Bleed Technique

jkvt

Active Member
I've bled Tektro Dorado brakes before and used the method where you put a syringe on the port up by the brake lever and one at the port by the caliper. I had no issues with it. I also used the cup at the top to try to get any little bit of extra air out and again on those brakes, no issues.

Today I did the syringe to syringe method on my other bike which has the Tektro HD E350 brakes. Seemed to go smooth, pulled the block out, put the pads back in and remounted the caliper. When I pushed the brake lever it went all the way down. The pads were moving, but just not much. So, I decided before I tried the syringe to syringe method again, I'd improvise, because it's Sunday and why not...

I put the syringe, with 20 ml of fluid in it back on the port by the caliper. I then put the cup at the port by the brake lever with a little fluid in there to avoid any chance of air being sucked in initially. I then pushed fluid from the syringe to the cup, hit the lever a handful of times and pulled the fluid back through using the syringe at the bottom. A lot of air came through. This makes sense because the brakes were not really working before doing this again. I did this a bunch of times (like 10-15 maybe?) until finally a relatively small amount of bubbles were coming through and closed things off. The brakes are much better, definitely good enough.

Again, this was kind of an improvised way of doing this but since I didn't get all of the air out of the system, I am wondering if I was somehow introducing air when I pressed the lever? When I pressed the lever, and when I pulled the fluid back through the system I made sure to not run out of fluid in the cup. Connections to the ports were snug and I didn't hear anything off while I was doing this. I should also mention I did this method a few times without pressing the brake lever and few, if any, bubbles seemed to come through. So either I was somehow introducing air by pumping the lever or pumping the lever was helping push some trapped air out. Any thoughts on whether hitting the lever is somehow causing issues? I don't see how it can but I haven't done this a whole lot. Thanks very much!
 

fooferdoggie

Well-Known Member
it could have been. I close the port on the caliper before I squeeze the lever. then you can Flik it to get the air out.