Over the past few weeks I have started to experience a wobble through the streering wheel when braking when coming off the motorway. Generally any braking over 50-60mph will produce the wobble.

I dont expereince any wobble at any speeds when not braking. A friend has suggested that rather than wheel balancing, this could be caused by a warped brake disc.

Any ideas..? And if it was this, would it be covered under warranty ?

Thanks

David

 

Could well be a warped disc.

Seem to remember another owner saying he had to have his discs skimmed on this forum and mazda not replacing just kept skimming them or something - try a search.

Warranty depends on mileage I would think.

Also check the insides of the front tyres in case they are severely worn - just in case as this could be possible cause.

 

It does sound like warped rotors. If it so happens to be that, then no, it's not covered under warranty - brakes are considered normal wear & tear.

 

Couple of posts about discs needing to be skimmed here:


https://www.mazdaforum.com/forum/sho...mmed#post47321

https://www.mazdaforum.com/forum/sho...mmed#post41253

 

Most likely rotors. But what is car vintage and history, and when was last brake maintenance done?
You may or may not have recourse to warranty. You did not provide enough data to make the call one way or another. Depending on the car, its maintenance history and how it's driven, rotors can be skimmed up to three times before they ought to be replaced. Translated into miles per reasonable driver, I would say that rotors should not need replacement until 150,000 miles minimum.

 

Thanks for all the replies so far.

The car is a 2008 Sport Nav model, with 15000 miles. It has just had its 1st service a month ago.

The car is 10 months old.

David

 

That's quick for a bad rotor. I'd have the dealer look at it, just don't approve them for the work if they say they will charge you. (A brake job is fairly simple to do)

Did it get parked for a long period of time? If so, corrosion of the rotor can leave a build-up causing a hot spot on the rotor

Did you recently have really heavy panic stops? If so, you can overheat and warp the rotor.

My Mazda6 repair manual shows:
Rotor runout limit: <0.05mm @ 10mm from the disc plate edge,
- uneven wear can occur on the disc because the pad contacts the disc unevenly. This would create a side to side wobble you could feel through the steering wheel.

Rotor thickness variation: <0.015mm

Minimum rotor thickness: 22mm

Minimum rotor thickness after machining using brake lathe on-vehicle: 22.8mm

(I would think specs are basically the same, double check @ your dealer to get specifics for the 5)

Are you feeling the shake through the brake pedal (brake judder) or in your seat (body wobble)?

 

It's the discs, mine does the same, my last car did to.

Do you generally brake gently, as this can generate a lot of heat on the discs, this is what I beleive is the cause with myself.

My last car had new discs with every set of shoes !!!!

 

Yes I do brake lightly when leaving the motorway. I will get the wobble from 60mph upwards, but only notice it when leaving the Motorway.

Is this covered under warranty? I forgot to mention it to my dealer last i was there...

 

If a disc, you should feel it in the pedal at all speeds. The pedal should pulsate in a rhythm related to the speed you are going.
My guess, though a bit of a long shot, is a bad tire.
The tread may be separating from the belts internally, and/or may be out of round. Balancing will do nothing if this is the case. Replacing the tire/tires is all you can do. It's rare when a bad tire gets past factory inspection, but it does happen from time to time.
I chased one (vibration problem) for nearly 2 yrs once. It turned out to be an out of round tire straight from the factory. Tires replaced. Vibration solved.