New drums rusting

[ltslimjim]

Okay, well...this sort of surprised me. Had previous drums go from being out of round(busted wheel cylinders).

The new drums that were installed just 2 weeks ago now work fine and are solid. (Beck/Arnley Premium)

However, just one week since installation(during a road trip) and I notice there is a distinct orange, rust-like splattering all over the exterior of the drum. Rust?

New to treating rust. It's early on and I don't want to waste these drums and pay out another $75+. I can post pics. It's all over...I want to address the rust and paint over the drums with something that will protect after treating the rust.

Any ideas or tips, I came here for the best. Thanks guys.

 

[Bluestream]

They're steel brake drums and they are going to rust; don't worry about it...

 

[ltslimjim]

Hmm, I suppose I never noticed rust on the stock Honda drums; replaced just now. They were on the vehicle for 20 years, so IDK.

 

[wallyuwl]

Same thing happened to the new drums on our Vibe last year.

I took them off, took a steel brush and soapy water to them, then brake cleaner. Then I sprayed 4-5 light coats of silver "caliper" (high-temp) spray paint on them (availably at any auto parts store). Took me maybe 3 hours total, including dealing with getting the rear wheels off (and on - and I didn't have an impact wrench at the time) and dry time for the paint. They look great ever since.

 

[Donald]

So want some type of caliper paint. The better paints have some ceramic in them. I just bought a kit on Amazon for under $20. They have all kinds of colors. Pink? Orange?

I am guessing, but the paint you brush may have more heat resistant stuff in it than spray.

But people have been using brake drums for 50 or 80 years (before I was born) and they have always been rusting, but were behind the steel wheel and hub cap.

The rust you see will not effect the life of the drum or breaking ability of the drum, just the looks.

 

[ltslimjim]

Well, that's great to know. It is nasty behind these old alloys anyway, so no big deal. I suppose the better question is rust and it's characteristics on a soft aluminum alloy?

I should have listed to the wife, she wanted us to paint them before installation.

Oh well, in a hurry for a trip I suppose. I think the paint type is important, will probably go that route. My biggest concern is how to deal with the 'beginnings' of rust forming now. Light enough to brush off is probably true, but any special 'prep' before painting other than getting as much off as possible?

The Civic made it 2,000 miles round trip without any problems, BTW.

 

[Bluestream]

Sandblast them first, then clean with Acid/vinyl wash. Then paint with DuPont Imron...

 

[benjy]

the higher the carbon content the more rust, a friend got a gift from a machinist for his race car years ago, very high carbon steel rotors that rusted so fast but thats how they stopped his car very fast, everyone commented on the rust he just smiled everytime he used the brakes

 

[morris]

soooooo. does rust disapate heat better than paint?

 

[Donald]

Originally Posted By: morris
soooooo. does rust disapate heat better than paint?


I would say the rust would dissipate the heat better as its rough surface would be more surface area. The paint would act as an insulator, but so would the rust. But I assume its the rear wheels and 2/3 of the braking is in the front.

If the rust bothers you paint them. But I would not loose sleep over rusty drums.

 

[zeezee]

Perfectly normal. Every drum I've ever owned has rusted. Every rotor has rusted on the outside edge.

 

[ltslimjim]

^Total derp moment for me. Yes, the front rotors definitely have rust around the non-braking/friction outer rim.

I'll try to ignore it, for now, but yeah...healthy rust coating on the new rear drums. Just never saw fresh rust setting in before like this, that's what threw me off track mentally. Those old drums must have been a dark hue of burnt orange already.

It is only rear drums(front discs), and yes the rear braking isn't doing as much of the stopping. I also use some engine braking to assist the front pads/rotors.

 

[JimPghPA]

Add chrome and the steel will not rust. Add enough chrome and it is called stainless steel.

The problem is adding chrome reduces the heat conduction, and raises the cost. To get enough heat dissipation with high chrome you have to increase the surface area, ie increase the size, this increases the rotation weight, and reduces the MPG because every time the vehicle accelerates it has to put more energy into the higher rotating mass.

To get better MPGs reduce rotation weight. To reduce rotation weight use metal with better heat conduction so it can be smaller, ie no chrome.

If you polish the surface of metal you drastically reduce the microscopic surface area, and therefore reduce the ability of that metal to dump heat into the air.

So one of the big things to keep in mind with any modification you make polish, paint, or what ever else, is: will the brakes end up being too hot because the metal can not transfer heat to the air as well with the modification?

Also some wheel covers such as chrome dome (that look like a small metal salad bowl) reduce the air flow to the brakes. Put as set of those on and you better not try any big hills with a lot of weight on board.

 

[JTK]

Every aftermarket rotor or drum I've ever installed gets rusty almost immediately on the non-contact surfaces.

OTOH, factory rotors and drums seem to remain rust free for a very long time.

Joel

 

[KrisZ]

Originally Posted By: JTK
Every aftermarket rotor or drum I've ever installed gets rusty almost immediately on the non-contact surfaces.

OTOH, factory rotors and drums seem to remain rust free for a very long time.
Joel


That's because they are coated or painted from the factory. You can buy more expensive aftermarket rotors that are coated as well.

 

[mechtech2]

I use Rustoleum spray . The standard stuff in gloss black.
Wire brush them, then give them 3-4 light coats.
Touch them up every year or two.
They'll look like new for as long as you want.

Problems with heat? With normal street driving, I have seen zero problems.

 

[Michael_P]

I use Amsoil MP on the outside of my non painted drums once a year. They look practically new after 16 years and that is with Ohio winters and all that road salt. It allows for better heat dissipation than does paint.

 

[ltslimjim]

^Okay, that's another idea. I have Amsoil's Heavy Duty MP on hand that I need to find uses for.

 

[antonmnster]

That's the one disappointment I have with buying a cheap set of pads/rotors from Napa: they don't have the zinc coating that others have and my rotors rusted on the non-contact surfaces almost immediately.

If I had spent $100 elsewhere the rotors would still look perfect; when I look at new versions of my car I'm envious of their nice looking clean rotors...

 

[hattaresguy]

Brake drums rust, won't hurt them.

If it bothers you spray them black, but they will still rust after awhile.