Peter Harper Posted September 20, 2009 Report Share Posted September 20, 2009 Hi Guys I hope you all had a great day out today in this mild weather. I started the Aviva MSA Classic from Andover with my son and were on route to the Williams Formula one museum at Wantage then going on to Prescot Hill, Gayden and Silverstone, It came to an end after only 6 miles. As we came to a stop at a road junction there was a bang and graunching noise from the front which was drooping on the nearside. Inspection found the front wheel at a funny angle jammed in the wheel arch, the lower front wishbone bracket had come off the chassis. Just prior to the junction we had been bowling along the country lane at speeds of 60MPH I get tingles down my spine when I think what the resullt of a failure 30 seconds before would have been. Under the car we found the sheared bol tand spacer shims On looking in the Moss parts manual I find that this bracket has been modified by using 2 bolts to attach it to the chassis for extra strength as the single bolt is a known weakness. My comments on this forum are to ask if I should replace the rear bracket with the revised part or as the arm is trailing do ony the front need to be strengthened? The second reason is to highlight the weakness to others I was lucky to have got away with no damage to me or the car, but I would ask other 4A owners to check this bracket to make sure yours has been modified it should be fixed by 2 bolts if only one is there the bolt could shear with no warning. In the Moss catalogue the part is No100 in the 4A front suspension diagram. This may apply to the 4 as well but i dont have the knowledge to comment. I would also like to thank all the fellow classic car drivers who offered assistance probably more than 50, the event organisers had RAC cover and sent a vehicle within 15 Minutes but it needed a suspension strip down (not at the side of the road) so Towergate to the rescue and a special transporter home organised by their recovery side all went smoothly and efficiently. Thanks Towegate Please check this bracket it is your llife at stake Peter Quote Link to post Share on other sites
TR4AIRS Posted September 21, 2009 Report Share Posted September 21, 2009 The same thing happened to my car on the driveway. A few days before I had tested the top speed, I must admit that I didn't sleep very well that night Quote Link to post Share on other sites
stuart Posted September 21, 2009 Report Share Posted September 21, 2009 Its extremely rare for them to ever fail at high speed. The two bolt type have been recommended for at least the last fifteen to twenty years so its very rare (except on unrestored cars or restored ones where someone has been pedantic ) to find the single type still fitted. Stuart. Quote Link to post Share on other sites
Peter Harper Posted September 21, 2009 Author Report Share Posted September 21, 2009 Thanks for your comment Stuart the fact that it is still happening we should check cars that have been restored in the past. That was the point of the reminder mine had been restored but should I now replace all 4 or just the front ones. Regards Peter Quote Link to post Share on other sites
stuart Posted September 21, 2009 Report Share Posted September 21, 2009 Thanks for your comment Stuart the fact that it is still happening we should check cars that have been restored in the past. That was the point of the reminder mine had been restored but should I now replace all 4 or just the front ones. Regards Peter Always replace all 4 as a matter of course. There is also reinforcement plates available that fit inside the box that the bracket is bolted to that spreads the load (although in typical repro style the holes in the plates need filing to suit ) Moss part number 139580R illustration number 73 page 195 in their TR5/6 catalogue. Stuart. Quote Link to post Share on other sites
Peter Harper Posted September 21, 2009 Author Report Share Posted September 21, 2009 Always replace all 4 as a matter of course. There is also reinforcement plates available that fit inside the box that the bracket is bolted to that spreads the load (although in typical repro style the holes in the plates need filing to suit ) Moss part number 139580R illustration number 73 page 195 in their TR5/6 catalogue.Stuart. Thanks for the advise Stuart I will replace all 4 and take the opportunity to Polybush the front end at the same time. Peter Quote Link to post Share on other sites
graeme Posted September 21, 2009 Report Share Posted September 21, 2009 Peter, Along with fitting the revised lower brackets, I would also recommend a thorough inspection of the attachment points were they are welded on to the chassis. These are prone to cracking and can be reinforced with a kit from Moss. Cheers Graeme Quote Link to post Share on other sites
