saaron34

after searching, I've determined my brake pedal sinking to the floor is a master cylinder problem. I have brake fluid leaking from between the booster and the mc. my pedal sinks to the floor at lights, and requires me to pump them to get temporary pressure. Problem is worse in this lovely midwest heat.

My question is, is MC replacement a plug and play affair? The shop manual (using 90-93 integra manual, as the original system was swapped--I did not do it) talks about needing a special adjuster tool, and a vacuum guage, and a feeler guage and it seems like a lot of stuff could be messed up as I'm doing this. What does everyone REALLY do when replacing JUST a master cylinder? Everyone seems to elude to this being a very simple job....

I have a new master cylinder on order from acura. it comes with a new rod seal as well, so I hope that will fix my problems. I'll be picking up the one-man bleeder kit from autozone also.

thanks

**edit** this is a 90 civic si hatch, with non abs brake booster, master cylinder, and 4040 valve from a 90-91 integra ls. rear disc swap from 90-91 integra ls, also.

Loserkidwac

I just did a MC swap in my DA...it is fairly simple just make sure you Bench Bleed the new MC, it should come with a kit to do so, unlike mine, if you don't it will cause excesive swearing and tools being thrown across the garage when you wasted the timing putting on the new MC and still having no brakes...but I digress...its really just an easy job, i bleed the brake system till the MC was empty then unbolted the brake lines from it...be carefull not to strip them, then unbolt the MC from the booster and pull it out, do the reverst to replace it, the front brake line is a little tricky to get lined up and threaded you kind of need to press it in 2 directions while starting it to thread...HTH and good luck

saaron34

ahhh thanks for pointing me in the right direction. I knew nothing of a bench bleed, so i did a search:

https://honda-tech.com/zerothread?id=874191

^^excellent write-up

again, thanks for the help.

PINKS

same boat

my brakes just suck, wont even lock up, brand new pads and rotors

zccr-xsi

im the same way brakes wont lock up

saaron34

well mine is to the point where I keep a bottle of brake fluid with me. It leaks at a pretty steady rate. It has already eaten the paint where its leaking.

I think I've also got vacuum problems going to the booster, but one thing at a time!

PINKS

my level doesnt change, my brakes just suck

george34

My pedal was sinking at stop lights and I replaced my MC last week and the pedal is fine now. It is not really hard to do. The bench bleeding took me awhile.Before you take the MC off have someone push the brake pedal in and look for movement in the MC resivor. This is done to check to make sure something is adjusted correctly(the rod of the brake booster). There should be movement in the fluid between 3/8'' and 1/2'' of the brake pedal being pushed in. Correct me if I'm wrong.

To maybe save people a mess: Once you have the MC bleed and you have it bolted to the brake booster can you let out some of the brake fluid so that when you take off the bench bleeder the fluid doesn't go everywhere? I had brake fluid all over from when I took off the bench bleeder screw and was hooking up the brake line.

saaron34

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by george34 &raquo;</TD></TR><TR><TD CLASS="quote">
To maybe save people a mess: Once you have the MC bleed and you have it bolted to the brake booster can you let out some of the brake fluid so that when you take off the bench bleeder the fluid doesn't go everywhere? I had brake fluid all over from when I took off the bench bleeder screw and was hooking up the brake line. </TD></TR></TABLE>

take it out how? siphon?

george34

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by saaron34 &raquo;</TD></TR><TR><TD CLASS="quote">

take it out how? siphon?</TD></TR></TABLE>

Yeah something like that, but then I would think you would get air back into the MC. Does anyone know a way to take the self bleeder off and attach the brake line without spilling fluid everywhere and without getting air in the MC?

PINKS

So wtf is going on

Pretend Im stupid cause Ive never bled brakes before or changed this brake cylinder

I know it has 2 hardlines going to it, I undo those and unbolt the MC form the firewall and off it comes right? Is fluid going to be spraying everywhere

Now I take my rebuilt unit and do what? WTF is bench bleeding?

george34

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PINKS &raquo;</TD></TR><TR><TD CLASS="quote">So wtf is going on

Pretend Im stupid cause Ive never bled brakes before or changed this brake cylinder

I know it has 2 hardlines going to it, I undo those and unbolt the MC form the firewall and off it comes right? Is fluid going to be spraying everywhere</TD></TR></TABLE>

You are correct. Make sure you use a flare nut wrench when you are taking the hardlines off. I took all the fluid out of my old MC before I disconnected it so that fluid wouldn't go everyhwere.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PINKS &raquo;</TD></TR><TR><TD CLASS="quote">
Now I take my rebuilt unit and do what? WTF is bench bleeding?</TD></TR></TABLE>
When you bench bleed the MC you out the MC in a vise. Then you connect the bench bleeder that should come with the new MC. Fill the resivor with brake fluid and then slowly push the rod of the master cylinder in untill there is just 1/2'' of the rod showing. You are done there is no bubbles when you push the rod in or when you release it.

