Based on Joe's response in the thread below, I bought an import version of the vacuum brake bleeder that works off my compressor. I'm completing the installation of an all new brake system in my 69 442. Its a stock power disc brake system with a hold off valve. In the past, I've found it very challenging to bench bleed the master cylinder, install it in the car and hook up all the brake lines without leaking brake fluid on something.

Joe - I just want to confirm that I can hook everything up dry and use the vacuum bleeder to bleed the brakes. This will make things way easier and way neater. Also, do I need to lock the pressure differential switch in the distribution block with this method?

Thanks!

https://classicoldsmobile.com/forums...system-166600/

 

That's how I do it. As I've said previously, I don't even bother to bench bleed anymore. My Vacula will pull the air out of the system including the M/C. Be aware that you WILL continue to see air bubbles in the clear line from the bleeder screw to the vacuum bleeder. This is air leaking past the threads on the bleeder screw. With my bleeder, I can hear a distinct sound difference when the air is completely out of the system and only coming past the threads. I can also see differences in the size and shape of the bubbles in the clear line - large bubbles of various lengths when air is coming from the system; small, relatively equally-spaced bubbles when the air is only coming from the threads. Once you get used to looking for it, it's pretty obvious. Pay attention to the level in the M/C - don't let it go dry. I now have one of those auto-refill tanks that maintains the level in the M/C as I bleed, so that's one less thing to worry about, but I did this for a lot of years without one. You just need to remember to check the level frequently.

 

Thanks Joe. Do you lock the pressure differential switch in the distribution block with this method? When I bleed with the pedal, I usually put one of those pin locks in the distribution block to keep the switch aligned.

 

I have one of those tools and I've never used it. The vacuum bleeder doesn't put enough pressure on the system to move the piston. It won't hurt anything to use the tool, I'm just lazy.

 

joe, i have always used neverseize on the threads of the bleeder screws, would that help slow the bubbles from the bleeder ? just a thought

 

I do the same (as well as on the flare nut threads) but I haven't noticed a difference. The air bubbles aren't anything worry about, but some people freak out about it. Since the vacuum bleeder is lower pressure than the rest of the system, there is no way for the air to go upstream so long as you maintain vacuum until you tighten the bleeder screw.