can anybody give me some tips on changing brake fluid with a pressure bleeder. (the how to thread is pretty old and the pics dont work) any assistance is appreciated, thanks

 

It's pretty simple. First make sure that your reservoir is full. Hook the pressure bleeder up to the brake fluid reservoir cap and pump a little pressure into it (just a little, no need for much). Then go around the car and put a piece of clear tubing on the caliper bleed nipple and open it 1/4 turn - fluid will start to flow, let it flow until it runs clean with no bubbles, then close firmly. Stop and check the reservoir, topping up as needed. Go around the car and do this for each brake.

The most important part is to NEVER let all of the fluid get pushed out of the reservoir. Either have someone watch the reservoir, or stop bleeding regularly to check it. If it runs empty you'll get air in the lines and that will be difficult to get out. [Some pressure bleeders contain brake fluid to prevent this, but some just use air pressure]

 

I just finished bleeding my brakes (actually flushed the whole fluid). I used the MITYVAC hand vacuum pump - one of those one-man brake job kit. It works, but there was a problem.

Biggest problem was that you need a nice real tight seal around the tube and the nipple. If this is not tight, you're going to see a lot of bubble in your tube. The tube doesn't have to be so tight if you are pushing the fluid out by pumping the brake pedal (old school method) or use top side pressure bleeder (one of those mounting to the brake reservoir cap). But any pistol-looking pump.... you need a really really tight seal around the nipple and tube.

For me, I never had a tight seal, so the bubble never stopped. I almost ended up emptying the reservoir....

I'm sure the vacuum bleeder works... but not for me. I'm going to build a top-side pressure bleeder that uses compressed air.

 

I built my own top-side pressure bleeder from plans I found on the internet, and it was cheap, easy, and works great. It's basically a hardware store hand pump garden sprayer with a length of hose attached to a spare reservior cap (got that at an auto parts store imports section).
Here's a link to one set of instructions: http://www.bmw-m.net/TechProc/bleeder.htm

 

I tried a Mityvac but didn't like the bubbles I got from around the hose/nipple seal and also the threads on the bleeder itself. Decided to buy a Motive pressure bleeder that fits both my Mini and my vintage VW Scirocco. Easy as pie to bleed everything now!! Just top off the brake fluid reservoir, dump a quart or so of fresh brake fluid into the Motive, pump up the pressure and bleed away. Makes flushing all the old fluid out a very simple process. Highly recommend the Motive unit.

Eric

 

The MityVac is crap and will only frustrate you.
Pay $30 extra and get the Motiv powerbleeder. It works.

 

goin with the motive.. thanks all, last time I bled the brakes was almost 30 years ago, and it was a 68 camaro...

 

The last thing I'd want to do is encourage someone to take on a brake flush or bleed on the Mini if they were less than 110% confident. It's an advanced maintenance task and it's doubly tricky on the Mini.

But I can say that with a vacuum bleeder, if you're seeing a steady stream of small air bubbles, that never lets up, that is typical of a bleeder valve or vacuum connection that is leaking. Because it is downstream of your brake lines, it isn't a problem other than it muddles the question of whether you're done bleeding or not. But real air in your brake lines looks like large bubbles and the small bubbles you see with a downstream air leak are quite distinct. You can simply ignore them and bleed until the big bubbles cease.

Regardless, it is easy to empty a reservoir and you need to be quite aware at all times of how much fluid you're drawing out and how much is left in your reservoir. Holding the tube vertically so the extracted fluid flows back down to your bleeder valve helps avoid draining too much -- anyway, you're intent on removing air, not fluid, at the bleeding stage.

This is verified by the manual that came with my Craftsman hand vacuum bleeder, and my own observations. But again, you'd be smart to buy the recommended bleeder pump for the Mini and not try to wing it with a substitute tool. And you'd be doubly smart to take it to a pro if you're unsure in the least.

Just saying is all...

 

Here's detailed description of how I'm tackling this next time. (Since I finished this time around, with old-school method. Wife pumping the pedal and I got to yell at her

I measured (somewhat eyeballed) how much pressure there is while brake pedal is depressed at the bleeder valve. You can do this with the pressure gauge attached to the MITYVAC, while your friend is pumping the pedal. About 10-15 PSI was what I saw. So I figured I just have to maintain 10PSI pressure on the top side. I verified it with the service manual, and it said 15psi. Bingo! I was close enough.

So I plan to build the pressurized bleeder that uses compressed air (You can adjust those household compressor to max out at 15PSI). I am aware of these plastic brake reservoir (and all the other seals and valves downstream) can only withstand so much pressure, so I must not over-pressurize the system.

I found a plastic container that can take 15PSI x F.S. of 2 = 30PSI... the pressurized garden sprayer. Hoses are usually rated much more than that, and so are the clamps. I pressurize the container with pistol -type tire inflation tool so I can modulate the pressure and watch the pressure build up.

I'd take it to a pro but knowing these pros (even those highly-recommended ones) do stupid things and try to cut corners like crazy..... I'd rather learn and do it myself as much as I can, if the task is within reasons.