Rusting Brake discs

[OneForTheRoad]

These are Mercedes OE ones.

As they say the best or nothing. Or something like that.


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Mercedes make nothing. All parts come from other companies like ZF . bosch . pagid . same parts that mercedes counters are happy to serve you with at twice the price.

 

[magpiemalemerc]

i know it's not the same but I got similar to wd40 on my bicycle disk brakes and the pads got contaminated they have not been the same talk about squealing....Contaminated pads with an oil base product is a no no in my book...My disc's are original and do not get orange even after a week a mild rust colour but nothing more my motorcycle disks are the same after one day.

 

[magpiemalemerc]

But too the same extent?


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Tek some pictures to show how bad ??

 

[DSM10000]

But too the same extent?


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Of course, it;s atmospheric, any air flowing around the car can deposit moisture.

 

[Petrol Pete]

WD40 is not a lubricant only a water repellent .And after time will evaporate .. I have done this in the past .

WD40 is 25% mineral oil. Its a lubricant. Sometimes you see idiots using it to 'help' them drill holes in steel. They remain idiots.

 

[steeevo]

Thought that was a joke when you said about spraying your discs with wd40

 

[Turbo1]

Thought that was a joke when you said about spraying your discs with wd40

Why would it be a joke. It’s a water repellent and stops rusting.


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[whitenemesis]

It's also a lubricant and will leave a layer of non-volatile slip agents on the disc (and pad) surfaces (which is what prevents rusting) ...

 

[Turbo1]

It's also a lubricant and will leave a layer of non-volatile slip agents on the disc (and pad) surfaces (which is what prevents rusting) ...

I’ll put it simply. You press the brake pedal and the car stops.

I didn’t apply any more wd40 and they’re now rusting. It’s safe to say there is no layer of slip agents on the brakes.


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[whitenemesis]

I’ll put it simply. You press the brake pedal and the car stops.

I didn’t apply any more wd40 and they’re now rusting. It’s safe to say there is no layer of slip agents on the brakes.


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II'll put it even more simply, there is ~30% lubricants i.e. non-volatile ingredients in WD40 and that will impregnate the pads and coat the discs.

Applying the brakes will stop the car but does it stop as quickly as one not sprayed with WD40?

Either way surface rusting is quite common and harmless, quickly removed on the first couple of brake applications. It happens to all mild steel rotors.

If the discs are now rusting then, correct, no more slip agent (rust suppressant) on the discs. That's not to say the pads aren't contaminated.

 

[Turbo1]

If the discs are now rusting then, correct, no more slip agent (rust suppressant) on the discs. That's not to say the pads aren't contaminated.

If they were I wouldn’t be here. Car stops fine and a hard stop triggers the ABS. Thus the pads grip enough to lock the wheels up. If they were contaminated this wouldn’t happen. Any heat generated after braking will “boil” any slip agents off the discs and pads.

This is a safe thing to do and it’s right to do it as it will preserve the life of the brake discs.




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[clk320x]

If they were I wouldn’t be here. Car stops fine and a hard stop triggers the ABS. Thus the pads grip enough to lock the wheels up. If they were contaminated this wouldn’t happen. Any heat generated after braking will “boil” any slip agents off the discs and pads.

This is a safe thing to do and it’s right to do it as it will preserve the life of the brake discs.




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This seems to be an issue only for you to be honest. I’ve left my car parked up for 2-3 weeks and the brake discs are looking like new after 1 min of driving.
As have many many members on here

I’d look into replacing your discs with ATE discs, as these are a known reputed brand. Perhaps what MB Have supplied is of an inferior brand (they use various different brands)

 

[Petrol Pete]

This seems to be an issue only for you to be honest. I’ve left my car parked up for 2-3 weeks and the brake discs are looking like new after 1 min of driving.
As have many many members on here

I’d look into replacing your discs with ATE discs, as these are a known reputed brand. Perhaps what MB Have supplied is of an inferior brand (they use various different brands)

Yup. My car was parked at the airport for 3 weeks this December. By the time I had driven to the exit the 'rust' had been worn off the discs before the boom opened to let me out into the traffic.
Not an issue.

