I have a soft pedal, but if I pump it gets stiff as a rock. Let 10-20 seconds go by and it's soft again. I marked the fluid level of the reservoir, pumped the pedal for a minute and had no loss in fluid .. so I don't think it's a leak. To double check I tried to follow all the lines and didn't see any leaks ... even from inspecting the calipers. So, I think it's purely an air bubble issue.
So, I went to each caliper and bled the brakes using one of those one man brake bleeder kits with a simple hose going to a magnetic bottle. I had ZERO air bubbles push in to there. I did each caliper twice with no luck. Same issue.
So, I'm guessing that means I need to bleed the Brake Master Cylinder? Well, I've seen some vehicles with a nozzle on it for bleeding, but I don't see that on this, just to lines coming out ... so how do you bleed it? And if you don't, what could my problem be?
Now, FYI, I use Toyota axles ... so is the other possibility that it's too small to handle Toy calipers and I need to go to a different MC?

You need to upgrade the MC. There is a link here that lists the different ones used that are direct bolt ins.

According to the following threads, a lot of people report that there is no need to upgrade the stock MC if it's bled properly. So ... if that's true, back to my original question ... what's my problem?

Also, in terms of a swap .. what's the cheapest/easiest MC to purchase that means no more pumping? Ranger sounds like a bolt on, the Civic swap sounds like one too but costs $400 I hear?

You know ... I am hearing a lot of Zuk people say they have seperate Front Left/Right outputs on the MCs? Mine has just two outputs on the side of the driver's side fender well. Is this not a Samurai MC?
Now, I'm so confused after reading all the posts ...

- Someone said the 4 Door Sidekick/Tracker MCs are a direct bolton swap but work great? This would sound like the easiest swap .. but what years work?
- Ranger sounds like a direct swap if you get the Metric/SAE adapters, or if you just run all new lines and put metric fittings on the ends.
- Firebird/Fiero swaps ... similiar to the ranger one.
- Civic/Acura swap ... about the same as the Ranger swap without adapters, maybe a splitter at the most.

So, can someone tell me what truly is the easiest swap to do without running new lines and is reliable (ie a 'standard' feeling brake pedal, that when stepped on locks up the brakes)?

Screw it, I'm doing the Firebird swap, it's easy enough and by far the cheapest when dealing with non-junkyard parts.

http://www.zukikrawlers.com/showthread.php?t=2237

why not the mazda swap?

http://www.zukikrawlers.com/showpost.php?p=25332&postcount=22

this is a link another guy on here shot me. its work a try to check out man. :D i personally have toyota axles, and a sammi, but no brakes yet :p

yeah, I got the same problem when I went to chevy calipers all the way around. I got to do a little -prepump- to get a high hard pedal. I think the problem is that the MC doesn't have quite the volume to close bigger brakes. we need something with more volume, a bigger MC. of course, we could just bore it out and make a new plunger rod.......

but seriously, I'd like to know the easiest and best thing to swap in, too. post up on how the firebird swap goes...

hey, post up on those adapters for metic to sae. I'll need to get some too. I didn't know the 'zone had some adapters like that. I'll be checking that out soon.

yeah, I got the same problem when I went to chevy calipers all the way around. I got to do a little -prepump- to get a high hard pedal. I think the problem is that the MC doesn't have quite the volume to close bigger brakes. we need something with more volume, a bigger MC. of course, we could just bore it out and make a new plunger rod.......

Hey cajunsuzukispider, I just read a thread that katoom started (which mastercylinder/brakebooster) and you replyed that you was running a stock MC. and you had no problems, (brakes work great.):shaking: :shaking: and then a couple of post down you posted this reply. Is this some more BS.? :confused: PS. I have been running a firebird 4 wheel disk for a few years with no problems.

You know ... I am hearing a lot of Zuk people say they have seperate Front Left/Right outputs on the MCs? Mine has just two outputs on the side of the driver's side fender well. Is this not a Samurai MC?
Now, I'm so confused after reading all the posts ...

