Stop rust getting on your discs

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APDevelopments
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Stop rust getting on your discs

Post by APDevelopments » 10/08/17 23:35

Hi guys.
On my mr2 lambo kit car. I spent serious money upgrading the brakes.
I wanted the same spec as a real Lamborghini so I got these 6pot front calipers with drilled and vented discs. 4 pot rear calipers with vented discs.
All made by hi spec motorsport in daventry.
Now that the cars on the road I gave the car its first wash after last weekends play.
The car then spent a few days under cover in the dry.
I can't beleave how the discs have started to rust. Surface rust in the vents and holes of the discs.
The calipers have been power coated so they won't rust.
Hell no. There is no way these baby's are going rusty.
I will not drive the car in any rain. If there's a hint of damp on the weather forecast she stays locked away in my garage.
What can I do to stop my discs going rusty when I wash the car?
They need to be cleaned as they make a lot of brake dust.
Other than spraying the discs with 3 in one oil before getting them wet to protect them from the water how else can I protect the discs from nasty surface rust?
Many thanks
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TonyleFrog
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Re: Stop rust getting on your discs

Post by TonyleFrog » 11/08/17 0:09

APDevelopments wrote:
10/08/17 23:35
What can I do to stop my discs going rusty when I wash the car?
If it bothers you that much, go for a drive and give the brakes a good work out to evaporate any residual moisture. Alternatively take the wheels off and dry the discs by hand using an old towel.
APDevelopments wrote:
10/08/17 23:35
Other than spraying the discs with 3 in one oil before getting them wet to protect them from the water how else can I protect the discs from nasty surface rust?
See above.

3 in 1 is a lubricant. If you value your safety you don't want this anywhere near your brake pads.
The only reason you might use it is if you are laying up the car for an extended period and you would still need to clean off the discs before driving the car again.
APDevelopments wrote:
10/08/17 23:35
All made by hi spec motorsport in daventry.
Btw, HiSpec Motorsport are based in Dartford (just up the road from me), not Daventry. http://www.hispecmotorsport.co.uk/
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Re: Stop rust getting on your discs

Post by jimi » 11/08/17 1:42

There's no way you can stop it happening to metal discs, the first few applications of the brakes will wipe out any light surface rust.
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Re: Stop getting rust on your disks

Post by Torero » 11/08/17 8:14

Keep it parked up and garaged out of the UK elements is the only real answer as it's the atmospheric moisture that causes a reaction with the ferrous compound in the brake disks.

I have to say that is one amazing looking car. :clapping:



BTW - Can you change the title slightly to "How do I stop getting rust on my brake disks" - it looks like you're offering a solution rather than asking a question.

Sorry to be picky - but it helps other forum users for archive and search purposes. :th:

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Re: Stop getting rust on your disks

Post by Rev5v6 » 11/08/17 9:55

Torero wrote:
11/08/17 8:14
Keep it parked up and garaged out of the UK elements is the only real answer as it's the atmospheric moisture that causes a reaction with the ferrous compound in the brake disks.

I have to say that is one amazing looking car. :clapping:



BTW - Can you change the title slightly to "How do I stop getting rust on my brake disks" - it looks like you're offering a solution rather than asking a question.

Sorry to be picky - but it helps other forum users for archive and search purposes. :th:
Exactly, I was expecting some hallelujah product (or snake oil) that would show us how its done…


But i'd go with the above advice, no rain, temperature controlled garage - hmm, with the no rain proviso its going to stay low milage ?

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Re: Stop getting rust on your disks

Post by Torero » 11/08/17 13:35

Rev5v6 wrote:
Exactly, I was expecting some hallelujah product (or snake oil) that would show us how its done.
:th: :th: :th:

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Re: Stop rust getting on your discs

Post by shinny » 11/08/17 13:57

"I don't want rust on my brake disks"... then drive the thing... often! Also, it's fun :th:

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Re: Stop rust getting on your discs

Post by chris » 11/08/17 22:47

Not sure whether this post is a p!$$ take or not?!?
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Re: Stop rust getting on your discs

Post by MR2DI4 » 11/08/17 23:40

chris wrote:
11/08/17 22:47
Not sure whether this post is a p!$$ take or not?!?
LOL

I removed and redid all the brake rotors on the Subaru 3.0R as someone had kindly put a nice set of slotted aftermarket rotors on it.

All you can do is rust prevent all the areas that don't come in contact with the pads and spray them with some heat resistant paint. Did mine in silver and they look great. I masked off the area in contact with the pads before spraying them.

Any rust on the surface of the rotor that comes into contact with the pad is not worth worrying about, it disappears after you first put on the brakes.

