Drumming noise from the rear end

[elvimto]

I have a drumming noise coming from the rear of the car it goes in and out of phase sore of like drummm drummm drummm.
Best I can do on paper,so here is what I have done.
New tyres Michelin on alloy wheels, wheels checked with a dial indicator so very little run out.
Car has all new bushings rubber on the rear diff mounting support.
Drive shafts all checked out new brake shoes and hardware brake drums turned and rotate free,
Diff is in good shape all bolting is new.
The noise is more evident at the higher speed range, 60ish.
I had 2 other tyre types on the car they gave me a road tire noise and also the the druming noise, the Michelins are fine in respect to road noise but i would like to eliminate the druming noise, am I missing something or do I need to look at another component.

cheers Stuart

[wilf]

Prop shaft balance?

Also swap wheels f to r, tyres may be out of round even if the rims aren't.

[jakesmig]

Stuart,
to me it seems unlikely that the drumming is related to tyres or wheels, too much coincidence that you get drumming on 2 different sets, especially if your dial indicator showed minimal run out, simmilarly unlikely to be brake component problem if the drumming existed before you replaced those components. I'd be looking at the propshaft & quill shaft bearing for wear / balance problem.
Quill shaft bearing wear was responsible for shuddering at 60 / 70 mph at the rear on my car last year.
Good luck with it,
Rgds, John

[elvimto]

I forgot to put that on the list i have rebuilt the extension and renforced it, its possible that the prop shaft could be the culprit its the original type with the rubber dampner my car is a 71 mk 1 auto box BW35. I never really got much of a chance to drive the car after I bought it and started to strip the suspension, drive shaft components and overhaul all the bits and pieces. I can drive it for now and continue with the other cosmetic stuff that needs attention. The prop shaft could well be the problem.

thanks stuart

[StagnJag]

My first thought was quill shaft bearing too. What sort of mileage have you done since rebuilding the diff extension? I had a quill shaft bearing start to give up after a few thousand miles. Rgds

Dave

[elvimto]

I would say about 250 I used an SKF bearing not a knock off, I swapped out the diff on Monday the one that was in had a really bad whine to it no surprise the gears were not in the best shape I bought one from Ebay that was a lot better and does not whine. I think the extension is ok any other bits that could be giving me grief.

Cheers Stuart

[4x4]

I forgot to put that on the list i have rebuilt the extension and renforced it, its possible that the prop shaft could be the culprit its the original type with the rubber dampner my car is a 71 mk 1 auto box BW35. I never really got much of a chance to drive the car after I bought it and started to strip the suspension, drive shaft components and overhaul all the bits and pieces. I can drive it for now and continue with the other cosmetic stuff that needs attention. The prop shaft could well be the problem.

thanks stuart

Some years back my car was running just fine, except for an oil leak from the diff extension.
Had that fixed (by a welll know Stag speacialist) - but they did not road test the car afterwards.
I picked it up - and the car proceeded to try and shake itself to pieces as I drove down the road. It was absolutely undriveable above 40 mph.

Quite simply - Propshaft UJ's were shot.
Well shot.

I can only reason that the quill shaft bearings were so shot too, that they allowed the quill shaft to move around a bit to compensate for the propshaft.
Which might be why the oil leak developed.
Once new bearings were in there, the tolerance was removed - and the car shook like hell.

I'd go looking at the propshaft.


Good luck

Adrian.

[elvimto]

I do not have any vibration as such transmitting to the car I replaced a u joint on the prop shaft and the other one was good. I need to think about this one a prop shaft and shipping cost from UK versus fixing the one I have ??

cheers Stuart

[jleyton]

I can't quite envisage your drumming noise Stuart, but one thing that doesn't appear to have been mentioned is the exhaust.

I've found, on other cars, that an exhaust can set up the most astonishing and annoying noises and vibrations if not aligned properly and on our beloved little beasties, it is a devil of a run and fitting. Maybe just worth slackening things off to see if it makes any difference ?

Cheers

Julian

[elvimto]

Hi jullian,
when I had all the lower components of the car the exhaust system was removed from the headers to the tail pipes. It is a stainless steel exhaust so I go with the theory that if I put it together I need to be able to take it apart. I had the headers coated at a local shop with a ceramic coating which was to keep some of the heat out of the engine bay and stop them from rusting up. i then set about fitting the exhaust from the headers back to the tails pipe, I made some tooling a few swages to round the pipes ends back and did some heating and bending of the pipes to the boxes and the intermediate pipes, I also fitted the hangers and replaced all the hardware bolting etc all in all the exhaust system is installed really well I just removed the tail pipes and intermediate pipe to install a diff last week came apart and went beck to gether without any problems. I need to see if I can get a sound bite of the drumming noise right now if I stay at around 55 its not that bad.
Still looking at all my options.

cheers Stuart

[jleyton]

Hi Stuart,

Sounds good what you've done with your exhaust, but I still think it might be worth just slackening it off - it will at least rule it out.

I've found it astonishing what just a little tension in the system can do.

Cheers

Julian

[jakesmig]

Sounds as if you've looked at nearly all the bases, but your original thread indicated that you originally had the drumming before you started all your works. Is there anything you haven't touched / adjusted. How is the oil level in the diff? , could the drumming be tired bearings in the diff, also have you checked the toe in / out of the rear wheels, they should be in the order of 1 degree toe in?
I know it is clutching at straws but you never know.
John.

[elvimto]

Its been four years since i got the car it had wire wheels on it and then I pulled the running gear out and replaced all bushings etc I did an overhaul on a diff but the ring and pinion were not the best shape got really whiney at 55 still had a the drumming noise then i did a switch to another diff which I did not rebuild but did inspect and it looked in good shape.I am running a oil made by Redline in the diff which was recomended by a Stag bloke who had been in the buisness for 20 odd years. I will be doing the alignment check in a bit and getting a big bag of straws. Its got me beat, but I don't give up easy.

cheers stuart

[TonyC]

Hi Stuart,

I couldn't drive my car because of very bad vibrations. The culprits were two things:
-The lower gearbox mounting bracket under the gearbox wasn't fitted as it should. Many people think that this part is symetrical but it isn't, there is at least 1 cm difference between left and right which puts the propshaft out of true.
-The bush and washer set for the above as most of the time, these are perished and reduced to dust with time and exhaust's heat. I made some myself from Jaguar rubber mountings I had left to isolate this bracket from the cars' floor and chassis, and the difference is amazing. No more drumming noise above 80/90 mph, gear changing clonks almost disappeard.
I wasn't far from selling my car because of these drumming and clonking noises but I'm now very happy with the car.
Hope that helps.
Cheers
Tony

[elvimto]

Hi Tony,
I did find that the bracket for the auto box mount did not line up and the small rubber bushings were bad, I replaced the bushings and I fitted the bracket.I did have to file the holes to get it to line up i may have induced this I will have to give this a second look. Thanks.

cheers Stuart