- Someone said the 4 Door Sidekick/Tracker MCs are a direct bolton swap but work great? This would sound like the easiest swap .. but what years work?
- Ranger sounds like a direct swap if you get the Metric/SAE adapters, or if you just run all new lines and put metric fittings on the ends.
- Firebird/Fiero swaps ... similiar to the ranger one.
- Civic/Acura swap ... about the same as the Ranger swap without adapters, maybe a splitter at the most.

So, can someone tell me what truly is the easiest swap to do without running new lines and is reliable (ie a 'standard' feeling brake pedal, that when stepped on locks up the brakes)?

Did you change the brake line configuration on the frame? They are front and rear hooked together from the factory. You'll need to swap a couple of lines around to change it to front on one line and rear on the other.

The rig has been through at least 5 owners .... so there is not much left of the original design.

In terms of the brakes, the MC has two line outputs on the right side (when looking from the front of the rig). From there, the lines cross over to the passenger side and move in to a splitter unit with 4 brake lines coming out of it, each of those go to the appropriate caliper/drum. The unit doesn't look adjustable from what I can see.

I think I'm just going to have to go for the Firebird one, then get an adjustable proportioning valve, and finally run new brake lines if things are crap. It's ok .. its just an excuse to rebuild the brake system so I know it won't fail on me in the future.

The line splitter on the pass frame rail is part of the problem. You're feeding all the brakes into a system never designed to equalize pressure like it does. Make sure the fronts are on one circuit and the rears are on the other. I did that, added a Wilwood MC and once bled, my 60s would lock up the 39.5 Swampers with about half pedal.

Well, the 1980 Pontiac Firebird MC for 4 wheel discs is $25 w/ shipping from Autozone. With either refitting or $10 in SAE/Metric adapters I'll have it hooked up and that will help a lot. Next step is to pull off that Proportioning Valve and put on an adjustable one. Also, It's obvious that the brakes have been replaced because the 4 way splitter is not on the frame .. its on the firewall by the battery ... so someone felt the need to change things at some point. Time for me to fix it ;)

I have toyota axles with disc/drum brakes hooked to a stock 87 Sami brake system with zero problems. If your master went dry at some point in time, you must bleed it. It can be done on the truck, either by pumping up the brakes and cracking each line until you get solid fluid, or disco the lines and use bleeder hoses run into the res and full stroke it slowly until no more bubbles. When you put on your new master, use method #2. If your rear pinion is pointed at the sky, you will want to level the axle so the wheel cyls are level front to back so all of the air can be bled out. You need to decide what is wrong with your system, don't just throw money at it.
Travis..

will the firebird and mazda M/C's work if you're not runnng disc brakes in the rear?

So, on your 87 Zuk, does the pedal feel stiff, or does it go to the floor and then lock the brakes? I hear most people saying that's how it feels. Well, I honestly am willing to spend the money to get the pedal to feel stiff again, AND I do plan on going for rear discs, so I figured I'd be willing to rebuild the brakes to do them right ... honestly, the guy who had this rig before me was an idiot so I don't mind being forced to redo things so I can be sure that it works when I need it to.

No pedal pumping issues with mine, high and hard. It feels just like it did on stock axles. The only thing I'd consider doing to mine would be to put adjustable prop valves on the rear. I have a touch too much rear brake. It is only an issue when I do a panic stop. I rarely drive mine on the street, so I don't worry about it. I think the rear locking in a panic is because the rear unloads so much due to soft-ish springs, not a brake system issue.
Travis..

Honestly, there's a good chance my MC is going out. And, I plan to just replace it this time with something bigger. I figure, if I have to swap it out, might as well do it this time with a bigger one ;)
Now for a good question though, where are you guys getting your proportioning valves from? If from a standard auto parts store, got a part number like for Napa?

Honestly, there's a good chance my MC is going out. And, I plan to just replace it this time with something bigger. I figure, if I have to swap it out, might as well do it this time with a bigger one ;)
Now for a good question though, where are you guys getting your proportioning valves from? If from a standard auto parts store, got a part number like for Napa?
Summit racing is where I got mine. But I think Jegs has them also. PS wilwood makes them