How to bleed your brakes

Chris

Chris

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When working on your TJ, it's inevitable that you'll eventually need to end up bleeding your brakes.

From personal experience, I can tell you that in invaluable tool to have when bleeding your brakes is a vacuum brake bleeder such as the Mityvac MV8000 vacuum brake bleeder.

If you happen to have one of those already, here's a great tutorial on how to use one to bleed your brakes:

 
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Flintstones.jpg

I know for a fact that my Flintstones glass is a far superior receptacle for brake fluid. It provides a full spectrum for fluid analysis.
 
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I am trying to get my new hydro boost brake system working. In that process I have run several quarts of fluid thru the system . Finall bought two plastic condiment containers - like ketchup, or mustard- snipped the lids's point until it was big enough to accept the bleeder hose. Makes almost leak proof seal and I can see the fluid level. The Motive power bleeder and Alta's two post lift makes bleeding relatively painless.
image.jpeg
 
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Chris said:
I personally use a vacuum brake bleeder I bought at Sears, works awesome!

What do you use @mrblaine
Click to expand...
I use and prefer the manual method. There are several misconceptions in the above though. First, never use line that isn't clear. You need to see exactly what is happening at the end of the bleed screw.
Never use an open end wrench, in fact, it's not even recommended to use a 12 point box end wrench. It is far too easy for the wrench to tip over sideways and round off the hex due to how narrow most of them are nowadays. If you don't have the right box end, get a 6 point socket and break the bleeder loose so you can use the open end on it. Don't forget and try to tighten it without the 6 point.

No need for fluid in the container. Go to any working brake system and open a bleed screw with the master cylinder reservoir cap off. Fluid will run out and if fluid is running out, air is not going in so no need to keep the hose submerged in brake fluid not to mention that the first time you open the bleeder, all the air in the empty hose would go into the caliper if that is how it worked. Fortunately it isn't.

To be clear, fluid isn't running out. It is being forced out by hydrostatic pressure and the bleeder is at the very top of the wheel cylinder so the only actual amount of air that could really get in is the amount in the bleed screw itself.

If you use clear hose and do a few pedal pushes, you'll see very quickly that when you stop, the fluid in the hose starts running into the container and leaves you with air just past the end of the bleed screw. Again, old wives' tale about submerging the end of the tube. For it to work due capillary action, the tube needs to be much smaller and the fluid needs to have a much higher viscosity. The viscosity is not variable and small tube won't fit over the end of the bleed screw easily.

If you need more than 5-7 bleeds per corner, stop and find the problem because flushing more fluid down the drain isn't going to fix the problem.

Do not ever do the pump and hold method, all that does is aerate the fluid.
Open screw, pedal to the floor hard and fast, close screw, let pedal up, repeat.
 
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I know this is an older thread but I'm a bit confused by what mrblaine said, I know he's the brake guru from other forums, I just want to be clear.

quote
"Do not ever do the pump and hold method, all that does is aerate the fluid.
Open screw, pedal to the floor hard and fast, close screw, let pedal up, repeat."

He said not to use pump and hold method, but pedal to floor hard and fast, close screw, let up pedal - so the bad part of pump and hold method is the pump part, not the hold part? Once to the floor hard and fast - Hold - correct?

I'm getting ready to just flush out old fluid and have to do it by myself which is why I was looking at the submerge hose in fluid 'one man' method until I ran across this. All those one man methods obviously aren't holding the pedal down, they all claim to be sufficient but then again they aren't bleeding a Jeep. TJ brakes are already sketchy, just want to make sure everything is done right.

So, is there a way to do it without a partner working the pedal?
 
AZSobo said:
I know this is an older thread but I'm a bit confused by what mrblaine said, I know he's the brake guru from other forums, I just want to be clear.

quote
"Do not ever do the pump and hold method, all that does is aerate the fluid.
Open screw, pedal to the floor hard and fast, close screw, let pedal up, repeat."

He said not to use pump and hold method, but pedal to floor hard and fast, close screw, let up pedal - so the bad part of pump and hold method is the pump part, not the hold part? Once to the floor hard and fast - Hold - correct?

