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To Bleed or Not to Bleed
Cameron Lovre

My Volvo and I have a clear understanding. I make the Volvo bleed every two years. In exchange, the Volvo makes me bleed regularly, frequently, randomly and without warning. Not a perfect world, but better than getting bled by leeches.

When I first learned to bleed hydraulic systems (brakes), my role was that of the Assistant. Pump the pedal a few times, then push on it, hold it, wait, pump it some more... all the while, wondering what the Other Guy was doing.

Later I graduated to the role of the Other Guy, and I enlisted the help of Assistants of my own. This practice has produced wildly varying results. I'm not sure why it's hard to understand what "hold it there" or "let it up" mean, but I've learned that it is.

So, in the interest of becoming more self reliant than I was before, I started looking for a way to bleed my brakes without needing an Assistant. The trick has been to find a Device that actually proves more reliable than an Assistant. Dubious as Assistants might be, they really can be pretty handy.

The first effort was to install bleeder screws that featured an internal ball-and-spring setup. Simply loosen the bleeder and pump the pedal a few times. (Found these at the local GenericAuto place). The ball and spring doodad would "automatically close the bleeder hole and prevent air from re-entering the system." The company that made mine unfortunately didn't do their math right, and the bleeder screw failed to properly engage the caliper. Fluid and air passed out through and around the bleeder screw, then air passed in around the screw. I was better off before I started. When I went to return these fancy schmancy bleeder screws, I learned that the manufacturer was no longer in business. Seems that people were bleeding their brakes, forgetting to tighten the screws up once finished, and crashing their cars.

This was the first experiment. I'd had better results with the Impatient Assistant.

The next device was the Mighty-Vac, a pistol grip device that attaches to the bleeder screw and uses suction to draw the air and old fluid out of the system. I had fun pulling air around the bleeder screw, slopping brake fluid around and making pretty bubbles, but I didn't really evacuate any air from the hydraulics. The second attempt with this thing was better though: I removed the bleeders completely, then covered the threads with grease and reinstalled. This kept air from passing along the outside of the bleeder, but still didn't fully evacuate the air bubbles.

This had been the second experiment. I still had better results with the Impatient Assistant. I learned that the Mighty-Vac is pretty handy for some stuff, but not for bleeding brakes.

At this point I moved toward the idea of pressurized bleeding. Everyone was talking like this was the best way to go, and after resisting change for as long as I could, I tried out the Eezibleed. This thing has a reservoir for your new fresh fluid, a fitting for a tire valve and a master cylinder cap-with-a-tube-on-it. Very easy to use:

  1. fill the reservoir with new fluid and put the lid on
  2. connect the cap-with-the-tube to the master cylinder reservoir
  3. connect the tire fitting to a tire (one with air inside)
  4. wander around the car and bleed the brakes by yourself with one hand
The tire pressurizes the reservoir, then the new fluid travels into the master cylinder and through the lines out to the wheel cylinders and calipers. That's it. My Assistant didn't assist -- he just stood there and watched. This was the easiest bleeding I'd ever accomplished.

The brakes worked fine -- this was our first success. After some months passed, the brake fluid did what brake fluid does: started looking yucky. After about the third time Marcus said something like, "I wouldn't drive with that," I decided to change the fluid again. We moved on to the fourth experiment: the Motive (that's the brand name) Power Bleeder.

Like the Eezibleed, this has a cap with a hose and its own reservoir. But instead of relying on tire pressure to evacuate the fluid, this thing has a nifty handle just like your backyard pesticide sprayer.

  1. fill the reservoir with fluid and put the lid on
  2. connect the cap-with-tube to the master cylinder
  3. pump the handle until the dandy pressure gauge reads 10 psi
  4. wander around the car and bleed the brakes by yourself with one hand
This one worked just as easily as the last one. Very super easy. Success again.

Bleeding With a Friend:
If you have access to one, I'd put the Impatient Assistant in the #1 slot. Though Impatient and not always good at following directions, the Assistant is most easily adapted to unusual circumstances and various other tasks.

Bleeding By Yourself:
The Motive unit comes in at #1. It doesn't require that you have a tire with air on hand (less tubes to trip over) and has a larger reservoir. The instructions say to add two quarts of new fluid to the reservoir before you begin to change the fluid. We added one quart and had a bunch left over. At around $50, this is the most expensive of the lot.

The Eezibleed comes in at #2. It's about as easy to use as the Motive, it's cheaper ($25-$30) and much smaller. Possible downside -- if you use one of your tires for the necessary air pressure, be sure you don't drive away with good brakes and a now flat tire. (Yes, this is what I did.)

The Mighty-Vac and the "spring loaded ball bearing fitted bleeder screws" are a dead tie for Don't Even Bother. I wouldn't use either of these for bleeding the brakes.

The Bottom Line:
If you want the best thing, get the Motive. If you want to spend less, the Eezibleed is just about as easy to use and will offer the same good results.

NOTE: neither of the pressurized bleeders we tested work on the early single circuit brake systems -- they'll only work on the later dual systems that use the plastic reservoir. We tried modifying a master cylinder cap from an earlier car and made a giant mess of everything even though we were really careful.

Always use new brake fluid. It's cheap -- and we're talking about your brakes here. Always new.

Drive happy!

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