is this the master cylinder going or something else?

[maka_RTH]

it started about a week ago. when i pushed the brake pedal, it was just fine, but then it started slowly going all the way to the floor. when i got home i checked my fluid, and noticed that the lid for the brake fluid had kinda come off. so, i put it back on and it was fine the next day. then, a couple days later, it started doing the same thing, just fine at first, then it'd slowly go to the floor, and i can let off and it does the same thing over, pressure at first, then slowly to the floor. it's worse when it's hotter, and it gets worse everyday now. i'm thinking master cylinder, cuz i'd think if it's air in the lines, then it would just be spongy right off. and i'm not losing any fluid as far as i can tell, it seems to be at the same level whenever i check it, and it doesn't appear to be leaking anywhere. i just don't want to replace the master cylinder if that's not it... any ideas as to what it may be? and, along those lines, any difference betweent the 86-87 MC and 88-89 MC (assuming both are from and LX-i)?

[nswst8]

If you get brake pressure initially and then the pedal fade the plunger in the master cylinder is failing, replace, easy fix. $40 @ auto parts stores.
Hope this helps,

[soljaboy2000]

Whoa.....thats the exactly problem I had for 1 1/2+ years of owning my car.And I still have that same problem but I gotten so used to that it doesn't even bother me and plus I just put it in nuetral whenever I come to stops automatically. lol
Hey but since were on the subject...i wanted to know what exactly needs replaced to fix this problem...pics if possible or detailed description of where the part is located. Or is it only the master cylinder etc. ???

[nswst8]

2 bolts hold it to the vacuum booster and just disconnect the brake lines attached to the master cylinder itself.
Bleed the brakes and your done.
Hope this helps.

[soljaboy2000]

You mean just disconnect the aluminum pipe looking pice right? Do I need drain the fluid or just use old rag to soak it out of the resevoir?

[nswst8]

Yeah the aluminum looking lines attached to the master cylinder disconnect and reconnect to the new master cylinder.
It will be replaced when you refill the resevoir and bleed the brakes.
When you bleed this is the order 1st. Driverside front, 2nd. Passenger rear, 3rd. Passenger front, 4th. Driverside Rear.

[maka_RTH]

Do I need drain the fluid or just use old rag to soak it out of the resevoir?
the hayne's manual says to use a syringe to get as much out as you can..., there's a fair amount in there(more than a rag could soak up). you'd prolly at least need something underneath it to catch the brake fluid (drip pan...)

[smufguy]

hehe, u explained it pretty good. That is nice :rockon:

Changing takes no time. I had to put the master cylinder on my 4g and one thing i did not do is bleed it cause i did not have enough time, but its good so far, just a little play, about an inch or so. i know its bad, but it sucks to have no one to help you, or a easy bleeder stuff.

[maka_RTH]

and, along those lines, any difference betweent the 86-87 MC and 88-89 MC (assuming both are from and LX-i)?

and to answer my own question, yes there is. i looked up the part numbers and stuff, they're different. i suppose i could look that stuff up before i ask it, huh? :rolleyes: lol

[smufguy]

the 86-87 Master cylinders on the lxi cars are the same as the 86-89 carb cars. Since their set up was the same as the carbs.

But the 88-89 lxi used bigger front rotors and hence the bigger master cylinder. Im sure they got different prop valve too.

[nswst8]

#639610 10mm X 1.25, 33mm long Open, pump the brakes and your done no more two man bleed process.
Hope this helps

[hkplayer]

its good to know that it is pretty cheap to fix that mc since i may have to down the road...thanks

[skull1441]

ok i just replaced mines like 2 days ago..... the new cylinder came with neat instructions and a 'bench bleeding kit' or something like that...... u can actually bleed the new cylinder on ur hand first b4 u put it in the car ......... i used a syrenge to take the old fluid out ....... when u put the new cylinder in.... connect the fluid lines but dont tighten them yet...... with the engine off, slowly press the brake pedal down till it hits the floor and hold it there (let someone hold it or use a pipe ) now tighten the fluid lines and fill up the resevoir to max and let go of the brake pedal........ and ur done.... if u do this right, u wont have to bleed ur system ..... worked 4 me

[maka_RTH]

yup, that was it. i replaced the master cylinder today, and now they work great. i'm one step closer to being ready to go to Cali.

[AccordAddict]

man if it is so easy, why do these mechanic shops want $230 to fix my leaking master cylinder? is it hard for a beginnner?

[maka_RTH]

it's not bad at all. you just undo the metal brake lines from the master cylinder, unbolt the master cylinder from the power booster, bench bleed your new one(should come with instructions on how to do so), then bolt it on, bolt up the lines, your good to go. it's not too bad at all, really strait forward. i'd say an hour tops taking your time. just one big recommendation: get a flare nut wrench or whatever they're called, made for brake lines and stuff. one like this: http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&fromAuto=YES&bidsite=CRAFT&pid=00944176000 the lines are 10mm. this would've made it MUCH easier to do mine, since they strip really easily...

[AccordAddict]

How much is a new master cylinder? or can a used one out of a junkyard be ok?

[maka_RTH]

i'd say go new. i believe new one was like $50..., lemme double check.... yah, it's like $55 with a core. just check your local parts store