homemade pressure brake bleeder

I was inspired by the Motive Products power bleeders, but didn't want to pay that much for them, plus I like to tinker in my workshop, so I built my own:

 

 

The above pictures were taken during a pressure test with my new "universal" reservoir cap fitting. If bleeding, I would have a liter of brake fluid in the sprayer, and it would be pumped into the master cylinder reservoir under pressure. No real chance for the reservoir to go empty and introduce bubbles into the system.

 

The basic parts were a 2.5qt sprayer from True Value Hardware ($13), quick-release parts (~$10), pressure gauge (~$8), 1/4" ID vinyl tubing, some chain, and eye bolts from the hardware store. You could just use a tubing barb fitting rather than a quick-release fitting.

 

I already had the gasket material from a previous project. It is 1/8" sorbothane (very soft polyurethane). That was probably about $4 for 4"x4". I got that, the pressure gauge, and the quick-release parts from McMaster-Carr (mcmaster.com). I love that place. They sell everything you could imagine.

 

For the reservoir cap, I had some scrap 3/8" aluminum stock. 1/4" would probably work fine. MDF and HDPE (plastic cutting board) do not work well. The MDF makes it difficult to seal the 1/4 NPT fitting, and the HDPE was too flexible, breaking the seal at the reservoir. This 3/8" aluminum is some serious overkill, just my style. I tapped threads into the aluminum to get a nice seal with the quick-release fitting.

 

Last weekend I replaced the fluid in my Volvo V70 with this. Even single-handed what a piece of cake! Jacking up the car and removing tires is by far the slowest part of the job. Pump up to 15-20psi, bleed until new fluid comes out clean. Pump a bit more, next corner, etc. 1 liter did the V70. I wonder if a liter will do the LGT too.

 

I am alternating between ATE Super Blue and Typ 200. They are the same fluid but different colors, so it is easy to see when you have the old out.

 

Hopefully I can do my LGT tomorrow. Since this is so easy, I plan to do it about every year/15,000 miles. I'm coming up on 1 year and 15,000 miles.

 

If I didn't like to tinker in my shop and have quite a few tools, I would have just bought the "universal" Motive Products bleeder for $45ish, which is really a pretty good deal.

 

--Lee

Very nice.

IN GENIE US!!

IN GENIE US!!

 

FAT FREE?

looks awesome!! but im not understanding how it's connected to the master cylinder?? maybe i just need to study the pictures more. and i completely agree, McMaster Carr is just awesome. i spent way too much money there when i was in college for Soph. Jr. and Sr. design classes!!!

 

Kenda:dm:

would you actually need the pressure guage? I'd think that you just need to pressurize the system and then bleed until clean. No?

FAT FREE?

http://www.illfindsomethingtoputhere.com/funforum/images/smilies/biggthumpup.gif

I like the check valve bleeder that SnoDork built for me. One check valve and a couple small lengths of vinyl tubing and voila, couple of pumps of the brake pedal and you are done. Best of all... it was all free!

The bleed went fine. I ended up using 1/4" ID tubing on the rear calipers and 0.17" ID tubing on the front. (I started with 3/16" ID on the front only to find it a bit loose and causing some false bubbles.) 1 liter is plenty for a thorough flush of the whole brake system.

 

Here is the bleeding in progress on the first corner:

 

http://www.csail.mit.edu/~ilh/pics/bleeder/bleeding-1.jpg

 

http://www.csail.mit.edu/~ilh/pics/bleeder/bleeding-2.jpg

 

http://www.csail.mit.edu/~ilh/pics/bleeder/bleeding-3.jpg

 

The 1-year-old original fluid that came out was suprisingly murky with some cloudy crud in it. I'm glad I replaced it.

 

This was the first time I jacked the front up with my floor jack. I used the front cross-member that is a little behind the oil drain plug on the engine (per the vacation pix). Even at stock height, I couldn't really operate my jack in that location until I came at it from the side with the handle just in front of the left front tire. Then I could pump by using the wheel well. Coming from behind the tire appears it would also work. I have the smallish Sears 2-1/2 ton floor jack.

 

I discovered that an old hockey puck makes a great pad between the floor jack and the front cross member as well as the rear differential. It seems to be just the right hardness to protect things, give a good non-skid connection, and not deform too much.

 

--Lee

 

PS: The pressure gauge was just so I had a good idea of how much pressure I was putting into the reservoir. I didn't want to blow it up. I ended up using 15psi-20psi.

