I am at my wit's end with these brakes!

[KDMatt]

Hi folks, thank you for the mountain of replies and support.

The calipers are mounted correctly, and shoes are adjusted as described in a previous post (as in, just barely dragging on the drums.)

In response to another question, this whole debacle began after one of the seals on a brake cylinder in the back went out (as in, burst completely,) prompting me to simply replace both rear brake cylinder units.

I've recently been in touch with one of my fellow Z-owners up here in Minnesota, and he's advised me to systematically go through my brake components to try and narrow down the source of the problem.

Today I plugged the outlets on my master cylinder and gave the pedal a bit of a squeeze -- tight as can be! At least now I know my master cylinder is A-okay. I guess I'm just going to keep moving down the line with my plug-bolts, and hopefully narrow lines and components down until I've found my culprit. I guess it beats blindly replacing components, even if they are all dirt cheap.

Any further thoughts?

[Zedyone_kenobi]

Can you describe your bleeding procedure to us all.

I am not trying to be insulting, but perhaps there is a procedural goof up.

[KDMatt]

Can you describe your bleeding procedure to us all.

I am not trying to be insulting, but perhaps there is a procedural goof up.

Sure thing.

I've bled the system three different ways.

The first way, was the modern, "poor man's" solo method -- using a mityvac to suck fluid through until there was no air coming out of the bleed screws. I started with the rear passenger side, and worked my way around, ending with the front driver side.

(As an aside, next time I will probably start with the rear driver's side wheel, as the FSM makes it look like there's more brakeline between the master and that wheel.)

The second way was the old-fashioned way -- Girlfriend got in the car, I'd open up the bleed screw a bit, have her push the pedal down, and when it was all the way to the floor, tighten up the screw again, tell her to let the pedal back up, and repeat the process a few times.

I was getting clean bleeds using both methods (albeit the second method was a bit faster...)

When neither of these bleeds (after multiple attempts) yielded any good results, I finally took the car to the shop and had them bleed it. They used both a pressurized (top down) power bleeder, AND gave it an 'old fashioned' bleed themselves, and still couldn't do much for me.

I guess I'm inclined to believe that at, this point, I've got the "proper bleeding" thing just about covered. However, I've been known to be wrong before.

[Marty Rogan]

Matt,

I had a hard time bleeding brakes on my Z after installing the Toyota 4x4 calipers. Here is a copy of the post I did back then:

I feel your pain. I had one hell of a time bleeding my brakes after putting the conversion on.

Make sure you thoroughly bleed the master cylinder first. Thne move to the right rear, left rear, right front, and then left front. I also had to crank up the rear drums a bit more.

If that doens't do it, try this racer trick that Rick taught me. Once the brakes are bled all around, go to the right front, remove the outer brake pad, open the bleeder screw, then take a pair of lock jaw pliers and force the pistons in. Be careful not to push them past the seals. Put the pad back in and do this to the inner brake pistons. Then repeat on the left front. I was amazed at how much extra air I forced out of the calipers.

Once I got it bled correctly, the brakes are killer!

I also highly recommend installing SpeedBleeders on all 4 corners and the master. It will make your life much easier.

Hope this helps!

Marty

[Zed Head]

The calipers are mounted correctly,

Marty Rogan's post on the racer's trick reminded me that, where air bubbles are concerned, you might be missing something. Others have found that, although the bleed points looked like they were correct, they weren't actually at the very top of the cylinder, where the air bubble is. You might have two choices of up or down, but the "up" is not the "top" where it has to be. Some people have removed the calipers and repositioned them so that the bleed point was definitely at the top, then bled them with the calipers unbolted. You just have to make sure they squeeze on the rotor, or insert a block of wood in to the space.

The racer's trick probably works because it squeezes almost all of the fluid out of the cylinder so the bubble gets pressed out even if it's not at the top.

[conedodger]

Recheck your rear wheel cylinders. Mityvac method can wreck the seal...

[KDMatt]

Update: I had to spend a bunch of time away from the car all last week following my most recent post (the weather here simply got too frigid), but I was able to spend all day with her on Monday, and here's what's going on.

I've been using my associate's suggestion of blocking off different lines and fittings at a time, trying to find the culprit to my woes. Even though I made new flared fittings to go on my master cylinder, it turns out that one of them was not up to par -- I had a pretty significant leak coming out of the rear circuit/fitting here, so I've replaced that. I moved on and reconnected the front driver's side line, letting fluid move to the caliper there. Using the "racer's" method described above, I bled the caliper, and the pedal was pretty stiff with just this one connected. I then reconnected the passenger's side front line and bled this one as well, pedal still seems nice and stiff.

I've got nearly everything hooked back up again, save for the rear brake line, we'll see how this goes.

Moral of the story is, I think my front lines are alright. I'll re-check the fittings for leaks before I move onto the back ones and see what I turn up.

Also, how much pedal play would you folks say is normal with a well bled system? Right now I'm getting maybe an inch to an inch and a half of travel before I can't really push it down any further. It feels a bit different than I remember it feeling before all of this began... but then again, I've essentially got an entirely brand new system now, so I don't have a point of comparison anymore. Suffice to say, this is a pretty substantial improvement so far.

Thanks for sticking with me everyone.

[KDMatt]

Okay, so I just got the rear brakes hooked back up, and bled 'em. I moved a pretty sizable bubble out of the rear circuits, and nothing is leaking as far as I can see, so now everything is bleeding cleanly. I fired up the car (wheels are still off though, so no driving), and with the assist from the booster, the pedal still feels a bit spongey. The pedal goes about half way down its travel, if not a bit more, with the booster.

[beermanpete]

Be carefull trying to evaluate the brake pedal feel without actuall driving the car. If you get pressure and it does not pump up go drive the car. When you are not driving it is easy to push harder than actually required to stop the car and then think the pedal is spongy.

[carrott]

Do not test drive on road if brakes dodgy , bad advice ! . I would check that the reaction disc behind the master cylinder to the booster has not slipped out when you had it out ,you will see it sitting at the bottom of the diaphram , I had a similar prob once with exact same symptoms . Worth a look.

[Travel'n Man]

After you have tried the above post.....

My bleed rotation is:

Driver Side Rear

Passenger Side Rear

Passenger Side Front

Drivers Side Front

Give that a shot - FWIW.

[John Coffey]

The second way was the old-fashioned way -- Girlfriend got in the car, I'd open up the bleed screw a bit, have her push the pedal down, and when it was all the way to the floor, tighten up the screw again, tell her to let the pedal back up, and repeat the process a few times.

Bad. Have her push the pedal down first before cracking the bleed screw.