Amazon: - Strange noises..... [Archive]

222s

Jul 6th, 2009, 00:16

Just been down to Devon for the weekend to visit family there, and on the way back this evening, the car started making a low pitched humming noise, which I'm sure wasn't there on the journey down on Friday evening.

It's difficult to describe, but it will still happen even when coasting with the engine switched off. Obviously that rules out the engine, as switching off made no difference at all. It kicks off at about 20mph. However the increase in road speed doesn't seem to increase the 'speed'* of the hum, which I find rather confusing.

*can't think of the proper engineering / scientific term so that will have to do!

The back axle is full (already checked that - I hate the smell of gear oil...), and hard cornering doesn't seem to increase the volume of the noise. The only thing I did find was that an exhaust joint is blowing slightly, but I can't see how it is connected.

Any ideas what on earth it could be? It's driving me nuts, firstly as I can't identify it, and also because I know it has the potential to be expensive :(

Any tips / advice on how to identify the problem would be very much appreciated.

ClassicVolvoShop

Jul 6th, 2009, 00:18

- Prop shaft bearing (center - the big rubber-donut)
- Do you have OD? - was the prop shaft professionally balanced? (if not/or anyway - a very fine unbalance)

:)

222s

Jul 6th, 2009, 00:24

Is that the classic symptoms of the centre bearing going? Also, how long should they last, as I'm sure it was replaced in about 2005 / 2006.

How easy a job is that to do, and are any special tools needed? I don't have a workshop / garage!

Thanks!

- Do you have OD? - was the prop shaft professionally balanced? (if not/or anyway - a very fine unbalance)

I do indeed have o/d, but that has been there since before my father bought the car in '94.

ClassicVolvoShop

Jul 6th, 2009, 00:38

Well...

Humming - use to be diff or prop shaft.

Easy? Depends - but to balance the prop shaft - is a machinery-job* - to change the bearing/donut - no problem at all doing with either side wheels on the kerb. (Ahh.. well, depends a bit on your physics.. but basically..)

*Take 2 hoseclamps (is that what you call them? - those you clam the hoses with) - put them arround the prop at the middle of the rear section - align them and:

1010 - Go for a drive, reach say 50-60 mph
1020 - If change in noise is increase of noise, go to kerb and losen the clamps - move them 95 degrees and tighten them - go to 1010
1030 - If noise has disappeared - be happy!
1040 - Make coffee

(Did anyone say Commodore 64 ??)

To change bearing or rubber donut:

Make coffe and go to www.volvoamazonpictures.se and find the Service Manual for prop shaft - and spend 20 minutes reading it to the coffee! :)

Alf ista

Jul 6th, 2009, 00:41

Could it just be a wheel bearing...?

ClassicVolvoShop

Jul 6th, 2009, 00:52

Could it just be a wheel bearing...?

Maybe - but if cornering doesn't change the sound?.. Prop shaf bearing is not influenced by sideways movement of rear axle.. Engine revs up and down on accelerating and changing through gears - prop shaft has a linear rev. patteren so different frequensies are "fixed" - noise wont kick in randomly, but useally in areas of revolutions - like between 40 and 50 mph etc.

But in theory, there are a lot more options.. like, shut bushes in rear suspension - (having changed alignment of drive shaft) and so on..

222s

Jul 6th, 2009, 01:07

Can't see how it could be the balance of the propshaft itself, as it hasn't been messed about with. Also the rear suspension has all new bushes (every single one) fitted about 4 months ago.

I'll look at the propshaft centre bearing - hopefully will be able to get one by Tuesday.

Cheers!

ClassicVolvoShop

Jul 6th, 2009, 01:08

....the 'speed'* of the hum.....

*can't think of the proper engineering / scientific term so that will have to do!

Buzz of the hum?..

ClassicVolvoShop

Jul 6th, 2009, 01:10

222s

Jul 6th, 2009, 13:01

Had a look in the manuals, and there are three different types of centre bearing. I'm pretty sure it's safe to say that mine doesn't have the early one, but of the later two, which would it have? It's a summer '67 build date (apparently before the factory's summer shut down).

Thanks!

ClassicVolvoShop

Jul 6th, 2009, 13:10

Type 3 - in 220's from chassisnumber 44600 and up - which means 1967 yearmodels and up.

(Only 2 different centre bearings - there are 3 types of prop shafts, but the 2 first early ones had the same centre bearing)

Derek UK

Jul 6th, 2009, 13:12

Could be a rear wheel bearing. They are less affected by cornering side loads. With front ones you can often diagnose which one is giving the problem when the noise goes away depending on whether you're cornering right or left. Sometimes they just need nipping up one flat. Front ones being taper rollers, you can do that, but rears are set with shims.
You do a lot of miles, so worthwhile tracking it down soon.
Centre bearing is a possibility. You may even be able to feel it through the floor adjacent to the bearing. Strange drones from exhaust leaks aren't unknown either and that's something to fix first I'd think.

