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Post by backwoodsLJ on Sept 4, 2011 16:20:36 GMT -4
-------------------------------------------------------------------------------- He's a brain thought for the mechanic inclined body's.The brakes stuck on the KJ yesterday all 4 and had to pull off and let cool down twice so we could continue home.When we left the last time they never stuck again.Checked the slides today and all are greased liberally and in great shape.All pads are new and rotors new and smooth.Pulled cap off reservoir and cap diaphragm is swollen as you will see in pic.This tells me that fluid is contaminated in some way.Not good.Did a test as brake fluid is not oil based and power steering is so if oil is detected it will float to top when mixed with water.Reading abit on PC and if system is contaminated they say all parts with rubber will need to be replaced.Master cylinder,flex-lines,calipers etc? What do you guys think.Could I try just master and flush system and see what happens?Give me your thoughts?Is it to late? Fluid on left is from KJ mixed with water and has risen to top.Middle bottle is new fluid from a bottle mixed with water and far right is water mixed with fluid from ZJ and is not rising to top but mixed evenly.Cap on left is from KJ and swollen from oil? and cap on right is from ZJ and exact same cap...  |
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Creepy
Administrator 
Dartmouth
Posts: 18,718
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Post by Creepy on Sept 4, 2011 19:00:29 GMT -4
got any idea how it got so contaminated with water?
Cap on loose for a long time?
I'd probably flush the system with a vacuum sucker at the wheels, then try new fluid without changing any parts.
If that didn't work, new master.
I'm not sure if brake fluid decomposes to water when exposed to air, or if it attracts moisture from air when exposed. Whichever it is - its probably the master cap that is the original problem.
did you just buy this rig? Been sitting for a long time? maybe the cap wasn't on right.
Good luck!
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Post by backwoodsLJ on Sept 4, 2011 19:23:15 GMT -4
Sorry Creepy did not explain right.The water was only a test from tap.If there was oil in brake fluid it would rise to top in water.If not basic brake fluid would just mix with water and not rise.Showing that there was a problem maybe.The ZJ brake fluid was out of my DD ZJ for test purposes only.The Kj fluid was the only one to rise to top like oil would do in water.Brake fluid normally does not contain any oils so? Oh explain a vacuum sucker? So I can use maybe to flush?
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Post by backwoodsLJ on Sept 4, 2011 19:27:40 GMT -4
The Liberty we just bought a week ago.Brakes are all in great shape and new.But all brakes stuck yesterday so thought it may be the Master Cylinder at fault till I seen the cap and how swollen it looks compared to my ZJ cap?  |
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jrm
Jeeper
Posts: 229
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Post by jrm on Sept 4, 2011 19:39:51 GMT -4
I have seen a master cylinder cap do that before. I would say that there was something other then brake fluid added to the the system. Try to clean all the fluid out of the master cylinder with rags or whatever. Then refill and bleed each line from there. You can do that two ways, like Creepy said with a vacuum bleeder at each of the wheels or just the normal way by pumping up the brakes and cracking the bleeder screw. Good luck from there! www.princessauto.com/workshop/hand-tools/automotive-tools/auto-repair/8050832-vacuum-pump-brake-bleeder-kit |
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Creepy
Administrator
Dartmouth
Posts: 18,718
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Post by Creepy on Sept 4, 2011 19:57:52 GMT -4
vacuum bleeder kit is what I meant. you can see when you start getting clean fluid, its a lot better than gravity or 'crack and bleed' to flush a system.
They are a bit pricey tho. Should be $20, but they are $50-$70.
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Post by backwoodsLJ on Sept 4, 2011 20:37:50 GMT -4
93 grand is not far from here,he has a vacumm bleeder he will lend me so will try to flush and refill with new in a.m.Wondering though if the cap swelled that much what would seals be like in master or even flexlines to brakes.They are rubber also could they be swelling and not allowing fluid to return to bottle and thats why brakes stuck?I guess I will flush and refill and bleed and see what happens?  |
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Creepy
Administrator
Dartmouth
Posts: 18,718
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Post by Creepy on Sept 4, 2011 21:14:13 GMT -4
Yeah, flush/fill is kinda the first step before spending $$$ on replacing everything.
look for little black crumbs during flushing...its broken down rubber, bad sign.
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