Brake fluid installation

I checked on the Brakes+fluid forum, but it did not prepare me for the hassle and mess of installing brake fluid from the bottom up.

I purchased a swell, large oil can which did a very good job ($35.00). I connected a hose to the oil can, pushed the handle and got the fluid all the way to the hose end, held it up high so the air bubbles disappeared, connec ted the hose to the bleeder valve and opened the valve up.

The hose leaked at the bleeder valve end quite profusely. I seemed to get to a tight spot. After MUCH leaking I heard a "pop". Looked around and did not see anything wrong, It seemed to come from the cockpit so I figured it was a brake cylinder popping open from the pressure. Checked with a friend and he suggested to place a ty-wrap around the hose at the bleeder valve. Continued on and finally, after more then a hundred pushes on the oil can handle, I got fluid in the lines and a small amount in the resevoir. Did much the same to the right side and then filled the resevoir.

What a mess, took a lot of time and trying to determine a better method, but was finally successful.

Surely, there is a better way???

The biggest problem was getting the hose tight enough at the bleeder valve.

carl nank said:

I checked on the Brakes+fluid forum, but it did not prepare me for the hassle and mess of installing brake fluid from the bottom up.

SNIP

Surely, there is a better way???

The biggest problem was getting the hose tight enough at the bleeder valve.

Click to expand...

There is a better way but it COST money.

See:

http://www.aircraftspruce.com/catalog/lgpages/hydraulicBleedertank.php

and

http://www.aircraftspruce.com/catalog/lgpages/brake_bledders.php

The second link MAY be able to be adapted to your setup.

I originally used a setup similar to what you described. A friend lent me the setup in the links when I changed out the O-Rings after 1000 hours of flying. After using the borrowed equipment, I went out and purchased the setup in the links. It now costs almost double what it did when I purchased mine.

From my building log

July 7, 2006
I tried to bleed the brakes with a little pump can like others have talked about doing. Well it made a big mess and did not work well. I asked a fellow RV builder about how he did it and found out from him that I could make a small pump sprayer into a pressurized brake bleeder. Here is how I made mine and it works great. It does take two people to do the job. I bought a 1-1/2 quart pump sprayer from Lowes allow with three different size pieces of tubing I put the tubing together and zip tied them to help hold them together. I used a small plug that came out of an instrument to attach another short piece of tubing to use as an overflow line to hold on the reservoir so the extra brake fluid could be caught in a bottle. (The next day I found the fitting that fits the reservoir it is 1/4"od x 1/8 MIP Quick connect maile adapter).Now this is the to do this job! When the job is all done the tubing can be stored in the tank to keep from losing it. 2.0 hrs

I've done it by myself after finding the fitting for the overflow.

Sounds like 2 issues to me:

1. These brake cylinders are notorious for not "returning" to fully open. Some people use return springs for this. I'm guessing that the "pop" you heard might have been the cylinder opening. Until it was open, you were just compressing the air in the lines. So...before you go to install your fluid, make sure your cylinders aren't inadvertently actuated...and think about return springs if you find that they were (they may not be).

2. Make sure you open the bleeder valve up enough to allow a decent rate of fluid flow. One of the gotchas I've seen is that you *think* you've got the bleeder valve open, but it's just barely cracked open. That's good for pressurized bleeding, but not for bottom-up fluid feeding. Gotta open that valve more than you might think.

I still use the cheapskate method of pumping in fluid, and with the above two points in mind, I haven't had any trouble.

I've always used the oil can method on many, many airplanes, pumping from the bottom up, and it worked fine. You might check to see that you have the bleeder valve on the brake assembly open enough. Sometimes that needs to be open 2 or more full turns to get good flow through the system, or it will appear to be very difficult to pump.

