First off - my car is a European(Ireland) '96 3dr 1.4L(euro only model-basicly 1.4 version of the d16y7, but with full electrics&airbags) Civic with '92-95 EG Civc SiR(JDM) braking system - front,rear(drum to disc conversion), master cylinder&servo-everything except the proportioning valve.

Need some advice here.
(before you go any further - any reference I have to "Drivers side"- bear in mind our cars are right hand drive.)

Last week I realised my drivers side rear caliper was seized ... AGAIN! This is the one I replaced only a couple of months ago. Now, while the one I replaced was off a '92 Esi(Euro model- same as US spec EX I think -with D16z6 engine), it seemed to be working perfectly.

However, it has seized.
I know these have been known to go - but when it seemed to work so well, and was only on the car a couple of months, and the car is being used every day it seems strange for it to go so quick??

I have a feeling fluid may not be flowing properly in the system but I need some help/answers:
-Am I right in saying that the master cylinder has in fact two cylinders inside or that the prop valve runs in two parts - passenger front + drivers rear, and drivers front + passenger rear?

The reason I ask this is that from the beginning when I fitted these brakes the passenger side front locks up early when I brake hard - if the system splits flow into two - and the drivers side rear was in some way blocked, then the excess fluid pressure would go to the passenger side front yes?

Strange part is that if Im right about this then why does the caliper seem to function perfect when its fitted and the system is bled - ive gotten my m8 to watch it while I pump the brakes after we've finished bleeding it.

Im getting one of the Gunson Easy-Bleed systems before I go at it, to be bloody sure there is no air left in there.

I have found somewhere that I can get a caliper - €75.... but I want to sort what is causing this rather just going and replacing it only for it to happen again in a few months.

Or does anyone know whats involved in re-conditioning a caliper? Is it something I could do myself? Do the calipers open up easy?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blade_Irl &raquo;</TD></TR><TR><TD CLASS="quote">-Am I right in saying that the master cylinder has in fact two cylinders inside or that the prop valve runs in two parts - passenger front + drivers rear, and drivers front + passenger rear?</TD></TR></TABLE>The MC has 2 pistions in the cylinder. Works kinda like 2 cylinders. One for LF&RR, one for RF&LR - it's a "dual-diagonal" system (I think yours is the same as here in US).

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blade_Irl &raquo;</TD></TR><TR><TD CLASS="quote">-everything except the proportioning valve.</TD></TR></TABLE>The proportioning valve isn't between the 2 circuits, it's between the front & rear within each of the circuits. It's job is like this: At low braking pressure, it doesn't do anything. When the brake-fluid pressure reaches a certain point, it throttles the rear pressure so it doesn't rise as much as the front.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blade_Irl &raquo;</TD></TR><TR><TD CLASS="quote">The reason I ask this is that from the beginning when I fitted these brakes the passenger side front locks up early when I brake hard - if the system splits flow into two - and the drivers side rear was in some way blocked, then the excess fluid pressure would go to the passenger side front yes?</TD></TR></TABLE>I think the secondary piston in the MC can float to prevent this from happening.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blade_Irl &raquo;</TD></TR><TR><TD CLASS="quote">Strange part is that if Im right about this then why does the caliper seem to function perfect when its fitted and the system is bled - ive gotten my m8 to watch it while I pump the brakes after we've finished bleeding it.</TD></TR></TABLE>If the hose at the right-rear caliper is bad, maybe it's inside wall collapses & blocks the hose. Maybe this only happens with higher pressure from real-life operation of the brakes? (I'm kinda guessing) Ever pinch that hose or let the caliper's weight hang by the hose? Those are not good things to do...

Before you go off with this, you should make sure that your handbrake releases. Check for rusty cables or an age-weakened return spring back at the caliper. I had a rusty shaft for the handbrake lever (on the caliper) so it was sticky & didn't release.

Taking out the caliper piston isn't too bad, it twists out from the handbrake mechanism. Dismantling that handbrake auto-adjusting mechanism inside the rear caliper is a little bit more work.

 

So if they are split Dual-Diagonal then could a blockage in the Right Rear cause excess pressure on the Left Front causing it to lock early since they work off the same piston and therefore the floating mechanism does not enter the equation??

 

The floating piston certainly does enter the picture. What I don't know is whether it'll run out of travel in your case. Once that happens, yes it'll increase pressure.

I think you first have to start checking out the sticking rear caliper & fix whatever's stuck. It's too easy to make 124 different guesses over the web; you have to start checking em.

 

Yup, I know, But Im stuck in work at the mo, and have a cold, and loads of assignments to work on for college so its gona have to wait until next weekend unfortunately!

If the two pistons are "pumping":
1. Front Left, Right Rear
2. Front Right , Left rear

Then are 1 and 2 not independant of each other? i.e. 1 having resistance at one of its ends could not be "compensated" by 2?

Or can both pistons "float" between the two calipers they "pump"??

 

There's only one cylinder. There's 2 pistons on the shaft/pushrod. The one furthest in floats. That floating piston is between the 2 sections of the MC.

So most of the time it lets the pressure balance equally between them. If you completely cut a hose somewhere, that middle piston runs out of travel. That's supposed to happen when the pedal is down closer to the floor. Then the middle piston prevents you from losing all 4 of your brakes.

I don't think you should worry about issues with that floating piston. Worry about the stuck caliper first. It just might be causing all your grief.

 

Cheers.
Will let you know if that solves it. Gona pull off all 4 calipers next weekend and wire-brush/clean/grease the pins, and bleed with a Gunson pressure-bleed("Easy-Bleed") system if it arrives(ordered off Ebay a few days ago.)