Bleeding Brakes with Power Bleeder
Thread Starter
Racer
Joined: Apr 2005
Posts: 339
Likes: 1
From: San Diego CA
Bleeding Brakes with Power Bleeder
I replaced the brake pads on my '71 last week, and must have let a little air get into the system, so this weekend, I broke out my old Motive power bleeder to get the air out.
It was a very frustrating experience. I've used the bleeder in the past with moderate success, but today was especially difficult. For those who are familiar with this bleeder, I used the flat, rectangular pancake looking master cylinder adapter.
I’m not sure what went wrong. I ran the chain below the master cylinder and equally tightened the wing nuts (and had them cranked). I started pumping the bottle, and after about ten pumps, fluid started spraying from the back of the cylinder. By the time I got the pressure off of the bottle, I had brake fluid dripping everywhere.
I pulled myself back from total rage, calmly removed everything from the master cylinder, then I carried all of the pieces of the bleeder to the trash can. It felt good to get rid of it.
A couple of hours later, I went back out to the trash can and pulled everything back out.
My question is why is this so difficult? I remember when I used it a couple of years ago, I had to play with it, and really crack down the bolts to get it to hold.
Am I doing something wrong?
It was a very frustrating experience. I've used the bleeder in the past with moderate success, but today was especially difficult. For those who are familiar with this bleeder, I used the flat, rectangular pancake looking master cylinder adapter.
I’m not sure what went wrong. I ran the chain below the master cylinder and equally tightened the wing nuts (and had them cranked). I started pumping the bottle, and after about ten pumps, fluid started spraying from the back of the cylinder. By the time I got the pressure off of the bottle, I had brake fluid dripping everywhere.
I pulled myself back from total rage, calmly removed everything from the master cylinder, then I carried all of the pieces of the bleeder to the trash can. It felt good to get rid of it.
A couple of hours later, I went back out to the trash can and pulled everything back out.
My question is why is this so difficult? I remember when I used it a couple of years ago, I had to play with it, and really crack down the bolts to get it to hold.
Am I doing something wrong?
Safety Car
Joined: Jun 2004
Posts: 4,374
Likes: 224
From: Beecher Illinois
I agree, throw just the chains away! When you crank the chain tight you flex the cover.
Use some clamps, one over each compartment, and pressure test it empty first. Sometimes you'll even need to loosen the clamps to get a good seal. When it holds pressure, THEN add the fluid.
Some guys like to NOT put any fluid in the container and constantly undo everything to check the master fluid level, but I feel that just defeats the purpose of the bleeder.
Use some clamps, one over each compartment, and pressure test it empty first. Sometimes you'll even need to loosen the clamps to get a good seal. When it holds pressure, THEN add the fluid.
Some guys like to NOT put any fluid in the container and constantly undo everything to check the master fluid level, but I feel that just defeats the purpose of the bleeder.
Last edited by KapsSA; Jul 11, 2011 at 01:08 AM.
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
I made my own and held it down with some big c-clamps:
However unlike the professional power bleeder that has a container full of fluid, I only had my master cylinder full. So I could only drain so much before I had to stop and make sure I wasn't getting too close to empty. Was it a complete 100% seal, no, but it was just air escaping so no brake fluid to squirt around unless I filled the MC too high. It only took a minute or so to take everything off or put back on and hook up my 10psi air supply from my compressor.
If I hadn't bought a mighty vac to try and do the brake job and wasted $40 on it, I would have bought the correct tool (power bleeder) for the $90 or so. In building mine I saved some $, not a bunch.
Jeff
However unlike the professional power bleeder that has a container full of fluid, I only had my master cylinder full. So I could only drain so much before I had to stop and make sure I wasn't getting too close to empty. Was it a complete 100% seal, no, but it was just air escaping so no brake fluid to squirt around unless I filled the MC too high. It only took a minute or so to take everything off or put back on and hook up my 10psi air supply from my compressor.
If I hadn't bought a mighty vac to try and do the brake job and wasted $40 on it, I would have bought the correct tool (power bleeder) for the $90 or so. In building mine I saved some $, not a bunch.