 

[DSM10000]

If they were I wouldn’t be here. Car stops fine and a hard stop triggers the ABS. Thus the pads grip enough to lock the wheels up. If they were contaminated this wouldn’t happen. Any heat generated after braking will “boil” any slip agents off the discs and pads.

This is a safe thing to do and it’s right to do it as it will preserve the life of the brake discs.




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If it was safe and the right thing to do then manufacturers would recommend it. They do not!

Just because you can lock wheels with your braking does not mean that your brakes are operating at the optimum level of performance, the limit here is the grip between the tyres and road surface plus there are other characteristics such as resistance to fade etc that you may be affecting.

It is possible that continued application of WD40 might also cause the pads to degrade and break up..

Discs become coated with surface rust, it clears with normal use, try contacting the manufacturer of WD40 and get their advice regarding your use!

 

[Turbo1]

If it was safe and the right thing to do then manufacturers would recommend it. They do not!

Just because you can lock wheels with your braking does not mean that your brakes are operating at the optimum level of performance, the limit here is the grip between the tyres and road surface plus there are other characteristics such as resistance to fade etc that you may be affecting.

It is possible that continued application of WD40 might also cause the pads to degrade and break up..

Discs become coated with surface rust, it clears with normal use, try contacting the manufacturer of WD40 and get their advice regarding your use!

That’s because they want your brakes to rust and the pads to thin off the metal causing premature replacement. Selling parts make them money.

To lock up a wheel requires the pad to grip the rotor hard enough to lock it - if wd40 was so bad the discs would slip through and the car not stop.


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[DSM10000]

That’s because they want your brakes to rust and the pads to thin off the metal causing premature replacement. Selling parts make them money.

To lock up a wheel requires the pad to grip the rotor hard enough to lock it - if wd40 was so bad the discs would slip through and the car not stop.


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You are misunderstanding or just plain ignoring the advice you have been given.

Discs made of steel will suffer minor surface corrosion, that is all it is! It does not make your discs or pads wear out any faster.

I average around 80,000 miles on a set of front discs from many manufacturers over numerous vehicles and around 40,000 on front pads without resort to WD40 or similar so your contention about manufacturers wishing your brakes to rust to speed replacement is just not true. Light surface corrosion is just a result of a natural chemical reaction it is not a problem as many here have explained.

Just because the clamping force can lock a wheel does not mean that the brakes are working to their true efficiency nor does it mean that applying WD40 has not caused damage to the pads.

Write to the manufacturer of WD40 and let us know their expert opinion on the wisdom or otherwise of applying the product directly to the surface of braking systems.

 

[Wolfie1]

Got the perfect solution for you, change out your discs for carbon ceramic ones, they will never rust again

 

[Quincross]

Jeez - whoever advised you to use WD40 needs to be shot!

As others have said contaminating your brakes with it will reduce your braking distance and cause them to squeal, but that's not the worst of it...

We use it to remove brake linings from bonded brake shoes - it does a great job of weakening the adhesive used to bond the brakes and linings together. You do not want your brake pads delaminating when you use them as you will not be stopping...

Then there's what it does to rubber (swells and weakens it) - your brake pistons have rubber seals....

Seriously mate - do not use it in any way near your brakes unless you plan to immediately replace them. Or alternatively, crack on and then sue the guy who recommended it to you when things go horribly wrong in about a year...

 

[Mactech]

The relationship brake friction materials have with discs can be wonderfully robust, but sometimes frighteningly fragile.
We expect our brakes to contend with air, water, salt and all manner of other nasties thrown at them without a second thought.
Most of the time they do just that, and appear to work 'just as they always do'
On racing cars, when we have done instant repairs to get cars back in to a race, then the brake parts have gone back to battle with all manner of contaminants on them....and worked and survived until the end of the race.
But I have also known instances where just the change in a surface finish from ground to turned has been the difference between massive vibration after just a few miles and perfect brakes. I have also seen pads delaminate after contact with some oils and carbon brakes corrode rapidly when painted with a certain colour of temperature indicating paint.....
So, maybe you will get away with WD40 on brake discs for a little while....but I would certainly not be tempting fate in that way.

 

[Flackadder]

It's a metal brake disc. It gets wet...it's not wiped off and it rusts a little. Every time, in fact. When they get worn..replace them. Simple really. Has been happening for well over a millennium. Give or take a year or two.