Motive brake bleeding question
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
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From: Fisher, IL
Motive brake bleeding question
I installed new lines during my body off on my 69.
Took the vette for a short ride yesterday and the brakes were still very soft.
I plan on bleeding again today and didn't know if while the Motive is attached I can see if the brakes are hard or are they artificially hard because of the pressure from the Motive?
What I'm getting at is i'll bleed till they're hard but don't want to have to take the Motive off every time I want to check to see if I got it correct or not.
Took the vette for a short ride yesterday and the brakes were still very soft.
I plan on bleeding again today and didn't know if while the Motive is attached I can see if the brakes are hard or are they artificially hard because of the pressure from the Motive?
What I'm getting at is i'll bleed till they're hard but don't want to have to take the Motive off every time I want to check to see if I got it correct or not.
Instructor
Joined: Nov 2005
Posts: 176
Likes: 0
From: Revere Massachusetts
You need to check the air pressure at the motive bleader, and there is no need to push on the brake pedal,just open one bleader at a time the air pressure in the motive will push the fluid and air out. Keep checking the pressure in the motive because it will drop and the fluid passes in to your brake lines.
Drifting
Joined: Feb 2005
Posts: 1,879
Likes: 38
From: Los Gatos CA
Here's what I do (others will chime in): Remove wheels and get the back end up in the air. Use low pressure (10 psi). Start with RR caliper. Bleed until clean fluid flows. Tap caliper with hammer to help trapped air. Work around car. Go around twice. If you are replacing Master, be sure to bench bleed. Anyways, that's what works for me.
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
I have a Motive and agree with the above posts but I don't put fluid in the Motive, I just keep the master cyl full and apply air pressure to it using the Motive. Makes for a cleaner job without spilling fluid.
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
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From: Fisher, IL
that was my question. If I can apply and what I feel with the Motive on will be the same as if I took the motive off.
What I don't want to do is bleed, take the motive off, put the cap back on, and then get in the car and test the pedal just to find out it's still sloppy.
What I don't want to do is bleed, take the motive off, put the cap back on, and then get in the car and test the pedal just to find out it's still sloppy.
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Race Director
Joined: Mar 2006
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From: Florida
The Motive only has from 0-50 psi compared to 0-~1800psi, so if nothing else it assures the pistons and linings were seated to the rotors. Brake pedal height also can test for air or leaks in the system, especially if there is no difference in color between old and new fluid.
I do it all the time without second thought.
I do it all the time without second thought.
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
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From: Fisher, IL
Found the issue. Passenger front had a ton of air bubbles in it.
And like stated above before I packed everything back up and put the tires on I was able to test the pedal and it was nice and hard!
God Bless the Motive Power Bleeder
And like stated above before I packed everything back up and put the tires on I was able to test the pedal and it was nice and hard!
God Bless the Motive Power Bleeder
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
Just need to keep it topped up, seemed like a waste to put a bunch in the Motive
Mooser
Thread Starter
Race Director
Joined: Dec 2005
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From: Fisher, IL
You can't see in the cylinder so how often are you releasing pressure, taking the top off, and checking, putting it back on, pumping it up again...
It just takes that one time bleeding it dry to cost you another hour of bleeding. And don't you have to bench bleed if you bleed the MC dry?
You can do what you want but I see no reason not to fill the motive. Mine last night didn't leak a drop when I took it off. when you release pressure the excess fluid gets sucked back into the unit and you're left with a nice full MC. That's what it was made for....
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
I've seen this so many times already but why wouldn't you fill the motive?
You can't see in the cylinder so how often are you releasing pressure, taking the top off, and checking, putting it back on, pumping it up again...
It just takes that one time bleeding it dry to cost you another hour of bleeding. And don't you have to bench bleed if you bleed the MC dry?
You can do what you want but I see no reason not to fill the motive. Mine last night didn't leak a drop when I took it off. when you release pressure the excess fluid gets sucked back into the unit and you're left with a nice full MC. That's what it was made for....
You can't see in the cylinder so how often are you releasing pressure, taking the top off, and checking, putting it back on, pumping it up again...
It just takes that one time bleeding it dry to cost you another hour of bleeding. And don't you have to bench bleed if you bleed the MC dry?
You can do what you want but I see no reason not to fill the motive. Mine last night didn't leak a drop when I took it off. when you release pressure the excess fluid gets sucked back into the unit and you're left with a nice full MC. That's what it was made for....
Removing the Motive top from the master is leak-free IF you don't fill the master to the top before you put the top on. I leave the master fluid level down about 1/2" before installing the top. If you start down 1/2" you will finish 1/2" down.I also only put around 6lbs pressure in the Motive , if I want pressure I step on the brake pedal , that gives REAL pressure.
In my case the Motive becomes a constant fluid supply but under low pressure,makes it really nice to have that constant slow flow while I tap all fittings, lines and calipers with my trusty 3/4" wrench.
Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Removing the Motive top from the master is leak-free IF you don't fill the master to the top before you put the top on. I leave the master fluid level down about 1/2" before installing the top. If you start down 1/2" you will finish 1/2" down.I also only put around 6lbs pressure in the Motive , if I want pressure I step on the brake pedal , that gives REAL pressure.
In my case the Motive becomes a constant fluid supply but under low pressure,makes it really nice to have that constant slow flow while I tap all fittings, lines and calipers with my trusty 3/4" wrench.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
If there is a small amount left I dump it,if there's a pint I fill the pint bottle and any left over I keep for cleaning purposes. I leave the tank upside down to drain for a bit then clean the tank with a couple ounces of denatured alcohol , put the pump back in until the next time.
