We're running into a problem with air bubbles in the brake lines of an RV-7a. There was definitely a leak in the connector between the soft line from the pilot's seat right brake to the aluminum tubing out to the wheel. We didn't notice the leak for a while and managed to let the reservoir empty and got air bubbles in both brake lines (at least that's what we think happened), leaving the co-pilot's brakes very spongy and not so useable.
Fixed that leak, rebled the brake lines and the right brake now seems to have the right amount of stiffness and appears to work well. However, we're running into an odd problem with the left brake. If the co-pilot's left brake pedal is pushed, an air bubble will show up in the line from the master cylinder to the reservoir, just outside of the master cylinder. If the pilot's left brake is pumped a number of times (20+ times), a bubble appears in the line between the pilot and co-pilot master cylinders, right after the pilot's master cylinder. We cleaned up the cockpit after the original leak and can't find any brake fluid leaking anywhere. We rebled the left line a couple of times, and ran into the exact same behavior each time.
Neither right brake is "spongy", but we're worried about these air bubbles and having to do this whole process after another couple of flights. The plane has about 60 hours on it, brake line design is according to Van's designs. Any suggestions on what could be going on or how worried to be about the air bubbles?
Thanks,
Brian
Fixed that leak, rebled the brake lines and the right brake now seems to have the right amount of stiffness and appears to work well. However, we're running into an odd problem with the left brake. If the co-pilot's left brake pedal is pushed, an air bubble will show up in the line from the master cylinder to the reservoir, just outside of the master cylinder. If the pilot's left brake is pumped a number of times (20+ times), a bubble appears in the line between the pilot and co-pilot master cylinders, right after the pilot's master cylinder. We cleaned up the cockpit after the original leak and can't find any brake fluid leaking anywhere. We rebled the left line a couple of times, and ran into the exact same behavior each time.
Neither right brake is "spongy", but we're worried about these air bubbles and having to do this whole process after another couple of flights. The plane has about 60 hours on it, brake line design is according to Van's designs. Any suggestions on what could be going on or how worried to be about the air bubbles?
Thanks,
Brian