Wagner E-coated drums are no longer coated on the inside

[SumGuy]

I had a pair of very old rear drums on my '67 Dodge shot-peened and turned earlier this year. Since they were now very clean, I painted the outside surface with DOM-16 (the Canadian version of POR-15). As far as I'm concerned, these moisture-activated urethanes are second only to powdercoating when it comes to durable anti-rust coatings for metal.

I did not paint the drum and hub mating faces, I've never had an issue with rust-bonding those surfaces, hard to see how water would actually get in there and stay there with the heat generated by the drums. A bit of grease on those surfaces will suffice.

I am curious if the OP's new drums came with balance weights welded to them. I've bought a couple new pairs of drums from rock auto this year (Raybestos brand but naturally made in china) and none of them had weights. Previous to this I had bought a pair of china-brand (Win Here) drums and again they came without weights, and a test at a local tire shop (put the drums on their wheel balancer) showed they were not balanced, one was out by 2.25 oz. These are 11-inch diameter drums, so being out of balance is noticable.

 

[Rust_Belt_Pete]

Why bother balancing them? The vanes inside will rust so badly they will lose balance in a couple of years.
Everything is getting cheaper and crappier and more expensive while you get less.

 

[SumGuy]

Why bother balancing them? The vanes inside

Are you thinking of rotors?

 

[Sumboodie]

I found Rust-Oleum engine paint that might work, but it's too cold to paint now, as they say it has to be 50-90-F. It has been 40 or below recently, and it probably won't get any warmer for awhile

Paint will dry colder. I wouldn't even fuss that it was 40* I've painted stuff when it was below zero. Obviously not ideal but it'll work. You're not painting a car or something that the finish really matters. Or spray outside and bring inside to dry... I have a shop, but it's also my house, so don't want to fume up where I eat and sleep.

BUT for the inside of a drum, just put a thin coat of antisieze or fluid film. It's got a better chance of keeping it from rusting then some paint. Least that's all I've done.

 

[Sumboodie]

Could you use something like Fluid Film or Surface Shield on them? I suppose it depends if the stuff might eventually migrate to the braking surface or not. I don't know what kind of temperatures you're supposed to spray that stuff at (Surface Shield has no mention of temperatures on the can) but you could always bring them inside and spray them in the basement if the smell doesn't bother you (you'll spend the next few days wondering why the house smells like manure).

Works fine. Just need a film of it, not globbed on. That'll have much more chance of working vs rattle can paint.

 

[Rust_Belt_Pete]

Are you thinking of rotors?

yes

 

[slacktide_bitog]

Biggest reason behind the insides not being coated anymore (at least e-coated) is the e-coat line is a pretty big operation. Most of the factories that offer e-coat require the part be sent off to another location for e-coating, then come back to get finish machined.

Even if the e-coat does occur in-house....it still requires multiple extra operations, the most problematic of which is re-fixturing and machining the friction surface while NOT machining other datum features after the coating process...this creates concentricity errors on a drum.

Ideally, we want the friction surface, the hub mating surface, and the center pilot hole all machined in the same fixturing, so they all end up with the correct relationship.

The non-coated drum, while some still might machine them "wrong" in multiple fixturings, have a better chance of being right.

It's also a much more cost effective coating process, but not as durable....which is only really an issue when we're dealing with a vented brake rotor, since it's not really possible to spray coat 100% inside the vanes, while e-coat is an immersion process which DOES coat 100% of the part.

But all of that is still being done anyway, if the outside is still being E-coated, isn't it?

I notice you're from California, where you don't have to deal with rust

Have you ever needed to hammer off a drum or rotor? Did a drum or rotor ever still not come off after repeated banging with a hammer? Did you ever need to lower the car until the drum or rotor hits the ground then jack the car back up? If you never had to do that, then you don't know how important it is for the inside to be coated!

And if E-coating is that hard, then switch to a Geomet type coating that can be done in-house and easier.

Plenty of cheap no-names like UQuality and Top Notch have Geomet type coated drums, and there's also Powerstop. If they can do it, then so can reputable names like Wagner, Centric, and Raybestos. Centric and DFC have Geomet coated rotors but no Geomet drums.

