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Whenever I wheel my brakes go spongy. Whenever the jeep gets on an incline or sideways I have to pump my brakes. I've bled the brakes several times. I installed a larger bore MC a while ago and bench bled that.

Brakes worked fine until I swapped in the new D44 front axle. Since then they are spongy off-road. The brakes always work fine on the flat road. Front brakes are Ford single caliper (5 lug). Rears are Ford 11" drums. Prop valve is stock wrangler. Any ideas?
 

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keithroo said:
Whenever I wheel my brakes go spongy. Any ideas?
Mine get a big spongy too after a day of wheeling, found out the exhaust pipe is heating up the proport valve. Are any of your brake lines running close enough to the exhaust to heat them up?

Just a thought..
 

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I've noticed the same thing on several occassions... doesn't happen all the time...
The first and worst time it happened, I checked my fluid level while still on the hill and it was low... Off course all the fluid was at the back of the MC... meaining it was REAL low at the bottom of the resevoir..

My theory is if your MC has room for the fluid to slop around while at an extreme angle, and you hit the brakes you could possibly push some air instead of fluid....
Just my 2cent theory....
 

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Dot 3 will also absorb water and cause a spongy feeling because water compresses differently than brake fluid. DOT 5 has a low absorbtion rate. Make sure to drain the complete system to prevent contamination!
 

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I had the same problem with mine when we put it back on the road a few years ago, went thru changing m/c,prop. valve,calipers, line sets,hoses and fluid same problem great when flat to the floor when angled. Wound up taking the calipers off making wooden blocks to hold pads in turning calipers different ways to get the air out. Do you have any place built into the line set that can trap air? I hope this helps because I'll have to do it again broke a brake line the last trip.
 

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Is it really related to the angles, or just going slow? Is it possible you notice it at the angles because that's when you are using your brakes?

Anyway, I suspect it could have something to do with low vacumm at slow speeds.........
 

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Is it possible that the master cylinder is not big enough for the new front end? As long as you are flat, the fluid level would be covering the draw hole. But when you are at an angle the front end has pulled enough fluid so that you have an exposed hole and are sucking air!!!
 

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Mine does the same thing with dana 44's on my zuk. I can stop faster than a stock zuk but off-road mine suck at angles. I am going to try the larger early 80's master cylinder off of a Firebird and see if that helps. So when I get mine ready to wheel again we will see if that helps.

Not much help at the moment but an idea.



L8rz

Chris Minerbitch

And yes I know it needs tubing :flipoff2:
 
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