Also I had no luck when I carefully cross drilled my brand new front stock MR2 rotors like that. For one they cause a "Whistle" under fast braking and the rotor wear was uneven and they ate the pads like a cheese grater. It will be the last time I run anything cross drilled again.

There are probably bigger things to worry about than a bit of surface rust.

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Re: Stop rust getting on your discs

Post by Rev5v6 » 12/08/17 0:19

MR2DI4 wrote:
11/08/17 23:40
chris wrote:
11/08/17 22:47
Not sure whether this post is a p!$$ take or not?!?
LOL


Also I had no luck when I carefully cross drilled my brand new front stock MR2 rotors like that. For one they cause a "Whistle" under fast braking and the rotor wear was uneven and they ate the pads like a cheese grater. It will be the last time I run anything cross drilled again.

There are probably bigger things to worry about than a bit of surface rust.
Now thats gotta be a p!$$ take! You cross drilled your own brand new rotors?! Have you been watching bro' town too much??

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Re: Stop rust getting on your discs

Post by pbmr2 » 12/08/17 0:33

Best tell Porsche to stop selling cars with drilled brakes then.

What bevel angle did you use for the holes?
How did you balance the discs afterwards?
Have they started to crack yet?

DIY cross drilled discs, that's classic pure internet gold that is!
"Stop buying parts to solve the problem, findout what's wrong first!"

"Time is the true wealth, spend it well."

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Re: Stop rust getting on your discs

Post by MR2DI4 » 12/08/17 3:37

I made a gauge that went into the slots to create a line for the holes.

The holes were not random but spaced based on the hole diameter, the theory is that if you then choose any point on the rotor, at some point there is part of a hole on it.i.e if you rotate it one revolution just about the entire pad has a hole pass over it. Obviously you cannot get right to the outside and typically not the inside either, thats why i recon slots are better, they cover the entire pad.

Having learned from racing Karts that came with a factory drilled rotor which was not correct because the holes did not overlap. The issue this causes is uneven wear in the rotors as the pad that is in contact with the holes wears at a different rate than parts of it that are not.

Probably the biggest issue is I went for 8mm holes, a bit to big. You want to go smaller then buy a tool that gives you a radius on the holes, the 45 Degree sharp edge is a killer if you use a standard countersink.

Hell what the heck they looked great but cross drilling them was a waste of time. Still got them but they are only good for one set of brake pads then you need to machine them again and most people over here do not have the right gear to do that properly, you need a decent rotational grinder not the lathe type setup so I just buy new rotors.

The rotors didn't need balancing, Toyota don't do that in the factory. The MR2 brakes are small by comparison, the aftermarket Subaru brakes are huge in 18" wheels and they are factory balanced, you can see the machining marks on the outside if they need it.

They don't crack, thats the advantage of a circular hole, no corners. You would only worry if you tried to run the rotors below the minimum thickness.Saw this in Kart rotors they tried to save weight, reduce the rotational inertia and the result was rotors that cracked and fell to bits because they were like 3 mm thick each side of the vents.

Loved the Kart racing from an engineering perspective, things destroy themselves about 100 times faster on the track compared to the road.

Post a :laughing reply and if I get enough of them I will post a picture of the cross drilled MR2 rotors.

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Re: Stop rust getting on your discs

Post by TonyleFrog » 12/08/17 9:40

Well, you asked for it...
MR2DI4 wrote:
12/08/17 3:37
They don't crack, thats the advantage of a circular hole, no corners.
:laughing :laughing :laughing :laughing :laughing :laughing

It is the very existence of the holes that increases the chance of cracks developing. Look up geometric discontinuity and stress concentration.

You are correct about the need for a radius at the edges. This is essential but it is still a palliative measure. Better not to drill holes in a stock MR2 rotor in the first place.

If you're hell bent on having them, everything depends on the material properties of the rotor.
I will bet £10 to any charity of your choice that those on, say, a Porsche GT3 are way different from (i.e. superior to) stock MR2 ones. Or, for that matter, any of the cheap aftermarket drilled offerings that most people buy.

I'm also prepared to bet that their choice of the latter is solely for the perceived aesthetic value, not from any sound engineering principles.

"Cool i n n i t bro'..."

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ETA for completeness. Even Porsche rotors are not immune to cracking. OEM guidelines.

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APDevelopments
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Re: Stop rust getting on your discs

Post by APDevelopments » 12/08/17 23:25

Just to update this post.
No this post is not a p1$$ take.
I am seriously looking for a way to stop my £3500 discs from getting rusty when I wash the car.
Well after a lot of searching I have come across this product.
Not sure how it works but I think it's worth a try at least.
So I'm ordering some.

http://www.motorgeek.co.uk/cgi-bin/ecom ... b_pid=1178
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