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Brake bleeding question

Charles in SC

Well Known Member
I have read all the brake bleeding threads I could find. I have a bug sprayer set up to pump etc. So far the only fluid I have gotten anywhere is on the floor. How do you keep it from coming out around the threads on the bleeder valve. I only have it open maybe 1/16 turn.
Thanks in advance!
 
Well I went back this afternoon and tried again. I unscrewed the bleeder more (about a turn and a half). Still not much love. I switched it around and put the pump on the other end to try pumping down. I did get fluid through and found some leaks. I worked on them and will try to bleed it again.
Thanks for the input!
 
Make sure your brake cylinders are unloaded/returning all of the way when released. Pull back on the brake pedal and see if you make any ground from the normal resting spot. If they don?t return all the way, you will need to address that.
 
HFS thanks for the info.
I worked on it some more today and I think I have it done.
I pumped from the bottom again and now I have good pedal and no leaks I hope. For whatever reason when I backed the bleeder out another turn the threads quit leaking. I think it would work better with a more powerful pump but then you might not be able to keep the hose on the bleeder. I think I was being timid with the pressure before as well.
 
Doesn?t really take much pressure to charge/bleed the brakes. As mentioned above make sure there not a blockage and all master cylinders are open. A few weekends ago I helped a friend with his initial charge. Was using a different pump but it was taking a lot of pressure. Quickly figured out his parking brake valve was engaged. Then we figured out there was just a bit of pressure on one of the pedals. After that was pulled back it all flowed as it should have and charged up nicely.
 
Charles- check your brakes again. It is my guess that one or both of your master cylinders are not fully open when the pedals are released. Get in, pump your brakes a few times, reach down and see if they are fully disengaged.
Your symptoms tell us that they stick from time to time. This means you may be dragging a brake without knowing. If you are, there are easy fixes.
A dragging brake can cause the airplane to pull during roll out, take off and landing, which can lead to loss of control.
 
I got in and checked the pedals and master cyls. and everything I could think of. They all have the same amount of plunger showing and the brakes seem to work fine and have plenty of pedal. Thanks for the tips!
 
My RV7 brakes are VERY sensitive. Almost any pressure above the bottom of the rudder pedal will cause a brake to drag. I've burned up the O ring in the left caliber twice from long taxies. So I know better now. But is there a way to back off the master cylinders?

Also - I was trying to top off the left side after one of these instances, using the oil can on the caliper nipple as you described, but the line would not take any fluid. Our work around was to bypass the parking brake valve with fittings. This worked as far as getting fluid and function back on the brake, but I lost my parking brake function. My thought is the builder (I was not) got the e brake valve in backwards??? Anyone have a photo or diagram of proper parking brake valve installation?
 
Probably goes along with the above, on my 7 I recently lost my left brake, turns out to have been a o-ring in the brake caliper (Maybe, it was def shot and we replaced it. Should have replaced both sides when I had the chance. Anyone know what size to order?) Anyhow we replace the oil ring on the left, and bled the brakes on the left, but still didn't have good braking on the left. I jumped into the Co-pilot seat (right) and tried the brakes, Left worked great, Right didn't (complete opposite from pilot seat). We then bled both sides and the pilot seat works, but the copilot seat still is not working as good as I think it should. The Mech thought it could be the master Cylinder on the Co-pilot side, I think there may still be an air bubble in the lines.

Any guesses?
 
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