Toyota Caliper going back to stock

[manny1973]

I did the rears at the same time as the fronts. When I adjusted the rears I tightened until the drums started rubbing on the shoel I think they are tight enough but not sure. The brake pedal height seems right, it matches the clutch pedal. Can look at the turnbuckle but that is tough to get at.

[manny1973]

Jack T, I did not move it out when I installed the new master. I will try that also. Good idea.

[Zs-ondabrain]

yup, same problem here. I needed to adjust the screw on the booster to basically touch the MC as soon as the pedal was pressed lightly. I also adjusted the rod on the pedal to my own liking.

Much better now,

Dave.

[WW2Winger]

Since you said that it "stops just fine", it would appear to be a linkage issue since the only real problem is where the pedal is when the brakes take hold. The adjustment of the rod or the pedal clevis should achieve what you need. I am in the middle of the conversion to the larger MC and I am interested in the results of your project. Please keep us informed.

[jmortensen]

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.

You're comparing apples to oranges.

When driving my friend's Z with the 4x4 calipers and stock master the pedal is mushy and the travel is longer, but this is because she has a smaller diameter master. That would fit just perfectly with how a smaller diameter master should feel compared to a larger one. Smaller = more pedal travel and less pedal effort. Larger = firmer pedal and more effort required.

A side note about this adjustment too. When this adjustment is made there MUST be free play in between the pin in the booster and the back of the master. I'm sure there is a spec in the FSM, but don't cut it short thinking you'll improve the braking feel. Without free play here you can easily end up with a situation where the brakes come on stronger and stronger until you're stuck by the side of the road with smoke coming out of the wheels. If the pin doesn't retract ALL THE WAY then it will close off the port to the reservoir, meaning that the pressure in the system can't go anywhere. The longer you drive, the hotter the brakes get, the more the fluid expands, the more the brakes are applied, the hotter the brakes get, the more the fluid expands, and so on. Seen that one a few times on brake upgrades, and I've personally made that mistake on a clutch. Clutch just slipped worse and worse as the day went on...

EDIT--reread the post and updated to fix

Edited December 4, 2008 by jmortensen

[jmortensen]

Jack T, I did not move it out when I installed the new master. I will try that also. Good idea.

Jesus freakin Christ! Guess I'm not reading this thread really well!!! Sorry guys...

If you installed a ZX master, then the pin needs adjusting as the others have said. If you installed a new Z master, then you'll need a bigger diameter master to fix.

[manny1973]

I did install the ZX master. I will try adjusting the pin. I will be careful to make sure it is not pressing on the master when not engaged. I hope this works. I'll let you know how it turns out. It's snowing out and way too cold for me to be working in the garage this weekend so hopefully next week.

[nwa240z]

I know this will sound really silly but did you accidently switch the lines from front to rear when you replaced the master cylinder?

[manny1973]

I hope not. the front one on the MC goes to the front brakes right. This is a 72Z

I know this will sound really silly but did you accidently switch the lines from front to rear when you replaced the master cylinder?

[jmortensen]

I hope not. the front one on the MC goes to the front brakes right. This is a 72Z

The front brakes go to the larger reservoir. I remember bending the lines by hand to hit the right reservoir. That won't cause your pedal issue, but as the brakes wear the fluid level drops, so you do want the front brakes attaching to the larger reservoir.

[Nigel1943]

I hope not. the front one on the MC goes to the front brakes right. This is a 72Z

Wrong. The front line goes to the reservoir nearest the booster on the ZX cylinder. The F & R embossed on the cylinder should have been the giveaway!

With regard to the booster piston rod I had the opportunity to measure the length out of the booster on the stock ZX and if I remember correctly it was 10mm.

[manny1973]

My brake lines to the new master cylinder are indeed backwards. I did not get them changed but will post after I do get them changed. On the orginal 72 MC the front brakes go to the front reservoir and on the larger ZX MC the front goes to the back reservoir. I hope this helps with the pedal.