Vic

Brake Bleeder

Thought I posted this earlier but it never showed up!
I use the brake bleeder that is in the Acft Spruce link but I bought mine from Aircraft Tool Supply. They sent me a sale catalog and it was around $80 and it included the adapter that Spruce charges you more for. Once you learn how to hook it up, it's fast and clean. I install a fitting on the reservoir and use a clear hose overboard to a clean coffee can on the ground. You can easily see when you have all the air out of the system. I've never heard a "pop" when servicing and I've used it on a friend's 6 that had no fluid in the entire system.
Edit 1: I just checked www.aircraft-tool.com and the bleeder is not on sale, it's $89.85 and the Cleaveland adapter is $20.95. It's a little more than Spruce is charging for the two but it's usually in every sale catalog that you'll get once you register with Aircraft Tool Supply.

Like Dan, I used the cheapskate method.

I bought one of these 1.5 gallon sprays:

Cut the end off the wand, insert a barbed brass fitting like this:

and stuck a vinyl hose on the fitting which plugged right into the brake bleeder.

The reason for the 1.5 gallon tank over a smaller one is simple; the smaller tank puts the air pump right in the brake fluid. Thus, when you pump up the tank, you are putting air bubbles in the fluid, which is not a good thing. The larger tank keeps the brake fluid away from the pump so it works fine.

To capture the brake fluid at the reservoir, take the reservoir plug with you when you go to buy the sprayer. In the hardware section they sell a brass fitting that matches the reservoir threads and has a compression adapter on the other end like this:


On the way home from the hardware store stop by an auto parts store and buy one of these brake bleeders and connect it to the compression fitting. Insert that in your brake reservoir and pump away. Just remember, that bleeder doesn't hold a lot of fluid so check it often:

ATS Bleeder

I paid the "big bucks" (a nit in aircraft $) for the ATS bleeder. I also bought direct from ATS.

It works great with minimal mess.

Just to back up what Dan said, I found recently during a brake line change that the brake pedals MUST be full aft or no fluid will flow. If the pedal is just a bit forward, the incoming flow valve where fluid must flow through to the reservoir is closed.

Even after getting a good flow all the way to the reservoir I still ended up with some air in the line between the left and right side. But the brakes work and are solid, so the heck with it.

I know one guy with an RV4 who serviced the system from the top successfully but he ran fluid through with quite a bit of pressure and it somehow pushed all the air down and out. I told him that made no sense to me but how can you argue with success.

I used cheapo....

....oil cans from the local hardware store and they work OK - once. When I tried to use one a second time I found that the fluid had rotted the seals and they wouldn't pump. They are cheap enough to throw away but I do like the look of the ATS system.

When I bleed the brakes I thread a pipe fitting with a clear plastic tube into the top of the reservoir and drain it into a jar.

Jim Sharkey

I feel lucky..... I haven't had any of these troubles and I bleed my brakes bottom to top with stuff I had sitting around. I use an old oil can dispenser - the kind with a trigger and a spout about 3 inches long, a piece of clear hose from homo depot (1/4" ID I think) to connect to the bleeder valve. I connect an AN fitting to the top of the resevoir on the firewall with about a 4 inch piece of Al tubing attached with a flare fitting bent into a 'U' and an empty water bottle to catch the overflow. The clear tube squeezes securley onto the 'oil can' and the other end to the tip of the bleeder. First pump fluid through the tubing into your 5606 can until there are no bubbles, then connect it to the bleeder valve. The AN fitting replaces the mesh fitting on top of the resevoir with the other end of the 'U' Al tubing going into my cleaned out used water bottle. Then, open the bleeder valve first, and start pumping the 'oil can'. You can see if there are any air bubbles looking at the clear tubing at the oil can and above the brake cylinders - if you used the Van's supplied stuff like I did. When I hear or see fluid squirting into the water bottle, I know the fluid has purged everything and filled the resevoir. Then I use a cleaned out McDonald's soft drink straw to siphon fluid back out of the resevoir until I've lowered the top of the res fluid to about an inch or so below the top. It took longer to type this than it does to do it - and I'm a pretty fast typer...... I only spill a few drops around the bleeder valves and when I'm siphoning.....

