Getting ready to bleed my brakes, please critique my technique
 

It's been years since I did my own brake bleed but last time I did it, I remember it was quite straight forward. I wanted to run my procedure by some of knowledgeable folk on this forum.

I own a '88 911 3.2 and will be using a Motive Power Bleeder.

1. Suck out most of the fluid from the master cylinder.

2. Top up the master cylinder with fresh brake fluid. I always alternate between blue and gold fluid so that I know when the new fluid hits the bleed port.

This is where I depart from the usual process for Motive bleeding. I don't fill the bleeder. I overfill the master cylinder instead. This is to keep the power bleeder clean and free of old fluid.

3. Pressurize the system to 10psi.

4. Starting from the passenger rear wheel, attach a clear hose to the bleed port, open the bleed port and bleed into a waste container.

5. Check the master cylinder and top up with more fluid if required.

6. Move on to next wheel.

7. Once finished bleeding all four wheels, I top up the master cylinder and close it up.

8. Open beer and pat myself on the back.

From what I recall, I didn't remove the wheels to do this. I could access the port by reaching behind the wheel. Am I mis-remembering? Any critiques on my procedure? I think it's been at least 10 years since I've done this and my memory is not what it was.

All good except you need to crimp the overflow line from the fluid reservoir. I pull mine off and add a small length of hose that is plugged at the end. Also, I remove the wheels just for better access. Good luck!

👍👍

Pressure brake bleeding..........
 

Coilerman,

Your above procedure is OK but I would add these:

• Plug the overflow drain tube with a drill bit or something.
• 10~14 psi. air pressure.
• Remove the tires for better access (optional).
• You might as well bleed the clutch saver this time.

Do not forget to remove the plug from the drain tube.

Tony

..good luck finding the blue fluid - discontinued about 6-7 years ago.
If you do manage to come up with a couple cans - check the date.

The two color option is gone, so make sure to flush enough fluid so that everything is fresh. Don't use fluid that's been opened before. Humidity from the air can contaminate it.

Since you shouldn't be using fluid that's been sitting in the Power Bleeder, always empty it after you're done. Therefore, there is no reason not to put the fluid in the Power Bleeder?

You do start with passenger rear, because it is the farthest from the master cylinder. Then driver rear, passenger front, driver front.

You use a clear hose so that you can be checking for air bubbles. You want to flush until there aren't any bubbles. If the bleeder fitting is too loose, air bubbles can come in from the threads; not the fluid. Wipe a little grease around the threads to prevent the air from sneaking in.

I have consistently had good luck just using gravity. Run a hose from the RR bleed nipple into a good sized container and simply open the bleed nipple. Take the cap off the reservoir. Keep checking and filling the reservoir, of course. When the fluid runs clear, move to the LR. Then the RF and the LF. Done.

I have blue fluid. Unopened cans. About 5 years old. Does this stuff expire?

Believe it or not, air and water can permeate through the metal can and contaminate the sealed fluid.
That being said, you are probably okay. Are you sure about that 5 years?

To expand on Superman's description, use a long-enough hose (see through) to extend from the bleeder valve upward; high enough so the top loop is above the level of the MC reservoir. The hose end drops down into a bottle or container to collect excess brake fluid.

Open the caliper bleed valve and allow fluid (and air) to exit into the hose. Lightly tap the rigid brake lines and caliper with a hammer to dislodge stubborn air bubbles.

Oh, and no compressed air pressure necessary. Cannot rush the air bubbles unless pricey BF goes with it. Using this method, only 1 liter of BF is needed to fill the entire brake system - usually impossible with pressurized air.

Sherwood

toss that old brake fluid - cut corners on paint or fuzzy dice, not safety areas

the Motiv gets filled with air not fluid

gravity works

FWIW, back when they had the two colors, I measured the volume I used to complete a color change. The farthest cylinder completely changed color when I got about 160 ml.

Why is there a pickup tube in the Motiv container if it's only for air?

Because you can put the fluid in the bleeder and not worry about running the master cylinder reservoir dry.

I prefer to keep the Motive unit dry.

If you use the Motive, also hook it up to the master cylinder before you start the process. Just to make sure there are no leaks in the system before you start putting brake fluid through. Though probably less of an issue in your situation if you're not filling the Motive with brake fluid, because even if there is a leak, it's not likely that brake fluid is going to be spraying about.

Everytime I use a Motive, I have to add some grease to the bleed nipple because air comes through the threads causing a million tiny bubbles.

That is weird since the motive is pressurizing the brake system snd should be pushing the fluid out the threads not drawing air in. I used to have this issue when I vacuum bled the brakes.

That is what I thought too, the physics didn't make sense when I was doing this to my Vantage so I figured I had a leak. The grease was the fix and the exact same thing happened on my sons S5.

Yes, with an open bleeder screw, there should be positive system pressure, either from the pressure tank or from atmospheric pressure. Thus, little chance of drawing in air. That's how workers mass-bleed hundreds of vehicles off-loaded from overseas ships. Those dock yards must be an EPA nightmare with tons of bf in the ground.

Let's hope the grease was compatible with the brake system. Dielectric grease perhaps?

Sherwood

The brake fluid in the drain tubing can act as a siphon and draw air in past the bleeder screws, especially if the brake fluid is flowing quickly. I use a pressure bleeder and open the bleed screw just enough to get good flow - that usually avoids bubbles.

I used to put some grease around the bleeders (the same grease used to rebuild the calipers).