My Willys 3A and 3B Community
3A, 3B, DJ Technical Knowledge Base => "Original"-- Technical Questions, Answers, Observations => Topic started by: Ryan_M on May 04, 2014, 10:44:12 AM
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I replaced the master cylinder along with the rest of the braking system on my 3A during the rebuild a couple years ago. This week I noticed I have brake fluid seeping out around the rubber boot.
I know there are MC rebuild kits available but they're nearly half the price of a new MC....might as well just replace the whole thing.
I'm curious if I may have done something to shorten the life of my existing MC. Is it typical for the seals to fail after only a couple years and a few thousand miles? Or do I have a problem with my pedal adjustment or something else? If I'm going to replace it I'd like to not kill off the next one quite so quickly. I adjusted the brake pedal free travel per the Service Manual right from Day 1.
Any suggestions or are these MC's just generally junk?
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Do you still have your original MC? If so you can get it sleeved for about the cost of a new repro MC..they sleeve it with brass so virtually no more corrosion issues...I sleeved the MC in the 3a and used a kit from Walck's..so far so good...
http://www.applehydraulics.com/
I used a repro in the CJ-5 a couple of years ago, and no leaks yet...but I haven't looked real close lately...
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Hmm....$85 for a brass sleeve plus the $20 rebuild kit plus shipping. And then I still am counting on the hope that I can install the rebuild components and not have it leak.
I tossed the MC from my 3A but a quick rummage through a junk bin in the shed turned up the rusty Wagner from my M38.
I'll put some more thought into it but laziness may win out and I'll try my luck with another repro from Walck's or KW.
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I have to admit that I sleeved mine because it was one of those weird cast aluminum MC's...
I don't know but the M38 might have a different bore size...something to check anyway..
I guess I'd try a kit first...if the bore is not pitted or rusted it ought to work...for another year or two at least!
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I think the location of the master cylinder has more to do with the tendency to leak than being junk. It's always getting wet and dirty. I try to replace the fluid in the reservoir yearly to help get the moisture out.
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Sounds like you have two choices.......
1.� Never go through water
2.� Never wash it..
[smiley=bath.gif] [smiley=bath.gif] [smiley=bath.gif]
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I've really only had the MC legitimately submerged one time (see avatar) and I don't drive the Jeep in the rain (no top). I do wash it pretty throughly so I could have killed it with the garden hose.
The brake fluid has been run through several times over the past two years for various reasons. Mostly due to brake lines being disconnected for some type of repair and the system needing to be bled. I never just bleed one wheel, I do them all....usually 2 or 3 times before it feels right.
Could bleeding them excessively cause damage? I can't picture what happens inside the MC when the pedal goes to the floor and the push rod buries itself in the MC. Any chance of damaging something there?
Either way, I ordered a new MC from Kaiser Willys today.
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Condensation from being outside? Cap gasket lets water in? Keeping it full will help with condensation. Fording it is bad on everything. When the military did fording tests, I've heard the mechanics *. Took them 3 days to get the water out of things. John
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The Jeep resides year round in a heated garage so condensation is unlikely. The cap gasket is in pretty rough shape so if water got in anywhere that's probably the point of intrusion.
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Well, when you get the old one out you can take it apart and see if it was corrosion or just degradation of the rubber seals....moisture could get in through the boot too...
For what it's worth, I used some NAPA synthetic brake fluid, it's not silicone, but it's not suppose to attract moisture like DOT 3. I have no idea if it works as there is nothing to compare it to...but I have neither submerged or washed my jeep...yet :D
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It's a little frustrating to hear it leaks after only a couple years. I have an old leaking one on ODie, a new one on the black 2A, and a leaky one on the current project, Whitey. I was hoping you would rebuild yours so I could follow along. ;)
Tim
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Honestly, all three "new" master cylinders I've installed ,both NAPA and I really don't know brands, on different jeeps have seeped out the push rod boot.
Last year,� I dug out an old Wagner master cylinder and rebuilt it using the napa kit after the brake pedal starting sinking to the floor with my last "new" replacement, it must've been built to Chinese good enough dimensions, so it was unrebuldable with the kit. Knock on wood!! The rebuilt one is still working! (and seeping just a little bit, lol)
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Well the new master cylinder lasted 4 months and about 3,000 miles and as of yesterday is puking fluid around the plunger boot at a fairly alarming rate. This is the 2nd MC that has given up the ghost after roughly 3,00 miles.
I don't see how any water got in to damage anything. It was installed back in May and I've lazily only washed the Jeep a handful of times this summer. I have not driven through any standing water.
I have ordered a new MC and a rebuild kit. I want to slap the new one in to keep me rolling (and stopping...) this fall and I'll do an autopsy on the one that comes out. If I can rebuild it with the kit I'll keep it on the shelf. At the rate I'm going I'll need it again in 3,000 miles or so. Kind of a bummer that oil changes and MC changes are on roughly the same schedule
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What kind of brake fluid are you using?
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DOT3
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Tonight, I discovered the baffle had fallen out of the MC cap. With the baffle gone it was allowing brake fluid to squirt out of the cap vent hole every time the pedal was depressed. That explains why I had multiple brake fluid puddles under the jeep. The fluid was spraying everywhere and then dripping down from multiple points, instead of just directly beneath the plunger.
I fished the baffle out of the MC and snapped it back into place in the cap. It seems pretty secure but I'll keep an eye on it. I'm planning on a significant amount of cautious driving tomorrow so we'll see how it holds up. I'd be pretty happy if it turns out that was the only leak and that I won't have to swap MC after all.
Here's a pic of the cap without the baffle next to an old crusty one that still has the baffle in place.
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And then what happened?
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Go dual MC and use R&Ps kit while you're at it. ;)
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I rolled another 180 miles over the weekend and no trace of any leaking brake fluid. I think it is safe to say it was all coming from the cap. At least now I well stocked in the MC spare parts department.
And, Nate, not ready to throw in the towel of defeat and actually upgrade anything just yet. :-)
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Half the fun of an old Willys is how hard you have to push on the brake pedal. Helps keep you sharp...and from doing stupid stuff. Like...tailgating. ;D
Tim