.Thomas

Ok, so i read some threads, and i already craped out one M/C on trying to do this, so i really dont want to screw it up.

So i put my fingers on the place where the brake lines hook up, put fluid in the M/C and push the pistion?

Is there a safe way to do it on car? is this even right?

one_boosted_si

Attach the M/C to a vise or something to hold it stationary. Install the reservoir and fill. Plug the output ports. Slowly push the piston in and out until no further air bubbles escape. They should have some sort of instructions in the box as well if you bought a remanufactured part. Hope this helps.

Slurp56

You should be able to purchase a kit for pretty cheap, essentially what you are trying to accomplish is fluid coming out of the brake line holes but not air going back in as it's released.

Typically a kit comes with plastic or aluminum fittings that screw into the brake line holes, then you put a 1-way check valve inline with a straw that runs from the fitting back into the fluid reservoir. As you pump the MC piston, fluids comes out of the brake line holes and is deposited back into the reservoir. As you release the piston, the check valve prohibits any air to be back fed into the system.

You may be able to accomplish the same thing without a kit but you're going to make a mess. Push the MC piston in, block the holes with your fingers, and release the MC piston. Repeat.

Once you are done bench bleeding, install the MC back into the car. Once into the car you can crack the brake line fittings loose, 1 at a time as someone depress's the pedal down, then tighten them before the pedal is release. This will essentially bleed out any air at the MC and line connection, rather than trying to force all that air completely through the system.

Good Luck

SlayANT

If you don't have a vice, you can use a big screw driver/long socket to push the plunger in. Brace the screw driver/socket against a wall and push the MC against the screw driver. Attach some hoses to the output ports (works well if u have an old set of hard brake lines) and route it back to the MC reservoir. Keep pushing the mc against the screw driver until the fluid that is coming out of the hoses are bubble free. Caveat -- don't push the plunger in too far, you might dmg the boot due to old debris.

d357r0y

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SlayANT &raquo;</TD></TR><TR><TD CLASS="quote">If you don't have a vice, you can use a big screw driver/long socket to push the plunger in. Brace the screw driver/socket against a wall and push the MC against the screw driver. Attach some hoses to the output ports (works well if u have an old set of hard brake lines) and route it back to the MC reservoir. Keep pushing the mc against the screw driver until the fluid that is coming out of the hoses are bubble free. Caveat -- don't push the plunger in too far, you might dmg the boot due to old debris.</TD></TR></TABLE>

True dat: a pic i fiddled up a couple years ago

.Thomas

thanks guys, is it really no big deal without a kit, just a little messyer?

.Thomas

can you do it bolted up on a car? and use the pedal as the screwdriver?

d357r0y

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TanCar &raquo;</TD></TR><TR><TD CLASS="quote">can you do it bolted up on a car? and use the pedal as the screwdriver?</TD></TR></TABLE>

I'm sure you could but then it's hard to watch for bubbles. Doing it the way slayant and I described is the easiest way without a vice. Don't make this into something complex, because it's not. Just get it done, it's very simple.

Ohmster

These are my brake instructions, maybe they will help you. I got them from two different friends:

Dear ohmsterino,

I would have put the entire master cyl on personally. Before doing anything that you mentioned, you need to pre-bleed the master cyl. You do this by putting the m.c. in a vice, then adding NEW brake fluid into the cup, then using a wooden dowel, press into the rear of the unit about an inch, SLOWLY. Then wait about 15 seconds and repeat till there is no more air bubbles coming up inside the cup. Be patient and repeat till no air bubbles!!! Then do what you said. It is good idea to use a 10MM line-wrench to crack the brake line nuts loose. You may use a penetrating lube on them first. Do same for bleeders. You will need a helper to press the brake pedal down after you crack open the bleeder. You should tell them to PRESS TO FLOOR after you crack it open about 1/4 to 1/2 turn. You should tell them UP after you tighten it back up. They should tell you Down to Floor, and Up after your commands. Keep checking to make sure there is fluid in the cup! I'm sure that you, like most people, have not replaced your brake fluid in a while. Do it! Old fluid wears out and if you really need to hit the brake hard, the pedal can travel to the floor, only compressing the old fluid. You might not stop on time. I changed my fluid in my Acura Integra at least 6 times in its 75,000 life time so far! I do drive hard, and depend on my brakes. I do all the work myself on all my vehicles, so I know it is done right. So go for it, cuss a little, but mainly learn as you go.
Good luck Paul,
Kevin


BlueIntegraBoy

I just replaced my master cylinder two days ago.

1. Remove the cap from the old MC and drain the fluid from one caliper (driver front) until no fluid in the MC.
2. Crack the brake line fittings using a 10mm flared nut wrench (I think a Del Sol VTEC might have one 10mm and one 12mm fitting.
3. Using a 12mm socket, undo the nuts holding the MC to the booster.
4. Bench bleed the new MC (instructions can be found by searching).
5. Bolt up the new MC and lines.
6. Bleed the brakes.

Tools needed:
- 10mm flared nut wrench (12mm, maybe)
- 12mm socket

Bleeding instructions:
- Bleed caliper (where bleeder valve is located) from furthest away from the MC to the closest.
- Pump the brake pedal 4-5 times and hold the pedal, then open bleeder valve and close it.
- Keep doing this until no air comes out or until new brake fluid comes out.

Good luck!