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Clunking/crunching rotational noise from the back


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Would be so grateful for some advice on this. Concerns my Triumph Spitfire 1500 (1977).

 

Getting a noise as the title suggests - not a rhythmical, consistent knocking sound, it's a more random crunching/clattering sound which doesn't seem to be related to speed/particular gears/cornering/braking. I expected to find something loose getting caught up in the drivetrain somewhere, like you would expect a bag of bolts going round and round one of the rotating parts to sound, but again there's nothing immediately obvious visually. Really baffled.

 

I've ruled out UJs, wheel bearings and prop shaft. The diff would be the obvious candidate but it's already been reconditioned (by a specialist firm) recently after becoming worn and producing the classic rhythmic knocking sound. The guy who reinstalled the diff (mechanic relation of mine) assures me that he doesn't believe this NEW noise is coming from there. But after poking around he is talking about checking the leaf spring first and seeing if anything stems from that, but I just can't see how a rotational sort of noise could be anything do do with the leaf spring or suspension... I fully agree there may be another noise coming from the suspension at the moment, but I think it's two separate issues.

 

Can anyone advise on the right course of action before I go on an expensive wild goose chase?! If anyone is near Eastbourne and thinks they might be able to lend an expert opinion, let me know! Or if anyone recommends a specialist near Eastbourne that could also be very helpful.

 

Cheers

Ben

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Hi Ben

 

Forgive me if you have seen this already, but if not, well worth a read first:

 

http://www.canleyclassics.com/technical-archive/rear-end-noises

 

Rear-end noises on our cars can be a real pain to chase down, as there are just so many potential sources, and often you don't get to the culprit until you have an assembly in bits on the bench. I hate to be pessimistic but I am afraid it is usually a slow process of elimination.

 

Good luck

 

Steve C

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Could be the exhaust, possibly. UJs on the drive shafts and prop shaft are easy to diagnose. Wheel bearings on the other hand can be in a dreadful state and still appear OK. I've had a needle roller bearing with no needle rollers in it. A roller bearing with disintegrated ball bearings and roller cage. Both appeared OK, until taken apart, but did make the noises you describe.

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Thanks guys - Canleys webpage didn't shed any light unfortunately, but helpful nonetheless - many thanks.

Interesting point about the wheel bearings from dougbGT6 - I'll pursue that first. Will report back.

 

Ben

 

 

Hi Ben

 

Forgive me if you have seen this already, but if not, well worth a read first:

 

http://www.canleyclassics.com/technical-archive/rear-end-noises

 

Rear-end noises on our cars can be a real pain to chase down, as there are just so many potential sources, and often you don't get to the culprit until you have an assembly in bits on the bench. I hate to be pessimistic but I am afraid it is usually a slow process of elimination.

 

Good luck

 

Steve C

 

 

Could be the exhaust, possibly. UJs on the drive shafts and prop shaft are easy to diagnose. Wheel bearings on the other hand can be in a dreadful state and still appear OK. I've had a needle roller bearing with no needle rollers in it. A roller bearing with disintegrated ball bearings and roller cage. Both appeared OK, until taken apart, but did make the noises you describe.

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Just had a call from my relative who's doing the work - it's exactly what you predicted Doug - wheel bearings shot to pieces on the driver's side despite appearing normal when the wheel was on the car. The only mystery remaining is that the whole assembly on that side of the car was replaced only a year ago (before I owned it) by a different garage... Maybe just a bodged job. Looks like I've also got a noisy leaf spring and possibly a knocking from the exhaust too. All good fun eh?

 

Could be the exhaust, possibly. UJs on the drive shafts and prop shaft are easy to diagnose. Wheel bearings on the other hand can be in a dreadful state and still appear OK. I've had a needle roller bearing with no needle rollers in it. A roller bearing with disintegrated ball bearings and roller cage. Both appeared OK, until taken apart, but did make the noises you describe.

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Well that's good, you've cracked it! Probably dodgy spares rather than workmanship,  there's a lot of poor quality stuff about these days, originating in foreign parts! There's a thread on here about it I think. Make sure you buy quality parts I'm sure someone will be along to recommend a supplier.

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Thanks chaps. Noted. No one has yet recommended a good supplier, but I'll see if there's anything else on the forum about it. Might be able to combine it with another post I was about to put up in 'General' actually...

 

Well that's good, you've cracked it! Probably dodgy spares rather than workmanship,  there's a lot of poor quality stuff about these days, originating in foreign parts! There's a thread on here about it I think. Make sure you buy quality parts I'm sure someone will be along to recommend a supplier.

 

And when its all refitted heck the drive shaft has not developed a bend

they form a torsional memory and if a n/s is fitted to an o/s it can unravel and develope a twist
If its been changed by previous work this can happen

pete

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most suppliers are selling reputable bearings ,

 

    was it ever greased after assembly,  

 

       its a simple ball race and a supporting set of needle rollers on the inner end of the casting , these control the alignment of the trunnion block

        its given 4 pumps of grease each service, any overspill leaves via a grease catcher and exits thro' a hole in the back plate (hopefiully)

 

          Pete

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  • 2 weeks later...

Didn't see your question till now, sorry Peter. I'm told there was plenty of grease on the needle rollers so it's still a mystery...

 

 

most suppliers are selling reputable bearings ,

 

    was it ever greased after assembly,  

 

       its a simple ball race and a supporting set of needle rollers on the inner end of the casting , these control the alignment of the trunnion block

        its given 4 pumps of grease each service, any overspill leaves via a grease catcher and exits thro' a hole in the back plate (hopefiully)

 

          Pete

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