 2012 by Kiwifrog Quote Link to post Share on other sites
Badfrog Posted November 1, 2012 Report Share Posted November 1, 2012 The trunion is machined for 3 degrees castor. The top wishbones are formed to set the ball joint towards the rear to produce the 3 degree castor. (top of post leans backwards) Cheers Peter W That's if you have a late type. Earlier types (such as my '63 CT20649L) have a 1° instead of a 3° trunnion. One last word of caution, the difference between early and late type TR4s is not linked to a definite CT. Type boundaries are specific for each part of the car. Badfrog Quote Link to post Share on other sites
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