Painting Rear Brake Drums.

[chrisash86]

Hi everyone I need to paint my rusting brake drums as I haven’t done it before I have a few questions.
1. What’s the best spray or paint to use?
2. Is it better to take the drum off.
3. Do u use rust remover on it before spraying and if so will I need to use primer .
Thanks everyone and stay safe

[thomas]

I would treat the rust first, or it won't last a fortnight, but some products might make such claims.

Can't say if this is the best, others will have their own preferred and maybe better techniques.

Scrape the worst off first with some 40 grit production-paper, then wire brush to get into the pitted areas. Then stipple in using an old stiff short paintbrush some phosphoric acid gel, something like Jenolite first (careful with this it can burn the skin, nip any small cuts or nicks), couple of applications, wash off with water and the same old brush, each time left on each for 8-10 hours, follow it up quickly with something like Kurust rust converter, leave to cure, maybe 4 hours or so, scuff off any excess with some rough sandpaper, then paint, prime if possible, a zinc-based anti-rust primer, you can probably sand this a little too, a finer grit, leaving it in any low areas, then some more hard wearing finish coat that can take the high temperatures, either engine paint, or specialist paint for brake calipers/drums.

It's how I would do it if not under time pressure or a need to use the car part-way through. Each to his own though, some might have had decent results with a quick blow over, but done right it shouldn't need redoing too soon and will look good for a long time. If they're never seen, then brushed on paint products trump sprayed on for coverage and again getting into any pits or depressions. It's best done in warm, dry, low humidity conditions.

Other perhaps quite different advice is just as valid. Good luck, take some pictures along the way!

[iangsi]

I did this on one of my cars a few years ago and I took the drums off wire brushed them off & just sprayed them with heat resistant paint looked OK & lasted a few years.

[Robsey]

Drums removed of course.

Probably get the drums bead-blasted,
then have the drums primered and painted.

Normally something like rustoleum should be enough, without need for separate rust treatment or primer.

But you should use a few mist coats before applying two or three decent layers.

But yes - the surface needs to be clean and dry, and painted on a warm dry day.

[James McGrath]

The best possible finish would be to get them powder coated. However that would be expensive.

Personally, I would take them off, give them a good going over with a wire brush inside and out, then use some 000 or 0000 grade wire wool to smooth them down, then paint them with Hammerite Direct to Rust paint.

[thomas]

I've always thought of drums as being consumable items on more modern high-mileage cars, thus not worth the trouble to spruce-up, but realise that most Cavaliers no longer fit that description and they could become scarcer if there aren't compatible equivalents still in production, and disks on the rear are becoming prevalent, so even old-stock aftermarket items could begin to dry up. Drums for the smaller, pushrod-engined Vivas are simply not available anywhere anymore and Morris Minor parts, requiring some modification on a lathe are having to fill in, but will at least ensure continued availability. ABS on facelift models could prove a curse if they're different from the basic non-ABS drum. It doesn't bear thinking about if so, but some day it will have to be faced. It's compounded too by the idiotic scrappage scheme and the disposable society too, which saw as well as some good cars, lots of good spare parts senselessly destroyed.

[Robsey]

The best possible finish would be to get them powder coated. However that would be expensive.

Shouldn't be too expensive for powder coating.

I suppose it depends on the colour.
If it is a colour that they use a lot, it could be done quite cheaply along with another cuatomer's batch.

A colour that is unusual or being used purely for your job could be more expensive, due to a minimum batch fee.

I had a whole rake of parts done in black four years ago, for £60.
That included both anti-roll bars, the rear beam, the front sub-frame, various clamps and a front suspension leg.

It looked fantastic too.

Two years later, I had five fan-blade alloys and four centre caps done in gun metal grey metallic.
A lot more expensive at £160.
Probably due to the colour.

[Robsey]

ABS on facelift models could prove a curse if they're different from the basic non-ABS drum. It doesn't bear thinking about if so, but some day it will have to be faced.

The ABS part is built into the hub assembly.
All drums are 200mm internal diameter.
1.4 to 1.8 engined cars have the same drums.

2.0 and 2.5 engines are disc brake vehicles.

[3cav3]

I'd be tempted to give the drums a light skin inside and out in a lathe, having said that a new set for my Astra Van was so cheap that I'll be etch primming them then spraying in something like hammerite black. For the few quid they cost I felt it was better than spending the time cleaning up the old ones.

[thomas]

ABS on facelift models could prove a curse if they're different from the basic non-ABS drum. It doesn't bear thinking about if so, but some day it will have to be faced.

The ABS part is built into the hub assembly.
All drums are 200mm internal diameter.
1.4 to 1.8 engined cars have the same drums.

2.0 and 2.5 engines are disc brake vehicles.

Excellent, thanks for that, it's good news, it must have been the hubs I was thinking about as had read something, probably here or in the Haynes book, mis-remembered it and expected something would have to be different in the rotating parts for the ABS to work. One less worry.

I'm trying to think of what other than actual consumables, pads, shoes and drums, tyres, bulbs, the odd battery, actually failed over 175,000 miles in the K-reg 1.6L, and it's a short list.

Timing belt only once spontaneously, though it was changed occasionally when having to replace a failed tensioner wheel once, water-pump once and again when camshaft and lifters were changed (for cheap Powertrain ones) and that only because it had developed a top-end clicking after using an engine-oil flushing product. Another belt too when the head gasket went, not catastrophically, but number 4 cylinder (nearest the dizzy) developed hydraulic-lock after the car had been left unused for a couple of weeks, I had sensed something was wrong months beforehand as it wasn't climbing hills with its usual gusto, but I continued to use it for six months even when it got worse and would not turn over after being left just three or four days, continuing still to use it for a while just by removing the plug, cranking it over to eject the water then replacing the plug and away it would go.

That was about it for major items, minor items were handbrake cables, a clutch-cable once too and a sometimes iffy headlamp height adjuster that sometimes just clicked, but simply pushing the parts together cured it. Some plastic part in the front suspension too, anti-roll bar linkage I think and a broken front suspension spring.

[Robsey]

I'd be tempted to give the drums a light skin inside and out in a lathe.

Be aware, that there is only a little amount of wear permitted.

I have never known anyone to measure it, but max internal drum diameter is 201mm.
So only 0.5mm thickness of material, before the drum is officially worn to excess.
In old English money.. only 19.6 thou of an inch.