home built DIY brake bleeder

[charm]

There have been threads of this sort in the past and they're all over the internet. What I can't find and was wondering if it would work is a setup that used, say, a Nalgene bottle and an air compressor.

 

My idea is this: Install 2 fittings into the lid of an old Nalgene bottle. One fitting would be barbed and would have a length of tubing on the inside of the bottle leading to the bottom of the bottle. The other fitting would be to connect the bottle to a portable air compressor.

 

Set the compressor to 20 PSI.

 

From the barb fitting on the Nalgene bottle, run a length of tubing, say 1/4 inch, to a modified bone yard collected master cylinder cap with a barb fitting on it.

 

From here it's the same as the rest of the DIY bleeder kits. Really, I'm just taking the garden sprayer and replacing it with a 1 liter Nalgene bottle. I suppose putting a pressure relief valve somewhere in the system would be wise too.

 

Thoughts? Would this work? Would it work better than the garden sprayer version? Worse?

[89Ru]

I think it would work just fine. So you are putting regulated pressure on the master cylinder, then you crack the bleeders one at a time (in the proper order of course). So the nalgene bottle is there in case there is a vacuum on the top end then the fluid sucks into the nalgene bottle and not into your compressor...good idea. The modified cap might leak pressure, maybe seal it with dielectric grease around the threads. Maybe add a valve to release pressure...you might be refilling the cylinder as fluid bleeds down. The more features, the more leak paths though...

 

I use the el cheapo piston pump vacuum cylinders on the brake bleeder side, they really suck and that isn't a compliment hardest problem is sealing all the pesky vacuum leaks around the collection bottle.

 

Post results if it works, might copy you.

[hankosolder2]

I did a very similar thing to build a "pump" to transfer manual trans fluid into my BMW. (Trans filler is a threaded plug on the side of the trans under the car, so it's hard to do via gravity!)

 

I fed the output of a blow gun into the oil filled bottle and then had the dip tube down low in the bottle. Used some hollow threaded rods to build it. Squeeze the blow gun handle to feed oil (brake fluid) in.

 

My one note is that plastic bottles blow out at surprisingly low pressures! 20 psi might be a bit high. I think the kits which use tire pressure recommend something like 12 psi.

 

Nathan

[charm]

The Nalgene bottle is there to hold extra fluid to keep the reservoir full thus ensuring no air bubbles.

 

This presents a problem...how to prime the tube? Or, I suppose that's how you would know you've gotten to the fluid from the Nalgene by the long air bubble. hmmm

 

I'll have to test and see how much pressure a Nalgene bottle can take. 20 psi doesn't sound like much for a rugged bottle like that. But, it's used to impact from the outside, not pressure from within so I really don't know.

 

I think it would work just fine. So you are putting regulated pressure on the master cylinder, then you crack the bleeders one at a time (in the proper order of course). So the nalgene bottle is there in case there is a vacuum on the top end then the fluid sucks into the nalgene bottle and not into your compressor...good idea. The modified cap might leak pressure, maybe seal it with dielectric grease around the threads. Maybe add a valve to release pressure...you might be refilling the cylinder as fluid bleeds down. The more features, the more leak paths though...

 

I use the el cheapo piston pump vacuum cylinders on the brake bleeder side, they really suck and that isn't a compliment hardest problem is sealing all the pesky vacuum leaks around the collection bottle.

 

Post results if it works, might copy you.

[89Ru]

Maybe build it in stages

 

First see if the modified cap will hold pressure...don't use the nalgene bottle, just pipe from the compressor to the cap, you'll have to refill the cylinder but its simpler, no air bubbles, even slight pressure should cause fluid to flow out the bleeder.

 

Then go from there.

 

How to prime the tube from the oil bottle...maybe a valved fitting on the nalgene to a turkey baster (or vacuum cylinder pump hehe) to draw air bubbles into the nalgene from the master cylinder...

[charm]

To get fluid into the tube between the Nalgene bottle and the cylinder, just suck. Sure, a vacuum pump would be easier, but I think you could create enough of a vacuum using your lips to bring fluid into the bottle.

[idosubaru]

no worries on priming it. any air that goes to the master cylinder will float to the top and reside inside the reservoir, not go into the lines. that's what mine does, i was worried at first but that's how they all work, very simple.

 

you only need about 10 psi. I think i get mine to roughly 7-8 and it works great there.

[lostinthe202]

I made one of the garden sprayer variety and as stated above the leaks are really the weakness in the system. I'd use some solvent resistant gasket maker on your connections along with hose clamps and give it the full 24 hours to dry. Sounds like a neat setup though

 

Will-

[GeneralDisorder]

I use a 20oz soda bottle which I have punched a hole in the lid for a length of rubber tubing. Fit the tubing over the bleeder screw and with the tube immersed in brake fluid at the bottom of the bottle start pumping the pedel. Then it's just a matter of filling the reservior after each wheel is done. Make the tubing long enough that you can set the bottle where it can be seen while pumping the brake pedal.

 

I haven't had the need for any other methods though I imagine they have their good points as well. I just can't see the time or money investment building some contraption to pressurize the system and/or avoid filling it after bleeding each wheel...... at the end of it the day someone still has to crawl under the car and loosen/tighten bleeder screws, etc.

 

But if I were going to build something I would just hook it up to shop air like a paint pot. To heck with pumping a garden sprayer! I have a compressor and it does all my pumping

 

In fact an old paint pot would probably be a good starting point.

 

20 psi is crazy high though. 5 would be more reasonable. You don't want to blow your reservior apart! Get a high quality regulator. Not some cheap Harbor Feight peice of crap either. Something that can measure psi down to 5 and is accurate. And you should put a gauge on the pressure vessel - it may not be the same as the point of use as it is at the reg.

 

GD

Edited January 3, 2010 by GeneralDisorder