Jeff
Last edited by StingrayLust; Jul 11, 2011 at 12:56 PM.
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Le Mans Master
Joined: Oct 2005
Posts: 6,247
Likes: 471
From: Glen Allen, VA
I used mine with the power bleeder tank empty and did as others suggested, in using a block of wood and clamps to hold the seal. My car also has DOT 5 fluid and it worked great. Yes I had to undo the clamps several times to check the master cylinder level, but knowing the Vette is the rare car I would bleed with DOT 5, i didn't want to fill the power bleeder with it, figuring if anything I'd fill it with DOT 3 for other vehicles. Basically I don't want to have to clean DOT 5 out to fill with DOT 3, it seems like too much trouble to me.
Race Director
Joined: Jul 2004
Posts: 12,706
Likes: 329
From: Scottsdale Arizona
As most of the folks above have already said, use a block of wood (I use a 2X4) and a clamp instead of the chains.
Also, I don't like to have fluid in the pressure bleeder. I just use it to pressurize air. The down side is that you have to be vigilant about keeping the master cylinder filled with fluid. I use a bleeder cup that I know is smaller than the M/C. The upside is that you never have to worry about spewing fluid ever again. Big upside.
Also, I don't like to have fluid in the pressure bleeder. I just use it to pressurize air. The down side is that you have to be vigilant about keeping the master cylinder filled with fluid. I use a bleeder cup that I know is smaller than the M/C. The upside is that you never have to worry about spewing fluid ever again. Big upside.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
i like my motive pressure bleeder and use it with no fluid just air i use c clamps....didnt need any wood.
stingray lust ...that looks good what is in between the 90* L and the cap with holes in it? what do you call that cap? it looks like you used a round neoprene ring washer in betwen them, is that all you need for the seal?
stingray lust ...that looks good what is in between the 90* L and the cap with holes in it? what do you call that cap? it looks like you used a round neoprene ring washer in betwen them, is that all you need for the seal?
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
The finished solution was never intended to hold a perfect seal, just get enough pressure to push the brake fluid through. In the end, Mityvac=0, my own power bleeder=1.
It wasn't dirt cheap, maybe $40, all from Home Depot and ready in 2 hours. As I said, if I knew from the start that the power bleeder was the way to go, I wouldn't have spent money on the mityvac and then try to save ($) face by building my own version of the power bleeder later.
Thread Starter
Racer
Joined: Apr 2005
Posts: 339
Likes: 1
From: San Diego CA
Thanks for all of your suggestions. I'm going to use clamps and a block of wood. I'm also going to keep the bottle empty. I'd rather keep re-checking the m/c fluid level than risk another spill.
As far as using Dot 5 fluid, I read that it has a higher heat rating, but are there other reasons for switching over? I also read that without proper flushing of the Dot 3 before use, the seals can be damaged.
I'm pretty easy on my car, so I assume I'm fine staying with Dot 3.
As far as using Dot 5 fluid, I read that it has a higher heat rating, but are there other reasons for switching over? I also read that without proper flushing of the Dot 3 before use, the seals can be damaged.
I'm pretty easy on my car, so I assume I'm fine staying with Dot 3.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
atop a piece of plexiglass. Then some rubber washers before my thick piece of metal. The elbows have a small extension piece that goes through the plexi, washer, some foam, metal plate for stiffness, another rubber washer, and the cap finishes it off. I drilled the holes in the cap myself.
thks i am going to make one for fun, what is the purpose of the plexiglass , the extension piece is just threaded brass cut to size? size of the holes in the cap 3/64? thks bob
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Safety Car
Joined: Nov 2008
Posts: 4,368
Likes: 9
From: Colorado
My experience with the motive pressure bleeder was similar to the op's and it went back in a box on a shelf immediately. I did use a clamp and 2x4 with lousy results, which leaves me wondering why the manufacturer doesn't correct the adaptor issues themselves. Anyway, is the NAPA adaptor a better way to go ?