Chumley

I need a refresher on the use of that button on the proportioning valve- Is it to be depressed and held open when bleeding part or all of the system? I bled the rear drums after wheel cylinder and shoe replacements, bled both sides, and there was improvement from before, but it still feels like I could get a firmer pedal. Also the fluid did not come out abundantly when using the Mighty-vac, but more like a heavy trickle. Maybe I should do a full bleed on all wheels again?

joe_padavano

In over 40 years of working on these cars, I've never held that button in while bleeding. I've also never been able to get a good bleed with a Mighty-Vac and have transh-canned the one I had. The problem with the hand-pump vacuum bleeder is that there is an air leak around the bleeder screws. Every time you stop to pump, air leaks back in.

I got a Vacula pneumatic vacuum bleeder years ago and haven't looked back. This is probably the best tool purchase I've ever made. One pass around the bleeder screws and I'm done, every single time. I don't even have to bench bleed the master - the Vacula will pull the air out anyway. Since the Vacula pulls vacuum constantly (unlike the hand pump tool), the air leakage around the bleeder screw threads is irrelevant, since that air always gets pulled into the bleeder and not back into the brake system.

In your case, be sure that the bleeder screws and openings are completely open. Frequently I find that rust builds up inside the bleeder screw passage, and even inside the wheel cylinder, blocking the bleeder passage.

Olds64

x2

I bought a Mity-Vac brand hand bleeder at Harbor Freight and the second time I used it I threw it away. It was a piece of junk. As I recall, the first time I used it I tinkered with it until it partially worked.

Here is a pneumatic bleeder similar to the one Joe has (I couldn't find the Vacula brand on Amazon):



Price seems a bit high, but it is cheaper than the Mity-Vac brand on Amazon. I just get on my back and have someone help with bleeding the brakes. I still have to bench bleed the MC though.

joe_padavano

Great find. That is exactly the same unit as my Vacula, under a different (and lower price) brand name. I actually found mine at a swap meet years ago for $15. No one else there knew what it was - I don't even think the seller knew.

Chumley

So it looks like the Vacula is operated with compressed air?

joe_padavano

Exactly. Air from your compressor blows through a venturi, creating low pressure that causes a vacuum in the main chamber.

m371961

I never had a problem with the hand operated vacuum pumps. I also remove the bleeder and apply anti-seize on the threads before bleeding. Maybe I am just lucky.

76olds

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X2, I've always done it the old fashion way pump it up till pedal is firm open bleeder screw until a good stream comes out and your done, move on to the next.
Maybe I lucky as well, but I like that deal Joe got for $15.00, I wouldn't have known what it was at a swap meet either. Good find Joe and thanks for posting !