Scott
RV-8 FB

Had a leak

Actually I had 2 leaks, one on the bottom of the left foot brake on the pilots side and one on the bottom of the right foot co-pilots side. After removing the elbows, cleaning and using more tight fill, I had and easier time replacing the fluid. I found a foot and a half of 3/16" inside diameter tubing and it fit much tighter on the bleeder valve then the 1/4" one I used before. I also kep't pushing the tube and bleeder valve so I had much less fluid loss around the threads then the first time.

Borrowed some electronic scales from the local airport today. Will try to do weight and balance tomorrow!!!!!

I used a cheap pump sprayer ($20)from the Home Depot aviation department and just got the clip on fitting... cheap. Works great.

Ok... I'm even cheaper... A friend turned me on to this.... I modified an old bicycle tire pump I had laying around (the kind with a 't' handle & a foot hold).. took off the hose and installed a brass fitting that took a plastic tube the size that would also fit on the bleeder valve (screwed right into the pump at the bottom).. Unscrewed the top of the pump canister and poured in the fluid... pump away... provides lots of pressure... Also used the overflow idea at the reservoir to catch fluid in a bottle.. If your supply tubing is long enough from the pump, you can be at the reservoir watching.... Sheldon

LifeofReiley said:

I used a cheap pump sprayer ($20)from the Home Depot aviation department and just got the clip on fitting... cheap. Works great.

Click to expand...

I just picked up a gallon sprayer, wondering if i should have gotten a larger one..

What clip on fitting do you speak of?

$15 Brake Bleeder

I took a suggestion from Mike Seager for an inexpensive, easy to build a brake bleeder. Here's what you need from the local Ace aircraft supply store:

(1) 2" plastic pipe nipple about 8-12" long with threaded ends
(2) 2" plastic theaded pipe caps
(4) 1/8" theaded by barb pipe fittings
(1) long length 1/8" plastic hose sized to match barb fittings

- Now drill and tap hole in center of pipe caps for 1/8" barb fittings. Screw barb fitting into those holes.
- Screw pipe caps on ends of pipe.
- Attach hose from barb fitting on bottom of pipe and the other end to fitting at brake.
- Attach another hose to barb fitting on top of pipe and the other end to outlet of air compressor hose. You'll have to figure out how to adapt the barb fitting to your air hose.
- You'll need to take pipe cap off top of pipe and fill with brake fluid about now. It also helps to wrap wire around pipe to hang it from something while you work.
- On brake reservoir on firewall I installed another barb fitting with short hose to clear pop bottle for overflow.
- Now crack the fitting on the brake connection open and slowly apply air pressure. Just make sure air regulator is at zero pressure when you start. Also don't get too agrressive with the air pressure or turn the regulator the wrong way as you don't want to blow off the hoses. Ask me how I know!
- The air pressure pushes the brake fluid through the lines and when you get a clean stream of fluid out the overflow you are done with that one. Go to the other side.
- Somewhere during that time I pumped the brakes until they were firm while having a friend tend the air regulator.

Very easy, inexpensive, effective system, thanks to Mike. I installed the brake fluid this way back in August and brakes are still working great.

I recently added brake fluid to my -6A project. I did it solo and it took all of about 15 minutes. I used about eight feet of tygon tubing from the hardware store and a hand cranked model airplane fuel pump. No runs, drips, or errors and the length of the tubing allowed me to see inside the cockpit enough to see the brake fluid travel up the clear plastic lines to the reservoir.

The procedure was to fill the left side such that the brake fluid filled the plastic tubing all the way to the reservoir plus about 5 turns on the crank. I then repeated same for the right side, except added 10 cranks. I then checked the brake reservoir and kept adding 10 cranks until it was about half full (I used a dipstick to measure this).

Cheaper yet

A method I have used successfully on all kinds of brakes is some rubber tubing and a turkey spice injector. Typically three shots from a 50 ml turkey injector syringe is sufficient fluid to fill the brake lines. Attach tubing to both the syringe and the fitting on the bottom of the brake assembly and push slowly. On the brake reservior on the RV remove the cap and insert a shaved down tougue depressor or straw with the end sealed and mark with a line at the top of the reservior to mark the empty position. It will rise as the reservior fills.