Supposedly, most drums are machined on the same equipment as rotors, but DFC touts their drums as being machined on drum-specific machines

Had I known that they stopped coating the inside, I would've ordered the Powerstop drums.

I had a pair of very old rear drums on my '67 Dodge shot-peened and turned earlier this year. Since they were now very clean, I painted the outside surface with DOM-16 (the Canadian version of POR-15). As far as I'm concerned, these moisture-activated urethanes are second only to powdercoating when it comes to durable anti-rust coatings for metal.

I thought POR-15/DOM-16 only worked on rust. These are brand new drums. Their FAQ page says it doesn't work well on good metal

I did not paint the drum and hub mating faces, I've never had an issue with rust-bonding those surfaces, hard to see how water would actually get in there and stay there with the heat generated by the drums. A bit of grease on those surfaces will suffice.

I am curious if the OP's new drums came with balance weights welded to them. I've bought a couple new pairs of drums from rock auto this year (Raybestos brand but naturally made in china) and none of them had weights. Previous to this I had bought a pair of china-brand (Win Here) drums and again they came without weights, and a test at a local tire shop (put the drums on their wheel balancer) showed they were not balanced, one was out by 2.25 oz. These are 11-inch diameter drums, so being out of balance is noticable.

I didn't see any balance weights on my drums. However, I have seen small cuts in rotors before, for balancing. I assume they'd probably make cuts rather than add a weight

If your Winhere drums aren't coated, and they don't make coated drums, and you ever need drums again, consider UQuality. They seem to be the cheapest coated drums available in Canada

 

[SumGuy]

I thought POR-15/DOM-16 only worked on rust. These are brand new drums. Their FAQ page says it doesn't work well on good metal

I didn't see any balance weights on my drums. However, I have seen small cuts in rotors before, for balancing. I assume they'd probably make cuts rather than add a weight

If your Winhere drums aren't coated, and they don't make coated drums, and you ever need drums again, consider UQuality. They seem to be the cheapest coated drums available in Canada

Those "paint over rust" paints of course will tell you they work fine when painted over rust (but not rusty chunks that you can chip off). They will have problems sticking to completely fresh, smooth metal, but sand blasted or sanded metal is great. The truth is, the paint doesn't know the difference. I used the stuff to paint the outside of a new steel gas tank that I believe is galvanized (and smooth). I wiped it down several times with several different solvents first to absolutely remove any traces of oil. The paint went on and stuck hard, absolutely no peeling anywhere, that was 6 months ago.

I've bought a few of those e-coated rotors from rock, but it's not a priority for me. I'm not interested in coated drums or if they say they're coated but you get them and turns out their not. The only concern I have for drums is when they come without welded balance weights. There is no way that drums can be cast or machined without needing balance weights. This is a far more important issue for drums than rotors. Practically all the rotating mass of a drum is on the outer perimeter. Not so with rotors.

All the older / oem drums I've ever seen have weights welded to them, big weights. You do NOT want to remove that much metal by cutting and drilling the other side to balance them. Drums aren't thick enough to tolerate losing that much metal.

 

[lbhsbz]

But all of that is still being done anyway, if the outside is still being E-coated, isn't it?

I notice you're from California, where you don't have to deal with rust

Have you ever needed to hammer off a drum or rotor? Did a drum or rotor ever still not come off after repeated banging with a hammer? Did you ever need to lower the car until the drum or rotor hits the ground then jack the car back up? If you never had to do that, then you don't know how important it is for the inside to be coated!

And if E-coating is that hard, then switch to a Geomet type coating that can be done in-house and easier.

Plenty of cheap no-names like UQuality and Top Notch have Geomet type coated drums, and there's also Powerstop. If they can do it, then so can reputable names like Wagner, Centric, and Raybestos. Centric and DFC have Geomet coated rotors but no Geomet drums.

Supposedly, most drums are machined on the same equipment as rotors, but DFC touts their drums as being machined on drum-specific machines

Had I known that they stopped coating the inside, I would've ordered the Powerstop drums.



