We prefer the pressure brake bleed system for most cars, but when it comes to cars 30 years or older, sometimes this method does not work. The problem is that more often than not the old brake fluid reservoir will leak brake fluid when you try to pressurized it. Then you say,"No problem, I will just use the pump pedal method."
But there can be problems with that method as well. If you pump the brake pedal too hard or too much you may damage the old seals inside the master cylinder. Kent has devised a bleeding or flushing method that will help prevent this damage as well as test the health of your brake lines and hoses. He likes to call it the gravity brake bleed method with "light" pedal movement / travel. This method will really only work on cars that do not have ABS.
The trick is to bleed ALL FOUR brake calipers at the same time. This requires FOUR small fluid capture bottles with stand pipe hoses in them to prevent air from being sucked back into the caliper. Start by sucking out as much of the old fluid out of your master cylinder as you can with an extractor. Then fill with new DOT 4 fluid. Once you attach the four bottles to the caliper bleed nipples, you can open ALL bleeder fittings at the same time (about one turn) and monitor the flow rate into each bottle. Be sure to keep adding new fluid to the reservoir as the fluid begins to fill the bottles. To get the fluid moving you may need to pump the pedal lightly (only half way down) a few times. If you find that any bottle is not filling up with light pedal hlad way pthen it is a good indication that your rubber brake hose is plugged (rotted inside). When each bottle is about 3/4 full you have flushed enough old fluid out.
This kit contains FOUR bottles that come with hoses and nipple fittings attached - ready to use on mercedes calipers. Each bottle has a cap if you need to store it will fluid inside. Two other nipple fittings are included with each bottle to use on other types of brake calipers. THESE WILL WORK ON ALMOST ALL OLDER CARS with the extra caliper nipple fittings included.
Here is how it looks when one bottle is attached to a brake caliper: Note we now use clear hose so you can see the fluid running out of the caliper and into the bottle.
PLEASE NOTE: You can also use these four bottles to speed brake pressure bleeding. Just hook up all four but only open one at a time after you have pressurized the system. If you open all four at the same time you will loose too much fluid in your master cylinder reservoir and before you know it you will be sucking air back into the brake lines.