I'm getting ready to just flush out old fluid and have to do it by myself which is why I was looking at the submerge hose in fluid 'one man' method until I ran across this. All those one man methods obviously aren't holding the pedal down, they all claim to be sufficient but then again they aren't bleeding a Jeep. TJ brakes are already sketchy, just want to make sure everything is done right.

So, is there a way to do it without a partner working the pedal?
Click to expand...

Speed Bleeders. Advance auto and lots of online parts stores (Amazon too) have them. I just ordered a set for both my rigs so I can eliminate the "begging girlfriend to help" part of the process.

With speed bleeders all you do is crack open the bleeder screw and pump a couple times then fill reservoir and repeat. Once done tighten up screw and move to next corner. Unfortunately with this method you are unable to watch the fluid coming out unless you rig up your phone to video capture it.

http://shop.advanceautoparts.com/p/...in.-12701/7621295-P?searchTerm=speed+bleeders
 
I'm not a fan of speed bleeders. Replacing your bleed screws with these one-way check valve versions still leaves you with one problem - air leaking around the (loose-fit) threads once the bleeder is open. Until the master cylinder piston retracts far enough to refill the chamber through an orifice, there will be some vacuum created in the lines.

If they made a similar check-valve bleeder with a single orifice through the center, you could swap it in and out of each corner as you go. That would eliminate the problem as you could tighten it properly. And air is not drawn in to the caliper/cylinder when you remove a bleeder, there's usually just a little fluid dribble from gravity so you'd only lose a teaspoon or two.
 
RaymondT said:
I'm not a fan of speed bleeders. Replacing your bleed screws with these one-way check valve versions still leaves you with one problem - air leaking around the (loose-fit) threads once the bleeder is open. Until the master cylinder piston retracts far enough to refill the chamber through an orifice, there will be some vacuum created in the lines.

If they made a similar check-valve bleeder with a single orifice through the center, you could swap it in and out of each corner as you go. That would eliminate the problem as you could tighten it properly. And air is not drawn in to the caliper/cylinder when you remove a bleeder, there's usually just a little fluid dribble from gravity so you'd only lose a teaspoon or two.
Click to expand...

Edit: I see what you mean now after a second read.
 
AZSobo said:
I know this is an older thread but I'm a bit confused by what mrblaine said, I know he's the brake guru from other forums, I just want to be clear.

quote
"Do not ever do the pump and hold method, all that does is aerate the fluid.
Open screw, pedal to the floor hard and fast, close screw, let pedal up, repeat."

He said not to use pump and hold method, but pedal to floor hard and fast, close screw, let up pedal - so the bad part of pump and hold method is the pump part, not the hold part? Once to the floor hard and fast - Hold - correct?

I'm getting ready to just flush out old fluid and have to do it by myself which is why I was looking at the submerge hose in fluid 'one man' method until I ran across this. All those one man methods obviously aren't holding the pedal down, they all claim to be sufficient but then again they aren't bleeding a Jeep. TJ brakes are already sketchy, just want to make sure everything is done right.

So, is there a way to do it without a partner working the pedal?
Click to expand...


You can do the submerged hose in fluid as long as you are patient, wrap the threads and only the threads on the bleed screws with Teflon tape and let the pedal up very slowly. But, how do you know when the fluid coming out of the hose has changed color to indicate fresh fluid to the caliper or wheel cylinder?
 
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mrblaine said:
You can do the submerged hose in fluid as long as you are patient, wrap the threads and only the threads on the bleed screws with Teflon tape and let the pedal up very slowly. But, how do you know when the fluid coming out of the hose has changed color to indicate fresh fluid to the caliper or wheel cylinder?
Click to expand...

I was just going to follow the instructions on one of the youtube videos I watched - one of them is eric the car guy, who has a lot of videos - but I see your point. The fluid is dirty and I have clear hose.

What about gravity bleed? If that is acceptable, does that have to be done all 4 at the same time or one at a time.
 
AZSobo said:
I was just going to follow the instructions on one of the youtube videos I watched - one of them is eric the car guy, who has a lot of videos - but I see your point. The fluid is dirty and I have clear hose.

