Product Test: brake bleeders & fluid testers
10 systems go head-to-head.
Repeatedly shouting instructions of “Up! Down! Hold! Pump quickly, push down and keep it there!” may get tongues wagging among the neighbours but will be familiar to anyone who has had to coax an assistant to operate the brake pedal, while you attempt to purge every last air bubble from the braking system.
Thankfully, one-person bleeding systems have negated the need to rope in a reluctant volunteer and are ideal for the home mechanic. Aware that fully depressing the brake pedal risks damaging the master cylinder seals, tool companies have introduced technologies that pressurise the braking system via the fluid reservoir, using a spare tyre (such as Gunson’s Eezibleed), instead of a compressor that would feature in a professional workshop. However, applying more than 20psi risks damaging the hydraulics and, because most modern tyres are inflated to well over 30psi, you have to adjust the pressure before starting work. If extensive repairs are required, you risk flattening the tyre fully and, unless you have another one to hand, or can inflate the tyre again easily, you may become stuck. Fortunately, tool suppliers have recognised this and have developed their systems with hand-operated pumps, ensuring that you will never run out of pressure.
The test procedure
One litre of brake fluid, at most, was used to test each kit, all of which were supplied with a standard 44mm cap, which tends to be the stock size for most modern vehicles. Once installed to the test car, the hand pump was operated to generate an indicated 15psi. The system was checked for leaks, prior to a rear caliper brake nipple being opened, and fluid was expected to flow for at least 30 seconds, without having to operate the pump again. We assessed how effectively each kit topped-up the master cylinder with fresh fluid automatically and checked if the reservoir was overfilled afterwards. We also measured how much fluid remained in each kit, once the auto top-up function stopped, to indicate the degree of wastage.
While we have taken official prices into consideration, we researched a lower target price and these bracketed figures are based upon those offered by credible Uk-based retailers.