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Unread 05-08-2013, 02:25 PM   #1
jdm27
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Axle swap from 1/2 to chevy 3/4 brake problems

hello, im sure there is a post on this but it takes me to long to look through all the threads -.-.

But anyway to the point, i have a 1981 cj7 and i just did a axle swap with Dana 44 and a 14 bolt full floater in the rear, i have a soft pedal after re hooking all the lines up and i have bled all of the lines several times with a power bleeder and then manually. and still a soft pedal. mind you i have put the 71 Chevy booster and m/c and re lengthened the shaft so it would reach the brake peddle. if anyone needs more details/pics/ or anything let me know I've almost tried everything i can think of, and after doing some research i have found that if replacing the front brake lines it is harder then heck to get all the air out of them cause of low power to front calipers.


the proportioning valve reads as if it was working properly.(from the stock chevy m/c) and do i delete out the stock cj proportioning valve or do i keep it and if i keep it how do you properly bleed it?

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Unread 05-08-2013, 05:24 PM   #2
jason m
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Your feeding 3/4 ton brakes with a 1/4 ton master Cyl, why did you expect great brakes? You need to upgrade your master Cyl or at least swap to a TJ. It takes alot to feed large wheel Cyl on that 14 B, or try swapping to rear disc and 1/2 ton calipers, you will at least get some pedel back, but its still not going to be like you want.

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Unread 05-08-2013, 06:59 PM   #3
MisfitSeven
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Rear disc kits are so simple. There are bolt on brackets from RuffStuff. You would be stupid not to. Good luck, and nice CJ!
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Unread 05-08-2013, 07:24 PM   #4
jdm27
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hey jason, its a m/c out of a 71 k5 blazer with 3/4 ton running gear, ive made it so it would fit up in there and replaced the stock one with a stock chevys. and it has the proportioning valve with it (off of the 71 chevy) but still nothing. but im wondering if the stock cj proportioning vavle has something to do with it or that the pedal isnt being pressed in enough cause of the booster and m/c are off the chevy and the rod might not be pushing enought into it but the pedal sits like 6 inches from floor, where from before it was sitting like 5. but still continued to bleed it all day everyway possible and still nothing.
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Unread 05-09-2013, 05:13 AM   #5
TimV
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You have two proportioning valves in there? I would guess that's the problem. Remove the stock one and leave the Chevy one.
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Unread 05-09-2013, 12:54 PM   #6
jdm27
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Quote:
Originally Posted by TimV View Post
You have two proportioning valves in there? I would guess that's the problem. Remove the stock one and leave the Chevy one.
ok i will try and remove the stock one, its going to be some what of a pain in the *** cause its part of the shifting linkage, but i will give it a shot. i will reply with a status update after it is done!
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Unread 05-09-2013, 04:20 PM   #7
TimV
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You shouldn't have to actually remove it, just reroute the brake lines so they go to just the new one.
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Unread 05-10-2013, 11:35 AM   #8
jdm27
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just a quick update, if anyone else has any ideas to throw at me let me know, i wont be able to work on it for about a month. (due to personal reasons) but as soon as i get a chance to i will post an update to see if that worked
thanks guys!
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Unread 07-03-2013, 12:31 PM   #9
jdm27
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another update, took jeep prop valve off and bled for over 2 hours and still nothing. went and got a new m/c and now im getting some pedal but still not a lot. i was also thinking about replacing prop valve with some individual check valves like a 10lb drum for rear and 2lb disc for front.

anyone got some idea just let me know! thanks!
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Unread 07-13-2013, 07:11 PM   #10
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Have you taken it out for a test drive? If you have, how well does it stop?
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Unread 07-14-2013, 07:28 PM   #11
TimV
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Just had a small thought. Are the calipers on the correct sides? With the bleeders above the line connection? If they are not, you will never get all the air out of the system. It's not hard to accidentally mix them up.
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