One Person Brake Bleeding with a Mityvac

Posted by Richter12x2 On 2015/5/12 22:59:57

I changed out my rubber brake lines for new braided stainless ones on the Triumph GT6 yesterday, so today it was time to bleed them.

I spent about 30 minutes by the passenger rear wheel, pumping the mightyvac like crazy to keep suction in it, and getting nothing but a long stream of bubbles that never improved. I finally gave up and moved over to the other rear wheel, with the same results. This is pretty much what happened last time, where it finally ended up good enough to get it to a shop and pay someone about $100 to bleed the brakes with a pressure bleeder. Wasn't looking forward to that again, but I knew I at least had to finish the 4 wheels to get some sort of brake fluid back in there before I could even consider getting it down and over to the garage.

Forearms hurting from pumping, I took a break, and pulled up Google on my phone and searched "How to bleed brakes with a mightyvac" and got this video:http://www.youtube.com/watch?v=KTY2iBkFeV0

So I'm watching, and he gets to the part about taking the bleeder valve out and putting 4 loops of teflon tape on it and putting it back in, and I'm thinking "Okay, that's probably overengineering, it can't make that much difference, you're just going to be wasting brake fluid while you put the teflon tape on". So I went back to the passenger front wheel, pumped up the mightyvac and cracked the bleed nipple, and same story, bubbles like crazy and no signs of improvement. So I thought "Well, heck, I'll try it, and if the guys at the brake shop laugh that I have teflon tape on my brake nipples, so be it." Stuck a cup under the caliper and pulled the nipple out, wrapped it around 4 times with teflon tape, and threaded it back in. Topped up the master cylinder again, hooked the mightyvac back up and pumped it up to 20 again. Cracked the nipple and a solid wall of clean fluid came through, with just a few microscopic bubbles (which he explained are usually just from sucking air up the threads.)
More telling, now, from the initial pump up to -20, it only got to -15 before I had to top up the master cylinder. Before I would pump to -20, crack the nipple open and run it down to -5 about 7 times before I had to top up. (I counted, because I'm doing this in the garage and it's a pain to get out from between the wall and the car to check the fluid level, but I didn't want to run it dry either.)
After another 2 top ups, I was satisfied I had a totally negligible amount of air in the lines. This is probably the 10th time I've bled brakes on a car and the first time I can really, honestly say that I feel good that I'm sure I got it all, and it took about 5 minutes to do the corner, vs 30 minutes of flailing to no effect.
Re-did the other wheels, with the same result, every time. I went ahead and ran through the rest of the brake fluid on the rear wheels since it goes bad storing it, just to be sure that I got it all, but it was pretty obviously perfectly fine long before I wrapped up.
A quarter's worth of teflon tape, and a minute to pull the nipple and wrap it, to save $100, (or a life, potentially, from dodgy brakes). I'm definitely a believer now.