DIY Brake Master Cylinder rebuild

[ECU-MAN]

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!


Aim: to stop your brake pedal from creaping to the floor. ( help make your car stop )
Required:
- OEM Brake master cylinder rebuild kit ( from your local Honda dealer )
- 500ml Brake fluid
- cir clip pliers
- allen key set
- 10mm spanner
- 12mm spanner

Do you have a Honda that has a dodgey brake pedal ?
does your pedal creap to the floor when you press the pedal ?
is it wors on hot days/weather ?

if so, then your brake master cylinder is rooted. You can try to bleed the brakes, but if the brakes are ok most of the times and sometimes it does the above symptoms you will have to replace or rebuild it.

a rebuild kit will cost you about 90 to 100 bucks, a new master cylinder will set you back about $250 to $280 depending on your car.

you will most definantly have to replace your master cylinder if it bore is badly scorred causing bypass, but 9 times out of 10 its due to wear on the seals on the two pistons.

Caution; During any part of DIY make sure you do not spill brake fluid on your paint work. It will get damaged from the brake fluid.

Steps: 1

suck out the brake fluid from the master cylinder resivour

http://ecu-man.com/diy/bb6-bmc/BB6100.jpg


Steps: 2

undo the two brake lines using your 10mm spanner (red circles bellow). Be carefull not to round the nuts. if you do carefully use vice grips.


http://ecu-man.com/diy/bb6-bmc/BB6102.jpg


STEP: 3

undo the master cylinder mounting bolts that hold it to the booster. ( blue arrows above and bellow pic )


http://ecu-man.com/diy/bb6-bmc/BB6103.jpg



STEP: 4

remove the seal from the booster if it isnt already on your master cylinder ( red arrow bellow pic ). do not damage it as you will have to reuse it on some cars, most kits will have a replacement. aslo you do not want to do a double sealer. causes vauum leaks


http://ecu-man.com/diy/bb6-bmc/BB6111.jpg



STEP: 5

place your master cylinder on a bench, use a rag as you bench will cop some brake fluid. undo the allen key bolt in the pic bellow ( red circle ) and slide the pin out. note it has an aluminum crush washer.



http://ecu-man.com/diy/bb6-bmc/BB6114.jpg

STEP: 6

undo the cir clip at the end of the master cylinder ( red arrow pic bellow ), then pull out the 1st piston along with the sleeve.


http://ecu-man.com/diy/bb6-bmc/BB6115.jpg

http://ecu-man.com/diy/bb6-bmc/BB6116.jpg


http://ecu-man.com/diy/bb6-bmc/BB6118.jpg



STEP: 7

remove the 2nd piston from inside the master cylinder ( red arrow pic bellow ), use long nose plires, careful not to touch the bore ( blue arrow pic bellow ).

inspect the bore for sevire damage




http://ecu-man.com/diy/bb6-bmc/BB6119.jpg

http://ecu-man.com/diy/bb6-bmc/BB6120.jpg


STEP: 8

replace the pistons, start with the 2nd piston, the last one you removed. before we put it back in the master cylinder you have to lube the seals with the pink grease that comes with the kit.

apply grease to the two seals shown in the pic bellow by the 2 yellow arrows.

http://ecu-man.com/diy/bb6-bmc/BB6122.jpg


STEP: 9

reinsert the 2nd piston back into the master cylinder. Spring end in 1st. Make sure the slot in the piston lines up with the ( green arrows in the pic bellow ). Use your long nose plires to put the piston in the bore, then slide it in using a screw driver.



http://ecu-man.com/diy/bb6-bmc/BB6124.jpg

STEP: 10


change the aluminium crush washer on the long allen key bolt. red arrow bellow.



http://ecu-man.com/diy/bb6-bmc/BB6126.jpg


STEP: 11


Push the 2nd piston in compressing the spring maintain the pressure on the spring and slide in the long allen key type bolt into the master cylinder. if you have lined up the 2nd piston correcely it should slide right in. do not force it.
now tighten the allen key bolt.

