So i recently did a rear disc conversion on my 98 EX. I used brand new calipers, rotors, PBR pads, SS lines and swapped the entire trailing arm. I also switched to a 4040 prop valve and bled the entire system 3 times. The brakes simply do not stop as well as the drums did. The pedal is mushy and i have to press much farther down to get the same braking power as before. The only thing that i could see causing this is the fact that im running SS lines in the rear and OEM up front, but i dont see how that alone can cause this. Has everyone who's done a conversion felt MORE stopping power, or are there some who've had similar experiences? Thanks in advance!

 

Master cylinder or you have a leak somewhere.

 

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

 

I too thought it could be the MC, but it was working fine with the drums. Im also pretty sure it doesnt have a leak. ive checked the lines (hard and soft) several times.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton &raquo;</TD></TR><TR><TD CLASS="quote">Master cylinder or you have a leak somewhere.</TD></TR></TABLE>


Its common for people who do swaps w/o the MC to experience exactly what you are right now

 

The 98 EX MC is the exact same as the 99-00 SIs, so i didnt think it was necessary to swap unless you had a LX, DX etc...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Iceman05 &raquo;</TD></TR><TR><TD CLASS="quote">The 98 EX MC is the exact same as the 99-00 SIs, so i didnt think it was necessary to swap unless you had a LX, DX etc...</TD></TR></TABLE>

Well i have yet to do this swap yet but i've read a lot about it and that mushy feel ends up being the MC 90% of the time. Check the FAQ at the top of the page to see if they're the same.

 

the FAQ is where i got my info from and it said u dont have to change the MCs cuz they're the same....

 

I didn't swap my M/C on my 99EX. I experienced the mushyness at first as well. Leakes were my MAJOR problem. I changed to all SS lines new rotors front and rear and OEM pads. and the 4040 porp valve.

 

I had the same feeling mushy feeling as you. Then I put in a 1" ITR MC with matching BB and now it feels really nice. It also helps to have a 4040 prop valve.

 

This is exactly why I am hesitating to do the rear disk conversion on my 99ex.

 

i thought ex come with rear disc already?

 

#1 possibly have air in the master
#2 possibly didnt line up the nipple in the inner brake pad with the groove in the piston
#3 leak somewhere


it should have an awsome pedal, probably an issue with the mechanic

 

I'm not sure about civics, but when I put discs on the front of my mini, (drums in the rear) I had to ad a bias/proporationing valve. If civics with front disc/rear drums have those, did you remember to remove it? Just a thought...

 

ive never done a rear disk conversion but...
did u use a distribution valve, or is it already in the m/cl?
did u bench bleed the m/c?

 

with my 5 lug I experienced the same thing, all I did was change the prop valve and my prob was fixed after the bleed.

 

try bleeding ur system again if that doesnt work might be your proportioning valve

 

I did the swap on a 99 CX with out the prop valve, mc, or ss brake lines... Mines seems to stop on a dime now....

 

Even though you may not've swapped BMCs, you still may've gotten air in it. Here are some links on how to Bench Bleed the BMC:
https://honda-tech.com/zero...63160
https://honda-tech.com/zero...39661
https://honda-tech.com/zero...54278

There is very likely a much more detailed thread on how to do this. This was just what I've found from the first 2 pages of a 400+ result search... You're welcome. (I have to do this soon anyway...). There have been people who have been able to do this without removing the BMC. Be sure to bleed your ENTIRE hydraulic system after doing this, in the proper sequence for your corners.

The symptoms you describe are VERY similar to those experienced by the users above. Since you haven't touched your BB/BMC and your brakes were working before your conversion, It's more likely that air got in your system somewhere than something being broken/dysfuntional.

As always, you can get your stuff checked out by a pro if you are unsure. Let us know how things go!
JasonGhostz

 

Oh yeah (for Iceman)... Coupe, Sedan, Or Hatch? Do you have ABS? Manual or Automatic?

AFAIK, the only USDM EK that came with 4 disc brakes was the 99-00 SI (and is non-ABS), I never found out for sure what ratio the EM1 Prop Valve's ratio is, but I know it's PN 46210-S04-902 and the BMC (whatever it's bore size) is 46100-S04-A14. Several other EK-EXs had the same BMC and BB (46400-S04-N11), but I'm pretty sure the Prop Valve is unique for the EM1.

