Molly Jones is one of those eccentric Englishwomen who appear capable of doing anything. When it rains, she puts on a raincoat and starts digging in the garden; when the sun shines, she goes for long walks because she didn’t see much sun while growing up in England. Molly shares a smallholding just outside town with a tribe of Corgis to show her loyalty to the Queen. She writes novels and in her spare time potters around the garden. She also services her Morris Minor convertible with the help of Richard, her gardener. The local Afrikaans women think she’s totally mad; the men are thankful they aren’t married to her.
Last week, I bumped into Molly at the butcher’s. I was glad to see her because I wanted to ask her a horticulture-related question. She was glad to see me because the brakes on her car were behaving in a mysterious manner. They were fine in town but, as soon as she crossed the mountain to get to the main road, the pedal felt spongy. She and Richard had bled them three times, but it made no difference.
I asked her which procedure she used to bleed the brakes. She replied that Richard helped her by pumping the pedal while she used a plastic tube dangling in a bottle of brake fluid to make sure no air would get in. Richard pumped until there were no more bubbles in the fluid. I replied that it was good enough for a Morris Minor’s primitive system, but added that she should bring the car to us so that we could use pressurised brake-bleeding equipment.
When the car arrived, Molly presented us with a large container of brake fluid in order to avoid being charged for fluid as well as labour, but I declined the offer. She protested but I calmed her with the remark that I would not charge her if the cure
was quick.
I then asked Japie to bleed the brakes using new fluid and afterwards took Molly with me to test the brakes. I braked hard from 100 km/h a number of times and demonstrated to her that the pedal remained hard.
Molly then wanted to know what’s wrong with her “bleeding procedure”. “Nothing,” I replied, “but you used old brake fluid. The stuff is hygroscopic; it attracts water so that old brake fluid always contains a small percentage of water, especially if the container is opened and closed a number of times.” When the fluid is cold, the pedal feels hard, but as the fluid heats up the water vapourises and this makes the pedal feel soft.