STEP: 12

lube up your new 1st piston seal. ( yellow arrow pic bellow ) and slide it into your master cylinder.


http://ecu-man.com/diy/bb6-bmc/BB6125.jpg



STEP: 13

now its time to replace the seals in the sleeve. first replace the outer seal, gently remove the old one with a screw driver. apply the pink type grease on the sleeve itself then on the new o ring, then put the new O ring on the sleeve.


http://ecu-man.com/diy/bb6-bmc/BB6129.jpg



STEP: 14


now pay extra attention to the way the inner seal sits in the sleeve. take it out with with a small screw driver and apply pink grease in the channel where the seal sits. apply pink grease to the new inner seal. push the new seal into the sleeve and menuvour it with your fingers to sit in its channel the same way the old one did.


http://ecu-man.com/diy/bb6-bmc/BB6130.jpg



STEP: 15

time now to fit your lubed up sleeve to the master cylinder. lube up the shaft of the 1st piston with the pink grease.

http://ecu-man.com/diy/bb6-bmc/BB6133.jpg


http://ecu-man.com/diy/bb6-bmc/BB6131.jpg



http://ecu-man.com/diy/bb6-bmc/BB6132.jpg


http://ecu-man.com/diy/bb6-bmc/BB6135.jpg


STEP: 16


put the 1st piston in the master cylinder if you took it out to fit the sleeve. put the new cir clip on and push it down with a screw driver to make sure 100% it is seated in its channel.


http://ecu-man.com/diy/bb6-bmc/BB6136.jpg

http://ecu-man.com/diy/bb6-bmc/BB6137.jpg

STEP: 17

open up your white gease satchet and apply some to the booster seal and to the master cylinder and the shaft of the 1st piston. smear it all around


http://ecu-man.com/diy/bb6-bmc/BB6145.jpg



STEP: 18

now fit the master cylinder to the vehicle in revers from the way you took it off. do not put the brake lines on just yet.

STEP: 19

bleed the master cylinder.
- put a small plastic bag under the two holes where the lines go into the master cylinder. the idea is to catch brake fluid as you bleed the master cylinder.
- fill your master cylinder with brake fluid.
- get your helper to press down on the brake pedal then block the two holes on the master cylinder with your fingers ( to seal the holes ) then get your helper to lift the pedal. uncover the holes. press down on the master cylinder then cover the holes then up on the pedal.

repeat this untill you get a good steady stream of brake fluid coming out from both holes.

STEP: 20

refit the brake lines to the master cylinder. tighten them up nice and tight ( not superman style )

and now its time to bleed the brake as normal. bleed all four wheels.

thats it


this should take half an hour to compleate, but take your time do not rush.
let me know if you have any questions


thanks to VTEK for his help with this Job and taking happy snaps :)

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

[SPEEDCORE]

Once again very nice write up :thumbsup:

Only thing I would suggest is to use flare spanners on the hard brake lines.

[ECU-MAN]

yes pipe spanners are the way to go if you got them, not everyone has. normal spanners will work but if used wrong you will round the nuts.

[wynode]

Once again nice writeup John :thumbsup:

+PQ point for you!

[ECU-MAN]

yes your right

Ill add it

ps I wrote this up very late :)

[bennjamin]

great writeup mate !

BTW , my pedal is quite naff and doesnt like emergency stopping ( sinks right to the floor almost with braking feel non-existant) so its off to honda to get this kit methinks.

John , ive noiticed there is a slight leak ( very gradual) at the back of the piston , where it joins to the master cylinder. Is this from a worn rear seal on teh booster and nothing to worry about ( since i am rebuilding) ?

[ECU-MAN]

yeah dude
its these seals that are causing the leak


http://b16a2.kicks-ass.net/diy/bb6-bmc/BB6131.jpg

[civiceg9]

Is the clutch master cyclinder the same method?

