thumping noise at approx 70KPH

Cynical · Post by **Cynical** » Sat Feb 23, 2008 10:14 am

Hi Guys, was wondering if i could get some thoughts on my current problem. details of the subi in question are as follows

82 MY manual wagon, no mods other then 14" with street rubber.(bought on ebay, but from BYB01)

Problem is as follows...
i get a fairly loud thumping noise at approx. 70kph's cannot feel the thump through steering, or gear leaver. hard to say. but might be coming through pedals a little. the noise appears to change frequency with speed. and most definately is coming from the front end. it goes away again after about 75-80 but reapears with a vengeance at 95-110.

currently have replaced CV's checked bearings, rotated tires. drained gearbox oil(no sign of metal fragments). Both myself and my very trustworthy mechanic are at loss as to what is causing my noise.

Any thoughts would be appreciated.

Cheers

Cynical

Rodster · Post by **Rodster** » Sat Feb 23, 2008 1:20 pm

When you say it is at two different speed zones is that at the same engine rev range in different gears? If not the same rev range it sounds like something showing itself at different 'harmonics'. If you've checked all those things its a tough one to me. Could it be engine mounts on the way out?

If you have the time and patience you could try the stethoscope method i.e. take some hose e.g. garden hose and feed it from the cabin into the engine bay and tie it in at various points around the engine bay listening to each location in turn (at speed of course). This can sometimes pinpoint it down to a quite small location.

Outback bloke · Post by **Outback bloke** » Sat Feb 23, 2008 6:52 pm

82 MY manual wagon, no mods other then 14" with street rubber.(bought on ebay, but from BYB01)

Do you mean you bought the wheels from me? New wheels I take it?

Generally a thumping noise from the front is associated with CV joints. You say you replaced the cv's. Was it with new ones? Or second hand?

A wheel balance problem will normally shake the wheel increasingly with speed.

littlewhiteute · Post by **littlewhiteute** » Sat Feb 23, 2008 9:54 pm

The same thing has happened to me tonight on the way home from out west.
Car was running normally, then the front started to shake and thump, I thought one of the front wheels was loose, so I pulled over, had a look, nothing obvious, got going again, stopped again, jacked up the front, checked each wheel bearing, seemed ok.

After half hour checking, got going again, seemed normal up to 90kmhr, then it started again.

It's definately a cv joint, only makes the noise/shake under load, not there while coasting or freewheeling.

The right hand has had a click for a bit now, both shafts are one year old reconditoned shafts, not happy, pulling the right hand shaft out and replacing tomorrow.

littlewhiteute · Post by **littlewhiteute** » Sat Feb 23, 2008 10:08 pm

Cynical wrote:Hi Guys, was wondering if i could get some thoughts on my current problem. details of the subi in question are as follows

82 MY manual wagon, no mods other then 14" with street rubber.(bought on ebay, but from BYB01)

Problem is as follows...
i get a fairly loud thumping noise at approx. 70kph's cannot feel the thump through steering, or gear leaver. hard to say. but might be coming through pedals a little. the noise appears to change frequency with speed. and most definately is coming from the front end. it goes away again after about 75-80 but reapears with a vengeance at 95-110.

currently have replaced CV's checked bearings, rotated tires. drained gearbox oil(no sign of metal fragments). Both myself and my very trustworthy mechanic are at loss as to what is causing my noise.

Any thoughts would be appreciated.

Cheers

Cynical

While the noise is happening does it disappear when you take the load away, either by coasting in gear or rolling in neutral?

That's what mine does.

AndrewT · Post by **AndrewT** » Sun Feb 24, 2008 8:46 am

Sounds like wheel balance to me, I've had that before where the severity gets worse, then better, then worse again with speed.
Are they relatively new tyres? Sometimes it can happen if they separate abit from age.

stamp_licker · Post by **stamp_licker** » Sun Feb 24, 2008 9:31 am

Tyres seperating ,dry cv maybe.

Cynical · Post by **Cynical** » Sun Feb 24, 2008 11:18 am

Noise is consistant with wheel speed not rev. and is not effected by either coasting in gear, or rolling with clutch in. once noise starts, i can press the clutch, coast what eva i like i stays for a bit then goes away for a minute or 2 at random.

As far as wheel balance goes, i rotated tyres, i'm assuming that should have made it go away. unless all 4 tyres have same problem. i also swapped my spare on both front (obviously not at same time!) spare is still original 13" steelie. its a very persistant noise!

as far as CV's go. i checked them initially myself. didnt see any problem. mechanic seemed to think the same at first, but then we changed them anyway. brand new CV's and my mechanic did the work. so i'm assuming they're not dry or bad reco's.

its a very frustrating noise at the moment...

Cynical

littlewhiteute · Post by **littlewhiteute** » Sun Feb 24, 2008 2:57 pm

Once mine had been driving for a while the noise and vibration came back really bad, if you stopped for a break it was gone for a while.

Put in a new recond shaft into RHF today, quiet as a mouse now.

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Sun Feb 24, 2008 7:59 pm

Your hub nut washer isnt rooted so in effect the wheel hub is loose?

Subafury · Post by **Subafury** » Sun Feb 24, 2008 8:21 pm

yeh check the bearing/hub assembly

ToyRX · Post by **ToyRX** » Mon Feb 25, 2008 6:52 am

is it 4WD? Check your driveshaft universals and mounts, my brothers Lib had exactly the same symptoms and it was a buggered uni joint

Matatak · Post by **Matatak** » Mon Feb 25, 2008 12:25 pm

ToyRX wrote:is it 4WD? Check your driveshaft universals and mounts, my brothers Lib had exactly the same symptoms and it was a buggered uni joint

Tailshaft u mean there

there wont be a mount on the MY shaft but there is 2 Universal Joints to check out on it

Cam · Post by **Cam** » Mon Feb 25, 2008 12:32 pm

had a funny noise like that when the inner front cv was a little stuffed. were the joints just replaced or was it the whole shafts ie inners and outers...

ToyRX · Post by **ToyRX** » Wed Feb 27, 2008 5:20 am

Matatak wrote:Tailshaft u mean there

there wont be a mount on the MY shaft but there is 2 Universal Joints to check out on it

Ah, sorry missed the MY part of the post, I know naff all about those beasts.
Tailshaft/driveshaft.... I'm easily confused, just ask the wife....