Ok I just bought a 1992 Accord EX and my brakes arent working right one minute I'll have a full pedal and it stops fine then another it'll sink to the floor and I have to pump them to stop its definitely random. So far I have bled the lines and manually bled the ABS module itself by jumping the relay and cracking the bleeder on it it definitely helped some but the underlying problem persists. Also the ABS light is on and I jumped the connector together under the dash and got the code 4-8 which is an ABS wheel sensor but I can't see that causing the issues I'm having it doesn't make sense. My first thought was the master cylinder but I'd like to get some opinions from people that have experience with these cars so any help would be greatly appreciated. Thank you in advance!

 

Sound like the master cylinder. To check unbolt it and check for fluid behind the seal where it meets the brake booster. Note there is not always fluid there even if the master is bad. What is happening is fluid is pushed past the internal seal(s) causing the pedal to drift to the floor. If you are not loosing fluid and the pedal is going to the floor then it is almost always the master.

 

Air in the system behaves like this:
Pedal is soft & mushy when first pressed, but pumping it up works.

Bad master cylinder behaves like this:
Pedal is hard when first pressed, but sometimes sinks slowly & smoothly to the floor. Releasing & pressing again often works fine, and it sinks more often with light pressure like holding at a red light.

More often, it's some combination of these...

A bad MC will usually leak back into the fluid reservoir - not always leaking back into the booster.

 

Normally with these symptoms the first thing I'd have done is changed the master and called it a day but I've been told it could also be the ABS modulator regardless I'm gonna try changing the master because it looks like it could be original still and my car does have 304,000 miles and still going lol. I do know I need a wheel sensor for the passenger rear but the cheapest one of those I found was $125.00! I just wanted to be sure before I started trying to spend money and go the trial and error route I've read numerous threads where people have had very similar symptoms as mine and changed the master with no change so I wasn't sure if there was something I was missing. Anyways thanks dudes your help is making my decision so much easier though I am definitely grateful.

Now does anyone have any tips on performance upgrades? I was gonna go with a cold air intake and put a header on it I've been told to get the manifold off of an f22a4 that nwould run better but I don't know any suggestions? I was also looking into a throttle body spacer but I don't know much about that. I'm wanting to get the maximum performance out of my engine without rebuilding it and spending lots of money so as of right now a turbo is out of the question Haha maybe in the future though..

 

Try Rockauto or autopartswarehouse for wheel sensor.

 

I'd go to a junkyard for an abs sensor.

A faulty abs modulator will not make your brake pedal drop to the floor. You may want to check the rubber brake hose going to your caliper. If the hose is bulging, then it could cause your problem.

EDIT: I think the performance upgrades on a 23 year old car with 300K+ miles is not worth the investment. I'd probably drive the car until the engine dies with the OEM setup. Bolt-ons will not help much, if at all. If you want more horse power, installing a H22 engine from the prelude will give you the most bang for buck.

 

Thanks man I will look into that. Normally I'd say you were right but somebody documented every time this car had an oil change, tune up, major repairs ect.. Since the day it rolled off the lot its crazy. Besides the brakes the only issue is very minor rust on the rear quarters. For this car being as old as it is and the mileage being high somebody took extremely good care of this car it blew me away seeing all that. Anyways I'm not looking to get a big boost or anything like that just anything to help it run to its full potential and help gas mileage. I have been reading alot about performance and ive seen alot of h22 swaps though. What are the perks of the h22 vs the f22a6?