[ECU-MAN]

yes, its the same concept

lately I just replaced them though. it all comes down to cost

[egSi]

is it pssible to put the pics back up? i need to do this asap and it would help allot. :)

[ECU-MAN]

dahm

dont know why there not there

see what I can do for yal

[ECU-MAN]

there you go

pics have been hosted on another server for a while

[wynode]

host em on OH john!

[egSi]

awesome. thanks for that mate. :thumbsup:

[EK4R]

got a qns. bout to do this myself.

ECU-MAN what did the rebuilt kit consist of exactly? is it a full kit or just pieces put together, not really a kit? did it come with new primary and 2ndary pistons? because i went to a honda dealership today and got quoted 150 bucks ?!

also when you drain out the brake fluid in step 1, thats the only place i should worry about right? once the resivour is empty, its should be safe to remove the cylinder?

[destrukshn]

your car would be pieces put together
promary, secondaty, and seals.

[EK4R]

your car would be pieces put together
promary, secondaty, and seals.

yea thanks i got quoted for the following.

primary : 60
secondary : 50
seal rod : 6 ea.
Gormment : 7 ea (do i even need this?)
Guide Assy Piston : 25 (do i even need this?)

[ECU-MAN]

http://b16a2.kicks-ass.net/tech/CRX121.jpg



what is in the red circle is what comes in the kit, they all come together and not seperate.

the kit cost about $90


once you drain the fluid from the resivour, thats it, undo the pipes and remove it, with great care as fluid could still leak from it.

dont spill brake fluid on your paint work.

[wynode]

Just remember to factor in the brake fluid also. Nice and detailed DIY there John

[EK4R]

^^ damn thx ecu-man.
i got quoted as you can see well over 100 for just the two pistons along...hmm i thought all honda dealership price r around the same...maybe i should change dealers?

[ECU-MAN]

try another dealer, got nothing to loose, except money

[heist]

host pics again?

and what would i ask for at a dealer? a brake master cylinder rebuild kit?

[ECU-MAN]

pics will be back soon

ask for a master cylinder rebuild kit

[shinji112]

omg this is way over my head.. i think i would hafta get hannys to do this for me.. can i ask how long it takes to do it?

[ECU-MAN]

less than 30 min

[JasonGilholme]

Did you do this on your del sol CRX?? Was it you that had the CRX?? lol

If so could you give me the part number??

Cheers
Jase

[ECU-MAN]

this diy was done on a BB2 VTiR Prelude

and yes I used to have a GenIII CRX, I dont know the part number for it but I can ask my honda dealer if you like. pm me your VIN if you really want it.

cheers

[Rasputin]

Is it possible to see the cause of the problem, once you have it opened?
i.e. would it be a noticeable crack/split etc in a seal?

And so you don't have to replace all of your brake fluid to do this? Is it common in shops for them to just 'top up' your old fluid, and bleed the brakes?

[EK4R]

^^ well mine started after my last service. probably let some air into the system so im going to bleed it this weekend with high boiling point DOT 4 fluid and see if it solves the problem. if not ill rebuild the sucker.

hmmm i was quoted 70 bux for a cylinder ...maybe ill just buy a 2nd hand one from the wrecker? just worried it might be leaked on the inside? cant really tell if i open it right?

[ECU-MAN]

why skimp on $7 woth of something that will save you life.

I wouldnt think twice about it, just use new brake fluid and bleed the braked when your done.

the seals on the pistons are noticably worn compared to the new ones.

[EK4R]

ecu-man u talkin to me??

im not skimping on 7 dollars....

i woulda used oem honda fluid if i wanted to save money to bleed the brakes...

and im saving myself alot of trouble n time from my busy job week by buying cylinder instead of building it and installing it myself.

plus i was quoted 50 bux a piston for the rebuilt kit in melbourne...yet to find a cheaper deal. will try another dealer when i have the time.

its not the money but getting ripped off isnt my thing.

neways will let u all know wen my brake bleed is done tmrw

[Rasputin]

If you meant me, I definately wouldn't just 'top it up', I was just wondering if that might have been what was done to me at a shop I went to.

[ECU-MAN]

ecu-man u talkin to me??




no dude

I was talking to Rasputin

[ECU-MAN]

If you meant me, I definately wouldn't just 'top it up', I was just wondering if that might have been what was done to me at a shop I went to.


ahh cool.

they have to bleed the brakes after this, which means replace the brake fluid :) for a good result

[Dylanamus]

Hey ECU-MAN, is it just me or do most of the photos in your DIYs not work? If it's not just me, would it be too much trouble to rehost and relink them? The visuals make these 100% easier to follow! Cheers

[ECU-MAN]

web server seems to be working ok,
it was down last week, your browser may have cached the page with out the pictures

press control and F5 at the same time to refress the page and let me know how you go.

anyone else not seeing the pics ????

[EK4R]

na pix fine with me. refresh your page and delete your old internet files and have a fresh load

[heist]

dont work for me either in FF or IE

[shinji112]

i called up peter warren today and they say honda doesnt make a kit for my EJ8. are they wrong? would like a EK4 for example use the same kind of BMC? coz if they dont then im gonna need an entirely new BMC >.<

[EK4R]

i called up peter warren today and they say honda doesnt make a kit for my EJ8. are they wrong? would like a EK4 for example use the same kind of BMC? coz if they dont then im gonna need an entirely new BMC >.<

i asked too. and they said with regards with EK4 they dont have a rebuild kit. you have to purchase the 2 pistons separately...i got quoted 150$ for the 2 pistons :thumbdwn: how about you?

im not sure if the EJ8 and EK4 are compatible, however the EK9 i can use on my EK4. check the part number. make sure it is ABS compatible.

[ECU-MAN]

pm me your VIN #,

I might be able to get you a kit

[shinji112]

i asked too. and they said with regards with EK4 they dont have a rebuild kit. you have to purchase the 2 pistons separately...i got quoted 150$ for the 2 pistons :thumbdwn: how about you?

im not sure if the EJ8 and EK4 are compatible, however the EK9 i can use on my EK4. check the part number. make sure it is ABS compatible.

the guy said i could only buy a whole new BMC which would set me back $238 plus GST. i called up hannys and they said they have the seals but not the pistons =(

[EK4R]

pm me your VIN #,

I might be able to get you a kit

ECU man ill pm u my VIN. so let me know if you can find a kit or not



the guy said i could only buy a whole new BMC which would set me back $238 plus GST. i called up hannys and they said they have the seals but not the pistons =(

well i got quoted the pistons so yea. for a new BMC i got quoted around same price as you.

[heist]

i rang peter warren today.

$60.35 for a rebuild kit (2 pistons, seals, crush washer)

or $380 for new BMC

thats for EG Si

[ECU-MAN]

EK/EJ is different to EG,

[heist]

yeah i realise that but i was just giving some prices for anyone with an eg...

[EK4R]

hey mike, i was told if the bore was broken a rebuilt wont fix the problem. how can i tell if the bore is too damaged for a fix?

[Eclipsor]

I was about to ask this same question.

Mine was leaking in a major way. Was loosing complete reseviours full of fluid. I've taken it apart now and there are marks on the bore. Just not sure if these are scores deep enough to render it useless. Is there any definite way to tell?

Also. My car is an imported cb3 and has an h22a swap done before I bought it. So I'm not totally sure what BMC I have and what part to ask for. Says it's a Nissin part and has 15/16 on it. Does this give any clues? The local honda parts dept hates my car so I doubt they'll be very helpful.

thanks

[Eclipsor]

Awesome. Thanks.

ps. brilliant write up ecu man.

[EK4R]

claymore what you mean by catching it?

