Coke Can for Brake Drums

[Ducked]

Encouraged by the rave reviews for "Coke Can for Brake Disks", here's a sequel.

Rusty brake drums don't seem to be as much of an issue / MOT inspection fail point as rusty disks, though they can make it difficult to get your wheels off.

Exhibit A : Mucky looking drum interior.




Exhibit B: Fair bit of rust and dust on the moving parts.



Exhibit C : Coke can makes a good scraper / clean-up tool, and leaves aluminium on surfaces and threads.




Exhibit D : Rub parts with aluminium foil with a very little sunflower or linseed oil. (self-forming metallic paint). Leave them in the sun.



Where the parts move against each other, substitute a very little high temp grease (or nothing) or you might glue them together.

I used a little PTFE tape around pivot axes and on the thread of the automatic adjuster, in the hope of finally seeing an automatic adjuster actually work.

Didn't, and therefore probably not worth the tiny risk of getting PTFE on the brake shoes.

Exhibit E. Rusty drum. I applied sunflower oil and "metallised" it with the can-disk you can see at one side.



Exhibit F: Aluminium-grey brake drum. Since I didn't want to glue the wheel on I sandwiched some polythene sheet between the wheel and the drum. The fire risk is....acceptable.



This is a FWD car so I couldn't use engine power on the rear drums, as I did on the front disks

 

[BigCahuna]

A cheap wire brush and some never -seize would be alot easier to use then a coke can, and give better faster results.,,

 

[InfmousCornholio]

Originally Posted By: BigCahuna
A cheap wire brush and some never -seize would be alot easier to use then a coke can, and give better faster results.,,


From Jersey To Taiwan...

Fellow NJian here.

 

[camrydriver111]

The final result looks really good!

 

[HerrStig]

A coat of high temp engine paint works. Don't get it on the friction surface.

 

[andyd]

I admire your your thriftiness, Duck. You cleaned up that drum really well. How long did it take? I use a bench mounted wire wheel. I don't use never seize, I use chassis lube on the hub flanges, the mounting face of the wheels and the lugs. Way cheaper and has more uses.

 

[Ducked]

Re wire brush, it'd maybe shift rust better, but it wouldn't deposit aluminium. The idea here is that using aluminium as an abrasive forces it into fairly intimate contact with the steel surface and so enhances its anti-corrosion effect.

Re anti-seize, VERY difficult to find here, though I have now located a place in the next city where I could buy a kg tub of Copaslip, which would last me until the heat death of the universe.

That's copper-base, though, which I don't like on (largely theoretical) electrochemical grounds. Its also a grease, and, while that's better on rubbing surfaces, I don't want it all over my brake internals. The vegetable oil is a paint, and sets.

Heat-resistant paint might be better (plus I could use it on the exhaust) but I dunno where to get it here.

Drum looks better than it is (especially in the thumbnail) but didn't take very long, maybe 10 minutes. I'll give it another go next time I have the wheel off.

 

[Ducked]

Originally Posted By: camrydriver111
The final result looks really good!


Thanks. I'd guess you're talking about the drum, which looks less good in real life, though still improved.

The brake internals (shown "setting" in the sun) were actually a more satisfying result.

Perhaps I can indulge in a bit of a "pitch" about that, since I find people don't "get" it.

Though it might not be sufficiently heat resistant in this application (dunno yet), this is a simple, effective (I've used it for a few years in different contexts), non-proprietary (If I thought there was a chance of patenting/making money out of it I probably wouldn't post) non-toxic (your fingers can get a bit black but it washes off), cheap (essentially free) one or two step rust removal/treatment/metal finishing method.

I think that could be mildly life-enhancing.

Of course in the First World these days cars are mostly too shiny and disposable for this kind of thing, but if I'd thought of it in the 70's when I first started messing around with bangers I think I could have reasonably expected to have a high-rise council housing block in Barnsley named after me.

They'd have demolished it by now though.

Wonder if the Cubans have tried it.

It'd probably work better with zinc rod or sheet, but that isn't so widely available for free.

 

[Ducked]

Rotating my least bad tyres to the back for the rainy season, the way you're counter-intuitively supposed to, so a chance to see how the disk and drum treatment has held up.

Drivers side disk: Not too well. This was the first one I did and I was concerned about contamination, so used no binder, and its re-rusted quite a lot.



I cleaned it up as before then used sunflower oil and foil (sparingly) on the disk rim but nothing on the inner boss because I thought it might get spun out onto the disk and pads. We'll see.



Drivers side drum, which was bound with sunflower oil, has held up pretty well, but I re-did it anyway.



Last time I just used a flattened can with a bolt through it. This time I tried a slightly more elaborate construction which didn't last very long.





Passenger side disk has held up better, but here I used a little superglue on the rim to bind the aluminium



I repeated this, and this time also used some on the inner boss, abrading/metallising with a bit of arrow shaft in a power drill. I thought this would reduce the chance of contaminating the disks/pads but wasn't very effective at laying down metal. If there's a next time, I think I'll just use the engine.