222s

Jul 6th, 2009, 17:29

You do a lot of miles, so worthwhile tracking it down soon.

Tell me about it!!! Also, even if it was something that didn't matter, I find the noise very annoying, as I've spent a lot of time tracking down and dealing with various squeaks, rattles etc.

Hoping it's not the rear wheel bearings as that's not something I can do out in the street.... Haven't got the equipment for setting up the shims correctly, or for that matter, the ability to use such equipment either. New centre bearing should be arriving tomorrow, & intending to fit it that evening - the moment of truth.

It's not the exhaust as the noise is there even with the engine switched off, and power on / power off has no effect either. Vaguely recall that it might have gone away under braking (both foot & engine) but can't recall for sure. The leak will be dealt with ASAP though! This morning, when pulling away with the engine still cold, I did manage to provoke some previously unexperienced vibration from the drivetrain, which I believe further incriminates the prop centre bearing / donut.

Btw, given that the rear bearings are also tapered type, wouldn't high cornering forces still have an effect on any improper noises?

In more positive news, it seems to be drinking noticeably less juice when out on the open road (maybe my right foot is lighter??) - regularly managing considerably more miles per tank than before. Still less than stunning around town though, but not hugely surprising given the nature of central / south London stop-start traffic....

Derek UK

Jul 6th, 2009, 19:34

Well OK the rear bearings are tapers but when shimmed correctly they should be OK for their working life. Doesn' mean to say one of yours hasn't done that though.The pair in each side at the front can sometimes find themselves a bit slack especially if they were greased a few months previously. Fitting your big wheels could well be a factor, as the forces under cornering certainly won't have got any less. (grin) That could affect front or rears.

ClassicVolvoShop

Jul 7th, 2009, 12:57

222s

Jul 7th, 2009, 13:04

Paul,

While you are under the car - check the rubber cushions for both engine and gearbox - it may sound strange, but a sliped/slided cushion changes the angle of the drive train - and a small humming easily comes from little changes..

Will do!

Thanks for all the advice etc everyone. Hopefully by the end of this evening I will have a quiet car!

ClassicVolvoShop

Jul 7th, 2009, 13:41

Pictures - results - fixes and full rapport expected!!!

222s

Jul 8th, 2009, 00:18

Tonight's score - nut on propshaft 1, me - nil.

Couldn't get the ruddy thing undone as I didn't have either the right sized spanner, or an adjustable spanner with large enough jaws, or a cold chisel to beat it with....

However.... spinning the prop as fast as I could by hand, I could just about hear some noise coming from the centre bearing! In contrast, when spun, both rear wheels were free from rough spots and & also quiet.

There was also a rubber padding piece between the bearing cap and the bearing carrier. Is that meant to be there? I can't fond any reference to it in the parts books or workshop manuals.

Rematch is tomorrow night.

Btw, what size is the large nut on the propshaft?

Derek UK

Jul 8th, 2009, 12:35

"There was also a rubber padding piece between the bearing cap and the bearing carrier. Is that meant to be there? I can't find any reference to it in the parts books or workshop manuals."

Is that what Volvo call "cork packing"? (item #17) It probably looks like rubber now after being soaked in oil. Is your bearing mount the earlier 2 pegs and grommets or the full rubber ring?

Can't help with the nut size unless I go to the garage later today............

You might need to push a big screwdriver through a yoke to stop it turning while you wrestle with the nut. Being in gear will help but unless the nut loosens with the first whack, best to lock the shaft.

222s

Jul 8th, 2009, 13:22

Mine is the big rubber ring / donut type. Worked out the nut size - flats were about 25mm but as Amazons are imperial, that's 1", so 2" overall size. Managed to find somewhere that has an adjustable spanner in stock that has jaws up to 2 5/8", so that will do the job. It's still going to get whacked with the chisel to start it off though.... whoever was last in there has already used that trick.

It's a strip of rubber (has a number moulded into it) - however given the apparent state of the carrier, I was wondering if it was a bodge to take up some slack....

Being in gear held the shaft surprisingly well, but thanks for the tip - will use that too. I'm going to attack the nut before going near the diff this time though.

The rematch is on. (Disclaimer - probably won't be in this evening's sports news).

222s

Jul 9th, 2009, 09:51

No luck I'm afraid. Spent all evening underneath, changing the bearing and its rubber carrier (definite play in the old bearing, & the carrier looked pretty tired and was likely to have been the original!) but it's made no difference. Tbh, all I can think of now is a wheel bearing / diff bearing. Very strange though, as everything pointed to the centre bearing. Oh well.....

