stuart Posted September 30, 2012 Report Share Posted September 30, 2012 4a`s originally had a single bolt fixing for the lower inner wishbone mounting bracket to the chassis box. These single bolt brackets havent been available for many years and most cars have now been converted and the mounting boxes drilled for the extra bolt but occasionally I come across ones that havent and as so many people are now running 195 tyres with bigger wheels it would be a good idea to check yours ASAP before they let go. Picture below shows original box with the white dot marking the location for the extra hole. Drilled out. Stuart. Quote Link to post Share on other sites
AlanT Posted September 30, 2012 Report Share Posted September 30, 2012 Thanks for reminding people about this. I could not believe my eyes when I first saw how the factory had done this. I think the whole bracket arrangement is a bit weak and reinforced mine considerably when I remade all this area. Cant see why they made one side bigger than the other and made fancy curves. The bits on the vertical face of the chassis dont really do anything. Just wanted two thick triangular bits and some good welds. Al. Quote Link to post Share on other sites
Mark1965TR4aBRG Posted October 1, 2012 Report Share Posted October 1, 2012 Thanks for the tip Stuart. I presume it's a total strip of the front suspension then to check?? Quote Link to post Share on other sites
stuart Posted October 1, 2012 Author Report Share Posted October 1, 2012 Thanks for the tip Stuart. I presume it's a total strip of the front suspension then to check?? If you look on the engine side of the mounting boxes you will see either two nuts per box if they have been done before or if there is only one then yes strip it down and convert ASAP. Stuart. Quote Link to post Share on other sites
ianc Posted October 1, 2012 Report Share Posted October 1, 2012 Whilst checking the front suspension, don't forget that all IRS Triumphs suffer the same sort of problem at the rear with the semi-trailing arms and the differential (they fall off!). Not for nothing do I refer to these cars as the 'wobbly wheel TRs'! The design and construction of the chassis and mountings was really pretty abysmal, and I remember reports of front suspension collapse being fed to me (as the Technical Editor in those days) in the mid-1970s. It's fortunate that most IRS cars have had the weak points strengthened, but I guess some are still out there, waiting to collapse! Ian Cornish Quote Link to post Share on other sites
Mark1965TR4aBRG Posted October 1, 2012 Report Share Posted October 1, 2012 On crikey - I'm off to the garage to have a look!! Quote Link to post Share on other sites
Mark1965TR4aBRG Posted October 1, 2012 Report Share Posted October 1, 2012 I have one nut! What would the thread be and subsequent socket/nut size AF? Should I stop sliding into corners now???? Quote Link to post Share on other sites
stuart Posted October 1, 2012 Author Report Share Posted October 1, 2012 Its a 3/8" UNF thread 9/16 spanner size. and you will need the four inner wishbone mounting brackets with the double studs as well. Whilst you are in there I would rebush them also. (and yes I wouldnt throw it about too much until you have done them especially if you are on larger tyre/rim widths ). Stuart. Quote Link to post Share on other sites
Mark1965TR4aBRG Posted October 1, 2012 Report Share Posted October 1, 2012 Noted and on the winter 'To Do' list ... Quote Link to post Share on other sites
Alec Pringle Posted October 1, 2012 Report Share Posted October 1, 2012 (edited) "The design and construction of the chassis and mountings was really pretty abysmal, and I remember reports of front suspension collapse being fed to me (as the Technical Editor in those days) in the mid-1970s." Indeed so, but as a member of the Triumph design team explained to me in the 70s . . . . the 4A mounts had been designed on the assumption of cross ply tyres or Michelin X radials being fitted, and the increased grip levels of other and rapidly improving radial tyre options were not taken into account. An omission that was only rectified with the XAS tyre specification for the TR5, and even then the improvement was inadequate, as we soon found out !! Cheers, Alec Edited October 1, 2012 by Alec Pringle Quote Link to post Share on other sites
AlanT Posted October 1, 2012 Report Share Posted October 1, 2012 I re-used the one-stud brackets and drilled them to match the chassis. The brackets were fine but the chassis part was full of cracks around the stud. Check for this. I welded the head of an ordinary bolt to stand in for the second stud. You need to be able to slack these off, to fiddle with the packing shims. You cant get a tool on the bolt-head when the wishbone is fitted. Al. Quote Link to post Share on other sites
2long Posted October 1, 2012 Report Share Posted October 1, 2012 Would this situation apply to the TR2 - TR3 front suspension set up as well? Dan Quote Link to post Share on other sites
Motorsport Mickey Posted October 1, 2012 Report Share Posted October 1, 2012 I fear this essential safety modification comes some way down the "must do" list for many TR owners, wheras replacing many parts in stainless steel or alloy (radiators) and having items anodised (especially anything visible in the engine compartment) really "rings their bells". Because of the distance in time that now exists from current vehicles to the 60s and 70s when this often came up with tales of wheel collapse with subsequent vehicle damage and possible occupant harm, many current owners have no idea that this is a mod that should really be regarded as essential along with at least one other. If asked what is your greatest fear when driving, these days there are not that many that would reply "dying in a fire". Modern cars with their more reliable fuel systems, inertia fuel pump cutoffs and crushable structures make this horrific death more and more unlikely. Our cars because of their age and original design parameters are from an era where this risk was not given the same importance and subsequently cannot compare to modern designs. We can however take certain steps to ensure that in the event of a heavy accident the driver, (and perhaps more importantly to them their likely spouse/passenger ) stands a much better chance of walking away unhurt. We should be able to be take it as a given that occupants will be restrained by seat belts of your chosen configuration, this coupled with a correctly engineered