Trouble bleeding rear brakes

[JimZRyd]

Hey guys! I'm attempting to bleed the brakes on my 94. Starting with the right rear. I've got new calipers from Mid America, stainless lines and speed bleeders from Russell. Using a Motive pressure pump AND a Mighty vac. I can barely get any fluid flow. When I open the bleeder screws I will get about an inch or so in the tube but that's it. I wait about 5 minutes and the tighten the bleeder back down and check the Motive pressure, pump the brake pedal a couple times, feels firm, and then go crack the bleeder screw again and all I get is just a trickle of fluid. I've removed the bleeder and it still trickles. I disconnected the line itself and get flow, not a lot but it does flow.

Am I not giving it enough time? I've bled many a brake, even Corvettes, and always had steady flow of fluid during my bleeding process. This is the first time I've tried a C4. Could I have gotten some sort of air lock? I'm stumped! Any advice will be greatly appreciated! TIA!!

[Billy Mild]

Try with the engine running.

[-=Jeff=-]

The way I do it now:

Speed bleeder with a piece of clear tubing into a container, tubing goes into a bit of brake fluid in the container. I then open the bleeder and pump the brakes and watch the tube for bubbles (I have my son pumping the pedal). I repeat at each caliper and then sometimes repeat the process a second time..

[JimZRyd]

These are new calipers so I assumed that I would have to wait till fluid flows freely in order to know I've filled the caliper with fluid and all air has been removed. I've been at this for days off and on and would have thought I'd see results by now.

I haven't tried it with the engine on. Always thought with an ABS system, with the engine running you are pressurizing the abs system and traditional bleeding of the brakes won't work. I might be wrong.

Shouldn't I be seeing a free flow of fluid at some point using both a Motive pump and a Mighty vac?

Thanks guys!

[-=Jeff=-]

I was having trouble with the mighty vac. I went old school gravity bleed.. Car off. That seems to work best for me

[JimZRyd]

Jeff, were you able to get a free flow of fluid or just a trickle? All I get is a trickle and seems to be better with the Mighty vac. I've tried it back and forth many times. With my last Vette, a C5, all I had to do was crack the bleeder and it flowed freely. Could easily do all 4 in less than 30 minutes. This being my first C4 I was wondering if I was missing something unique to these. I've read some say it took a little time to get them to bleed but good gracious how long should it take?!?! My 94 only has 11.5K miles on it so this is probably the first brake bleed she's ever had. Would that make a difference?

[-=Jeff=-]

no I don't recall it flowing.. it needed 'help'.. If you have a helper, have them pump 3-5 times and hold the pedal, then crack the bleeder.. OR

do what I said and pump it yourself a bunch of times, I actually use the mity vac container with the mity vac hose, the hose connects to the lid with the internal tube.. all self-contained minimal mess

[JimZRyd]

Mines Definately not flowing. When I did my C5 the whole tube would fill and flow and there was a definate change from old to new fluid. Maybe it'll just take some time. I've waited as long as 15 minutes and barely got out an once. Hopefully there's nothing blocked, that's my fear. Everything mentioned thus far I've tried. Thanks for all the advice. Anybody got anything else to try, I'm all ears!

[Billy Mild]

Have you taken the bleed screw completely out?

[JimZRyd]

Yes Billy. After my first attempt today with little to no results I took the speed bleeder completely out and blew air through it to make sure it wasn't clogged. I got a small trickle of fluid from the hole. I then disconnected the brake hose from the caliper and got decent flow, not a flood or anything. I did remove the brass washers thinking they might be displacing the hose and/or the bleed screw. Put it all back together and then using the motive/mighty vac I was able to get about and ounce or so out over 10-15 mins. Think I should just give it more time ? These calipers are brand new so they are dry. How much will one hold?