What about gravity bleed? If that is acceptable, does that have to be done all 4 at the same time or one at a time.
Click to expand...
It isn't an issue of dirty or clean, you need to know when you have good fluid all the way back and the only way to do that is to watch the fluid change color in the hose and it won't be clear unless you flush each corner with about a quart which is needless. Gravity bleeding is only good to fill the calipers or wheel cylinders after you install new ones.
 
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I've thought about getting one of those Motive power bleeders, mostly because allegedly it would make bleeding one man possible. Holding me back is they say right on there website about air bubbles in the line going to reservoir, I'm afraid I'd introduce air from the start.
If I go old school, I guess I'll have to wait until I have a helper who won't complain the whole time, that could be some time.
 
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AZSobo said:
I've thought about getting one of those Motive power bleeders, mostly because allegedly it would make bleeding one man possible. Holding me back is they say right on there website about air bubbles in the line going to reservoir, I'm afraid I'd introduce air from the start.
If I go old school, I guess I'll have to wait until I have a helper who won't complain the whole time, that could be some time.
Click to expand...

I give the lady the Ipad and have her sit and play on it while she pushes and releases the pedals. Facebook keeps her entertained.
 
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Ahoragi said:
I give the lady the Ipad and have her sit and play on it while she pushes and releases the pedals. Facebook keeps her entertained.
Click to expand...
HA HA!
Mine has a Amazon reader attached to her but I can already hear the loud exhalation after the fifth or sixth "press and hold" "Ok let go" on the first bleeder screw - by the time I wrap up two I'll be telling her I'm done just to get her out of the garage. We've been together for over 30 years, been to this dance many times and know how it ends.
 
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AZSobo said:
I've thought about getting one of those Motive power bleeders, mostly because allegedly it would make bleeding one man possible. Holding me back is they say right on there website about air bubbles in the line going to reservoir, I'm afraid I'd introduce air from the start.
If I go old school, I guess I'll have to wait until I have a helper who won't complain the whole time, that could be some time.
Click to expand...
Mine works well.
 
AZSobo said:
Did you get the model with the plastic cap or aluminum?
Click to expand...
I got plastic. You also need to get a model specific master cylinder cover of each different type of cylinder. I maintain 7 vehicles and rarely can find a helper when the time comes. This thing was a God send for me.
 
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TJ4Jim said:
View attachment 1357
I know for a fact that my Flintstones glass is a far superior receptacle for brake fluid. It provides a full spectrum for fluid analysis.
Click to expand...

mrblaine said:
I use and prefer the manual method. There are several misconceptions in the above though. First, never use line that isn't clear. You need to see exactly what is happening at the end of the bleed screw.
Never use an open end wrench, in fact, it's not even recommended to use a 12 point box end wrench. It is far too easy for the wrench to tip over sideways and round off the hex due to how narrow most of them are nowadays. If you don't have the right box end, get a 6 point socket and break the bleeder loose so you can use the open end on it. Don't forget and try to tighten it without the 6 point.

No need for fluid in the container. Go to any working brake system and open a bleed screw with the master cylinder reservoir cap off. Fluid will run out and if fluid is running out, air is not going in so no need to keep the hose submerged in brake fluid not to mention that the first time you open the bleeder, all the air in the empty hose would go into the caliper if that is how it worked. Fortunately it isn't.

To be clear, fluid isn't running out. It is being forced out by hydrostatic pressure and the bleeder is at the very top of the wheel cylinder so the only actual amount of air that could really get in is the amount in the bleed screw itself.

If you use clear hose and do a few pedal pushes, you'll see very quickly that when you stop, the fluid in the hose starts running into the container and leaves you with air just past the end of the bleed screw. Again, old wives' tale about submerging the end of the tube. For it to work due capillary action, the tube needs to be much smaller and the fluid needs to have a much higher viscosity. The viscosity is not variable and small tube won't fit over the end of the bleed screw easily.

If you need more than 5-7 bleeds per corner, stop and find the problem because flushing more fluid down the drain isn't going to fix the problem.

Do not ever do the pump and hold method, all that does is aerate the fluid.
Open screw, pedal to the floor hard and fast, close screw, let pedal up, repeat.
Click to expand...

What size hose fits best to the bleeder screw?
 
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