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Rust on brake drums

12K views 17 replies 6 participants last post by  voxmagna 
#1 ·
Hello all,
I just purchased a 2012 Luxe with 10K miles. I love the car. The previous owner purchased the Eos rubber mats, wind screen and the nicer alloy wheels so I lucked out. I live in Phoenix AZ. I have several questions. We had a long rainstorm which is rare here. I went outside to clean the rain water off the car and noticed that the brake drums have rust spots. What's the best method for not only removing the rust without screwing up the wheels but preventing rust in the future?

Additionally, when the next service is done does the dealership lube the rubber seals?

Thx
Patti
 
#2 ·
Hello all,
I just purchased a 2012 Luxe with 10K miles. I love the car. The previous owner purchased the Eos rubber mats, wind screen and the nicer alloy wheels so I lucked out. I live in Phoenix AZ. I have several questions. We had a long rainstorm which is rare here. I went outside to clean the rain water off the car and noticed that the brake drums have rust spots. What's the best method for not only removing the rust without screwing up the wheels but preventing rust in the future?

The Eos does not have brake drums as it has 4 wheel disc brakes - the rust spots on the disc where the brake pads apply are normal for a car left in the rain and not driven shortly afterwards. The rust is cosmetic and will disappear the first time the brakes are used.

Additionally, when the next service is done does the dealership lube the rubber seals?

It may depend on your dealer as service practice often varies between countries and often between different dealers in the same State depending on how they structure their service charges and their commitment to their customers. As far as I am aware, the VW-specified service schedule does not include seal lubrication; presumably to allow the dealers to make additional profit by charging whatever they can get away with to their customers.

Thx
Patti
See comments in your post above.
 
#3 ·
There is something nasty about the EOS oem disc pads:

When most cars are left standing in the rain unused, it is normal for the rotors to develop an all over film of rust which soon gets wiped off when driven. Sometimes in the first mile or two you can hear the pad making an unusual rubbing noise, which will go away.

When I replaced my front disc pads last year, I left the old pads out in the rain overnight. Next morning I was amazed at the amount of rust on the pad surface. I was also surprised that the front discs (TDi Sport) had only managed 30K with quite a lot of wear. I have another car that went 70K on the oem discs.

Now, disc pads come in all kinds of different compositions and hardness. These VW oem pads look like the HH hard type. Pad manufacturers have been embedding metal in pads for years to increase friction and reduce brake fade during heavy braking. In the past they were using brass.

Looking at the oem pads I removed, I think they are using cheaper steel (not stainless!) in the pad mix and that is what goes rusty, leaving an outline of the pad as rust on the rotors if the car is not used.

This is really bad news if the car has been left standing for a while, as the rusting steel in the pad composition and rotor can fuse together causing the pad to glue itself to the rotor. When you then drive the car and the pads get unstuck, a large lump of pad surface material gets ripped off.

The OP needs to get the pads checked for wear thickness at next service.

The pads I replaced along with new rotors were German aftermarket. They were spec'd. for the car, so I suspect they have the same steel metal content as the oems. I am looking into alternative organic or ceramic based pads for the next pad change. I can accept more brake dust around the wheels, as long as they keep the steel out of the pad mix. You can check for steel mix in a pad with a magnet.
 
#4 ·
Voxmagna,

We live in a marine environment where we are less than 500 metres [1500 feet] from the ocean - the Eos is always parked in the garage and I have never observed any rust on the disc rotors even after the car hasn't been driven for several weeks when we are away from home. The only problem I have observed is squealing from time to time due to pad "glazing" caused by prolonged gentle use of the brakes by SWMBO and this is quickly fixed by a couple of hard braking applications from high speed.

I suspect the VW OEM brake pads for Australian vehicles are premium pads rather than soft pads due to our abrasive road dust and predominately dry driving conditions - I would expect the metallic iron content [primarily for heat transfer purposes to minimise overheating] in the pad would be cast-iron powder rather than steel due to its availability and cost arising from its use for sintered ferrous components.

When it becomes time to change the pads [and also the discs at the same time due to wear], feedback from other DIY owners suggests ceramic pads with new discs are the way to go.
 
#6 ·
I agree with Silver. Ceramics are the best, at least for cleanliness. I have used them in many of my previous cars when replacing brakes. In fact, I never use anything else.

However, the ceramics do take a bit longer to stop as compared to the stock German brakes. Never the less, when it comes time for brakes, I am willing to take that risk.

They also cause a bit more wear on the discs, especially for those who are heavy footed on the brake pedal. I am not. I tend to anticipate my maneuvers and stops. Got into this habit due to having spent a lot of time operating boats.;)

On a positive note, the ceramics resist heat fading, so that can be a good trade-off.
 
#7 ·
I have had similar discussions on motorbike pads. Soft pads for least rotor wear, average stopping but not extreme and black dust to put up with. Hard pads: Great for high speed more spirited driving, but wear rotors (expensive on bikes) very fast.

A Tdi diesel seems to need more braking into curves. I never really understood that, because you would think higher compression would give higher engine braking. I put it down to reduced 'responsiveness' and slower reaction of the motor compared to gasoline.

Incidentally, the problem with pads gluing themselves to rotors when a car is laid up, is more likely on the rears when left with the rear brake on. Best to chock a front and rear wheel then leave the hand brake off when laying up for some time.
 
#8 ·
A Tdi diesel seems to need more braking into curves. I never really understood that, because you would think higher compression would give higher engine braking. I put it down to reduced 'responsiveness' and slower reaction of the motor compared to gasoline.

