fryman

A few years back I installed rear trailing arms with disk brakes from a Del Sol SI onto my eg Honda Civic DX Sedan. I was told that it's recommended to replace the brake master cylinder with a rear disk master cylinder when doing this conversion so that the master cylinder will provide the proper amount of pressure for the rear disk brakes. I always meant to do that but never got around to it. My master cylinder is now failing(brake pedal slowly goes down to the floor when pressure is held on it at traffic lights) so I want to replace it with the proper master cylinder to match my rear disk brakes. The thing is that I recently read somewhere that I will need to also replace my brake booster and proportioning valve with ones from a rear disk brake car also. I only ever heard of replacing the master cylinder prior to reading about the brake booster and proportioning valve so I thought I would post to ask if those really need to be replaced as well. Also, what cars can I get these parts from to make sure they bolt right up without needing modification?

24TEN

iTrader: (2)

I believe this is covered in the FAQ. FWIW I've never done anything outside of just the rear disc swap myself and it's had no issues for the last 10 years or so. Maybe it's a non issue on a daily driven car? I don't know, check the FAQ I recall reading some in depth discussion about it.

94eg!

iTrader: (2)

You definitely don't need the booster or master cylinder. Your stock DX master & booster are the same parts found on the Del Sol Si.

The only time you need a larger master is if you get larger front calipers. The only time you need a larger booster, is if your master upgrade makes the pedal too hard (larger master requires more foot force).

24TEN

iTrader: (2)

^That's what I remember, front brakes were the difference. Thanks for the clear and concise explanation.

fryman

Hmm... I just checked the part numbers and you're right 94eg!, 46100-SR3-043 is the part number for the master cylinder on my car and Del Sol SI. Well that's a relief since that master cylinder is pretty cheap. This is what I had read before 92 civic ex rear drum to disc conversion. Page1 - Honda Tuning Forums at Super Street Magazine. The "ToyCivic" guy is the one who said to change master cylinder/brake booster/proportioning valve. So my proportioning valve should be fine also? Just want to be sure, I'm really paranoid when it comes to the braking system.

94eg!

iTrader: (2)

Many people don't change it, and their cars handle fine. Even the fastbrakes guys who have done every swap under the sun say the stock one is fine.

Personally I changed mine with a 4040 from a DA integra. I can't tell you if it made a difference or not since I added it at the same time. The problem is a 4040 from a DA has a bracket that does not work all that well in the EG. Only one bolt works and slightly different way it sits makes getting the hard-lines in a pain. Personally I would stick with what you have and not worry about it.

If you are super obsessive, you might be able to find a 4040 from a DC (an LS model without ABS). These have the 3-bolt bracket identical to the EG and fits perfectly. You can also try swapping your original bracket, but I don't like that idea. Honda says never to disassemble the valve, and they even crimped the threads on security torx bolts to ensure you don't do it. On some valves, the threads get destroyed trying to remove those bolts due to the crimped threads.

Your stock 3-bolt 3030 valve & bracket:


DA integra 2-bolt 4040 valve & bracket:


Very rare DC LS integra 3-bolt 4040 valve & bracket:

94eg!

iTrader: (2)

As for master cylinders, here's the facts.

Honda uses 7/8" master cylinder with 54mm front caliper pistons (10" rotors). This setup is on Non ABS 93-95 EX Coupes w/o ABS, 90-91 CRX Si's, 94-97 Del Sol VTEC w/o ABS. The master cylinder from those setups is a direct bolt-on to your stock booster. It looks the same but says 7/8" and has a blue colored reservoir:


Honda uses a 15/16" master cylinder on 57mm front caliper pistons without ABS (10" rotors). This setup is found in the 90-91 Civic EX Sedan and 94-98 Integra LS w/o ABS. The integra MC doesn't fit your stock booster (bolt flange angled different), but the 90-91 EX one fits perfect. The EX unit looks the same as your stock one except it has larger master cylinder: