Strange noise from underneath - can't figure it out

Hi All,

sorry, I know this isn't the only 'strange noise' thread of the evening, but hopefully you wont get too bored.

So, when maneouvering in the car park at very very low speeds, and with a quiet engine (as quiet as it gets), I've noticed a strange noise. It's as it someone was tapping some metal with the metal bit of a screwdriver. At low speeds, I would swear that it seems to be occuring in a rythym, in time to the road speed - sounds like it's once per wheel revolution, or perhaps once per drive shaft rev?

anyway, as you speed up, the noise sounds slightly different - same pitch, but the predictable nature changes. It sounds more like you are towing a metal rod under the car, on a string.... and it's bouncing along the tarmac making high pitched tapping sounds.... make sense?

I looked under her (with handbrake on, for ref) shook all the UJ's - no play at all evident. I did tap the outer tube surrounding the read drive shaft - that sounded nice and hollow and metalic, but I couldn't how anything could be interfering with it.

Same for the wheels - all look clear.

As for the area - hard to tell from the cab, but i'd swear it was somewhere bewteen the tbox and the rear diff - probably slightly closer to the tbox if anything. also, might not be central - sounded quite a lot like it was coming from passenger side sort of area (exhaust?!)

above 3rd gear, the noise dies away - probably because the engine and road noise overtakes it. still makes the noise occasionally if I coast round a corner out of gear.... can't think of anything else useful...

thanks in advance!

FS

CV joints?

http://www.landyzone.co.uk/lz/f41/cv-joint-renewal-68945.html

As Buster says

But try checking for play in the prop/uj's with the handbrake off cos i find it makes everything 'tight' if the handbrake has any resitance on it.

Chock wheels, out of gear too or just park on a dead flat area then check

scott02464 said:

As Buster says

But try checking for play in the prop/uj's with the handbrake off cos i find it makes everything 'tight' if the handbrake has any resitance on it.

Chock wheels, out of gear too or just park on a dead flat area then check

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Brill - will do.

and nice one buster

either U/J's or handbrake slightly sticking are my thoughts.

Thanks all for the thoughts thus far. I got under and buggered about with the rear drive shaft last night - no sign of play in the UJ's at either end, without the handbrake on this time. Am I calling it the right thing, or is it a prop shaft?

There was a bit of up/down/sideway movement in the handbrake drum unit... is that normal?

The noise sounds a bit too tinny for a UJ (mind you, I've only ever heard 1 on the way out).... I could well be wrong. Also, this morning on the way to work, I was trying to pin down the noise... sounds almost like it's coming from under the passenger seat area. Obv this is not a scientific method to locate something like this - lol.

It deffo sounds rotary in nature though - at least at lower speeds anyway.

have you tried spinning each wheel while off the floor? this will help you find the noise.

If it happens with both back or front wheels then possibly ujs and yes they can sometimes sound tinny or at least mine did.

If it only happens on a certain wheel then take it off and have a look around, could possibly be a stone caught, bearing or cv joint.

bobbler said:

have you tried spinning each wheel while off the floor? this will help you find the noise.

If it happens with both back or front wheels then possibly ujs and yes they can sometimes sound tinny or at least mine did.

If it only happens on a certain wheel then take it off and have a look around, could possibly be a stone caught, bearing or cv joint.

Click to expand...

hmmmmm, no - i haven't, but there is a reason...

last time I owned a landy, I bought one of those big socket sets, which has the 27mm for the wheel nuts (and goes up to 40mm odd). Well, when I sold the landy and got the saab, I thought "I wont need these anymore", and gave them away with the landy! STUPID!

So at present I have a draper 12 tonne bottle jack which is too small to jack up the landy without 2ft of blocks under it, and no socket set!!!

Have you seen how much these sets cost nowadays!?! sheeesh! I'll have to get one now though... sigh.

farmershort said:

There was a bit of up/down/sideway movement in the handbrake drum unit... is that normal?

Click to expand...

NO:doh:

ratty said:

NO:doh:

Click to expand...

oh balls - another bug to fix!

is there a how to on that one aswell?

farmershort said:

oh balls - another bug to fix!

is there a how to on that one aswell?

Click to expand...

No.

http://www.landyzone.co.uk/lz/f41/handbrake-shoes-renewal-98882.html

for sockets you could buy them separately i can only think of 2 in that range for the landy 27mm for the wheel nuts and 32mm for the drain plug. there are probably more but havent come across them yet.

Halfords are having a half price sale on socket sets but dont know if they will go into the sizes you need.

my wheel brace is now a breaker bar with 27mm socket on the end

bobbler said:

for sockets you could buy them separately i can only think of 2 in that range for the landy 27mm for the wheel nuts and 32mm for the drain plug. there are probably more but havent come across them yet.

Halfords are having a half price sale on socket sets but dont know if they will go into the sizes you need.

my wheel brace is now a breaker bar with 27mm socket on the end

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Thanks! might nip over there in a bit and see what they have. Got to do some DIY first - I get in trouble if I spend all my free time in the landy

I did managed to nip via AMD 4WD to pick up new front brake pads - so got some handbrake shoes as well! thanks for the link ratty - you lot are ace!

2 things... firstly your handbrake acts on the transmission, so you won't be able to test for play in the drivetrain with it on. Secondly, you say your bottle jack won't lift the landy without 2ft of blocks underneath it??? Why don't you just put it under the axle?

Langers said:

2 things... firstly your handbrake acts on the transmission, so you won't be able to test for play in the drivetrain with it on. Secondly, you say your bottle jack won't lift the landy without 2ft of blocks underneath it??? Why don't you just put it under the axle?

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Lol - that 2nd bit seemed quite obvious to you didn't it???

I'm afraid I'm a child of the computer age, and the farming bit isn't really "in the blood" either - just learning as I go.

Thanks for the tip! I've been and got myself a breaker bar, 27mm socket, and 32mm sockets... and a set of AF spanners - as it says on the 'how to' that you need a 9/16 spanner.

right, best put a coat of paint on the skirting boards, then i'll be free to bugger about with the landy all evening

Right - I now I have new handbrake shoes!

Quite proud of myself - which is a bit sad given it's a **** easy job for most of you on here...

It was a bit of an arse, as I realised halfway through busters' "how to" that my brake drum was the new type, and his was the old type... a little brain power, and a consult of the haynes manual overcame the confusion though!

Sadly the noise is still there.... I did try and grease up UJ's, but I think all the nipples are blocked.

Also discovered a new oil leak!!! It's inside the brake drum, it's leaking from the centre part that the studs come out of - there's some sort of bearing ring, or seal, and it's leaking from there.... It's a good job I'm not bored yet innit!

I've still had no joy tracking this noise down..... It sounds bloody painful, and I'm sure it's going to result in an expensive repair bill if I don't catch it soon....

I took my neighbour out in the landy today, with the central seat bottom plate removed. He's a bit more naturally mechanical than me...

He couldn't figure out what it was either. He's more into smaller thing (he's just got a lotus excel), so he said a landy expert would have more joy - BUT, he seemed to think it wasn't the right noise for a CV joint, and it seemed to be rotary in nature - at least most of the time.... also seemed to be linked to road speed (again, most of the time), AND seemed to happen a lot more often when you just put the power on, or just as you lift the power off...

he also said the same things as me about the noise itself - liek something tapping a metal tube of some sort - i.e. something hitting the exhaust....

It's deffo not something hitting the exhaust, or the rear prop shaft - I've been up and down them both several times....


so, any more ideas anyone!?!

TIA

FS

Took the pigs to the abattoir this morning in it down the whole length of the M42.. it help up alright, but the noise is as aparent as ever... i'm trying to figure out if it's getting worse of not. it's deffo more apparent when coming on the power, and when going off the power, rather than at constant speed. could it be something gear related? or a bearing somewhere? could it be related to the very slight leak in the handbrake assembly?

have you tried jacking each wheel up in turn and spinning them while off the ground? This could help pinpoint the area where the noise is coming from.

If it is wheel specific then you could be looking at cv joints / bearings but if it is there for both front or rear wheels then likely to be prop/uj/box related.

bobbler said:

have you tried jacking each wheel up in turn and spinning them while off the ground? This could help pinpoint the area where the noise is coming from.

If it is wheel specific then you could be looking at cv joints / bearings but if it is there for both front or rear wheels then likely to be prop/uj/box related.

Click to expand...

Well, have to admit - I realise now I'd been a bit half arsed with this. during the course of renewing the handbrake shoes, and then the front pads, I have had 3 out of the 4 wheels in the air. The rear drivers side was spun with the wheel on, and made no noise. The front 2 hubs were spun without the wheels on - so not very scientific. Neither of them made any noise - aside from the normal noise you get when engaging a gear and the accumulated freeplay in the diffs is taken up... does that make sense?

So really I guess I need to jack up each corner in turn, and spin the wheels whilst the wheels are on it, in order to make it a relevant test.

I'll give it a go tonight... Any other bright ideas, please step forward.

Sorry to keep pestering, but it is a truly disturbing noise... one of those that sounds like pounds and pounds falling out of your pocket