Newbie questions regarding the mechanical workings of Motion Pro 08-0143 Hydraulic Brake Bleeder

Wheelin

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Aug 13, 2017
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Southern CA
Hi Gang-

In the hopes that this tool will make my arthritic hands not have to do so many things at once when bleeding the brakes, I'd like to understand the mechanical workings of the Motion pro 08-0143 Hydraulic Brake Bleeder a little better so that I don't introduce a lot of air into my brake system OR strip out the bleeder screw in one of my hamfisted efforts.

Since it's a one-way check valve, does that mean that, once I prime the tool, I no longer have to go through the repeated process of tightening the bleeder screw over and over to let the pressure build and then unscrew the bleeder screw enough to pump out more brake fluid? In other words, can I keep the bleeder valve open while I continuously pump the brake lever/pedal and add fluid to the reservoir?

Sorry for all the questions. As I'm not as experienced in wrenching a bike as most of you, any wisdom shared is sincerely appreciated.

Wheelin
 
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B

ballisticexchris

Guest
While that's a good tool, there is no need to open/pump/close/open the bleeder screw. Simply attach a hose to the end and tie a tight half hitch knot. Let the end go into a container. Then simply pump your lever slowly and replenish the fluid as the level goes down. The half hitch knot prevents air getting back in the system. When you finish, pull off the brake/clutch levers and let them hang overnight. Lightly tap the lines with a screwdriver a few times up and down each line. In the morning you will have rock solid brakes.
 

Wheelin

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Joined
Aug 13, 2017
Messages
261
Location
Southern CA
While that's a good tool, there is no need to open/pump/close/open the bleeder screw. Simply attach a hose to the end and tie a tight half hitch knot. Let the end go into a container. Then simply pump your lever slowly and replenish the fluid as the level goes down. The half hitch knot prevents air getting back in the system. When you finish, pull off the brake/clutch levers and let them hang overnight. Lightly tap the lines with a screwdriver a few times up and down each line. In the morning you will have rock solid brakes.
Thanks for the tip. It's nice to know that I won't be screwing up my braking system or stripping my bleeder screw by following your technique.
 
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Wheelin

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Messages
261
Location
Southern CA
That sounds pretty interesting, what kind of hose have you actually used for this ?
Cycledude, I'm assuming your question is addressed to Chris, but for what it's worth, the hose I've used that fits snugly even before doing the half hitch knot is a clear rubber hose, 3/16" inner diameter.
 

EricV

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@Wheelin - The Motion Pro tool works as you believe it does. There are as many ways to bleed brakes as people doing the job. At $14 the Motion Pro tool, LINK , is cheaper than Speed Bleeders, which are essentially the same thing, just permanently installed at each bleed point. And yes, you can keep the bleeder valve open while you continuously pump the brake lever/pedal and add fluid to the reservoir.

Chris's hose trick works too, as long as the hose is flexible enough for the cinch knot to close the hose. The pressure pushes the fluid past the make shift valve, but there is not enough return pressure to pull air back in. Sometimes it takes a little practice to get the knot snug enough to work well for this, but it's not rocket science.

In all cases, remember that air can be pulled into the flow from the screw threads at the bleed screw. For pressure bleeding I will dab a bit of grease around the threads before I start. Stickier the better. It usually acts as a make shift seal while the bleed screw is open, and can easily be wiped off when you're done. This air typically shows up as bubbles in the exiting fluid, and is not entering the system, so it's not really a big deal, it just reduces stress levels for some that are watching for air in the line going out of the bleed nipple.

Auto parts stores sold "one man brake bleed" kits with a simple hose and clip valve that mimics the same process. Putting the hose into some clean brake fluid in your catch can also prevents any accidental back flow.

Another reminder, the master cylinder will squirt a pretty good stream strait up and back a little when you pull the lever in. Squeezing slowly helps. But cover the paintwork with a heavy old towel before you start and don't squirt yourself in the eye. ;)

Another tip - You only need to open the bleed screw 1/4 to 1/2 a turn. Just put a box wrench on there and leave it in place the whole time you're doing that bleed point. No fumbling when you're ready to close it that way.
 

Wheelin

Active Member
Joined
Aug 13, 2017
Messages
261
Location
Southern CA
@Wheelin - The Motion Pro tool works as you believe it does. There are as many ways to bleed brakes as people doing the job. At $14 the Motion Pro tool, LINK , is cheaper than Speed Bleeders, which are essentially the same thing, just permanently installed at each bleed point. And yes, you can keep the bleeder valve open while you continuously pump the brake lever/pedal and add fluid to the reservoir.

Chris's hose trick works too, as long as the hose is flexible enough for the cinch knot to close the hose. The pressure pushes the fluid past the make shift valve, but there is not enough return pressure to pull air back in. Sometimes it takes a little practice to get the knot snug enough to work well for this, but it's not rocket science.

In all cases, remember that air can be pulled into the flow from the screw threads at the bleed screw. For pressure bleeding I will dab a bit of grease around the threads before I start. Stickier the better. It usually acts as a make shift seal while the bleed screw is open, and can easily be wiped off when you're done. This air typically shows up as bubbles in the exiting fluid, and is not entering the system, so it's not really a big deal, it just reduces stress levels for some that are watching for air in the line going out of the bleed nipple.

Auto parts stores sold "one man brake bleed" kits with a simple hose and clip valve that mimics the same process. Putting the hose into some clean brake fluid in your catch can also prevents any accidental back flow.

Another reminder, the master cylinder will squirt a pretty good stream strait up and back a little when you pull the lever in. Squeezing slowly helps. But cover the paintwork with a heavy old towel before you start and don't squirt yourself in the eye. ;)

Another tip - You only need to open the bleed screw 1/4 to 1/2 a turn. Just put a box wrench on there and leave it in place the whole time you're doing that bleed point. No fumbling when you're ready to close it that way.
Cool, thanks EricV. I was struggling a bit yesterday, but I think your words and the advice of ballisticexchris make me comfortable in bleeding the brakes. :cool:
 
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