:: I posted this in the hybrid section with no luck, so here is the question::

I have the 99 gsr disc brakes on the car already and I have the 99-00 SI proportioning valve waiting to be installed. I am buying a GSR master cylinder from my friend too. What else might I need before I start this?

 

i believe all 96+ civic hb comes with a 40/40 pp valve. a gsr break ms is meant for abs, and it has one 12mm fitting.

 

So you have gsr (10.4") up front already, and want to get the rear discs swapped in?

All you need is the bigger 99-00 Si m/c then; its is 15/16th versus your current hb's 7/8ths. The prop valve is the same between Ek HBs and the EK Si.

Note, however, if you keep your stock 9.5" front brakes and just get rear discs swapped in, you do not need a bigger m/c, you only need the bigger m/c when you also get bigger front brakes. But this also depends on how much pedal travel you like or dont like.

 

So the proportioning valve is the same huh? And I cant use a gsr mc? The si mc is the only one I can use?

 

The 99-00 Si m/c is easier to use because the brake lines go on the same side and line up the same and are the same size flare fittings as the ek HB.

If you chose to use the gsr one, you'd have to cut and reflare and rebend one of the lines.

 

EK hatches have 13/16th MC, while the 99-00 SI have 7/8. You can use a MC from a 98-01 Integra with ABS which is 1" and it will be a direct bolt on, that is what I use in my Si so I know for a fact it works.

 

Hold on here. From what I've read, everyone is talking about different things...

First off, all 96-00 hatchbacks have the same proportioning valve as the 99-00 Si with 4 wheel discs. If you have a Si valve you were going to be putting in, you should just sell it since it's the exact same part thats already in there.

Second, if your keeping your stock FRONT brakes, you do NOT need a new master cylinder & brake booster. If your rear disc swap left you with a mushy pedal, it is because you have air in the lines still. Bleed Bleed Bleed. I have this setup & my pedal is rock hard.

Third, if you did swap your front brakes for larger ones, you will need to replace the master cylinder. You will need to know where the front brakes came from so you can get the proper master cylinder to match. If your using Civic/Del Sol 10.2" brakes, you need a 7/8" master cylinder. If you using integra 10.2" brakes, you need a 15/16" master cylinder.

 

***edit***

 

If you do need the master cylinder for integra front brakes, here is some info:

98 Integra RS does not have ABS and the master cylinder looks like a match to your DX one. It may bolt directly to your existing booster. You should take a trip to the autoparts store & compare the bolt patern (distance between mounting holes) on your stock MC to the 98 Integra RS one to know for sure. Either way it will be the perfect size for GSR front brakes on a NON ABS brake system.

Also, don't bother swapping out the booster if you don't have to. The pedal feel & modulation will be better with your smaller stock brake booster...

98 RS master cylinder (#25, not #1):


96 Civic DX 3dr master cylinder:

 

Thanks for clearing that up for me. Looks like I bought something I didnt need. I did buy it a few years ago and never installed it. Thanks for the info on the rs integra master cylinder too!!!