Passenger side drum the polymerised sunflower oil is rust-stained, as it was after treatment, but theres no sign of further rusting of the treated surface, so it appears to be largely stabilised.



I re-treated it though it probably wasn't really necessary



There's not much aluminium in the centre of the hub, probably because it was quite smooth due to the use of grease on the studs, so the treatment rate is to some extent self adjusting.

The drums were quite deeply rusted, and would have been difficult to clean to bright metal, but the sunflower oil seems to soak in and stabilise the surface.

There seems to be a possibility of finding a protective treatment for the disk rims and boss that wont contaminate the disks. Without one they re-rust badly.

 

[Shannow]

FWIW, boiler throats (the bottom of the furnace) in BIG boilers, coal and oil fired, and I think Gas fired were flame sprayed with Al for erosion, and corrosion back in the day.

Cool thread.

 

[Ducked]

The passenger side caliper surface treatment seems to have held up quite well too.

The method was the same, but I had trouble stripping this caliper because I didn't know to ignore the prevailing internyet advice (to use compressed air) and just blow the piston out with the brake pedal, so it was off for quite a long time, and probably got more thorough treatment as a result.

 

[Ducked]

Originally Posted By: Shannow
FWIW, boiler throats (the bottom of the furnace) in BIG boilers, coal and oil fired, and I think Gas fired were flame sprayed with Al for erosion, and corrosion back in the day.



I believe that is/was sometimes done for steel hulled boats too, though I think zinc also works in that application. It might melt on boilers.

Zinc would probably be better in this application too, but I don't have a readily available source of free zinc.

If I thought I had any chance of commercialising it (Oops, another patent opportunity gone) I'd use zinc, perhaps in combination with an alkyd resin.

 

[Brad_C]

Noooooo. Zinc continues to slowly react. Aluminium oxide lasts a lot longer as a protective surface.

 

[Jetronic]

alu/zinc sprays are very common here, and they do tend to work well.

 

[Ducked]

Originally Posted By: Brad_C
Noooooo. Zinc continues to slowly react. Aluminium oxide lasts a lot longer as a protective surface.


Not sure what you mean. Zinc is higher in the elecrochemical series and is widely used as a galvanic protection coating, so I'd expect it to work better.

 

[Ducked]

Originally Posted By: Shannow
FWIW, boiler throats (the bottom of the furnace) in BIG boilers, coal and oil fired, and I think Gas fired were flame sprayed with Al for erosion, and corrosion back in the day.



Re flame spraying, I had an exhaust manifold-downpipe gasket failure recently and took the opportunity to shove some rolled beer can into the pipe. I made a new gasket of 3-layers (too many I think) of dimpled aluminium sheet (aircon pipe cladding I found on the roof of one of the teaching buildings) with potters clay from the art department dump (or maybe fireclay, looked more cementitious then potters clay I used last time, and they've been making kilns) in the dimples.

When I make an upper gasket for a (non-cat) exhaust I don't bother making an accurate hole but just cut a cross and bend the triangles downward. This locates the gasket and the excess burns/melts off.

My theory is that this will flame spray the inside. I put about a teaspoon of portland cement in too for extra acid buffering.

Of course if the can had rolled itself up and caused a blockage I'd have looked pretty silly, but so far, so-so.

 

[Ducked]

Long, long time ago I saw some photo micrograph sections of flame-sprayed hull plate. IIRC it looked pretty porous, like sintered metal, with adherent microspheres of metal, but I suppose its tight enough for galvanic effect, and maybe provides a good key for overpainting.

 

[Brad_C]

Originally Posted By: Ducked
Originally Posted By: Brad_C
Noooooo. Zinc continues to slowly react. Aluminium oxide lasts a lot longer as a protective surface.


Not sure what you mean. Zinc is higher in the elecrochemical series and is widely used as a galvanic protection coating, so I'd expect it to work better.


It does, until it's all gone. Zinc is a sacrificial coating.

 

[Ducked]

Originally Posted By: Brad_C
Originally Posted By: Ducked
Originally Posted By: Brad_C
Noooooo. Zinc continues to slowly react. Aluminium oxide lasts a lot longer as a protective surface.


Not sure what you mean. Zinc is higher in the elecrochemical series and is widely used as a galvanic protection coating, so I'd expect it to work better.


It does, until it's all gone. Zinc is a sacrificial coating.


Nothing lasts forever.

I'd guess in a zinc-rich primer any metallic zinc that's consumed galvanically will leave zinc oxide behind, but maybe that's permeable. If the same thing happens to aluminium (less likely, but possible) it'll leave Aluminium oxide, which is relatively impermeable, so long term it might be better, IF there is a long term.

 

[Shannow]

Originally Posted By: Ducked
It might melt on boilers.


Can't use zinc on the boilers.

Even marking pens have to be low melting point metal free (and chlorine free).

Low melting point metals (or pigments containing them) can seep along the grain boundaries and cause failure...chlorinated compounts do Stress Corrosion Cracking in stainless.