BLiNK Motorsport Posted January 27, 2016 Share Posted January 27, 2016 Quite often the problem is caused by the locknut not being kept tight !!! Nail on the head there Terry. Quote Link to comment Share on other sites More sharing options...
SootySport Posted January 28, 2016 Share Posted January 28, 2016 Quite often the problem is caused by the locknut not being kept tight !!! After one of mine coming loose, I put a dab of Loctite on each locknut, been fine ever since. Quote Link to comment Share on other sites More sharing options...
corsechris Posted January 29, 2016 Share Posted January 29, 2016 I don't think this is a common issue though is it. Of course, 'construction and use' are going to have a massive impact on how long the components last but we are still on the original joints from when I built it in 1991. Only about 30k miles in all that time but they are still sound and free of play. Potentially a loose locknut or even a manufacturing defect. Broke a trunion (Oooh, Matron) on the Marcos once - snapped clean off the upright. Close inspection showed the stress-raiser where the thread ended and the ensuing crack propagation over time up until the final failure. Quote Link to comment Share on other sites More sharing options...
mr_mcp Posted March 14, 2016 Share Posted March 14, 2016 The exact same thing happened to me. Fortunately it didn't result in anything catastrophic, but the bolt snapped in the same way you described. I did a spirited launch from standstill and noticed the car felt quite loose at the rear end. Assuming it was just the rear tyres lighting up, I carried on my way, only to realise I felt the same sensation under acceleration again. I pulled over immediately to inspected the rear setup and noticed this to my horror! I bought a couple of replacement items from mcgill motorsport - they're far better quality and customer service was excellent. Quote Link to comment Share on other sites More sharing options...
Lyonspride Posted March 14, 2016 Share Posted March 14, 2016 Surely this would have to be caused by a tension force as opposed to shear force and i'd imagine that torsionally these are seriously strong. So basically caused by load under cornering? When I did my alignments, these were insanely hard to turn and it's got me a tad concerned that they've been somewhat weakened. Quote Link to comment Share on other sites More sharing options...
tisme Posted March 14, 2016 Share Posted March 14, 2016 When I did my alignments, these were insanely hard to turn and it's got me a tad concerned that they've been somewhat weakened. When I tidied up my rear wishbones I also found that the rose joints had corroded themselves into the wishbone threads - I managed to gently free them up but I suspect if any great force was used it could well start to weaken the joint even if it wasn't apparent at the time. I suspect the moral here is if they're really difficult to turn to adjust, then remove them, probably discard and then re-assemble with good quality new ones and copper slip Quote Link to comment Share on other sites More sharing options...
mr_mcp Posted March 14, 2016 Share Posted March 14, 2016 For what it's worth, when I removed what was left, the bolt span freely and the threads hadn't stretched or warped. Quote Link to comment Share on other sites More sharing options...
Davemk1 Posted March 14, 2016 Share Posted March 14, 2016 It's important to remember that these things see high bending loads during braking as the brakes grab the rotor and the wheel tries to twist the upright around in the same direction as the wheel. Wide sticky tires and big brakes will up the loads. And all of this load is taken by two rose joints as the third contact point is a metallic bushing that no doubt has enough movement to not bear its share of the load. I think it might be best to buy the best you can and replace them if you have any serious off track excursions. Just my opinion. dave Quote Link to comment Share on other sites More sharing options...
tex Posted March 20, 2016 Share Posted March 20, 2016 my rear lower rose joints have been replaced twice in 4 years with not many road miles tbh. accept they will wear out pretty soon and thats the life they have. the thread into the wishbone on one of mine was tight last time i replaced them so i bought a tap and ran that through first - blew out any swarf left inside, applied some copper slip to the new threads. should be ok. dont let the parts be covered in crud for long periods and they should be ok. Quote Link to comment Share on other sites More sharing options...
Dodgey Posted April 4, 2016 Share Posted April 4, 2016 Add me to the list, though not a rose joint: The break also bent the top one: I "suspect" it was after leavign my car with a company that set up your ignition map on the open road. I noticed a dent on the alloy the same side the joint broke - this happened a day or two after collecting the car and also one of the fitters telling me my car must be "quite a handful in the corners?" Quote Link to comment Share on other sites More sharing options...
mr_mcp Posted April 4, 2016 Share Posted April 4, 2016 crikey, that's a shocking service Quote Link to comment Share on other sites More sharing options...
Dodgey Posted April 4, 2016 Share Posted April 4, 2016 Well, it's an assumption. The dent could have always been there, and the lower joint may have been fatigued for ages, and let go on a hard corner (which it did) - so - it could be coincidence - hence I didn't pursue it - it's a bit too easy to put 2 and 2 together and get 5. However, the wishbone is very slightly bent. If I'd not driven home on it, then I'd definitely be speaking to the garage, but as I limped home like it, then I could well have bent it myself. Quote Link to comment Share on other sites More sharing options...
CosKev Posted April 4, 2016 Share Posted April 4, 2016 Add me to the list, though not a rose joint: Oh dear.What is the dent like on the wheel,as if it's hit a kerb sideways? How does that joint to upright work? Never seen one like it before,only seen tubes with poly bushes or rod ends Quote Link to comment Share on other sites More sharing options...
BLiNK Motorsport Posted April 5, 2016 Share Posted April 5, 2016 This thread shows exactly why we believe (and many others in motorsport) that rod ends should NOT be used on front wishbone mountings! Rod ends are weak in shear and the forces on the front wishbones are far greater than the rear due to the 'twist' from braking forces. 1 Quote Link to comment Share on other sites More sharing options...
phelpsa Posted April 5, 2016 Share Posted April 5, 2016 This thread shows exactly why we believe (and many others in motorsport) that rod ends should NOT be used on front wishbone mountings! Rod ends are weak in shear and the forces on the front wishbones are far greater than the rear due to the 'twist' from braking forces. By mountings do you mean outboard upper? The shear strength of a decent 1/2" rod end is more than likely greater than the buckling strength of the wishbone it's threaded into. It's not the best engineering practice but certainly not the biggest structural issue on a Westfield! Quote Link to comment Share on other sites More sharing options...
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