[vinnY]

any chance you can get the pics back up?

[Moya]

Pics still work for me? Nice write up.

My brake is really spongy at the moment. By looking at it I know the Fluid needs to be changed (both clutch and brakes). But how can I tell the difference between needing to rebuild the master cylinder, needing a new one, or just replacing the fluid?

At the moment, if I sit at lights. The brakes get spongy and I can feel it lose pressure/pedal moves around. And braking at speed is basically useless. Like, seriously - I wouldn't drive in front of my on a highway.

The write up is beyond me, I'm asking from a 'she needs to go to the shop' but I don't want them to replace the fluid then find out it doesn't help and needs new master cylinder.

Thanks

[ECU-MAN]

sounds like you need to rebuild the master cylinder more that just bleed the brakes.

you look in the bore of the master cylinder to determin the extent to the damage to the bore.

its not a bad thing if you bleed your brakes to find you need to rebuild the master cylinder. brake fluid if very cheep.

take it to a shop if you unsure

[lw316]

Thanks ECU-man. I'm sort of a car newbie but I've managed to rebuild the master cylinder from your tutorial.

At the end of last summer my pedal was sinking to the floor (sometimes) but once it got less hot I didn't have the problem throughout the whole year. Now that summer is back, I thought I'd rebuild it, so hopefully the problem is solved. When you said "check the bore" for damages, what sort of damages were you talking about? The inside of my bore looks pretty clean and smooth, but near the outside edges there were a bit of brownish/greenish stuff? I could clean most of it, but some of it were "stuck" to the metal?

Oh by the way, the kit costed me 64 bucks from Honda North in Perth. (1992 EG Civic GL)

[ECU-MAN]

good work

what is ment bt check the bore, is to inspect it for excessive ware and scoreing from the pistons. its pretty obvios when you see it.

most times they are ok.

[EF9]

Hi ECU-MAN,

I'm new at all this. I've brought a 89 Civic with B16a1 conversion a couple of years ago, the BMC and booster was still the original 89 GL ones (with DA integra front rotor/brakes etc, and original civic GL rear drum), and the brake pedal feels really spongy.

I've brought a complete set of CRX Gen 2 rear disc brake (including arms, handbrake cable and BMC) from a wrecker. Got it installed by my mechanic, worked prefect for 3 weeks, then it's gone very spongy again, and a week later, it's gone stiff, and now with brake drag (the brake pad constantly touch the disc).
I can't even drive it down to my mechanic anymore as the brake pedal is now max to the top and I can't even push it down.

Any suggestion? Should i try the DIY rebuild ? My mechanic said to just buy a new one, which could cost about $200.

Thanks heaps.

[wynode]

It's normal for the brake pad to touch the disk.

Could possibly have a seized caliper if you pressing down on the pedal has no effect (and the pedal is hard).

[ECU-MAN]

as Wynode mentioned you may have a seized caliper, check all 4

the front pistons in the calipers should just be able to be pushed in quite easy, the rears must be screwed back in. make sure your caliper slides are free to slide in and out for the top and bottom slides. front and rear.

you can try to bleed the brakes again. also make sure your booster is getting vacuum.

[vinnY]

just had a question about bleeding the booster/MC

if i were to loop those two holes on the MC back to the MC itself, in theory i wouldn't lose fluid as its returning to the reservoir and as long as i have the hoses higher than the mc itself it would bleed as well correct?

[ECU-MAN]

not a good idea, teh fluid that comes out will be airated

brake fluid is not expensive, dont reuse the fluid.