 

PPS: The ATE Super Blue was definitely heavier than the stock fluid that came out. In my collection jar, the old stuff settled on top of the ATE.

 

PPPS: What a great color blue!

Sweeeet!

mhh, interesting. i am working on a vacum system right now for my car.

Very creative. I love DYI stuff like this.

This looks pretty easy. I may have to stop giving the dealer my Subaru Bucks and save them for the next new car purchase.

 

Do you guys ever take out the bleeder screws completely and coat the threads with anti-seize? Or will cracking them open every 2 years keep them from freezing up? (Lotsa road salt here in Minnesota.)

 

That also doesn't look like an official brake bleeder wrench to me. Doesn't it want to fly off the bleeder screw and imbed itself in the garage wall?

 

Sweet device.

^ Teflon Tape on the bleeder screws. Also prevents air from from getting in around the threads while bleeding (especially if you use a hand pump to bleed by yourself).

looks good, I've done a similar setup that runs off of my air compressor instead of a hand pump.

 

Only change I would make is to extend a piece of tubing from the universal cap down into the brake fluid. by just letting it pour in, you are giving it one more chance to aerate and pick up humidity from the air. I know, thats probably being overly anal aobut it, but it gives you a good excuse to go back to the garage and tinker some more.

http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml

 

Summary: you might be pressuring your new fluid with moisture and air!

 

This brings us to the imitations. There seem to be a rash of products available lately that claim to be pressure brake bleeders at a fraction of the cost of the professional units. Like most things that sound too good to be true, well, it’s exactly that.

Like the professional units, these imitations contain a pressure vessel into which new brake fluid is poured. However, in order to pressurize the fluid, an integral pump handle is cycled to build the pressure inside the vessel without any measures taken to separate the pressurized air from the fluid. For those of you who have ever bought a $19.95 do-it-yourself potted plant and bug sprayer from Home Depot you get the idea.

Of course, having pressurized air in contact with the brake fluid will certainly force the fluid through the system just as effectively as the high-zoot professional unit, but as an added bonus we are stuffing air into the brake fluid at the same time. Talk about an unwanted surprise!

While it may not be visible to the naked eye (air can actually entrain itself in the fluid as to be visually undetectable) it’s there right along with all of the nasty moisture trapped inside of it. This of course begs the question: if you are stuffing air and water contaminated fluid into your brake system, why even bother bleeding it in the first place?

Naturally there will be those who argue that the amount of air in question is not important enough to worry about, but think about this for a moment: nearly every automotive manufacturer stores their bulk brake fluid in large containers which are subjected to a constant VACUUM. Talk about an expensive process! If just storing your fluid under regular atmospheric conditions isn’t good enough to keep air and water out, just imagine what shoving 30psi worth of compressed air on top of it is doing.

The professional units can cost hundreds of dollars, and for good reason; unfortunately the cost keeps them beyond the reach of most of us normal folks. Your best bet is probably to get back in the driver’s seat and begin stroking the pedal with your foot again, but ultimately the choice is yours.

ilh.....any problems like Ed_T quoted? I have all the parts to do this and would like to change teh lines to SS and get some better fluid. If there are no ill effects I think I might end up doing this soon.

http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml

 

Summary: you might be pressuring your new fluid with moisture and air!.......Of course, having pressurized air in contact with the brake fluid will certainly force the fluid through the system just as effectively as the high-zoot professional unit, but as an added bonus we are stuffing air into the brake fluid at the same time. Talk about an unwanted surprise!.......

 

Seems like a plausible theory, but I have not read of any complaints of a soft pedal after using this type of pressure bleeder, which you would expect if air is being entrained in the fluid. I would not store the fluid in the bleeder, but for the short time that the brake fluid is in contact with the pressurized air, there do not seem to be any adverse effects.

Why not put the fluid in a flexible container inside the pressurized chamber so that it is not in contact with the air? I'm thinking maybe one of those hydration pouches in Camelbaks.

 

I think this is still a great idea. But I'm leaning towards a check valve, it seems easier.

now to add a shop air suply to the resivour!

wow, thats nifty! now if one didn't have this nice tool and one person was pouring while the other drained, would the fluid still come out without pressure?

nope just the force of gravity then

Most track guys I know use a pressure bleeder. Its so fast. I use it almost exclusively. Stoptech has awesome products but they always claim the sky is falling it seems like! LOL

 

ilh - do what I did and stop using that wrap-around contraption. Find a salvage Subaru and get the MC lid off and put your bleeder into that. No strapping just put the lid on and go!