Here are my problems. I have a GSR brake swap on my EG. I recently changed out the brake fluid, but can not get it to bleed out. I switched to DOT 4, which is compatible with those brakes. I'm thinking my problem is booster related because it builds brake pressure when I bleed the lines with the car not running. As soon as I start the car, the pedal fades to the floor. It will pump up, but continues to fade. I've tried bleeding them with the car running and they continue to fade. Because the booster only see's vacuum when the car is running, and that's when they fade, I'm assuming it's booster related. I did notice some leaking between the master cylinder and the brake booster. So I removed the master cylinder, cleaned the rubber gaskets, put everything back together, and now there's a huge vacuum leak around the master cylinder. Now I just filled the master cylinder up, but didn't bleed it. However, the leak never existed before. The booster is such as pain in the butt to replace, but I think that's what the problem is. My question is, can I use the EG booster with the GSR master cylinder? Is there any definitive way to determine it's the booster before going to the extent of replacing it?

 

If its ABS you need to bleed the brakes with the key on. If not its alright, Start your car and hold the brake firm, if the pedal slowly goes toward the floor your booster is bad. also make sure your check valve is working and flowing in the correct direction.My EJ I use a 91 RS integra master and booster out of the junkyard. The first one I pulled had the leak like you but the second , I still use it today.

 

It is a non-ABS system. I agree that it's the booster. Can I run the stock EG booster with the GSR master cylinder?

 

If the bolt pattern and lines are the same locations yes. The ONLY 1 I know personally that works on my EG STOCK booster is a 91 EX 4dr master cyl,. The lines are in the correct locations and the bolt pattern is the same.

GSR master is ABS similar to other ABS civic, the lines are in a different area and bolt pattern is different I believe than NON ABS. Thats why I used a 91 integra non abs.

 

I'll take at look at how the master cylinder bolts to the booster to see if it'll work.