Brake master cly replacement.

[Redlight]

I have a small pool if what I think is brake fluid on the floor under the brake pedal. Brakes are still working. What are the odds that it the master Cly or line. How much time does it take to replace the NC? Can a reasonable backyard mech be able to replace the MC?
Thanks in advance.

[m3a1]

Likely as not it's the banjo washer (a copper washer that is meant to act as a seal between the banjo and the master cylinder) or a line to the banjo fitting has simply come loose or has perhaps even cracked.

To the matter of the banjo washer leaking, I'm guessing a lot of folks use new copper washer without first annealing it. A softened copper washer seals so much better than a hard one. A lot of guys get tripped up by skipping over that one tiny step.

Anyhoo, my guess is that is the most likely place you'd find your leaks.

There is also a chance your master cylinder could be bypassing (leaking out the back).

Yes, you can do this remove and replace work in your back yard. It helps to have a healthy back because there will be some bending and twisting involved. Plenty of guys on this site have done it.

Cheers,
TJ

[rickf]

50/50 on whether it will be the leaking washers or the master cylinder. Did you recently bleed your brakes and push the pedal all the way to the floor? If you did then it will be the master cylinder. Yes you can do it yourself but as TJ says it is not a real fun job. Take out the front seats and get a couple moving blankets from Harbor freight to lay on, that will make life a lot more bearable. Also be aware that the copper washers used are two different sizes, so if you need replacements be sure to match them up.

You do not mention A1 or A2 but if A2 with emissions tank you might also want a thick piece of cardboard to cover all the crap on top of the gas tank.

[m3a1]

I will add that it really isn't necessary to lay upside down in the truck. I have done two of these jobs and began with really looking over the work online (research here on this site, to be specific) and with a mirror. I did all my work, kneeling alongside and reaching up under the dash... Much of the work is by feel which is why it is necessary to familiarize yourself with the assembly beforehand.

(not quite as bad as you might imagine, because the whole thing is rather straightforward but unpleasant if your back ain't what it used to be)

The tricky bit is that one, long, transverse bolt that is pretty much out of sight and out of mind. In short, what you will be doing is removing the brake and clutch pedal and the frame from which they hang (which is what holds the master cylinder) in its entirety. It sounds far worse than it is.

Anyone who tries to do this without removing the whole assembly is asking for a lot of trouble because that master cylinder is really, really wedged in there! Don't believe me? Remember, our M-series vehicles were designed to be highly modular. Remove the assembly and save the cursing.

I think I did a piece on this process on the g838 with photos. Not sure where, tho. A few good images here -

https://g838.org/viewtopic.php?f=27&t=8 ... =alley+cat

Maybe more further into the thread but I haven't the time at the moment to go looking for ya. Whether all the pictures survived The Great Photo Bucket Debacle, or not, is anyone's guess.

It'll take you an afternoon to R&R it, including that extra 10% (if you love your truck) - a level 1 tidy-up and lubrication of the pedal assembly.

Cheers,
TJ

[csmith]

Its a simple job swapping out the MC, but it sucks as you have to contort your body to do it. I had a strong drink, took my drivers seat out, laid pads down got upside down, got into position, cursed a lot, I mean a lot, the MFer bomb was heard for miles, but got through it. Its that or hire it out....

[Mark]

I took out the pedal assembly, then R&R the master cylinder, M3a1 already had the answer.

[rickf]

Taking the clutch pedal out first makes a world of difference in getting everything apart. One bolt on the end of the shaft to take the hook off for the clutch rod and the pedal slides out the other end. Be sure to take the clutch return spring off first, it is under the exhaust and carb.

[Chef]

Be aware, (if you're not already) that any brake fluid other than DOT 5 will destroy paint. So if it's nice under there and you want to keep it that way, make sure to not let any brake fluid stay in contact with anything painted.

[halftracknut]

All you have to do is roll the jeep onto the passenger side and it is easy , nothing to it....takes about 45 min.....

[rickf]

Heeee's back!!!!! Welcome back to posting HTN.

[glcaines]

If you have an A2 with the ROPS installed, the lighting switch has been relocated to the right. If you remove the switch and plate you have much better access to the bolts. It is not a fun job, but I did it in about1-1/2 hours. As suggested, remove the pedal assembly. I made the mistake of trying to re-use the copper washers. I used emery paper to smooth them down, polished them, and annealed them, but didn't work. Make sure you get the correct washers, which are different. Also, the replacement MC I used was of excellent quality, except for the filler plug. The plug was junk. It was a very rough casting, the threads were crude and it would hardly screw in, and the plug did not have the tiny vent hole, which is necessary. I re-used the original plug which was in perfect condition.