Toyota Caliper going back to stock

[manny1973]

I have read most all of the info on the toyota caliper change over. I put new toyota calipers on my 72 Z. Brakes work fine, not much better than the stock calipers but my brake pedal is way down and I can't get it to come up. I hate it and think I should go back to orginal to get good pedal feel. FYI, I changed the master also to a larger one from a later Z, no help. Any suggestions before I go back to the way it was.

[WW2Winger]

Search the words "reaction disc".

[manny1973]

Should have mentioned. Have checked the disk and it is also good. Still there and the master vac is also new.

[240ZMan]

my brake pedal is way down and I can't get it to come up.

I'm assuming this means that you have to depress the pedal farther than you used to before the brakes begin to engage.

If you haven't already tried this, with the engine off and the car stopped, depress the pedal several times until the vacuum assist is used up. If the pedal stops near the top as it should, then the rotors probably have too much runout. You can shim them, or replace them. You might get away with turning them, but I wouldn't recommend it.

Another possibility is excessive play in the wheel bearings. You didn't say if you made any other changes when you installed the new calipers, but if the wheel bearings aren't properly torqued (too loose) then you can have this problem as well.

In either case, changing calipers wouldn't solve the problem.

Other than that, a 15/16" MC along with the Toyota 4x4 calipers shouldn't result in the pedal going down an excessive amount. Mine doesn't.

[manny1973]

Daniel, Thanks for the reply, I have new rotors, calipers, pads and wheel bearings. I'm stumped. I'm in Colorado Springs, we should get together some time.

[240ZMan]

Manny, I'd be careful of assuming that just because a part is new that it is defect free and/or properly installed. Please try the test I suggested and let us know what you find.

There is a group of us in the CO area who own older Zs and have an informal email list and occasionally do a drive. PM me with your address and I'll be glad to add you.

[jmortensen]

The problem is that the 4 piston calipers have a much greater volume of fluid than the stockers. So when you put the 4 pots on you need more pedal travel for the same amount of piston travel at the caliper. Solution is to use the ZX master cylinder, or like you said switch back to stock calipers. I've never run that setup, but I'd wonder about the ability to get the bias right. It's tough to do with ZX rear disk setups, so I'd imagine the fronts would be way overpowered with stock drums too.

[JimmyZ]

Just taking a few stabs/throwing some ideas out. I havent used Toyo calipers on a Z but have toyed with lots of brakes over the years.

Silly question but have the master cylinder or brake lines been changed? If so then you might have swapped the front and rear circuits on the MC depending on what year it is. That might affect things a bit.

A disc that is too thin, pads, shoes or drums that are worn will cause increasing amounts of pedal travel. If all calipers/wheel cylinders require minimal travel to brake the pedal will be higher. When you say the calipers are new do you mean that they are the Toyo calipers or something equally as thick?

Also.. Are the rear brakes working properly? Is there a fluid leak? If your rears are not bled and/or out of fluid this would also cause the pedal to go down more.

On stock 240Z caliper it's possible to install them wrong by swapping sides. This puts the bleeder on the bottom of the caliper. It won't bleed as trapped air can't get out. You might be able to get most of the air out but will find that "perfect bleed" unobtainable. Are the bleeders on your Toyo calipers on the topmost side?

2c

Jim

Edited December 4, 2008 by JimmyZ

[manny1973]

The car stops just fine but the pedal does not grab until it's almost completely down. I will try the suggestions from Daniel the 240z man this weekend if it's not too cold out. The caliper bleeders on on the top. I have new stainless steel brake lines that replaced the rubber lines. I have new rebuilt rear cylinders also. Brakes seem to be working correctly. When I lock them fronts lock and the car goes straight. Does not pull. I have bled the system three different times.

[JimmyZ]

The turnbuckle on the mastervac... (brake pedal height) adjusted right?

[Arne]

Did you do the rear brakes at the same time? I'm wondering if the rears are way out of adjustment.

[Jack T]

Manny I recently changed over to the Toyota caliphers and upgraded the master cylinder as well. I had the same problem, no matter how much I bled the brakes (after bench bleeding the master cylinder) I still had too much travel before the brakes would start to grab hold. What I discovered was that an adjustment needed to be made in the rod extending from the vacuum booster to the master cylinders. You may want to unbolt your master cylinder from the vacuum booster and turn the rod counter closkwise a few turns and see if that does the trick. It did the trick for me, picks up according to spec now.

Best regards,

Jack T