I have terrible brakes, but why

I agree with putting on the new master cyl with a new brake booster. Still, be aware that this will not fix a pulsing pedal. Make sure to check out the front wheel bearings and other stuff I told you about so that you can fix it all at once.
 
No worries on the high idle, it does that already.

winterbeater - I understand. My main goal is to get the brakes working. I can deal with a little pulsing.
 
you'll need to fiddle with the brake light switch to get it to work correctly with the newer pedal assembly. I swapped a 96 unit into my 87 and screwed up drilling and filing the old switch, and ended up transplanting the entire pedal assembly from the 96 donor into mine as well (my 87 pedal assembly didn't have any provision to mount the newer style contact switch from the 96). If you decide to go with the newer style, you'll see that the contact switch has 6 wires coming out of it, but you only need two of them.....splice them into your existing brake light circuit and you're good to go. I have a pic of mine installed somewhere on my photobucket account, lemme see if I can find it and post it up for you.

Jeff

edit:

brakespring.jpg
 
The way you discribe going that far down to the floor and then feeling spongy is usually caused by a leaking master cylinder, wether its an internal leak or its leaking out back by the booster or into the booster it can definitely cause this. If you dont see a leak at the master cylinder, unbolt it and see if its wet behind it if it is you know what to do.

As for your pulsating brakes it could be as simple as warped rotors, this can happen in many ways, usually by the brakes overheating under hard braking. Or belive it or not you can actually warp them by overtighting the lugnuts, sounds stupid but its true. I would have the rotors turned and put new pads on.
 
bigalpha said:
Even if you replace the PV, BB and MC?

The only things that would be different would be the connections from the lines on the truck to the new installed system.
Click to expand...
Oops... missed that you were going to move the prop valve. You still might need line adapters, depends on what the PV is made for.
 
Regarding Jeff in VAs post, he did not mention the cruise control brake switch, or the upper switch on the cruise control switch that also tells the TCU to disingage the torque converter lock up in the AW4 on the Renix models!!!!!!!


So AW4 versus manual tranny, and cruise control on the two jeeps becomes an issue if you mess with the brake peddle hardware, or try to swap it.
 
I have a '96 Country, and my son has a '96 Classic (born 9-96, a late one?), and we've had similar issues with new cylinders and crappy pedal feel. It feels like there's air somewhere in the system, but after numerous bleedings, we can't seem to get any bubbles. Could there be some air unbleedably (?) trapped in the proportioning block? I've had the system opened on my '92- new line to the rear, new cylinders, calipers, etc., and it feels good, after more than 200k, with the original MC and booster (knock on wood). I wanted for years to upgrade to the newer setup, reading all the threads about how much better it is, and now that I'm going on a year tweaking the '96s, I'm not impressed. Every time I think I have my '96's brakes feelin' good, my wife will take it and later ask if the brakes are OK? I guess that since she's been out of her ZJ for almost six years, and in her Outback, she forgets what Jeepin' is all about!
 
:doh:

Went back out and looked again. Ran my fingers along the boot on the MC inside the cab .. lo and behold, goopy gunky fluid. I suppose this means the MC is bad, haha.
 
Uh oh...... that's rather potent stuff. Make sure you check over that monster connector below it. Brake fluid will soften the plastic in that bulkhead device.
 
Under the dash, the fluid didn't drip our leak out onto anything. The fusebox is off to the side as well.

Against the firewall, there's just a trace of leakage on teh front of the booster.

I'll be swapping in the components from the 99 (PV, MC, BB). Would it be worth it to swap the brake pedal assembly as well, to eliminate the problem with the push rod?
 
Ecomike said:
So AW4 versus manual tranny, and cruise control on the two jeeps becomes an issue if you mess with the brake peddle hardware, or try to swap it.
Click to expand...

Ooops....sorry about that.....thought we were talking about manual trannies here. Nice catch Mike:thumbup:

The entire pedal assy is fairly easy to swap, especially if it's an auto (manuals have an extra piece that extends over to the clutch master and it's a PITA to line everything up if you're doing the work alone). Since I dorked up my original switch, I just swapped the whole sheebang out.

Jeff
 
Luckily, I'll be having a hand to help so I don't accidentally set something on fire.

Since the 99 rod is going to be way too long to fit the 88, we may just swap the pedal assy over instead of worrying about doing a rod-swap.

Can you swap the rods fairly easy, or would it be best to just swap the pedal assy?
 
Not 100% sure but I believe you have to disassemble the entire booster to swap the rods. I didn't see any easy way to do it when I replaced mine.

If your M/C is leaking, you should swap both at the same time. The pedal assembly is held to the firewall by the 4 studs on the back of the booster. You can pull the old master off, then remove the nuts on the booster studs and pull the booster forward to remove the pedal assembly. There's also two bolts # the top of the pedal assembly that thread into the dash that you have to pull as well, and a dash brace or two that need to be loosened and pivoted out of the way to get the pedal assembly out/in.

Jeff
 
Yeah, we'll be swapping it all over at the same time.

Now I'm doing research on what I need to do to make the new PV compatible with the rear brakse.
 
I've been dealing with the terrible brakes in my 89 XJ for a while, I'm interested in getting this resolved. I would like to go to the double diaphragm setup if that works better, than simply to replace my existing stuff with new parts. I just want to be 100% on this... If I buy a brand new booster and MC from a 95 or 96, will I still need to get a pedal assembly from somewhere, or can the factory brake pedal work with the newer booster/MC? Based on photos it looks like they are about the same length?

Edit: http://www.madxj.com/MADXJ/technical/technicalfiles/ARbrakeBoosterUpgrade/BrakeBoosterUpgrade.htm
Based on the pictures and text from Matt Homan on that site, I think the 95/96 boosters have the same rod length? Thinking about going to a local parts store tonight and ordering a new booster/MC from a 96, then I'll just have to figure out the brake light switch. Also are there still the metric/SAE fitting differences to deal with?
 
Last edited:
Be sure and try to stay away from aluminum in the MC body! Even if it is new.
 
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