Has anyone used an electric vacuum pump to bleed their brakes?

I bought a small vacuum pump to do refrigeration work a few years back.

I have been in need of bleeding my brake system for a few months now. I've been postponing the job and have just left the truck parked mainly because it's just been too cold out and frankly getting under the truck with a hand-held vacuum pump will just take forever. I had to replace the master cylinder so I have to bleed the entire system from font to back.

I rigged my vac pump to accept a 1/4" vinyl hose. I took an old glass juice jar and with a rubber stopper have an in/out combination the same way the mighty-vac jar works. A long tube going all the way to the bottom of the jar and the vacuum port that pulls vacuum from the top of the jar. I could just bleed the system as usually done and by switching on the pump and VOILA it should be done.

I feel though that this "plan" sounds too easy and we all know when something sound too easy there's always a drawback to the system somewhere. Any thoughts on if this will or will not work before I go dragging everything out in the cold to attempt to do this???

EDIT: I should also not I added a small ball valve to throttle the amount of vacuum the pump can pull. This way if it's pulling too much I (in theory) can throttle back the vaccum and have less pull.

I'll have to post a pic of my contraption a little later.

Thanks,

 

I would say this will work fine, but the ball valve is a rather good idea. Refrigeration vac pumps can pull 25-30" vacuum, which could be more than the hydraulic brake system can handle.

 

Sounds like it should work OK. Just bleed them in the right order, going from furthest from the master cylinder to closest.

I use a 'one man' brake bleeder. Basically just a check valve that connects to the bleed nipple. You just hook it up, pump the brakes, shut the nipple and remove the bleeder. I have a manual vacuum bleeder, but found the one-man one to be easier for me.

Automotive Service Tool Sets - Tekton by MIT Brake Bleeder Kit

 

I have used the hand vacuum pump before to bleed the brakes. It doesn't work very well. You can't tell when all the air is out because it draws air from around the threads of the bleeder when it's loose.

 

Sounds like you have made one of these;

Air Boy Brake Bleeder Kit. #124143120

The Air Boy vacuum brake bleeder, I've got one and it is my most usefull tool. I use it for all sorts of fluid extraction, oil, power steer etc.

 

I like the "speed bleeders" take off the OEM bleeders, installs these. They have a "check valve" in them. Open the bleeder 1/2 turn, push on brake and return, check valve does on permit air to flow back in the line. A few pumps and the line is bled. Crawl back under and tighten bleeder. Done

 

Amen! I've had fits bleeding with my Mityvac. In one case I put PTFE on the threads of the bleeder valves before I started and it worked perfectly. But a year or two later when I tried to bleed the same brakes again the stuff had dried and leaked. So I don't like using the Mityvac but do anyway.

 

Yeah that's funny I went to bleed my brakes with a mityvac for the first time 3 days ago or so, and I had absolutely no success. It was sucking a TON of air around the bleeder. I know in the booklet they say to put some grease around the fitting to prevent this, but I didnt have the patience to mess with it at the time.. I ended up just getting my dad to jump in the cab.

Rocket good luck with your system.. I hope you bench bled the MC before you threw it on, I didn't do this (thinking because my whole brake system was empty I didn't have to) and I really wish I had. I've since bled the MC in the vehicle and re-bled the brakes and I still have a soft-ish pedal. Might just be the DOT5 though, god knows.

 

I have never done it yet, but I have the idea of putting a plate over the top of the master cylinder with a pipe fitting in it, and then screw in a air regulator and set it to about 5 psi. Put shop air on it and let that push the fluid through while you go around and open the bleeders.

Something I haven't worked out; There are many different styles of master cylinders, so it would need to be adaptable to different setups, it would be nice to have a "one fits all" setup. Also it needs to be easily removed to add fluid, or make some sort of sealed cap or port so the air can be turned off and fluid can be added during the bleeding process.

 

Use a pump up "garden sprayer" rather than a regulated air hose. As long as there is still fluid in the pressurized jug, there's still fluid in the master cyl.
I built one of these for using on my RX7's, and it works great. In fact, mityvac and other companies started making something similar, but they offer a wide range of resevoir caps, with a quick disconnect type fitting on them. we have one at the shop, and it comes in handy for bleeding and flushing brake/clutch hydraulics.

 

Hey ya'll thanks for the replies. I thought I'd do a little showing off. I started putting this thing together the other afternoon and by time I was nearing completion I ran out of day light so I didn't have a chance to actually put it to use SO i decided to go a little overboard and jazz up the base I made with some leftover formica laminate I had from a customers kitchen counter I did a while back. Looks pretty dang professional if you ask me and the only thing I really had to "buy" was the ball valve and the oil for the vacuum pump. Dang the vacuum pump oil cost me $20 for a quart. Holy hell....I hope there's traces of gold in that oil at that price. Anyway, here's a pic:



I already realized though this thing might pull too much vacuum. The other problem is that the ball valve really doesn't throttle the vacuum all that well. I think I need to re-pumb the setup with the ball valve in a different location so it can bleed off the vacuum rather than just shut the supply. I found in bench testing the setup that even if you close the ball valve it is still going to pull the same amount of vacuum (about 25" of mercury) just at slower rate. I guess what i'm trying to say is the way the ball valve is installed now its just lowering the volume of vacuum not reducing the pull or inches of mercury which is what I really need.

Ya know I have had this thought many moons ago. In the plumbing world anything with a thread is sealed with either teflon tape or pipe dope sealant. The thing I found with the teflon tape is that the brake fluid eventually "eats" it. I may pull the bleeder and carefully use some pipe dope to seal the threads. On top of that, the pipe dope should further prevent the bleeded from rusting completely closed.

Psssssh the about too requires manual labor. Not my cup of tea just kidding

I saw these years and years ago and have always wanted to use them but always forget to order them ahead of time. I'll have to check and see if a pep boys/advance chain store carries them!!!

I'm right there with ya. I have a mighty vac too which is what sparked my interest in making this thing. I just hate having to pump-pump-pump-pump continuously with the mightyvac.

Great idea. I had even thought about doing this just to keep my brake fluid at the M/C from running out. I thought about using an old m/c lid and modifying it to hold a brake fluid bottle. I'll see what I can "jimmy" up.

 

Manual labour? No way, this baby uses a Venturi powered by your air compressor.

 

Be safe when using a glass jar with vacuum, it can IMPLODE! Glass will fly and that's not fun. I know.... the hard way....