roll cage preferably that locates to the floor or chassis through strengthened mounts gives you a reasonable chance. The other modification should appeal to many TR owners, it's in alloy ! A profiled alloy sheet cut to the same shape as the rear of cockpit 3mm fibreboard and sealed into position with fibreglass behind the aforesaid fibreboard riveted to the cockpit frame is undetectable. It also has the advantage that when the Transit (replace with your choice of large/heavy badly driven vehicle) T bones your TR at a road junction, it stands a much better chance of isolating the contents of your split asunder fuel tank from the driving compartment which is quite important especially when it's on fire ! You may think that in an accident as described it is possible that any such bulkhead would rupture, but of course your well fitted and engineered roll cage has also done it's job (at least as important as saving your life when the car is inverted) by helping prevent incursion into the driving compartment of foreign bodies (the Transit or your chosen weapon) and supporting the structure of the shell preventing lozenging. If you doubt this is possible please argue it out with the RAC Motorsports who also think as I do that it is not only worthwhile but essential, all competition TRs have to have it fitted. I would urge all TR owners who do not have this essential modification in place to make it the very next mod added. The alloy bulkhead blank (18 guage or less is fine) will cost a minimal amount of money from fabrication shops ( I also think some TR specialists offer it) and is easily cut to shape using the fibreboard as a template. This and the fibreglassing pack (non setting winscreen sealer underneath helps also) will cost less than £50 and is easily fitted by yourselves in a day. Mick Richards Quote Link to post Share on other sites
AlanT Posted October 1, 2012 Report Share Posted October 1, 2012 Most interesting to read about the "fire-wall". When I rebuilt mine I could not face the idea of driving about with only a fibre trim-panel to separate me from the fuel-tank. I filled in the hole with ordinary 1mm steel sheet using the obvious existing flanges. Later I had nightmares that the tank would not go in. But it did. I always thought this may have meant I was a bit neurotic. So I'm pleased that others feel the same. Stuart did a great job to bring up the one-stud wishbone brackets. I am amazed that so many seemed not to know about this. I have a rule that anything with just one fixing will fail. Al. Quote Link to post Share on other sites
AlanT Posted October 1, 2012 Report Share Posted October 1, 2012 (edited) Remembered I have a photo of this. http://flickr.com/gp/90670218@N04/7238N5 Al. Edited December 2, 2012 by AlanT Quote Link to post Share on other sites
Alec Pringle Posted October 1, 2012 Report Share Posted October 1, 2012 Well said Mick. Those who knew me in the late 70s may well recall that I have particular reason for seconding your comments re death by fire. If a standard TR 2-6 (as opposed to a tintop Wedge) lands upside down, the likelihood is that it will be flat and it will catch fire . . . . and if the occupants are not already dead on impact, if it does ignite then the likelihood of avoiding cremation whilst still screaming is sod all. The hood/surrey/hardtop/windscreen frame won't help. You really do not want to go there. As for t-boning, some will remember that happening to my late friend Lodewijk van Hunnik, TR4 en route to IWE Shepton Mallet 1998. His wife died that day, Lodewijk succumbed to the long-term results of his injuries two years ago. Seat belts and a roll bar and both of them would have still been with us. No ifs, no buts - at the time I went through the vehicles, the circumstances, and the inquest in conjunction with the police as an "expert witness" and representative for Lodewijk. A proper rear roll bar, hoop with two additional downstays and a diagonal, is not particularly expensive in the grand scheme of things - nor is it difficult or expensive to fit. A firewall is available off the shelf from Revingtons for fifty quid or thereabouts, and a doddle to fit. Priorities. Cheers, Alec Quote Link to post Share on other sites
Mark1965TR4aBRG Posted October 2, 2012 Report Share Posted October 2, 2012 Good points well made. Thankfully I do have roll hoops and 4 points and will for sure add the Al fire wall and front wishbone mount modifications to my immediate 'To Do' list taking it easy along the way. This is what makes the forum so valuable - thanks chaps. Quote Link to post Share on other sites
ianc Posted October 2, 2012 Report Share Posted October 2, 2012 In answer to Dan's query: the TR2/3/4 front suspension is very strong - the lower wishbones are connected to a solid bar running fore and aft, and this is welded to the chassis at a number of points. At the rear, the bracket holding the spring shackle at the rear end of the leaf spring can rust - it's between 45-55 years of age, has been subjected to spray from the wheel, oil doesn't get there and it is rare but not unknown for the mounting to break! So, if working on the chassis, it is helpful to weld a tube inside the mounting as reinforcement. This was a standard modification to the chassis of the Works' TR4 Rally cars. Ian Cornish Quote Link to post Share on other sites
stuart Posted October 2, 2012 Author Report Share Posted October 2, 2012 the TR2/3/4 front suspension is very strong - the lower wishbones are connected to a solid bar running fore and aft, and this is welded to the chassis at a number of points. Ahem they can still bend though! See picture below of 3a front suspension inner mounting, note the discrepancy fore and aft. Stuart. Quote Link to post Share on other sites
PaulAnderson Posted October 2, 2012 Report Share Posted October 2, 2012 (edited) And here's what happens if your car gets impacted with standard TR4A suspension mounts. This was mine as purchased some years ago. The chassis mounting was cut off and replaced, complete with the strengthening plates front and rear. Paul Edited October 2, 2012 by PaulAnderson Quote Link to post Share on other sites
AlanT Posted October 3, 2012 Report Share Posted October 3, 2012 Very interesting photo. I put a plate on the top of the mounting, the one thats wonky in your photo. The plate tied this mounting back to the side of the turret. Will try to post a photo, perhaps. Al. Quote Link to post Share on other sites
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