Peter Harper Posted September 21, 2009 Author Report Share Posted September 21, 2009 Peter, Along with fitting the revised lower brackets, I would also recommend a thorough inspection of the attachment points were they are welded on to the chassis. These are prone to cracking and can be reinforced with a kit from Moss. Cheers Graeme Willl do as you suggest thanks Graeme. Peter Quote Link to post Share on other sites
Allan Westbury Posted September 24, 2009 Report Share Posted September 24, 2009 Willl do as you suggest thanks Graeme. Peter Hi Guys, Had my 4A aligned on Jigsaw Racing's 4 wheel laser kit about a month ago. Expensive but well worth it, the car now sits on the road much better. At the time they commented that they were suprised I only had one bolt in the lower front wishbones as most IRS cars had two. Didn,t think anything of it as have already strengthened the attachment points. Have just returned from the european tour in Germany having done 2000 miles, much of it at speed or pushing hard on 180deg mountain bends. Great fun & some of the best roads have driven in owning the Tr for the last 30 years. Should I be worried? Would replacing the bolts help? Can I drill an additional hole either side? If I do replace the bracket with a two hole mod will i have to have the alignment redone? answers on a postcard please! thanks, allan Quote Link to post Share on other sites
stuart Posted September 24, 2009 Report Share Posted September 24, 2009 Hi Guys,Had my 4A aligned on Jigsaw Racing's 4 wheel laser kit about a month ago. Expensive but well worth it, the car now sits on the road much better. At the time they commented that they were suprised I only had one bolt in the lower front wishbones as most IRS cars had two. Didn,t think anything of it as have already strengthened the attachment points. Have just returned from the european tour in Germany having done 2000 miles, much of it at speed or pushing hard on 180deg mountain bends. Great fun & some of the best roads have driven in owning the Tr for the last 30 years. Should I be worried? Would replacing the bolts help? Can I drill an additional hole either side? If I do replace the bracket with a two hole mod will i have to have the alignment redone? answers on a postcard please! thanks, allan I would change them as a matter of course as its been a known issue since the 5s came out. You have been unable to buy the single bolt versions for at least the last ten years or more as far as I know. Provided you replace the shims located behind the brackets in the same order and position and dont disconnect the rod ends then the alignment shouldnt change. Stuart Quote Link to post Share on other sites
PaulAnderson Posted September 24, 2009 Report Share Posted September 24, 2009 I'd also double check any newly purchased two bolt brackets for quality. They're essentially studs and when installing a few years ago one of them started to turn on mine during tightening of the nut. The stud had not been welded / secured into the bracket properly. I had to part strip the suspension down again to put a small tack weld on the back of it to stop it from turning. Paul Quote Link to post Share on other sites
stuart Posted September 24, 2009 Report Share Posted September 24, 2009 I'd also double check any newly purchased two bolt brackets for quality. They're essentially studs and when installing a few years ago one of them started to turn on mine during tightening of the nut. The stud had not been welded / secured into the bracket properly. I had to part strip the suspension down again to put a small tack weld on the back of it to stop it from turning. Paul Essentially what the factory did to all the single bolt ones they had left over was weld an extra bolt in, though obviously with a proper weld! Stuart Quote Link to post Share on other sites
phil3uh Posted August 2, 2014 Report Share Posted August 2, 2014 Hi all, I was alerted to this problem whilst on holiday, without myTR4a, and have since checked and find despite it being a very late car, one of the last 500 TR4a's built, mine has a single bolt bottom suspension mounting . However I have checked the chassis around the mounting and all looks fine. Do we need to rush to replace them as after all the previous model ,TR4 ,was a successful rally car, which must have taken much more hammer than most people would subject their cars to, were they modified to a double bolt arrangement, If so why were these not implemented onto the production line? How much have the bad state of today's road caused this concern to rear up. We can always ,and do, improve older cars, it's called progress.I wonder if the fact that the single bolt bracket is no longer available more to do with rationalisation of parts for the purveyors of spares rather than strength and safety of what seems an adequate suspension set up for a forty six year old car. Cheers Phil Quote Link to post Share on other sites
