Changing out Honda master cylinder, need brake bleeding help

Old 05-10-07, 09:33 PM
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Changing out Honda master cylinder, need brake bleeding help


I'm about to change out my master cylinder on my 1994 Honda Accord. According to the Chilton's manual, it looks pretty straight forward. However, the directions aren't very clear on how to bleed the brakes once the cylinder is installed. Can anyone out there give me the short version on how to bleed my brakes? Thanks for your help.
Old 05-11-07, 12:37 AM
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I will try my best to explain the steps, and i have always done it this way. some might not agree, but it had worked without a problem ever before. Do this at your own risk as i will not be held responsible.

1. Drain the brake fluid from the master cylinder.
2. Disconnect the brake fluid level switch connectors.
3. Remove the reservoir cap from the master cylinder.
4. Disconnect the brake pipes from the master cylinder. There should be 2 lines on the side of it. and make sure you don't kink any of the lines, which can cause the fluid to not flow as it should (meaning car will not brake).
5. Remove the master cylinder mounting nuts (there are 2 nuts) and the master cylinder from the brake booster (the big round thing that the master cylinder is mounted onto).

Note: the following steps will require you to do this out of the car. you can consider this as preping the new master cylinder before the install.

6. With the new master cylinder, open the reservoir cap, have a friend to help you cover the 2 ports with their thumb (so air will not get in) where the brake line will connect to. do not remove the 2 small caps in these ports just yet. it will help during the out of the car preping (bleeding).
7. Fill the cup to the top with brake fluid, close the cap it when it reaches the max linel.
8. While your helper is still holding the 2 ports (hold it tite so air cannot get in), use your hands and push the rod (only on end has a rod sticking out, the end that will connect to the booster). this will pump the fluid down.
9. keep pumping it until fluid starts to spill out of the 2 port where your helper is holding. do not let go of the ports.
NOTE: Do not allow air in during this process, it is a pain to have to redo this. have the helper hold the ports firm and tite. better yet, you should hold it and have the helper do the pumping.
10.Open the reervoir cap and fill it to the MAX line and close it if fluid becomes low. if no more pumping is needed, and the pump is releasted, who ever that was holding the 2 ports, can now release it also. keep the 2 small cap in the ports and do not remove yet.

11. mount the master cylinder in reverse order as you have removed it.
12. now remove the 2 caps where the lines with be connected to. 1 at a time. and install the brake line. now bleed all 4 of your brake, and test drive it. start slowly. do it in a residential street. the responsive instantly. now take it to a main street where u can accelerate, find a red light and do some hard braking. do it far from the light, so there will still be time for u to think of another way of stoping the car if it fails to do so. play it safe. everything should be good as new.

it is midnight and im tired, if there is any error, typo, please correct it. i have not proof read these steps.
Old 05-11-07, 01:02 AM
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i misread your question. bleeding would be easy,

lift the car up and just jack stands to support it while in the air.
assuming that you have break the torq of the lug. remove the tire.
on your caliper. there will be a rumber boot that covers the bleed screw.
remove the boot by gripping it and pull out. just that simple.
the bleed screw has a hole in the middle of it. hook a bleeder to this screw.
make sure the fluid is to the MAX line in the reservoir.
have somehow to pump the brake padle serveral times and hold it down so it can build pressure.
now loosen the bleeder screw while the padle is still down.
this should allow the dirty fluid to flush out along with any air.
when you see clean fluid coming into the bleeder, and without any bubble, you can now tighten the bleed screw.

start at the right rear, then left front, then right front, the left rear.

keep you eye on the reservoir and not let it go below the MIN line. make sure to tighten the bleed screw if the padle is released.
this will not allow air to enter the system.
do this to all 4 wheel. and you are good to go.
Old 05-11-07, 06:41 AM
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And before you get that far be sure you bleed the master. Should be instructions and adapters with the new one.
Old 05-11-07, 07:23 AM
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If just replacing the master cylinder..

I prep the Master the same way that MrT does,than attach both brake lines just to the point of snug.
Then while a helper pushes the pedal down I open both lines,then close them before he/she lets the pedal up.I do this until just fluid comes out,no air.
I"ve never had to bleed all the brakes when just installing a master...all the air seems to stay right there at the lines going to the master.
Old 05-11-07, 08:35 AM
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Another tiny tip -

if you have one, connect a flexible hose to the bleeder tip (on the brake assembly). Put the loose end into a glass jar containing clean fluid. As your friend pumps the brake pedal - you will be able to see the air bubbles/dirty fluid as it expells from the lines into the glass jar. The clean fluid in the jar will prevent air from going back into the system on the upstroke.......

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