I have a 90 Accord LX 5 speed. Here recently the brake pedal has been going all the way to the floor board, but only does this after the car has been running for 30+ mins or if it is very hot outside. I do need pads, but they have just started to squeak. I was told its the master cylinder or the booster but just want to be sure. I have priced the master cylinder at Auto Zone for $44.95 with the reservoir tank.

Also if anyone know's of a good DIY on it let me know. Thanks!

 

How long has the brake fluid been in the system? Brake fluid absorbs water over time which reduces the boiling point, so if the some part of the system is getting hot enough (unhood temp, a lot of braking, etc), the fluid can actually boil and create vapor bubbles that result in a lot of pedal travel. You might try bleeding the system real well (left rear, right front, right rear, left front, in that order) until you see new clean fluid at each wheel. Make sure you don't let the master cylinder resevoir get too low, or you will be introducing air into the system (not good). If the problem remains, and there are no other leaks, it is probably the master cylinder.

 

i tell customers this and they think i'm making this stuff up LOL FINALLY someone else knows its true

 

I seriously had this same exact issue. Literally.

And I thought the same thing, dirty fluid and possible water in there that was boiling.

Flushed the system, had all sorts of dirt and rust and stuff. Did that, but it still dropped after it got hot and all. Replaced the MC and that fixed that issue.

Agree with them ^. Flush first, try it, then replace MC if necessary. Honda recommends flushing brake system every 3 years regardless of mileage.

 

actually i like to do the brake fluid every 15000 miles or every 12-months

 

well better for you then. i wish customers would. i mean you got people whose brake fluid has never been changed for 3, 4, and 5 years. Could not be blacker. And everytime, no, not today. Oh well. Not my loss, well it is, less money, but not my car haha.

 

Ah thanks guys. Will flush first =D And thanks for putting the bleed order fleetw00d, that was going to be my next question lol

 

kinda weird why they make you go that way, as opposed to the normal farthest from the MC and proceed (RR, RL, FR, FL). Any reason why?

 

good catch LOL i didnt catch that myself. i do the order your way as well. since 2001 when i was in the dealership. never heard of that other way.
man, when i was in the dealership i was changing brake fluid the correct way and the service manager told me to not do it like that...he said to suck out the dirty fluid in the resivore, spray the resivores outside with parts wash,and add new fluid to the resivore and hide the rest of the new brake fluid in my cabinet. WTF? so i did it like that but i dont do that bull **** here. honestly, i get alot of customers off educating them on that and other bull **** moves shops do. i up sell alot of fan switches, suspension bushings, cabin air filters, fuel filters, battery services, motor mounts, even hose replacements for little coolant lines that arent leaking but are old. try the "preventive maintenance" approach. if they say "not today" give them a tow truck company card in case they need it sometime. just be sure you keep track of your services so you dont recommend fan switches too many times in a row. once a year is okay

 

they can go RR to Fl and RL to FR because there are 2 main systems on that controls the RR and FL brakes and then one that controls the RL and FR brakes thats why there are only 2 brake lines coming from the master cylinder.

to op:
well here is a video: http://www.youtube.com/watch?v=trotrlIG2sk

this video helped me do mine, and it explains it in the video