Bleed breaks with pressure

[agallant80]

Well my endless POS trailer did it again. This time the master cylinder failed. I oredered a new one. It will be here Tuesday. My question is has anyone bleed the breaks with compressed air? Open a bleeder valve put a little pressure in the resivowar and let the fluid drain out the bleeder then close it? I have the old cap and a portable air tank. I set it to 10PSI drilled the old cap and put a fitting on it.

I have seen youtube videos with people doing this on car and posts with people doing it.
The DIY $20 brake bleeder


Thoughts?

 

[bruceb58]

Re: Bleed breaks with pressure

I have done it using a Motive Power Bleeder with a trailer master cylinder adapter. I still had to pump the master cylinder at least with the Tie Down master cylinder I had so not sure how much its worth it using it. It's pretty easy to do it manually with a helper. Forget about using the mity vac method. Never had luck using those.

How did it fail so soon? Did it get water in it? What brand?

 

[agallant80]

Re: Bleed breaks with pressure

I guess I can't really blame Venture on this one. When I was putting on the pole tong adapter for my WD hitch I pushed too hard against the reverse lockout solenoid which is brass and broke off. I had the brilliant idea of using a tap to drill out the part that was left inside the master cylinder. Lots of metal shavings getting in contact with rubber seals and you get the idea. Bone headed move my fault I admit it and accept the $120 lesson. Its a Titan 20 hitch.

 

[gm280]

Re: Bleed breaks with pressure

I've used both a helper method and a hand squeeze vacuum pump method with perfect success. 10PSI is a lot of pressure with an open line bleed. You'll have to watch real close to not run the reservoir out of fluid using that setup because it could happen quickly.

 

[bruceb58]

Re: Bleed breaks with pressure

The Motive bleeder says to use between 10 and 20PSI but never above 20PSI.

 

[Scott Danforth]

Re: Bleed breaks with pressure

I have created a vacuum bleeder with my shop vac, an orange juice container and a bit of vacuum line. sort of like an industrial version of the mity vac.

however on a trailer, you still need to move the master cylinder a bit, and keep it topped off.

Now I just have my stepson help. he pumps, I bleed.

 

[Thalasso]

Re: Bleed breaks with pressure

Get yourself a short piece of clear tubing. Put it in a mason jar with enough brake fluid to keep the hose end covered. Now open the bleeder and go back to the MC and pump it until there are no air bubbles. One man job.No pressure bleeder to buy for the one or two times you might need it.

 

[Splat]

Re: Bleed breaks with pressure

Get yourself a short piece of clear tubing. Put it in a mason jar with enough brake fluid to keep the hose end covered. Now open the bleeder and go back to the MC and pump it until there are no air bubbles. One man job.No pressure bleeder to buy for the one or two times you might need it.

Does this actually work? I would think any bubbles would be sucked right back into the caliper. I've never heard of this method.

 

[Thalasso]

Re: Bleed breaks with pressure

Yes it works. Air can't be sucked back in because the end of the tube is immersed in brake fluid.(One end in bottle the other on the bleed fitting). When the bubbles stop move on to the next wheel.What you do is pump the emergency brake away lever. No need to push on the M/C.
What M/C (model)do you have?


Found this for you.
The only diff. is i put fluid in the jar to keep air from coming back up on the release stroke.

How to Bleed Hydraulic Surge Trailer Brakes | etrailer.com
www.etrailer.com/question-47437.html

 

[Splat]

Re: Bleed breaks with pressure

Yes it works. Air can't be sucked back in because the end of the tube is immersed in brake fluid.(One end in bottle the other on the bleed fitting). When the bubbles stop move on to the next wheel.What you do is pump the emergency brake away lever. No need to push on the M/C.
What M/C (model)do you have?


Found this for you.
The only diff. is i put fluid in the jar to keep air from coming back up on the release stroke.

How to Bleed Hydraulic Surge Trailer Brakes | etrailer.com
How to Bleed Hydraulic Surge Trailer Brakes | etrailer.com

I get the tube being submersed not sucking up air, but I would think the bubbles in the hose would go right back into the caliper. I'll have to give it a shot someday.

 

[bruceb58]

Re: Bleed breaks with pressure

I get the tube being submersed not sucking up air, but I would think the bubbles in the hose would go right back into the caliper. I'll have to give it a shot someday.

That is pretty much been the standard way of bleeding brakes since the beginning of time!

 

[oldjeep]

Re: Bleed breaks with pressure

I've got the motive bleeder as well, works great for trailer and cars. x2 on not over pressurizing, if you do you'll get air bubbles in the fluid and all the bleeding is a waste of time. Never had any luck with vac bleeders.

 

[UncleWillie]

Re: Bleed breaks with pressure

I get the tube being submersed not sucking up air, but I would think the bubbles in the hose would go right back into the caliper. I'll have to give it a shot someday.

Yes, the air still anywhere in the system backs up a little on the release stroke.
It is a three steps forward and one step back type of process, only more like 10 forward and one back!

 

[agallant80]

Re: Bleed breaks with pressure

Just to follow up it worked really well.

Get extra cap and drill hole in it
attach hose to bleeder and open up
put some compressed air in the cap via the hole you drilled
watch the fluid pour out
close bleeder
remove hose


Took me about 10 min to change out all of the break fluid and purge air from the system. I must have had some in there before because it seams to be breaking better now.

I used one of these with the black tip to put air in through the hole.
http://www.homedepot.com/p/Husky-12-Piece-Brass-Air-Compressor-Accessory-Kit-HDA51300AV/100392283