Brake fluid flush questions
Burning Brakes
Joined: Feb 2018
Posts: 906
Likes: 196
From: Northeast, PA
I use the same power bleeder but only use air to pressurize the system. I never put brake fluid in the Motive bleeder. Just think of the mess if it was to leak!
Please DON'T use the supplied RED Metal cap, it will destroy the locking lugs on your reservoir, ask me how I know.
Just write to Motive and they will send you a new cap, Black Plastic, and try that. I received one but of yet not tried it. Might have to modify it so it does not contact the locking lug on the reservoir.
Good luck.
Please DON'T use the supplied RED Metal cap, it will destroy the locking lugs on your reservoir, ask me how I know.
Just write to Motive and they will send you a new cap, Black Plastic, and try that. I received one but of yet not tried it. Might have to modify it so it does not contact the locking lug on the reservoir.
Good luck.
I came here to comment the same thing. I ruined my reservoir by using the red cap. The OEM cap still went on after using the red motive cap, but it went on loose. Not until I was working on someone else's C7 did I realize mine was messed up. Replaced the reservoir with a new OEM one and contacted Motive for the plastic version of the red cap. The plastic version goes on just as tight as the metal one, I never fully tightened it because I think it's going to damage the reservoir the same way the red cap did. I think the way to do this without ruining your reservoir is by modifying a stock cap. I don't use my motive anymore due to this, went back to two-person bleeding.
Heel & Toe
Joined: Oct 2024
Posts: 20
Likes: 9
I've got the Motive bleeder and ordered the GM cap kit off Amazon for $29 last fall. I use 2 liters ATE Type 200 (used to be called Super Blue), did both my C5 and C7 with it. Cap is black aluminum and worked fine on both.
Thread Starter
Drifting
Joined: Apr 2022
Posts: 1,856
Likes: 792
From: Earth
I have the black metal cap with Motive MTP0108 and it seems like the thinner gasket will work? I will be attempting it today.
I will be following your method Bill, thanks for that.
UPDATE: Motive bleeder worked as advertised. Mine came with a black metal cap and I used the thinner rubber gasket. It was easy to install and remove without any damage to my reservoir. I followed Bill Dearborn's instructions in post 16, thanks for that and everyone who replied. I did extract the old fluid out of the reservoir before I started and filled with new stuff. Thats a good tip that Bill mentioned and some others in videos I watched. The old fluid was red in color but now it's clear, so I am glad I flushed it. One thing that was crazy was that the bleeder nipples were installed by King Kong, lol. Next, down the road will be trans and diff fluid changes......
I will be following your method Bill, thanks for that.
UPDATE: Motive bleeder worked as advertised. Mine came with a black metal cap and I used the thinner rubber gasket. It was easy to install and remove without any damage to my reservoir. I followed Bill Dearborn's instructions in post 16, thanks for that and everyone who replied. I did extract the old fluid out of the reservoir before I started and filled with new stuff. Thats a good tip that Bill mentioned and some others in videos I watched. The old fluid was red in color but now it's clear, so I am glad I flushed it. One thing that was crazy was that the bleeder nipples were installed by King Kong, lol. Next, down the road will be trans and diff fluid changes......
Last edited by 17 Z06/Z07; Mar 30, 2025 at 11:47 PM. Reason: Update
Le Mans Master
Joined: Jun 2019
Posts: 5,484
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From: Loveland
Team Owner
Joined: Jul 2004
Posts: 28,474
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From: Hartford WI
Heel & Toe
Joined: Jan 2025
Posts: 25
Likes: 4
From: Waterford MI
I just purchased the Motiv power bleeder along with a catch bottle to flush the brake fluid. After watching videos on you tube and reading your guys posts I think I’m comfortable doing this on my own. But one thing I’m unsure of is when I’m bleeding each line, how do you know when to stop? How do you know when the brake line has all new fluid in it? Thanks a lot! Sam
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
I just purchased the Motiv power bleeder along with a catch bottle to flush the brake fluid. After watching videos on you tube and reading your guys posts I think I’m comfortable doing this on my own. But one thing I’m unsure of is when I’m bleeding each line, how do you know when to stop? How do you know when the brake line has all new fluid in it? Thanks a lot! Sam
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Burning Brakes
Joined: Feb 2018
Posts: 906
Likes: 196
From: Northeast, PA
I just purchased the Motiv power bleeder along with a catch bottle to flush the brake fluid. After watching videos on you tube and reading your guys posts I think I’m comfortable doing this on my own. But one thing I’m unsure of is when I’m bleeding each line, how do you know when to stop? How do you know when the brake line has all new fluid in it? Thanks a lot! Sam
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
Mine is done every 2 years so color is very similar.
