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View Full Version : kung-fu on fire!



chopshop
01-18-2005, 09:08 PM
I run a 93zj, copied AlaskaZJ's kung-fu brakes pretty much exactly. only difference being rear discs are 95xj with '88xj calipers/pads.



so I thought I had a sticky front brake caliper a few days ago, then driving to work tonight on the highway, big time dragging from the brakes.

could bearly keep up speed, then had to pull over. brake pedal was hard as a rock. let it cool down for a minute or two, then made it to my exit.
had to use 1st gear n 4x4 to keep it moveing.

pulled over again, it stinks like burning brake BAD!! get out and look and the goddamn rear rotors are full cherry red and shit is on fire under there!!!! fronts rotors are not as bad, but are still burning up.

so I hop in real quick and plow through a bunch of snowbanks to cool it down and put out the fire. it works, I didn't blow up!!!

brake pedal still hard as a rock, and brakes seem fully, all 4, stuck on.

WTF happened?

after sitting for a 12hr shift in -10C, the brakes weren't stuck on and seemed ok. I can get home without brakes or people around at that time of day, so I went for it. made it. 25min highway drive.


any ideas?

MaineZJ
01-18-2005, 10:15 PM
all parts new but the rotors and calipers?
maybe the rotors were too wide for the calipers?

OverkillZJ
01-18-2005, 10:36 PM
PICS OR BAN!

chopshop
01-18-2005, 10:38 PM
I've been driving it since dec.24, and mostly all new parts.
used xj booster, and regular d30 front brakes in good con.
rear is all new.

I'll double check rotor width, but don't think that's the problem.
it sets up nice, plenty of room it seems.

I'm going to bench bleed master first, then bleed lines.

when I first put it all together, there was dead swing in the brake pedal, then it would hook up the brakes. it kinda went away......

so maybe there is air in the master. Also maybe I should lengthen the little rod from the booster. I can't find any info on this having to be done with this swap, but it would explain the pedal doing nothing until it swung down a bit. but this went away after a day or 2.

edit: :arrow: all brake swap pics are in this thread
http://www.mallcrawlin.com/phpBB/viewtopic.php?t=891

OverkillZJ
01-18-2005, 11:28 PM
... didn't you cook the calipers if they locked up to red-hot?

JpRngr
01-19-2005, 02:08 AM
Take it for a short test drive. When you get back, jack it up and see if any of the brakes are still applied. If so, loosen the bleeder screw at said wheel. If there was pressure inside the caliper and afterwards the wheel is free, you have a problem besides your calipers(like a MC holding pressure). If it is still bound up after opening the bleeder, you have a caliper problem.

Also, sounds like you had a misadjusted pushrod between the booster and MC. I guess it could be possible that it might now be lodged in there if it was too short to start with.


Corey

chopshop
01-19-2005, 02:27 AM
sounds like a good plan.

I bled the master and adjusted the pushrod out 1/8". no dead spot at the top travel of the brake now.

when bleeding the master, got a pretty big shot of air at the last bit of travel. maybe from where the pushrod wasn't reaching.

i got it out for a test, seemed ok until some heavy highway braking, then they were dragging pulling away from a light shortly after.

I'll get them hot tommorrow and try the bleeders.

thx.

chopshop
01-19-2005, 01:29 PM
ok. tried the bleeders when the brakes were stuck on. the pressure released. so I got another master, trying that now.

thx.

chopshop
01-19-2005, 04:39 PM
talking to myself....

sourced and modded new master, bench bled, installed, bled all brakes.

took it out, a bit better, but not all the way. brakes still dragging.

set pushrod 1/8 BELOW stock, brakes not dragging now after a short test run. I had it 1/8 over stock.

So I guess the pushrod was out too far, and in effect, the brakes were always on.

it is important to note that a little goes a long way on the pushrod adjustment!!!! I think too that I didn't have all the air out of the first master.

i hope it's fully fixed.

Peak ZJ
01-28-2005, 10:47 AM
I ran into the same problem with that setup.. Had the f'n push rod out to far.. Luckily I found out on the trail...