The Stovebolt Site Forums The Shop Area General Truck Talk mightyvac

went out and bought a mightyvac despite hearing some problems others have experienced. the way I read instructions says to pump-up vacumm and then open bleeder screw...I did this approx 20 times on one wheel alone and barely got 1/2" of fluid. (forgot to mention that drums are off and I was using this after replacing all lines and hoses, so systems was almost bone dry)
I got so frustrated I went back to the old style and bleed manually. used about 32oz of brake fluid so far and still must have air in line as pedal goes to floor.
two questions: am I using mightyvac right? normal to run that much fluid through lines and still have air in them? :confused:

I seem to have problems getting the little fittings to hold seal on the end of the bleed screws so rather than pulling air thru the lines it sucks air around the bleed screw. Rather than a one hand job it turns into a 3 hand job......

I too had trouble using the mityvac. But that's not why you aren't getting any pedal. With no drums on it's a wonder you haven't blown the guts out of your wheel cylinders. You need to install your drums and adjust your brake shoes before bleeding.

Cletis,
still having problems with mightyvac...even after I INSTALLED THE DRUMS!!!sometimes I amaze myself

I've had some of the same problems with my mitivac. Some tips that have helped me. Make sure vehicle is level. I use a helper 2x4. Here's the procedure. Setup mitivac and pump it up, top off master cylinder and replace filler cap. Apply brake and hold in place with the 2x4 wedged between the seat edge and the brake pedal. Release bleeder 1/4 turn only!! (otherwise air will enter the system around the bleeder screw threads) When the fluid flow dribbles down, close the bleeder, punp the brake and re-position the 2x4 helper. Repeat this process and top off the master cylinder again for every inch or so you get in the mitivac resevoir.

Never had real good luck bleeding with mity-vac either- always end up recruiting someone to pump the pedal

The Mity-Vac will not work well unless you seal the threads of the bleeder valves. If the valve threads ARE sealed then it works like a dream.

I have used Blue Locktite by letting it dry on the threads before screwing them in and I have used teflon tape (just make sure you don't get the tape down around the nose so that it comes loose and gets in the system).

You will also want to use a clear tubing so that you can see the bubbles that are coming out.

Beyond the Mity-Vac I have found that the little reservoir that comes with the kit is best when used with a higher volume vacume source. You just can't squeeze the handle fast enough to pull volume fast enough to "sweep out" the air.

I hook up the shop vac by putting a length of vacume hose (2') up the vac hose and turn it on. This gives a consistant high volume supply while you concentrate on cracking open the bleeder and watching bubbles and flow. JUST DON't let the master cylinder run low on fluid.

I've got pictures if you need them.

Paul

Mine was sucking air with the bleeder valve closed. I couldn't get a good seal with either the bare hose or the adapters that came with it.

I only use the vac to get the process started. I always finish with the pump-and-bleed method. It gives me peace of mind that way,
Scott