Wedge rear lower suspension bolt
Discussion
mrzigazaga said:
Don't some do that for chassis?
When I did the factory tour at Back Home in the late 90s I asked the 'guide' if they did any x-ray or ultrasonic inspection on the chassis... his eyes did that shifty side-to-side thing and he said "...er yeah, something like that...".
At the time they were building Cerberas, Chimaeras etc.
adam quantrill said:
Hmmmm... better do the other side then.
Anyone know about ultrasonic inspection? Could one check for impending cracks by sending a sounds wave down the bolt head and looking for a reflection?
Yes and no. You can't see an 'impending' crack but you could spot the start of one - or, more likely, cross-section loss due to corrosion. The issue is that in these cases the bolt has usually corroded to the inner sleeve of the bushes it's passing through as well as the steel hub carrier, so you get a nice confused set of reflections.Anyone know about ultrasonic inspection? Could one check for impending cracks by sending a sounds wave down the bolt head and looking for a reflection?
We've just done a job for a company trying to identify x-section loss in reinforcing bolts of a railway bridge... essentially several bolts have already snapped and they want to know which ones will go next!
The bolts are 30mm diameter and 5m long, so you can tell they aren't just holding a picture on a wall
Safest option is to periodically slacken all suspension bolts, give them a few turns and nip back up again.
Anti-sieze (copper) grease is also worth investing in.
pasogrande said:
I just checked mine, and it is different; I have a nut at each end; so instead of a bolt it is a rod with threads at each end. The nuts take a 19mm spanner. I was able to rotate the rod without difficulty, and left it turned 90?.
Maybe the US models are not the same.
Wilf.
If you have the alloy hub carriers then as far as I recall yours is how it was originally done. Didn't help because of course you can't turn one end as a bolt head, it just unscrews both nuts.Maybe the US models are not the same.
Wilf.
I think (and it was 19/20 years ago so I may be wrong) that I got mine apart by taking one nut off and then building a washer stack under the opposite nut, it eventually pulled the rod out.
Avoid clouting the threaded ends or you're into another world of grief (not just because you damage the threads but because it mushrooms the end of the rod and it won't pass through the bushes).
Cheers Ian I looked into ultrasonic inspection machines on the flea and they are £2-3k so not really cost effective ;^(
I calculated that an echo from where we don't want it would take maybe 20us and from the very end about 48us, so maybe an oscilloscope, a transducer and a power amp could be rigged up....
In my case there wasn't a corroded bit on the edge of the crack, it looked pretty clean and given the time of year went right through fairly rapidly.
I calculated that an echo from where we don't want it would take maybe 20us and from the very end about 48us, so maybe an oscilloscope, a transducer and a power amp could be rigged up....
In my case there wasn't a corroded bit on the edge of the crack, it looked pretty clean and given the time of year went right through fairly rapidly.
Wedg1e said:
mrzigazaga said:
Don't some do that for chassis?
When I did the factory tour at Back Home in the late 90s I asked the 'guide' if they did any x-ray or ultrasonic inspection on the chassis... his eyes did that shifty side-to-side thing and he said "...er yeah, something like that...".
At the time they were building Cerberas, Chimaeras etc.
adam quantrill said:
Cheers Ian I looked into ultrasonic inspection machines on the flea and they are £2-3k so not really cost effective ;^(
I calculated that an echo from where we don't want it would take maybe 20us and from the very end about 48us, so maybe an oscilloscope, a transducer and a power amp could be rigged up....
In my case there wasn't a corroded bit on the edge of the crack, it looked pretty clean and given the time of year went right through fairly rapidly.
Between you and me, there's a Chinese-made UT set that we've started seeing in our lab for calibration that is way better than the money suggests it should be AND it has features lacking in some more-expensive big-brand sets (and it's just as accurate).I calculated that an echo from where we don't want it would take maybe 20us and from the very end about 48us, so maybe an oscilloscope, a transducer and a power amp could be rigged up....
In my case there wasn't a corroded bit on the edge of the crack, it looked pretty clean and given the time of year went right through fairly rapidly.
The big problem with UT (or indeed any of the inspection techniques) is not in acquiring a 'reading', it's interpreting it correctly... which is why NDT techies have courses galore and refreshers (plus eye tests) to keep them current.
Luckily all I have to do is make sure their kit works OK
Be interesting to define whether it's tension, shear or impact that's breaking the bolts though, if it's not x-section loss from corrosion.
Wedg1e said:
Be interesting to define whether it's tension, shear or impact that's breaking the bolts though, if it's not x-section loss from corrosion.
I can see a lot of corrosion around the outer bolt that has snapped, So I'm convinced that the seizure of the bolt in its bush sleeves and hub is the telling factor...Also I'm aware there is around a ton of force on the bolt when cornering....
...
mrzigazaga said:
I can see a lot of corrosion around the outer bolt that has snapped, So I'm convinced that the seizure of the bolt in its bush sleeves and hub is the telling factor...Also I'm aware there is around a ton of force on the bolt when cornering.......
I was thinking about this as I bimbled round Peterboghorror earlier on... in theory the bush inner sleeves can't turn anyway as they're under the compressive force of the nut'n'bolt pinning the sleeve in place laterally. So even if the bushes do corrode to the bolt it shouldn't matter (other than getting the b4s+4rd$ out). Similarly the hub carrier shouldn't be rotating on the bolts otherwise there would be wear and as there are no bushes, that would write-off the carriers pretty quickly....The early Tasmins had alloy hub carriers and they were known for the long 'bolt' that ran through from front to back seizing in so badly that often you had to drill it out (once you'd hacksawed it to get the tie-rod and damper off).
Mine was only seized in the shocker bush, and that came free (i.e. broke the rubber) after twisting with a breaker bar.
Anyhoo, here's some piccies of the end that didn't get ground off - at first when I removed it I didn't think there was much corrosion but looking at it now you can see almost "tree rings" were the crack as deepened and then a little corrosion has built up.
So it might have been getting worse for some time, maybe ripe for ultrasonics.
The "sticky out" bit looks to be where it was hanging on for a while...
Anyhoo, here's some piccies of the end that didn't get ground off - at first when I removed it I didn't think there was much corrosion but looking at it now you can see almost "tree rings" were the crack as deepened and then a little corrosion has built up.
So it might have been getting worse for some time, maybe ripe for ultrasonics.
The "sticky out" bit looks to be where it was hanging on for a while...
Good news...Poppy back all done all thanks to Mr King...Top bloke...
The passenger side was seized and the long bolt had a bend in the threaded end so it was just a matter of time before that snapped as well...Both rear wishbones have new bushes and new bolts..And have been copper slipped...
Feels much more compliant to the road surface now...
Here are all the old bushes and bolts.....
Cheers Mr cake....
The passenger side was seized and the long bolt had a bend in the threaded end so it was just a matter of time before that snapped as well...Both rear wishbones have new bushes and new bolts..And have been copper slipped...
Feels much more compliant to the road surface now...
Here are all the old bushes and bolts.....
Cheers Mr cake....
adam quantrill said:
Have you got the ends of the snapped one? It would be interesting to see if they are similar to mine - any corrosion in the crack.
A happy ending then.
Hopefully Paul can share those pics...I looked at the passenger long bolt and as Paul pointed out that was bent on the threaded part so was already being stressed, a ticking time bomb ....So glad both sides were done..peace of mind is a wonderful feeling...And so is driving the Wedge after being two weeks without it...Even if it was raining with the roof off....A happy ending then.
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