I thought POR-15/DOM-16 only worked on rust. These are brand new drums. Their FAQ page says it doesn't work well on good metal



I didn't see any balance weights on my drums. However, I have seen small cuts in rotors before, for balancing. I assume they'd probably make cuts rather than add a weight

If your Winhere drums aren't coated, and they don't make coated drums, and you ever need drums again, consider UQuality. They seem to be the cheapest coated drums available in Canada

Its not e-coat...it's spray paint. Geomet is also a spray process (on brake rotors and drums).

Most don't really care too much about drums anymore, they're a dying breed. Why invest in processes and equipment to for something that you sell fewer and fewer of every year?

 

[Hohn]

I'd prefer not to spray oil on the brakes

Anti seize is thicker, so less of a chance of it getting on the shoes. If I did use some kind of oil, there are enough products that aren't a spray can and could be applied cold.

And of course, paint dries

Antiseize is only thick when not hot.

You have to think how things well behave at brake temps. I don't think you want any lube or grease anywhere near your friction surfaces.

 

[slacktide_bitog]

Antiseize is only thick when not hot.

You have to think how things well behave at brake temps.

So this is why it can't be used in place of a real coating

I don't think you want any lube or grease anywhere near your friction surfaces.

Correct, which is why I go out of my way to get coated rotors and drums and recommend others to do the same.

it's also why I'm so disappointed and pissed that the Wagner drums aren't coated on the inside despite the pictures and description saying otherwise.

 

[PF52]

POR-15 makes a product that is meant to etch new metal, thus giving a better surface for the paint to bite into, for lack of a better word. I suspect it's kind some sort of acid. Of course, painting the actual paint indoors is still going to be just as stinky.

 

[nthach]

Could you use something like Fluid Film or Surface Shield on them? I suppose it depends if the stuff might eventually migrate to the braking surface or not. I don't know what kind of temperatures you're supposed to spray that stuff at (Surface Shield has no mention of temperatures on the can) but you could always bring them inside and spray them in the basement if the smell doesn't bother you (you'll spend the next few days wondering why the house smells like manure).

Fluid Film will melt, which drum brakes can if a hub bearing is seized/worn or the brake shoes are tight and dragging.

Someone showed me dry moly spray can help - and it has the advantage of being a high-temp lube. I’m trying that out on a car that sees Tahoe.

 

[Hohn]

POR-15 makes a product that is meant to etch new metal, thus giving a better surface for the paint to bite into, for lack of a better word. I suspect it's kind some sort of acid. Of course, painting the actual paint indoors is still going to be just as stinky.

It's just a phosphoric acid rust converter kind of product. It works, but don't pay a premium for generic phosphoric acid.

 

[Rust_Belt_Pete]

surface prep is 90% of pain job.

 

[slacktide_bitog]

Going back to Rock Auto's catalog, I noticed something else: some have those bolt holes where you can screw in a bolt if the drum gets stuck on the hub.

The Wagner drums don't have those holes, but Powerstop does, even though it's less likely to freeze in the first place.

Centric and DFC have those bolt holes, and even a window to turn the adjuster without removing the drum, but only for the non-ABS base model. The drums for the ABS cars don't have either, no bolt holes and no adjuster window. The Centric Ctek (the cheaper economy drum) has the bolt holes for the ABS drum, but the Premium drum doesn't

From this, I'll basically only recommend Powerstop drums or other drums with a Geomet-type coating, and I'll even look for bolt holes too

 

[slacktide_bitog]

UPDATE
I decided to keep the Wagner drums, and I painted them with some black caliper paint I found on hand. I had to paint them inside, so it smells a bit, but that should go away in 1-2 days. I put painter's tape in the area where the shoes contact the drums, so not to get paint on them. Full cure time is 7 days, but that's ok because it will be much more than a week before I actually install them!

Sending them back would mean I'd have to pay return shipping, and the Powerstop drums cost a lot more. Once the drums and shoes are installed, they should outlast the rest of the car itself.