Bleeding brakes

AK Mauler · Post by **AK Mauler** » Tue Oct 31, 2006 6:29 pm

I replaced my brake lining last weekend and when I tried it out, the right brake was spongy like I got air in the line or something. I didn't break any fittings and didn't notice any brake fluid leaks, so I have no idea how the air got in the system. It looks like I will need to bleed the brake cylinders. Has anyone out there done this and are there any special tricks involved? I called the factory and they recommended an oil can filled with brake fluid to squirt the brake fluid into the fill port of the cylinders. He also mentioned that you fill and bleed the system through the pilot side only, not sure how this gets any potential bubbles out of the co-pilot brake cylinders? Oh yeah, and lots of rags to catch any drips. Let me know if anyone has any tips.

maules.com · Post by **maules.com** » Tue Oct 31, 2006 10:09 pm

Lots of rags under and around the pilot side master cylinder.
Pump fluid into bleed nipple on bottom of brake caliper and as it pushes fluid up through master cylinder onto the pile of hopefully very absorbent rags, it will bring the air with it.
If it gets past your rags it will be under the floor eating paint, soaking insulation, and causing all kinds of future problems.

twheel · Post by **twheel** » Sat Nov 04, 2006 8:00 pm

Will this work for getting the air out of the co-pilots side as well? I've had problems in the past getting the air out of the co-pilots side and the interconnect lines. Thanks.

maules.com · Post by **maules.com** » Sun Nov 05, 2006 6:32 pm

Yes, the fluid goes from the calipers to the co-pilot slave cylinders and then to the pilot side master cyls and resevoirs. Keep it moving when you start for quickest results. If you have to refill your pump can halfway, then there is a chance of air ingress. Lot's of super-absorbant rags, or pull the floorboards. If the master cyls are kept topped up then air is unlikely to get in.
BEWARE. Make sure the master cyl. plugs (which should have vent holes in) do not foul the brakelock mechanism after refit.

AK Mauler · Post by **AK Mauler** » Mon Nov 06, 2006 10:28 am

Jeremy, thanks for the valuable information. I completed the task over the weekend with good results. The shop where I purchased the aviation hydraulic fluid had the following advice.
Open the bleed nipple on the caliper and pump out the old fluid into a small plastic cup. This empties the system of the old stuff, and gives a rough idea of how much fluid needs to be filled. In my case a small amount of fluid drained after several pumps on the pilot side brake pedal. My guess is my fluid level was too low and allowed air into the system. From here I attached a clear plastic hose to the caliper nipple and filled the system with a plastic squeeze pump I got at the auto parts store. I placed several rags tightly around the master cylinder and pulled the orange plastic fill plug. I checked the fluid level with a white golf tee to see when the level was up. I got lucky and managed to fill it with no drips. Brakes were nice and tight after filling.

Kirk · Post by **Kirk** » Thu Nov 09, 2006 5:18 am

That white golf tee is a good idea. Wonder if Aircraft Spruce or someone would sell me one for about $20? This is aviation after all.....

Kirk

Hottshot · Post by **Hottshot** » Thu Nov 09, 2006 6:24 am

Kirk--

If you give me a little time 1-2 years I should have a PMA'd STC'd Golf Tee ready for you.

donknee · Post by **donknee** » Thu Nov 09, 2006 11:18 am

Do you think you could put a little Bushwheel on the tee?

Bleeding brakes

Bleeding brakes

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