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
Le Mans Master
Joined: Jun 2019
Posts: 5,484
Likes: 2,193
From: Loveland
I have used the tank both ways. Filling the tank with brake fluid also has it's issues. The reservoir can be filled to the brim and can be a huge mess. Mostly I tried this on an open top master cylinder, old school. Both ways you have to be very careful. I threw away the stupid chains that were supposed to hold it on top of the reservoir and just used a clamp. With the new clear reservoirs, it's easy to see when it gets to low. I also figured out, you don't really need that much fluid. Also, using pressure in the tank is good but so is pumping the brake pedal. Each one eliminates air from different places in the brake system.
Burning Brakes
Joined: Feb 2018
Posts: 906
Likes: 196
From: Northeast, PA
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
I have used the tank both ways. Filling the tank with brake fluid also has it's issues. The reservoir can be filled to the brim and can be a huge mess.
Also, using pressure in the tank is good but so is pumping the brake pedal. Each one eliminates air from different places in the brake system.
Also, using pressure in the tank is good but so is pumping the brake pedal. Each one eliminates air from different places in the brake system.
Besides making it a 2 player game of coordination, where does it eliminate the air from that the tank won't? And where does it get air from now that the cap is on and the system is sealed?
Le Mans Master
Joined: Jun 2019
Posts: 5,484
Likes: 2,193
From: Loveland
If there is an air bubble on the top of the fluid in any cylinder, sucking from the bottom will not suck the bubble out, nor will trying to push an air bubble down that is in a cylinder. Think about a clear water bottle, put a hose on the bottom and try to suck the air out that is on top, wont happen. Try the same bottle, pressurize it from the top, you will never push the air bubble out from the top either. It depends on the orientation of the of the master cylinder and the wheel cylinders, and where the bleeder screw are located.
IF there is an air bubble on the top of the bottle/cylinder and there is a bleeder on top of the bottle you can suck it out until the air is gone gone, then get to the fluid or push it out from the bottom.
IF there is an air bubble on the top of the bottle/cylinder and there is a bleeder on top of the bottle you can suck it out until the air is gone gone, then get to the fluid or push it out from the bottom.
Last edited by kodpkd; Apr 1, 2025 at 02:03 PM.
Heel & Toe
Joined: Oct 2024
Posts: 20
Likes: 9
ATE fluid used to be blue or yellow so you could bleed the whole system with one liter easy. The DOT in their infinite wisdom says all US brake fluid has to be amber now making it harder to tell when you hit the new fluid so I just use two liters to make sure any old fluid is out of the system,.
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
If there is an air bubble on the top of the fluid in any cylinder, sucking from the bottom will not suck the bubble out, nor will trying to push an air bubble down that is in a cylinder. Think about a clear water bottle, put a hose on the bottom and try to suck the air out that is on top, wont happen. Try the same bottle, pressurize it from the top, you will never push the air bubble out from the top either. It depends on the orientation of the of the master cylinder and the wheel cylinders, and where the bleeder screw are located.
IF there is an air bubble on the top of the bottle/cylinder and there is a bleeder on top of the bottle you can suck it out until the air is gone gone, then get to the fluid or push it out from the bottom.
IF there is an air bubble on the top of the bottle/cylinder and there is a bleeder on top of the bottle you can suck it out until the air is gone gone, then get to the fluid or push it out from the bottom.
At this point when you have say 20 psi, you can lift the canister above the reservoir and open the cap of the canister and the air will be pushed into the canister without spilling. Not important but if you are afraid of any air in the system.
When you are done, depressurize the system by opening the cap on the canister and any pressure goes back into the canister. Put the canister down and crack open the cap on the reservoir. Air will enter and gravity will pull any fluid in the lines back into the cylinder. Take off the cap and that should end the whole thing.
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
ATE fluid used to be blue or yellow so you could bleed the whole system with one liter easy. The DOT in their infinite wisdom says all US brake fluid has to be amber now making it harder to tell when you hit the new fluid so I just use two liters to make sure any old fluid is out of the system,.