The only other thing I can think of are having washers for your banjo bolts. These allow for proper alignment of the holes for your brake hose fittings. I don't know if they come with new caliper assys, but the caliper/seal repair kits usually contain them, and are likely available at any local store. *Keep an eye on your BMC's fluid level*. If it goes down, then you'll know there's a leak somewhere...

Anyway, GL, drive safe, and let us know...
JasonGhostz

 

ok guys, lets see where to start:

First, i DID bench-bleed the MC, twice (did it the second time once i felt the mushyness after taking it for a test drive)

Second, i DID use a 4040 prop valve (for those who obviously didnt read my first post)

Third, (JasonGhostz)- Coupe, Non-ABS, Auto (for now...)

Fourth, I did check for leaks numerous times, but i will double-check.

Lastly, HapaHaole, the comment bout the mechanic being the problem.... let's not go there.

Bottom line, i meticulously researched this conversion and followed the procedures to the T, but that's not to say i couldn't have missed something. Ill go back and check everything to be sure. I appreciate all the input!

 

Dang... In that case, I don't know what else could be causing this. The mushy pedal suggests either unsealed hydraulics or air. But if you don't notice the fluid level going down and you've bled the system twice (BMC, RR, LF, LR, RF), then it must be coming from something else. I remember reading some posts of people who had their BMC and/or BB come apart while trying to bench bleed, but... I am at a loss...

Here's something I noticed from an online OEM Honda Parts Dealer..
The 1997 Civic 2DR EX Coupe AT has 2 PNs listed for the BMC: 46100-S04-A14 ("Master Cylinder"); 46100-S04-A12 ("Master Cylinder Assembly"). Both show the same price and diagram #. The 1999 Civic 2DR SI Coupe MT only has 46100-S04-A14 listed. They both use the same BB (46400-S04-N11). I don't know what the difference is between 46100-S04-A12 and 46100-S04-A14, if any...

As far as the Prop Valve goes, I will likely die never really "knowing" the ratio (nor the BMC's bore size), but I just wanted to give you the OEM PN in case you (or anyone else) needed to reference it... I don't know much about brake hydraulics (other than PNs), but is it possible that the ratio for the PV you have is correct, and still not "working" correctly? I have read posts about people who bought *used* PVs, only to find that it wasn't working properly. Did you buy this part used, or did you take it off of the *stock* donor vehicle yourself (or do you have documentation that can convince you as such)? Unless the part came in a Genuine Honda sealed bag with the PN inked onto it, it's going to be a matter of faith and trust. I don't mean to suggest that your source is unreliable, but I just wanted to relay what I've read from others about clogged or otherwise dysfunctional PVs.

I feel for ya, man. I am starting to imagine how frustrating this can all be, and I'm not liking what I'm feeling. I wish I could help more, but this is about as far as my brain can go.

Hang in there and you'll be back on the road driving comfortably soon. I'll be keeping an eye out...
JasonGhostz

 

thanks man, i appreciate it. I am kinda frusturated since i spent so much money on new calipers etc and now it doesnt stop as well. Its driveable right now, and u can lock up the brakes, u just have to push all the way down. I always try and do things 100% right the first time and it pisses me off when things dont work well... (as goes our hobby i guess.) Anyway, im up at school now but when i get back home over break im going to make sure everything checks out. I had a kinda similar prob before when i upgraded the front rotors/pads. For the first 200 miles or so, the pedal would sink pretty far, but the braking force was still there, unlike now. After a week or so, the pedal was stiff again, and im hoping the same thing happens now.

 

Sounds good. GL in school. That ****'s important.

You mentioned around a 200 mile period for your previous setup to regain normalcy. Did you remember to break-in your new pads/rotors? While in a rush to get things done, this can sometimes be overlooked. You strike me as a dilligent ****, so I'm only asking because you haven't mentioned it yet.

Anyway, keep an eye on the brake fluid level. A very slow leak might take a while to show. GL with all.
JasonGhostz

 

I broke in the pads/rotors for 300 miles, and i plan on doing that with this setup before i use it hardcore. Ill be sure to keep an eye on the fluid level, and ill keep the tread updated once i get back.