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Ok, don't laugh, but as I think about this,,,,, With a new master cylinder, can I attach it to the booster, attach the bleed kit to the ports, run the hoses into the reservoirs, fill the reservoirs, and then bleed the master cylinder by pumping the brakes until no bubbles? Seems a lot easier than putting it in a vise and working the piston by hand?
That will work as long as you don't stress the seal inside the master cylinder. Putting the master cylinder on the booster sure holds it nicely and securely. If you push the rod too hard or too far, it can damage the master cylinder and that can make a mess inside the brake booster.
I use a Reverse Bleeder to do the very similar thing. I use the appropriate hoses and can bleed the master cylinder without using any vice at all. I can do the entire job while holding the master cylinder in my lap. My kit came with the hoses to help use the reverse bleeder to bleed the reservoir easily with just a little pumping the fluid is clear and free of bubbles.
Your way of bleeding the parts is new to me so hopefully it can and will help others trying to do the job of bleeding more easily! Good work!
Every Master Cyl box it came in, states you must bench bleed before installing.
I don't see why you think that is a lot more labor. If you don't bench bleed, you will enjoy hours & hours & hours of trying to get that last air bubbles out.
That IS more labor.
Here is the thing. Once the Master is installed, it can not be tilted forward or rearward. And that tilting is what releases any trapped bubbles.
<<<<<<<<<<< Click on my avatar to the left <<<<<
Look for photo albums of tips & tricks to bench bleed.
Yes you can do it on the car. No problem. But also remember that any time you change the M/C, you must verify that the length of the actuator pin is correct for it.. There are no "one size fits all" pins.
The pin MUST fill the whole space between the booster and M/C valve except for about .010" gap. You don't want the M/C to always be actuated (hence the 'gap'); but you also want the brakes to actuate whenever you apply them.
I’ve done this on my C3 and many other vehicles. I’ve had no issues doing it. It seems simplest to me also. One time I placed my camera near it and took a video to see clearly that the air was all removed. Then, I usually do gravity bleed at the calipers. Results= perfect pedal.
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Have fun with the repair. .
To get the last little bubble of air out park on a slope so the top of the master cylinder is slightly down in the front. Take the top off the master cylinder and push gently just a small amount and if you don't see any bubbles coming out of the holes in the bottom of the bowls then you're good to go. Caution if you press the brake pedal fast brake fluid will spray up out of the holes.
I took a piece of aluminum big enough to cover the master cylinder bowls and used an old gasket to seal it off with a C clamp to hold it in place. I threaded a hole over one bowl and hooked a bicycle pump up and pressurized to 2-3 psi then bled the rear brakes until no air came out. Caution you need to check the level in the bowl often and top it off. It took me maybe 10 minutes to bleed the brakes using this method.
The booster rod to master piston gap should be 0.060 or around 1/16 of an inch.
There is a special tool to measure that gap or a gob of Silly Putty will work also.
Some people just get lazy and try to take the easy way out of bleeding the master.
It's not difficult at all. Two nuts mount the master to the booster. That's all.
Two brake lines get attached to the master. Simple.
You still have to bleed all six bleeders regardless.
That is beyond my computer functionality. Sorry.
I just checked the photo album site. Its working.
<<Left <<< Avatar then right side of my page, photo albums > bench bleeding
I rebuilt my mc and replaced the booster, made sure rod length was correct added fluid then used an adjustable prop rod between the seat and brake pedal to depress the pedal much like they do during a suspension alignment, left it that way for 3days then added more fluid, gravity bled the brakes on the fourth day and have had zero problems, oh and I had also rebuilt all four calipers.
As mentioned in here, and from my preparations (studies and storage of good posts/threads) for when I will be doing this, I might recommend this tool. Various ‘Vette vendors sell them, but they are also available for less elsewhere. As in a previous post, the rod length is crucial to not damage things. This tool helps set the depth.
That will work as long as you don't stress the seal inside the master cylinder. Putting the master cylinder on the booster sure holds it nicely and securely. If you push the rod too hard or too far, it can damage the master cylinder and that can make a mess inside the brake booster.
I use a Reverse Bleeder to do the very similar thing. I use the appropriate hoses and can bleed the master cylinder without using any vice at all. I can do the entire job while holding the master cylinder in my lap. My kit came with the hoses to help use the reverse bleeder to bleed the reservoir easily with just a little pumping the fluid is clear and free of bubbles.
Your way of bleeding the parts is new to me so hopefully it can and will help others trying to do the job of bleeding more easily! Good work!
Can you provide a link to the tool you use to reverse bleed the master cylinder?
Master Cylinder Bleed