Loserkidwac

Well Don't buy a master cylinder at Pep boys...it was cheaper than everywhere else but when I opend the box there was no bench bleeder kit...Ok so i go back and ask them for one, the kid there was cool, real helpfull they just had some rando one sitting around with 2 different size fittings...so I asked if I could have 2 of the kits since I knew that my MC had the same size fittings, he grabs another kit and I'm on my way free of charge like it should be....Try to bench bleed it but of course these kits are not universal and neither fitting work so since they were plastic i grinded them down and threaded them it, threw a littl teflon tap on to make up for any leaks and the worked perfect...Now try to bench bleed...finally....but for some reason only the back line is moving fluid, I was like maybe the back needs to fill up before the front will?? Nope was trying to do this for hours try different methods...blew air through th MC to see if the port worked yea all this so i finall was like expletive it can't get worse so i take off the "C" clip/snap ring on the back and pull the piston out and swap it over to my old MC...Bam the old one has now been rebuilt and it worked fine, took like 5-10 min to bleed it..reinstalled it and then bleed the brake lines and it works perfect After work today i going to atleast try and return my "New" MC and get all my money back since they gave me a defective unit


Clif notes...If you don't want to have to redo the MC again just get a New one form Honda

Oh and Pep Boys blows donkey dick

thesmogman

A simple syphon - a vacuum hose and a container with lid. Put hole just big enough to fit the vac hose into. squeeze container and let it suck out the old fluid.

Bench bleed - use a small amount of fluid and pressurize it first, use the cap's included. insert screwdriver into the rod end and push a couple of times is all that is needed.

So you have removed and replaced the MC and hooked up the lines, now you fill and bleed. I bled mine til I got clear fluid through. Make sure the MC doesn't get close to empty. Do drivers rear first then pass front then pass rear then drivers front. Also in the middle of the bleed you need to use the pedal pump it a couple of times during the process. Just make sure all the bubbles are out.

It's easy Have fun.

civicandy

what happens if you don't bench bleed, but just throw the MC on and fill. then proceed to bleed the brakes?

Loserkidwac

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civicandy &raquo;</TD></TR><TR><TD CLASS="quote">what happens if you don't bench bleed, but just throw the MC on and fill. then proceed to bleed the brakes?</TD></TR></TABLE>

Well i tried that first but It would even push fluid out of the some of the calipers but my MC was also defective..a friend of mine said he did his accord that way without a problem but his integra he had to bench bleed...the pedal was the same as the bad MC untill he bench bleed it...

civicandy

i put a new MC in my hatch and didn't bench bleed, but i bled the heck out of the lines at each wheel. the pedal feels very firm. i believe the point of bench bleeding is so you don't have to bleed at each wheel, correct?

Dave_Darling

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civicandy &raquo;</TD></TR><TR><TD CLASS="quote">i put a new MC in my hatch and didn't bench bleed, but i bled the heck out of the lines at each wheel. the pedal feels very firm. i believe the point of bench bleeding is so you don't have to bleed at each wheel, correct?</TD></TR></TABLE>

Nope, you will always have to bleed all four wheels. The point of bench bleeding is because it often takes about for ever to get all of the air out of the MC with regular bleeding.

Any time you break open a fitting in the brake system, you have to bleed the brakes! And it's best to bleed all four, no matter where in the system you opened it up.

--DD

haggar

Bench bleeding just helps get the air out fo the MC itself, which can take a while.


Frankly, its not the end of the world if you don't have a 'kit'... Been replacing MCs for about 15 years, if you don't have a kit, then just get a short brake line from each port back to squirt into the resevoir.

When no more bubbles come out of the lines, its bled, then just move quick when you need to undo them and reconnect th elines in the car.


Gotta do this myself in a week or two on my 91 hatch, as well..

civicandy

well it did take awhile to get the air out of the MC, but everything seems fine in the end. next time i will bench bleed it. it will probably save me some time.

george34

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Loserkidwac &raquo;</TD></TR><TR><TD CLASS="quote">Well Don't buy a master cylinder at Pep boys...it was cheaper than everywhere else but when I opend the box there was no bench bleeder kit...Ok so i go back and ask them for one, the kid there was cool, real helpfull they just had some rando one sitting around with 2 different size fittings...so I asked if I could have 2 of the kits since I knew that my MC had the same size fittings, he grabs another kit and I'm on my way free of charge like it should be....Try to bench bleed it but of course these kits are not universal and neither fitting work so since they were plastic i grinded them down and threaded them it, threw a littl teflon tap on to make up for any leaks and the worked perfect
</TD></TR></TABLE>

I got mine from Napa and ran into the same problem with the bleeder kit. I just put a socket on the fitting and forced it in.

Loserkidwac

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by george34 &raquo;</TD></TR><TR><TD CLASS="quote">

I got mine from Napa and ran into the same problem with the bleeder kit. I just put a socket on the fitting and forced it in.</TD></TR></TABLE>

Yea i made do with what i had, i also used a 1/8 fitting for my air compressor and it threaded fine so you could probably go to a store an buy some barb fittings...i think i am going to cut off the ends of some break lines at the Junk yard just incase i have to do this again

Sucks because I was only doing this so i could sell the car and i was such a pain

Dave_Darling

All I did was unplug one outlet at a time, while compressing the piston into the MC by hand. When fluid started coming out, I plugged the outlet again and moved on to the next. Bolted the new MC up, then quickly removed each plug and bolted up the brake line.

Took a little while to bleed the air out, but not too awful. Went through just over a quart of fluid, just be absolutely certain.

--DD

PINKS

Is there a walkthrough somewhere?

Ive never touched brakes before, not once and I get my new MC tomorrow

civicandy

https://honda-tech.com/zerothread?id=874191

try using the search button next time. or reading the thread you are posting in