.
Is it possible that the TDI engine is heavier resulting in more front end push when going through the curves which causes under steering? Thus, more braking is needed to keep the car under control.



 
#9 ·
I used to think that, but I can't imagine the 3.2 petrol V6 is lighter than the 2l Tdi.:confused: A tank of diesel is heavier than the same tank full of gasoline though.

I still think it is the more sluggish and delayed responsiveness that does not allow you to fine tune the power on cornering as much as the gasolene variant. I don't know how the deceleration engine braking varies between the two or dsg versus my manual transmission. I'm not complaining with 47 mpg from a heavy EOS mind you. Just thinking a perkier gasolene motor could mean more control over (i.e less) braking.
 
#10 · (Edited)
I know that the petrol engine is aluminum. What about the Diesel? Aluminum or cast iron.

Also, doesn't the diesel have higher compression than the petrol, which should relate to better engine drag while slowing?
 
#13 ·
I was going to say I have rarely encountered brake fade on U.K roads except when I used to tow, but mountain driving is a hard test for the braking system on any car. When I first looked up the weights for the EOS, I thought at the time it was quite a heavy car and that swung me towards the Tdi for its mpg.

As far as I can see, the Tdi motor is substantially ali. Compared to the first diesel car I owned based on a truck engine with ali heads and a steel block, I think these new diesel designs are lighter.

For your road conditions I would think ceramic pads would be a plus. For me I think front discs worn down near their limit and replaced at 32K is far too soon. I may also look at the softer organic compositions and tolerate a bit more dust. They are pretty large pads and rotors anyway compared to my previous cars. Given my less arduous driving on the brakes and lowish annual mileage, changing pads more often is preferable to replacing rotors.
 
#14 ·
Normal to see oxidation on the disc, next braking rubs it off - should be an issue, all do that.

What I didn't like was to see rusting on the wheel hubs. I spent a day with the car, removed each wheel, sanded and painted each hub and other parts and no more of that. The other parts stand out more now, such as behind the brake rotor and the caliper's.
 
#15 ·
What color and did you use heat proof paint?

So as to not go "off topic", why don't you post a new thread with details and pics?:)
 
#16 ·
I used heat-proof silver, that matches the rest. Yes, I've planned a post with pic's and how-to. Want to contribute more here; have about 1500 posts on the Miata Forum. I also undercoated the wheel wells while in there. Several others things too; I can't leave a car alone, must make it better...
 
#17 ·
Brake Discs Replaced due to Rust at les than 18,000 miles

Hi there. My Eos is just coming up to 3 years old. I have therefore just had my 1st MOT test and also had the Car serviced. I was contacted during the service to be told that the Brake Discs were very Rusty and I should consider replacing them. I said Fine, the Car is still under Warranty. They said But work on Brake Discs is Not covered by the Warranty ! I said so you mean to tell me that you would have to replace Brake Discs at less than 18,000 miles. They still said it was not covered. I had them replaced and then complained to VW. Their response was to basicly Ignore me and Fob me off when I contacted them.
APALLING CUSTOMER SERVICE !!!
These Brake Discs had Not worn out, they had corroded. I feel that this should have been covered by the Warranty. I have told VW this.
Reference to the Warranty shows that Brake Discs are only covered up to 6,500 miles along with Lots of other things. So it sort of makes you wonder whether the Warranty is worth the paper it is written on.
 
#18 ·
Rusty discs per se is not an mot fail, provided they are not worn below the manufacturer recommended thickness, the pads are not worn to their minimum,there are no cracks in the discs and they pass the roller brake test. You should first ask the dealer if they consider your discs an mot failure and why, asking them to quote the relevant paragraph in the mot testers manual.

They will normally just feel the ridge at the top ege of the disc and then say 'failed due to worn disc' when they are not worn to minimum spec. when you check thickness with a vernier. I normally stop their opinionated conclusion by grinding off the wear ridge. That forces them to do a measurement with calipers. Of course. I've already done that and know what the thickess is. If they try it on I formally appeal. In the past I've had 2 fails converted to passes where they have not followed the rules in the testers manual.

Brake discs will often corrode quickly if the car is left standing for long periods, used infrequently on salted roads or left parked for long periods over grass. Without seeing your discs it is difficult to say whether their opinion is fair or not, but remember VW replacing discs is an easy peasy job with a lot of markup (profit) at the end. You can buy a pair of new aftermarket front discs for around £60.

Not all is good on VW discs and pads. I replaced mine on our EOS sport TDi at around 20K and I thought that was very poor being only 2 years of average mileage for most. The disc wear was higher than I expected and I noticed a considerable amount of steel embedded in the old pads which soaks up water and increases rusting if the car is not regularly used.

My gut feeling is the VW pad composition is extremely hard, great for high speed breaking with reduced fade, but increases wear on the discs. Although I replaced the old pads and discs with equivalent spec. aftermarket pads, I shall be measuring the disc wear after 10K and probably change to a softer pad composition.

In case you are wondering about the size of the EOS discs, they are HUGE so pad and disc wear is not due to poor sizing design of the disc or pad area.

Warranties do not normally include 'wear components' like pads, discs and clutches because a car can be driven unusually hard and these are the things that take more wear for a low mileage.

Get confirmation on whether the discs and pads will pass an mot first as they are. Ask them to show you the rusting (and wear) then decide if you want to get the discs replaced. Of course you would not replace discs without a complete new pad set so I would wait until I needed new pads if they had more than half the friction material left - probably about another 8-10K miles.
 
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