Hi

My 03 JTD has a throbbing noise from the rear drivers side wheel.

I suspected a bearing, replaced this ( hub nut done up tight using 2' bar on rachet for leverage). How tight do these things need to be, cant find a torque setting ?

The noise is exactly the same, I did notice that the brakes slightly rub on one part of the disc. Could this be the cause of the noise ?

I always thought that warped discs were a myth ?

Help !!


Thanks

Simon

Warped discs aren't a myth!

A main cause of discs warping is pulling the handbrake on tight and parking up when the disc is already hot from braking (they can get seriously hot). This prevents the disc from cooling evenly, causing distortion.

Cupped tires, "sawtooth" profile, happens a lot on modern, fwd cars, and almost only at the rear tires, exactly the same sound as a worn bearing.
Change front and rear regular, and you prevent it,
Now the only thing is to buy new rear tires, I'm afraid...

Was pretty sure that these bearings should not be tightened to within an inch of their lives! When I have replaced these I have just nipped them until I can feel a slight resistance against rotation and staked the nut in place there. Never had any problems this way.
Is the hub warm to touch after driving the car? If you have loaded the bearing too much it will fail prematurely and you don't want that!

Staked the nut ?

The old nut had the usual 'grove' dented in .

The new one did not have one to dent in, but seemed to taper in.

Why cant we just have a split pin

S

It's almost not possible to over tighten these bearings with normal tools and skill.( and they have to be VERY tight!!)
It's also good practice to use some Loctite 2701 on the nut and thread, some official Fiat workshop manuals will tell you so, others won't, I always use it, just to be safe.
I'm 99,9% sure cupped tires are the blame for the noise you described.
Feel on the outside, against driving direction, you will probably notice this "sawtooth" tread, that's making the noise like a worn bearing.
Oh, and you have to dent the new nut yourself when it's in place......!!

Hi

Your right with the tyres, thanks .

Hub nut. I have fitted these to past car's (VW) and dented the nbut, no problem. But the nut with this new bearing is different, does not have the 'edge' that you dent, but the thread seems to taper towards the outer of the nut.

just worried, as I have never seen one like this.

S

Are you sure you have the correct nut from Fiat?
I changed many of them, and there's always room to dent them!
You can reuse the old nuts once, if necessary and hit a new dent in them, and do use some Loctite, as I mentioned before.

As for the cupped tires, what sometimes helps, is to increase the air pressure in the rear tires, and, of course change front and rear at least once a year!
Some people may say worn shocks, but that's absolutely not the case, it's the geometric of the rear axle, designed by the factory, and you can't change that, I'm afraid.

Hi

Thanks again.

the nut is a pattern part, not FIAT.

Do they sell just the nut ? think I mught put a proper one on.

Thanks

S

Yes, you can buy just the nut.
Every Fiat dealer will stock them, as they are used on various models!

New nut, new tyres...... problem solved

Thanks

S

Happy motoring

Sorry a bit late but my replacement nut was the same but does the same job it bits in on its own not requiring it to be tapped into the keyway.