A dead spider and bleeding the brakes...

[David-aviator]

Late last fall I pulled into the hangar after a flight and was reaching for the log book when I noticed this brown spider on the instrument panel next to the airspeed indicator. He was about as big as a dime and before I could call 911, disappeared behind the panel near the vent outlet. (I do not like spiders)

What to do? I considered fogging the interior but decided not to not knowing what that stuff would do to instruments. I finally decided not to do anything for now and maybe he would leave like he arrived.

I was in the airplane today. The left brake pedal was leaking just a tad of fluid on to the floor and it was time to check it out. Turns out the flex hose was leaking ever so slightly (when under pressure) where it goes into the brass fitting . I happened to have another hose so proceeded to crawl under the IP and get at the fittings and change it out. Not a fun job but got it done while capturing about 5 ounces of brake fluid in a small pan. In the process the brown spider was discovered - dead. Thank goodness, again I do not like spiders.

This may or may not be useful information, but I use a gravity theory to bleed the brakes. I've done it from the top and today I tried it from the bottom and it seems to work ok. A ladder is set up near the airplane and a container of fluid is suspended and connected to the brake system with a plastic tube at the brake housing bleed valve. The container is about 2 feet above the reservoir. When the flow process was started the left brake lines to the passenger brake pedal and to the reservoir were clear. Three hours later, the lines were filled with fluid and reservoir was nearly full.

It is almost a no mess way to service the brake system but it does take a little time. I have not figured out the hydraulic mechanics of the system but do believe when servicing for the first time, it needs to be done from the top to get all the air out.

[txaviator]

Got bit by brown recluse back in my days of crawling through attics and crawl-spaces, installing security and fire alarms.

NO FUN!

Had to go to the hospital and get the bite lanced, which was really a bad scene.

Still have a scar to this day......

[Randy]

I have used a good quality oil can to pump fluid from the bottom up for years. I remember going through two or three oil cans before I found one that would not pump any air. Then it takes a little messing around to get a plastic tube connected that will not leak at the oil can spout. It helps to change out the tubing from time to time as it gets hard and loses it elasticity.

The plastic tube is of a size that just fits on the bleed connection at the caliper. Up in the cabin I put a nipple in where the plug was in the master cylinder, and another plastic tube running in to a jar. This way I can keep right on pumping till it overflows with no mess, close the bleed fitting and check for air in the overflow tube at the master cylinder, job is done when the overflow tube is full with no bubbles in it.

In my system it takes about 100 to 150 pumps to fill the system from dry. If the oil can gets low on fluid I can stop, close the bleed valve, refill and proceed without any problems.

A nice pressure bleeder would be nice to have, but this has worked for me for years on several aircraft.

The oil oil squirt cans that did not work had plastic internals, metal pump innards seem to be needed.

BTW, I use the little individual brake resevoires on each master cylinder rather than the one up on the firewall feeding both. I like them.., available at AC Spruce.

Randy C

[pierre smith]

Mornin' all,

Years ago I built a 427 Shelby Cobra kit and a friend who was racing in IMSA then, showed me a neat trick to fill new, empty brake lines using a small electric vacuum pump. He connected the plastic line to the furthest wheel from the reservoir...left rear, I believe and sucked the fluid through a 1 gallon, clean mayonnaise jar to prevent it from locking the hydraulic vac. You stand by the reservoir, keeping it from emptying and when you see fluid running a steady stream into the jar, tighten the bleed screw and go to the next wheel...and so on. Painless and you save the fluid in the jar for another day.

Regards,

[David-aviator]

Originally Posted by David-aviator

This may or may not be useful information, but I use a gravity theory to bleed the brakes. I've done it from the top and today I tried it from the bottom and it seems to work ok. A ladder is set up near the airplane and a container of fluid is suspended and connected to the brake system with a plastic tube at the brake housing bleed valve. The container is about 2 feet above the reservoir. When the flow process was started the left brake lines to the passenger brake pedal and to the reservoir were clear. Three hours later, the lines were filled with fluid and reservoir was nearly full.

It is almost a no mess way to service the brake system but it does take a little time. I have not figured out the hydraulic mechanics of the system but do believe when servicing for the first time, it needs to be done from the top to get all the air out.

I must have had a brain cramp. The information on gravity feed to the brake system in a Van's airplane is useless. I have used it successfully in the past, perhaps on another airplane, but after checking the brake, that pedal went flat and the plastic line from the reservoir was full of air again. Pressure is needed to properly service the RV brake system. Here's why.

The leaking line replacement goes from the firewall up and over the rudder bar and down to the left cylinder. It is filled with air when installed. The top of that line does not fill with fluid using the gravity method because fluid just rises up on side and slides down the other not removing any air. I ran half a quart of fluid through the system and it did not move the air down and out of that line and never will.

What does work, in either direction, is fluid under presser. I rigged up a receptacle on the lid of the gravity feed container so the hose from the compressor could be connected to it. With the pressure cranked down to 5 psi, I just stood there and watched a ton of bubbles comes through the reservoir which was hooked up to a bottle to catch fluid coming through. After about a minute the fluid had no more bubbles and the pedal is solid once again.

Most of you probably know all this stuff but in case you don't, this is what I learned this time. It takes pressure so don't spend $60+ on that gravity feed system in TAP and ACS for an RV.

[Skyflyer]

I have used the oil can method Randy describes for years when servicing my Cardinal. Works like a charm and will push air against gravity to purge the system very effectively.

Chuck