Brewers did not disinfect anything until at the very least the early XIX c. František Ondřej Poupě, a Czech brewmaster, was one of the first to take a scientific approach to brewing in his book Umění vařit pivo fyzicko-chemicko-hospodářsky popsané (The Art of Beer Brewing - A Physico-chemical Economic Description), published in the late XVIII c.. It mentioned the importance of sanitation, but it failed to capture the imagination of his colleagues at the time, something that greatly disappointed Poupě.

Before that, once the brewing proper was finished, brewers could only hope for the best. To prevent infections, they used a host of herbs and other ingredients, of which hops would ultimately come out as the standard. And still, infections with lactobacillus and other bugs, plus other defects caused by improper temperature control, etc. were par for the course.

Another way to prevent, or at least, minimize those problems, was brewing during cooler months. In most countries, the brewing season started somewhere by the end of September or in October and would finish in April or May. That is because many of the bugs that can fuck up your beer are inactive at cold temperatures. This is the reason why lager so popular and widespread once reliable refrigeration systems were developed in the late XIX c.

In any case, even the most terribly infected beer is safe to drink. Yeasts and other microorganisms that convert sugar are very picky with their environment, and if fermentation takes place, you can be pretty sure the end product will be safe to drink, whether it will taste good or not, that's another question, but I guess our forefathers were used to different standards.

Did winemakers disinfect their equipment before we figured out what bacteria was?

First a bit pedantic nuance: winemakers realistically aim to sanitize their equipment not fully disinfect. Disinfection (fully killing all yeast and bacteria) outside of laboratory conditions and without bleach otherwise is not really a realistic possibility. Bleach can not be used because it causes "corked" aromas and flavors in wine.

Anyway, being clean is and was very important in winemaking. Most wine until extremely recently (and still to a large extent) was meant to be drunk soon after it was vinified so as long as you keep your winemaking equipment clean and drink the wine quickly, you stand a good chance of not having spoilage. Of course it was a possibility anyway and thats why winemakers later turned to so2 as a preservative and sanitizer but most wine would be ok with good practices.

After vinification, an important strategy in preserving the wine from microbial spoilage was storing it in vases and wooden barrels that were lined by pitch (burnt wood resin).

For a historical example of the importance of cleanliness and preserving wine we can look to Columella (c. 70 AD) who was the most important writer on agriculture during the Roman empire. He wrote alot about winemaking and viticulture and he had commented on the importance of cleanliness. Here is a quote from Wine and the Vine by Tim Unwin:

The importance of cleanliness is stressed throughout Columella's writings on vinification, and he advocated the fumigation of wine cellars before the grapes were harvested (XII. xviii. 3). The must was to be pressed, and then stored in jars which had been lined with pitch. Interestingly Columella comments that in order to preserve the wine some people boiled the must, thus reducing its quantity by up to onethird or even one-half (XII. xix. 1), but ideally he recommends that the best wines should have no preservatives added to them 'for that wine is most excellent which has given pleasure by its own natural quality' (XII. xix. 2; Columella, 1955:229). Other popular methods of preserving musts and wine were through the addition of pitch (XII. xxii–xxiv), and, following the method used by most Greeks, through mixing it with salt or sea-water (XII. xxv). These practices recommended by Columella illustrate that by the first century AD Roman viticulture was highly developed, and most of the practices other than the concoction of various medicinal wines and the methods of wine preservation, that were then current may still be found in use today.

EDIT: I should note that there is some evidence that so2 was also used some in the times of antiquity as well, but its unlikely its use as as ubiquitous as it is now.