Jeff R
Well Known Member
Bleeding these brakes is starting to rank right up there with one of the most frustrating things I have had to do. I have never bled brakes before but didn?t expect too many problems. How na?ve I was! I decided to go with DOT 5 fluid, as that was available locally, and a friend lent me a hand operated vacuum pump he uses to bleed brakes on his Harley. I had read of the oilcan pumping method, but I really don?t see why one would get more bubbles using a vacuum vs. pressure, plus I didn?t want to have to make an oilcan pump and this vacuum pump gizmo was pretty neat. So, Friday I started on the left side and it workeds pretty good. In no time at all, I had that side done and I was really feeling happy. Then I started on the right side. I pumped until my hand was too sore to pump and I could not get the fluid past the right brake cylinder. It was getting time for the KU basketball game so I came inside and was happy after a convincing win, but this morning was such a beautiful day I decided to go out to the airport, pay my empty hanger a visit, and see what else was going on.
I ran into Chuck, my hanger neighbor who built a Glasair and I asked him about brake bleeding and he espoused the conventional wisdom that you need to pump from the bottom and he lent me this oilcan pumper and gave me a quart or so of 5606. I figured I would try it on the right side. I pumped and noticed some leaking from the AN fitting at the landing gear to fuselage connection. It was tight, but I gave it an extra tug, then I pumped some more and it still leaked. Urgh! I disconnected the fitting and discovered the flaired end had snapped. Yikes. I pulled the fitting off, dug out some new ones, re-flaired the tub and put it all back together. I re-pumped, but I could never seem to get the fluid up the tube. It seemed like there was a clog in the lines or something that stopped the flow. I verified the parking brake was not set and systematically disconnected various fittings to isolate any clog, but nothing.
As a sanity check, I moved back to the left side and tried pumping, and I had the same problem. What the? I knew there were no clogs as I have sucked fluid down the day before. But, as I pumped the can, the pressure would build up and the pump would start to leak or the nozzle fitting would come flying off. (That little bleeder value nipper is tooooo danged small.) This was what had happened on the right side, too.
I was getting pretty frustrated and running low on DOT 5. I had 2 pints and I think most of it was contained in clean-up rags that were piling up. I also started wondering about all that silicone. Would traces of silicone end up on the areas I would want to paint, and cause terrible fisheye problems? I decided to switch to the 5606. Draining out what all I could of the DOT 5, I started pumping on the right side. Man, it went right up and all the way to the reservoir. It was cool! Not having any idea why the DOT 5 wouldn?t pump up but the 5606 did, I moved back to the right side, thinking my first attempt at bleeding brakes was about to be over with a successful finish. No such luck. After a heck of a lot of effort and disconnecting fittings and reassembling them and finding nothing, it all started to pump and the fluid almost made its way to the reservoir when I noted another small leak from that AN fitting I had changed out earlier. I gave it another hard tug to tighten, but it still leaked. Dern. I dissembled the fitting and discovered I had again snapped the flair. Sheesh. And I was out of spare fittings, so I will need to order some more. I think I will also order some more aluminum brake line, as I saw that when I was tightening it, it was twisting, so I may have work-hardened it.
At least some of the frustrations were reduced for a bit as I got to see the last half of the KU-Missouri football game, where we pulled out a win, but it went down to the final few seconds, literally, before it was really over. Amazing game.
Anyway, I guess tomorrow I will work on something else, but this brake bleeding has sure been a pain. I would encourage others to bleed the brakes as early in the build process as they can. I can?t image the frustration if I had my instrument panel ribs and all riveted in.
I ran into Chuck, my hanger neighbor who built a Glasair and I asked him about brake bleeding and he espoused the conventional wisdom that you need to pump from the bottom and he lent me this oilcan pumper and gave me a quart or so of 5606. I figured I would try it on the right side. I pumped and noticed some leaking from the AN fitting at the landing gear to fuselage connection. It was tight, but I gave it an extra tug, then I pumped some more and it still leaked. Urgh! I disconnected the fitting and discovered the flaired end had snapped. Yikes. I pulled the fitting off, dug out some new ones, re-flaired the tub and put it all back together. I re-pumped, but I could never seem to get the fluid up the tube. It seemed like there was a clog in the lines or something that stopped the flow. I verified the parking brake was not set and systematically disconnected various fittings to isolate any clog, but nothing.
As a sanity check, I moved back to the left side and tried pumping, and I had the same problem. What the? I knew there were no clogs as I have sucked fluid down the day before. But, as I pumped the can, the pressure would build up and the pump would start to leak or the nozzle fitting would come flying off. (That little bleeder value nipper is tooooo danged small.) This was what had happened on the right side, too.
I was getting pretty frustrated and running low on DOT 5. I had 2 pints and I think most of it was contained in clean-up rags that were piling up. I also started wondering about all that silicone. Would traces of silicone end up on the areas I would want to paint, and cause terrible fisheye problems? I decided to switch to the 5606. Draining out what all I could of the DOT 5, I started pumping on the right side. Man, it went right up and all the way to the reservoir. It was cool! Not having any idea why the DOT 5 wouldn?t pump up but the 5606 did, I moved back to the right side, thinking my first attempt at bleeding brakes was about to be over with a successful finish. No such luck. After a heck of a lot of effort and disconnecting fittings and reassembling them and finding nothing, it all started to pump and the fluid almost made its way to the reservoir when I noted another small leak from that AN fitting I had changed out earlier. I gave it another hard tug to tighten, but it still leaked. Dern. I dissembled the fitting and discovered I had again snapped the flair. Sheesh. And I was out of spare fittings, so I will need to order some more. I think I will also order some more aluminum brake line, as I saw that when I was tightening it, it was twisting, so I may have work-hardened it.
At least some of the frustrations were reduced for a bit as I got to see the last half of the KU-Missouri football game, where we pulled out a win, but it went down to the final few seconds, literally, before it was really over. Amazing game.
Anyway, I guess tomorrow I will work on something else, but this brake bleeding has sure been a pain. I would encourage others to bleed the brakes as early in the build process as they can. I can?t image the frustration if I had my instrument panel ribs and all riveted in.