Regarding the engine & gearbox mounts, - the noise is still there, even when coasting in neutral with the engine off. Can an iffy engine / gearbox mount still do that?

Logically, it is therefore either a wheel bearing, or between the rear wheels and the output shaft in the gearbox. Whatever it is is constant, and road speed related, not engine related. Doesn't matter which gear is selected, nor whether in or out of overdrive. Actually - would that rule out the back of the gearbox / o/d?

The rear wheel bearings are not something I can do myself due to the shimming - ditto anything inside the axle. I'm also pretty skint at the moment, so probably won't be able to afford to get it sorted for a while.

222s

Jul 16th, 2009, 16:37

I've put the (now freshly sandblasted and enameled) steel wheels back on, to eliminate the other tyres from being the list of suspects, but no such luck.

Also had to separate the prop again as realised that I hadn't aligned the UJ yokes correctly. In the process, discovered a few other issues - return spring for the (hydraulic) clutch arm had broken its end off (pulled a coil straight and bent it around as a temporary fix until I get a replacement) & I can feel & hear play in the front UJ. LH front engine mount is also not long for this world. So a few other things to sort out still....

I guess it's possible that the noise is actually that UJ but we'll see.

Alf ista

Jul 16th, 2009, 17:09

The "joys" of classic motoring...

222s

Jul 16th, 2009, 18:14

Actually, it's normally much better behaved. Given that it has 280,000 miles on the clock, is my everyday car and driven irrelevant of weather conditions (there's no point having a car with a heater like a sauna if it doesn't get driven in winter!!!), I think it does pretty well. The main issue here is my lack of ability & experience at mechanical diagnostics, and that some of the likely culprits are also (annoyingly...) beyond my ability to fix.

ClassicVolvoShop

Jul 16th, 2009, 21:40

Paul,

I would still investigate if the complete drive train/transmission has changed angles (like if a motor-mount has given up or the like).

Imagine the angles through the drive train - then imagine how little it would take to change for instanse the differential's angles - and thereby a "new" load on any given bearing in the system.. (Ehh.. I hope you get my tech english!)

Another view - say your gearbox-mount has given up - and gearbox now sits 1-2 centimeter lower than before - or a bushing in the rear axle suspension (like in upper support arm) - that changes the differentials angles with the prop etc. etc.

- that could give a new stress to any bearing i the system and provoke the humm..

(I stick to this theory, because you say it's the same with or without engine running - and like said before: Prop/diff spins in smooth correspondance with speed of the car)

222s

Jul 17th, 2009, 00:43

Gearbox mount looks ok (but don't know for sure) - NS front engine mount is definitely dead, OS front seems to be behaving. Going to replace all of them though. Rear suspension should be ok, as it was all rebuilt & rebushed earlier this year.

Doesn't seem to be the stereotypical diff whine noise, as that isn't constant - above a certain speed, the noise I have is always there, irrelevant of what I do (except of course turning up the stereo to drown it out!!)

222s

Aug 5th, 2009, 16:30

All is now fixed!

The right hand rear and left hand front wheel bearings were knackered (the other two were ok, but were replaced anyway). Not sure which one was actually making the noise, but I guess that if both were noisy, that could expain why there was no difference when cornering. The bearing face on the section that goes on the halfshaft was especially icky - gory pic to follow. Given the sort of tools needed to get everything out and then back in place properly, I didn't do the bearings myself as that was beyond my mechanical ability.

However in the process of diagnosing all that, with assistance from a very knowledgable friend, we found that the front UJ was also on the way out (noticable play, & the spider was starting to sieze in the front yoke), so the propshaft has been fully reconditioned too (new UJs, new front yoke and balanced) by Propshaft Services (http://www.propshaft-services.co.uk/index.php) in Feltham, near Heathrow, whom I can highly recommend; in particular their customer service is excellent.

Thank you to all for advice etc! :)

ClassicVolvoShop

Aug 5th, 2009, 16:43

Always good to hear how things turned out - Thanks for letting us know!

And GOOD for you! - Good job! - That's near a new Amazon there!.. ;)

222s

Aug 5th, 2009, 18:24

Thanks!

Sadly the outside doesn't look near new! Underneath isn't too bad though ;) Front suspension rebuild (it's not bad, but I want to get it all blasted & painted up properly) is on the cards soon too. Front hubs & discs were fine when inspected yesterday, which will save a bit of cash. I already have all the rebuild parts (bushes, balljoints etc) waiting to go on, so just a case of having the time really.