Painting the rear brake drums of a car is often accompanied by two interrelated problems. The first of these is the choice of the paint itself. Anyhow, which one is not suitable here because of the special conditions in which the brakes are operated. The second well-known problem is that the paint begins to fall off after a year, rust appears and the result of painstaking work is reduced to nothing. The solution to these two problems, their causes and other nuances of painting brake drums are discussed in detail in this material.
Why paint brake drums
Before you do any tuning on your car, you need to set a goal and strive for it. In the case of painting brake drums, there can be as many as three of them:
- Improvement in appearance.
- Corrosion protection.
- Removal of excess heat.
On the first point, everything is obvious, since, probably, all motorists start this kind of tuning solely for the sake of appearance. Especially those whose car runs on discs with thin spokes or large holes. Rusty red brake drums are clearly visible through such wheels. They really catch the eye, spoiling the appearance of the car and the mood of the car owner.
The second point is corrosion protection. Because brake drums work under extremely difficult conditions, rust attacks them as quickly as if they had been soaked in water for days. One of the reasons why corrosion develops faster on these parts of the car than in other places is the temperature. During braking, the drums heat up. And sometimes very strongly. And the process of rust formation, like many other chemical reactions, proceeds the faster, the higher the temperature.
Of course, it takes a very long time for brake drums to rot to the impossible. After all, these are massive pieces. Nevertheless, due to corrosion, if you do not fight it, the bolts will soon turn sour, the hand brake will wedge, and the shoe drive mechanism itself will not get better from rust either.
The last point is debatable. Some say that there is no heating of the rear brake drums. Others are taken to suggest that there are 120-140 degrees Celsius. There are also those who (according to them) have brakes heated up to +600°C. And this, for a moment, is almost the melting point of aluminum. In general, who just does not say anything.
Meanwhile, nevertheless, there is information that when painting brake drums, the goal is often to improve heat dissipation. At least not make it worse. Whether such a goal would be reasonable for you should be looked at locally. Fortunately, today there is no problem at home to measure the surface temperature of any part of the car. To do this, just load the brake system, and then put your finger on the brake drum or spit on it, use a multimeter with a thermocouple. You may be surprised by the results.
How to paint brake drums
The issue of choosing paint is most complicated by the disagreements described above. Some say that any enamel will do, since the drums do not heat up in any significant way. Others say that you need a heat-resistant paint that can withstand one and a half hundred degrees Celsius. At the same time, by the way, they often spray it on the most common primer. There is also a version that the best option, what kind of paint to paint the brake drums, is powder. Allegedly, it will not even have to be baked in the oven. The temperature to which the brakes are heated during natural operation will be sufficient.
Who to believe? And you need to believe in real practice, which has repeatedly shown that ordinary heat-resistant paint is the best suited for these purposes. But only under certain conditions. First, the parts must be properly prepared for painting. Secondly, it is worth looking for a heat-resistant primer, or else abandon its use altogether. Thirdly, the painting process itself also greatly affects whether such tuning will last less than a year, or will please for several years.
A few words, probably, should be said about how to paint brake drums in terms of application technique. After all, there are disagreements here too. Especially motorists spit in the direction of painting with brushes. Allegedly, because of this, divorces, furrows and other jambs remain. However, they are wrong. It is bad to paint with a brush, not because it is done with a brush, but because the hands grow from the wrong place. If you correctly approach the process, then manually it will turn out perfectly. The key factor here is the consistency of the paint, or, more simply, its density.
Just because the prepared paint is too viscous or, conversely, too fluid, either brush furrows or gaps remain. With the right consistency and a well-prepared surface, the paint lays down perfectly on the part. Believe me. It takes practice to get that result, of course. At the same time, it is important to train on exactly the paint and surface with which you want to get an excellent result.
Of course, for many it seems much easier to paint brake drums from a spray can. But that's just how it seems. In fact, if there is no special experience, then far from everyone can apply paint evenly from a spray can. There are gaps left, and even more often - influxes and drops hanging down then. And this is despite the fact that the manufacturer writes on almost every can of paint: two thin layers are better than one thick one. Believe me, this is the most important. Again, it takes practice to get good results. Moreover, it is with the paint and surface with which the main work will be carried out.
If among the information presented above you missed the main thing, then here it is:
- the paint is suitable for ordinary heat-resistant;
- if primed, then also with heat-resistant primer;
- if this was not found, it is better without soil at all (contrary to myths, it will hold on no worse);
- with a brush or a spray can - it doesn’t matter, since you can mess up with both (as well as get a good result).