[vinnY]

thanks for the info ecu-man :thumbsup:
i wasn't concerned about buying the brake fluid, just looking for options to make it easier to bleed and being less messy about it while keeping the brake fluid off my paint

so say i didn't route it back into the reservoir, and into a separate bottle, could i bleed the MC using my method? as the air shouldn't have a chance to run back into the MC itself since the tubing is run above the MC itself and the air should follow the tube upwards

[vinnY]

just an update
it appears the boys from the states do what i descibed initially and do loop it back into the reservoir itself
see here for honda-tech instructions (http://honda-tech.com/zerothread?id=1939150)

also some video footage here (http://www.denlorstools.com/home/dt1/page_7445/automotive_brake_bleeding_exclusive_tech_article.h tml) on how its done about 3/4 down the page

some more info here (http://forums.nicoclub.com/zerothread?id=250896) if you can't find a mc bleeding kit and feel like making a little diy

[Limbo]

just a question, sorry for bring up the old thread.

The ITR MBC i got doesn't have a piston sticking out of it, only a rubber seal on it?
I brought a new OEM MBC - 46100-S03-Z01

Is that normal? i haven't taken mine apart as yet

[ECU-MAN]

im not sure about part numbers, however an ITR DC2 BMC should have the shaft petruding out of the back of the BMC

[Limbo]

i dunno, it does it has a black rubber cover, with a round clip on the end.

But it does say '1" where my original says '15/16'. Also i did a part number check online and it says Integra type r & Ek9

Judging by this could it be the 'seal rod'? i can see the circlip holding in place a rubber nipple like seal?
http://www.crxsi.com/jdm/ek9-1004248/Steering-Brakes-Suspension-Brake-Master-Cylinder-Master-Power.htm

[Limbo]

I loaded some pics to help

http://i890.photobucket.com/albums/ac103/limbie/th_IMG_1442.jpg
http://i890.photobucket.com/albums/ac103/limbie/th_IMG_1445.jpg

see the black nipple (inverted). It seems to be a hard plastic. Its already lubed

[vinnY]

weird i'm pretty sure mine had the piston coming out of it and i don't ever remember having any nipples there on mine when i took it apart
can you remove the nipple? might be a dust boot or something

[Limbo]

dunno haven't tried yet.
Was gonna compare it to my stock one when i take it apart

[Limbo]

ok found out the piston setup is the same. The other type sticks out and over. On this newer piston, there is no part sticking out. The black bit just covers the piston hole.

Looks like my older BMC was fine anyway. It seems like my braided brake lines are leaking from a pair

[grifty]

do you have to use a new piston guide assembly?

i wasnt able to purchase the guide since its a discontinued item but i was able to get the o-ring that sits on the outside of it.

[ECU-MAN]

you can reuse the old one with the new o-rings

[grifty]

all i got was the outer o-ring, am i able to reuse the inner o-ring?

[ECU-MAN]

its more than an O ring, Its a seal. if you didnt get a new one and the old one wasnt leaking then reuse the old one

[grifty]

looks like it was leaking before so i went out to peter warren to buy it, turns out the seal is sold together with the piston guide assembly.

The bloke said he would contact me in a couple of days to see if honda japan will remake the part for me, i hope they do remake it otherwise i gotta go to the wrecking yards and find a good one that i can use.

[chingaling]

hey there may i ask what kind of greases did u use? was it just rubber grease (red) , what about the white one ? are they nesscessary to get the grease on ?

cheers

[vinnY]

I believe they were provided with the kit

[grifty]

You can just use brake fluid instead.

[ECU-MAN]

the white grease is like vasoline, its purpose is to seal the BMC to the booster to prevent vacuum leaks

the pink grease is a type of rubber grease to prevent damage to the seals during assembly. ensure any rubber grease you use is brake fluid compatible.

[OMG]

Hey ECU-MAN thanks for the write up!! brake pedal fells abit sluggish will Give this a go hopefully i can get it done with out any issues

[chingaling]

:idea:thanks boys !! this info help and Gifty got ur kit here but going to start soon lol ... :thumbsup:

[grifty]

:idea:thanks boys !! this info help and Gifty got ur kit here but going to start soon lol ... :thumbsup:

Just make sure you bore does not have any damage before you install it.