Rumble from front end Peugeot 306 Dt

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caeclyd
Posts: 64
Joined: 07 Jul 2001, 15:11

Rumble from front end Peugeot 306 Dt

Post by caeclyd » 06 May 2002, 16:55

There I was driving through N.Wales enjoying the scenery when all of a sudden there a light rumbling noise from the front end. At first I thought it was the road surface but no on smooth tarmac it was still there.
Arrived home jacked the front end up checked both front wheels for loose bearing or sounds etc, nothing found. I also checked the rear, oh and just in case I also checked the oil level in the gearbox. everything seems fine. The noise is still there.
It is also there when I dump the cluch and it is speed related it is not coming from the engine. I suspect it is one of the front wheel bearings BUT HOW CAN I TELL ?
Is it a big job to change the bearings ?
Rory

Dave Burns
Posts: 1916
Joined: 14 May 2001, 05:30
x 2

Post by Dave Burns » 06 May 2002, 23:18

Hi Rory, when a front wheel bearing is in trouble it usually makes more noise turning in one direction and less or no noise turning in the opposit way.
See if you can feel any play or roughness in the bearings, if you can't the only thing to do is go for the bearing on most load when the noise and vibration is at it's worst, that is to say if it's worst turning to the left then go for the right hand bearing, this is mostly the way it pans out but not allways, so be prepared to go through it all again if it's wrong.
As for replacing them the most difficult part will be getting the old bearing's out and new one back in, they are an interference fit so a press or good puller will be required.
I did one on the car on a 205 but in hind sight it would have been easier to take the hub carrier off and get it on a bench.
If you are going to do it yourself, drive the new bearing in using only the outer race, to use the inner race will trash the bearing.
Check also the support bearing on the right hand drive shaft.
Good luck
Dave

caeclyd
Posts: 64
Joined: 07 Jul 2001, 15:11

Post by caeclyd » 07 May 2002, 14:38

Dave, thanks for the reply by e-mail I had lost the cookie.
On your e-mail you said "I would expect the noise to change when on the over run as opposed to accelerating". What do you mean by over run?(idling)
If you mean(both front wheels were off the ground) idling then the noise at the idle speed was ok it is when I put the car into gear & accelerated that is when the noise would get worse, I did not try to turn the wheels from left to right.
I have just ordered the wheel & intermediate bearings (from AS) for when I start taking things apart. When the car arrives back this afternoon I will try your suggested checks .
Thank you,
Rory.

Dave Burns
Posts: 1916
Joined: 14 May 2001, 05:30
x 2

Post by Dave Burns » 08 May 2002, 00:07

Hi Rory, if you take your foot off the throttle while going along, the wheels are then driving the engine, this is commonly refered to as "over run".
I mentioned this as way of checking the diff bearings, while accelerating the pinion is obviously driving the crownwheel, this places a high downward load on the diff bearings, on the over run thing's are reversed, the crownwheel is now driving the pinion, this loads the opposit side of the bearing, upwards in this case.
So you can see that it might be possible to identify a bearing in trouble by knowing what forces cause a rise in the noise and vibration produced or conversely to attenuate it.
Not allways but more often than not when a bearing goes bad it does so where the loadings have been the greatest, also this is usually somewhere on the outer track due to centrifugal force which throws debris away from the inner parts of the bearing.
If the damage is on the inner track it is very difficult to pinpoint because the damaged area is then revolving and will still cause noise and vibration with any directional changes of force.
Dave

caeclyd
Posts: 64
Joined: 07 Jul 2001, 15:11

Post by caeclyd » 12 May 2002, 18:42

Hi Dave,
Just to let you know that it was the front offside wheel bearing which was at fault. I also replaced the intermediate bearing at the same time, just in case.
When I removed the front hub and spun the bearing there was hardly any play, you could only detect a noise if you placed the hub against the door of the car which in turn would act as an amplifier.
Anyway job done, thanks for your advice.
Rory