peejay4A Posted August 2, 2014 Report Share Posted August 2, 2014 (edited) The TR4 chassis is very different. Roger H's 4A suffered this way recently so you'd be well advised to upgrade. Edited August 2, 2014 by peejay4A Quote Link to post Share on other sites
boxofbits Posted August 2, 2014 Report Share Posted August 2, 2014 I have the two bolt brackets in a box somewhere......awaiting fitment. In the meantime if I take a sudden unintended diversion on a leisurely drive out one day I shall know why! Quote Link to post Share on other sites
AlanT Posted August 2, 2014 Report Share Posted August 2, 2014 A 4 has a completely different method which is about ten times stronger. The 4A design is POOR. This problem has been known about since 1980 to my knowledge. Much will depend on HOW you are driving. In 1970 I did research on breakages in front suspensions. Its the cornering forces that create the biggest loads. Its much worse on wider tyres. This WILL break. Its just a matter of when. But fatigue will get it in the end. Quote Link to post Share on other sites
RogerH Posted August 2, 2014 Report Share Posted August 2, 2014 Hi Phil & Boxo, as stated the TR4 has a totally different and much stronger design (although can go rusty and fail) from the TR4A. There are two failure modes - 1 - the structure that the bracket attaches to can rip off the chassis - this may be detectable prior to failure. 2 - the single stud in the bracket and snap - this is instantaneous and can not be predicted or seen before hand. Cost to replace = apprx £60 Cost to repair after failure - £1000 DO IT NOW Roger Quote Link to post Share on other sites
boxofbits Posted August 2, 2014 Report Share Posted August 2, 2014 Okay Roger I was hoping for a relaxing weekend for once.....but looks like things gave changed! Quote Link to post Share on other sites
ianc Posted August 2, 2014 Report Share Posted August 2, 2014 The 4As started failing in the mid-1970s (I was Technical Editor then, and letters started to come in). The TR2/3/4 chassis design is much stronger in the provision of a great big fore/aft pin to which the lower wishbones are attached. This pin passes through and is welded to the suspension turret and to the chassis rail. The 4A design might have been cheaper, but it was poor engineering. As Roger says, do it now. Ian Cornish Quote Link to post Share on other sites
AlanT Posted August 2, 2014 Report Share Posted August 2, 2014 You can drill the existing ones and use a bolt. Quote Link to post Share on other sites
RogerH Posted August 2, 2014 Report Share Posted August 2, 2014 Hi Al, I would recommend new ones. It is highly likely that any old single stud bracket may have cracks starting and could put excess strain on the good bolt causing early failure. Roger Quote Link to post Share on other sites
AndrewMAshton Posted August 3, 2014 Report Share Posted August 3, 2014 Hello, I ended up replacing my brackets with the Revington ones with longer studs, not because I was doing anything fancy to the front suspension, but once I fitted the plate behind the nuts to spread the load there were insufficient threads to get a couple clear of the nyloc nuts, plenty showing now!!, cheers, Andrew Quote Link to post Share on other sites
John Morrison Posted August 4, 2014 Report Share Posted August 4, 2014 Seems a simple dismantle/reassemble job am I missing anything? John. Quote Link to post Share on other sites
RogerH Posted August 4, 2014 Report Share Posted August 4, 2014 Hi John, Fairly straightforward. remove damper and insert a rod to compress the spring a little. Undo the bracket nut at the back of the bracket. Undo the big nut from the bolt holding the wishbone to the bracket - if you are lucky it will slide out - otherwise bigger dismantle. Fit new bracket to wishbone and rebuild. Complications - The big bolt is seized and you will need to attack the bracket/bolt/bush to reuse the wishbone. Only one hole in the chassis support - drill new second hole. Roger Quote Link to post Share on other sites
John Morrison Posted August 4, 2014 Report Share Posted August 4, 2014 I cheers, Roger, have aguy in the group, one side of his car has been done, other needs to be sorted. John. Quote Link to post Share on other sites
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