Let's go further.
To remove or not to remove drums
There are only two answers to this question. But with clarifications. First, don't shoot. But with this approach, you will need to work hard to protect the rest of the details in the vicinity from paint. It is also quite difficult to properly prepare the drums for painting right on the machine. Or rather, it won't work at all. And all because it is impossible to completely remove rust from parts without removing them from the car. Although this, just the same, is much more important than the choice of paint and the method of its application.
Accordingly, the second approach - when you need to shoot - is preferable. Of course, it will take a little longer to tinker. However, unlike painting calipers, in this case, at least the brake system does not need to be drained, and then pumped, and so on. But you can better prepare the parts for painting. You will remove traces of corrosion that cannot be left, even in a minimal amount. In addition, it will be possible to choose any convenient place for painting, avoid getting dust and dirt on fresh paint, and apply paint in any chosen way with better quality.
How to paint brake drums
The process of painting brake drums is described on the example of parts completely removed from the machine. If you decide not to disassemble anything, then you will need to carefully close the area from accidental paint ingress. How to dismantle the brake drums in your case, see the owner's manual for a specific vehicle. As a rule, the procedure is not too complicated. Especially if you do a lot on your car with your own hands.
Algorithm for painting brake drums:
- The first step is to remove rust mechanically (brush, grinder with a brush, sandpaper, etc.).
- For the best effect, the drums should be soaked in a solution of some kind of acid. Suitable lemon or vinegar.
- After soaking in acid, it must be carefully neutralized. To do this, the parts are washed for several minutes in water in which baking soda is previously dissolved.
- Instead of soaking in acid, you can use a rust converter. These funds also contain it in their composition.
- Rust converters have proven themselves especially well, which form a ready-made primer layer on the surface of the workpiece (transparent or zinc-colored).
- All these five points can be skipped if it is possible to remove traces of corrosion by sandblasting.
- Cleaned drums are degreased. Be careful with degreasers. Many of them "conflict" with some types of paint. The manufacturer writes about this on the packaging.
- Next comes the priming step. We repeat that it makes no sense to use a conventional primer. If your drums get hot (how to check, described above), then no matter what paint you buy, it will peel off in less than one season.
- Paint application is carried out in accordance with the recommendations on the package. The main rule is thin uniform layers, between which there is a break. Only it is necessary to wait not so much, for how long the paint completely crystallizes. Each next layer is important to spray (or apply with a brush) over the still slightly “raw” paint.
- Painted brake drums can be varnished for a sheen. Only, again, not the first varnish that comes across is suitable, but only heat-resistant.
After completing all these steps, it is important not to rush. The applied materials must be given time to crystallize. Otherwise (and more often it happens) there is a risk of damaging the paintwork during the reinstallation of the brake drums. Riding with freshly painted parts won't improve them either. Dust will stick to the paint that has not yet hardened, chips and scratches will appear. If this happens, then you can safely assume that you have wasted your time. After a few months, the drums will rust again and the paint will start to peel off in places.
What color to paint brake drums
The question of what color to paint the brake drums belongs to the category of those that are about common sense. However, if you are having difficulty with this issue, here are some universal solutions to the problem:
- paint in black - here this color is appropriate in any situation;
- silver also applies to universal colors;
- it is better to take dark paint for light discs, and vice versa;
- poisonous colors (red, pink, purple) are not bad taste.
Even in such situations, the so-called color matching tables help a lot. There are plenty of these on the Internet. From them it is quite easy to understand which color of the drums will look better with certain discs or the main shade of the car.
You can see an illustrative example of working with such tables right on this site. At the time of this writing, only two colors appear here. The main one is grey. And menu items, links, and other things that you can click on are painted in a dark turquoise version. Since you are reading this, it means that your eyes have not fallen out yet. And this, in turn, means that the colors are chosen correctly. On machines, this principle also works fine.
Why paint doesn't last long on brake drums
Instead of the traditional results, let's talk about the mistakes that cause painted brake drums to lose their presentable appearance in less than a year:
- Details were not carefully prepared for painting.
- The acid has not been neutralized after use.
- The surface of the drums was not degreased before painting.
- Inappropriate primer.
- Not heat resistant paint.
- The layers are too thick.
- Brake drums put into operation immediately after painting.
In fact, these are all the main reasons why “experts” later write on the forums and in the comments under the articles that the paint began to fall off earlier than we would like. If these nuances are taken into account when performing work (without exceptions), then you can even get closer to the quality of factory painting. There is even hope that there are some among you, and you will share your successes in the comments below.