Mailing List lml@lancaironline.net Message #56127
From: Jeff Peterson <jeffreyb.peterson@gmail.com>
Sender: <marv@lancaironline.net>
Subject: brake bleeding
Date: Tue, 07 Sep 2010 10:48:36 -0400
To: <lml@lancaironline.net>

I have bled the brakes on my 360 from the top using a vacuum pump.

Works so well that transparent lines should not be needed.


My procedure:

The fill hole at the top of the reservoir has an 1/8 inch NPT thread,
normally a plug with a small hole goes there.

I took out the plug and put in an NPT-to-hose-nipple, and connected
a vacuum pump via tygon tubing.

The brake plumbing inside the cockpit is "nylaflow" tubing which is
translucent, so I could see bubbles vs red brake fluid.

I turned on the pump, and watched the bubbles grow to about 100 times their original size.

Because I could watch I have confidence the fluid does not boil, but

the procedure itself does not need clear lines,..you will just miss the fun of watching the process work.

Most of the greatly expanded air makes it to the reservoir, bubbles up
and ends up passing into the pump.

With vacuum applied the calipers open about 1/4 inch.

Since the motion of the bubbles eventually stopped
(1 min) I know there was no leak in the system.  After the bubble
stopped moving I let air back in,
watched the few remaining bubbles shrink, and
pumped the peddles to push the calipers back into position.

Repeated this process maybe 5 times. Pedals very firm now.   Not a
drop of fluid on the floor.
Topped up the reservoir at the end. Process takes maybe 15 min.



--
Jeff Peterson
N273CK L360
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