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Discussion Starter #1
I tried "search" not working..

I just did a '02 TJ Dana 44 swap into an '97 TJ Sahara, automatic

the swap was a no brainer... I thought, and I had no issues except I can't get rear brakes to work

The facts I know:
we did a complete F & R swap to achieve higher gears (4.88) and get rid of the Terdy Five rear, the donor Jeep was a functional '02 Sport, no ABS, drums rear, (the brakes worked on it before swap!)

The receiving Jeep is a '97 Sahara, auto, no ABS drums in rear
the shoes have been adjusted from, to very tight, to very loose
the parking brake works normal, the rear hard lines and flex hose are the original '97 in good shape "and same looking as donor" I even tried another tj flex line

what I tried:
-gravity bleed whole system
-2 man bleed whole system (Jeep off)
-2 man bleed whole system (Jeep running for booster) at least 4 times, when bleeding rear I got what seemed to be normal fluid and pressure from wheel cylinders (I don't have a line pressure gage)
-swapped in a known "good" master and power booster from another '97
bench bleed master, with good results

When rear axle is on jack stands after all above, you can push brake peddle as hard as you can when ideling in drive and it won't stop rear drums, the parking brake will.

What have I missed? proportioning valve, clogged line, wheel cylenders?????
 

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Discussion Starter #2
I do get movement from the wheel cyl's but not enough pressure to stop
 

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Discussion Starter #4
Yea I hear ya, I've used about 80oz of fluid so far

I don't have a vacume/presure bleader, I have used big shop type in the past and if I remember correctly you need an air supply, I don't have :eek:

would one of the small hand vacume bleaders work? or should I keep 2 man bleeding
 

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Front brakes work good? Any chance air could have gotten inside the master cylinder? Worked when it was taken out, how long did the axle sit, a year, one week? What about your front axle, what type did u swap in? Does that have bigger brakes as well? It might be a proportioning valve issue maybe.
 

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Discussion Starter #6
front axle is out of same '02 (dana 30) same calipers as '97 and they work well (they stop the Jeep alone!)

The axles were disconnected from a running jeep for less then 24hrs

Air in master,?? the first master never drained or had fluid pushed in, the second master was drained cleaned, bench bleed till no air in streem

prop. valve??
I'm about to remove it and take apart and check, anyone know if there is a check valve or something that may blocking rear pressure? the prop. valve is the original 97, never removed

Thanks for the help!

Front brakes work good? Any chance air could have gotten inside the master cylinder? Worked when it was taken out, how long did the axle sit, a year, one week? What about your front axle, what type did u swap in? Does that have bigger brakes as well? It might be a proportioning valve issue maybe.
 

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Might be a dumb question, but when you did the gravity bleed, did you go in the order of the farthest point away from the master cylinder to the closest? IE. Passenger rear tire, drivers rear tire, passenger front, driver front?
 

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did you make sure the adjuster in the drum are tightening instead of loosening??? i accidently switched the adjusters from left to right and had that problem, by the time i bleed the brakes they were adjusted way to loose to even make contact
 

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JUST IN CASE you are using Russel (earl's?) speed bleeders, take them out and throw them as far as you can.

MY buddy and I spent DAYS trying to bleed the brakes on his TJ, and changed out the WHOLE friggin brake system, with the same results...no pedal.:mad3:

Finally we discovered that the springs that return the little valves to closed when you release the pedal were STUCK OPEN.

Changed the bleeders to NORMAL ones and it bled immediately.:shaking:
 

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Lightly clamp the rear brake hose shut. step on pedal. If the pedal is now OK the problem is at the axle. If still real soft the problem is at the front.

If front, pull the lines at the master and screw a couple of bolts into the holes and step on pedal. If soft, the master is at fault. If rock hard look at the propotioning valve sticking.
 

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Discussion Starter #13
Let me see if I can update and answer some of the trubble shooting Qs:

First, the pedel feels normal after any type of bleeding, (not soft), almost as if a valve has closed to rear line after bleeding

these are stock jeep wrangler axles, no mods, calipers and wheel cylinders in place like stock (nothing was taken apart) (stock bleeders) (drums adjusted correctly)

it had a power bleeder hooked up to it (by someone who knows how to use it), and STILL NO rear brakes

**on the original gravity bleed: I opened rear first then front (not sure of R/L order) when pressure bleeding, I always start from farthest to closest

I haven't removed and opened/cleaned the propertioning valve yet, is it possible some crap got in there and is blocking the rear orifice, or a safety valve has diverted all pressure to front??
 

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i wopuld double check the MC. Any chance when you removed the old MC any other substance got in? Also why did u remove the old MC? I believe the prop valve is teh same for both 35 and 44 (at least mine was). I woudl try bleeding again, and since you did teh sawp you may know the basic, but start from passenger rear, driver rear pass fornt and driver's front. I normally use a fishtank clear line, and doa two man job, I am not too crazy about the forced beeders.

Good luck!
 

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When the power bleeder was hooked up, here's what I did:
-10psi, held it the entire time
-cracked rears, no air at all
-cracked lines at master, seemed normal
-cracked prop valve, seemed normal
-re-bled backs, no air.
I unhooked it and checked the brakes, pedal was high and hard, I could rotate the tire(with my hands) with the brake pedal depressed though:shaking:, parking brake stopped the tires.
I re-hooked up the bleeder, rebled the system again. Unhooked it and same result. All brake lines are ran correctly and the front brakes work great.
BTW, I have used this bleeder to fix hyd abs systems(air in pump) and many standard brake bleeds. Everything seems correct, except the rear brakes are not working.
 

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Discussion Starter #16
Thanks guys!

reason for putting on a known good master and power booster was, it was available and out of a 97 TJ Sahara, it was one of the first things I did when the rear would not function (no cost 1/2 hr swap to rule out two things) after swap there was no change.

any substance that could of got in lines when transfering a fresh bench bleed master was some air in lines (lines were hooked back up within 1 minute)
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i wopuld double check the MC. Any chance when you removed the old MC any other substance got in? Also why did u remove the old MC? I believe the prop valve is teh same for both 35 and 44 (at least mine was). I woudl try bleeding again, and since you did teh sawp you may know the basic, but start from passenger rear, driver rear pass fornt and driver's front. I normally use a fishtank clear line, and doa two man job, I am not too crazy about the forced beeders.

Good luck!
 

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I know this is going back...............But...... did you readjust the rear calipers to take up the slack they might have had when they were on the other rotors?
 

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I haven't removed and opened/cleaned the propertioning valve yet, is it possible some crap got in there and is blocking the rear orifice, or a safety valve has diverted all pressure to front??
That could cause the problem. Pull the piston from the front of the prop valve to make sure it's not stuck. If you are pressure bleeding it will ususally push the piston back where it belongs, but it may have gotten stuck.
 

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just scanned teh thread quickly, but you need to adjust the rear shoes until they're just dragging on the drums. I just had this same problem on my CJ, swapped a rear axle and lost brakes. Turns out after assembly, the driver's side rear shoe adjust fell out from between the shoes, allowing full travel at that cylinder, keeping the MC from building pressure in either chamber, and I lost all pedal.

You can try plugging the MC ports...you should get rock solid pedal with this.

I'm not sure how the TJ prop valve works, but i know some valves are designed to check flow to where they think a "leak" exists, IE, if you're trying to bleed the rear, it will attempt to stem flow to the rear line and therefore prevent a good bleed.

good luck
Paul
 
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