4x4 toyota caliper swap now barely have brakes. HELP!

[Slide Star]

Hey guys! I swapped the toyota 4x4 calipers onto my 72 Z and now the brake pedal nearly goes all the way down to the floor and can barely stop the car. They are so bad that I won't drive the car on the road being a safety issue. There is no air in the lines at all and I am completely lost. Need this fixed by this weekend if possible! Any ideas??? Thanks!

[darrel]

bleeder screws up?

[datzenmike]

The bleeders need to be the highest point to let the trapped air out. If they aren't, swap sides. I put these on my 620... well the whole front axle and man do they stop.

[Slide Star]

Bleeder screw is on the top half of the caliper if that's what you guys mean.. :geek:

[datzenmike]

How large a diameter is the master cylinder on your 72????

 

 

 

Also were these rebuilt?

Was master replaced?

[Slide Star]

The calipers are brand new, so is the master. It is the factory 72 sized master don't know the specific diameter sorry!

[datzenmike]

Did you bench bleed the master. Air can be trapped in it. Get a short length of brake line about 16".  Thread into the F outlet and bend the other end up and down into the open reservoir under the fluid level. Pump the brake repeatedly until no more bubbles are expelled. Now do the R outlet. Bleed the system normally.

[Slide Star]

Ok i will give that a try, thanks for the help! I was also thinking maybe the 240z master is to small to power these bigger calipers... Maybe a 280zx one would do the trick if it's a little bigger? 

[72240z]

You should be fine with the stock master and booster. It sounds like you still have air in the system. 

[datzenmike]

What size is on there now? I have them on my stock 13/16" 620 master and the pedal is good. I was expecting it to move closer to the floor but not. A 7/8" is probably good too. If you go too big the foot effort will go up.

 

The zx is 15/16" and only the '79-'81 will fit correctly.

[72240z]

The popular upgrade now is a 1" wilwood. The 15/16 are getting hard to find and pricey. 

That said though I run a 15/16 lol, with a 73(larger) booster and the yoda non vented. Not bad for the price but they do have lock up issues. 

[Slide Star]

It's the oem size for a 72 240z. I guess my old man and I will try getting the air out of the master cylinder!

[datzenmike]

That's why I'm asking I don't know. It's likely embossed on the side.

[Slide Star]

I have a wilwood my dad bought for another project of his. Problem is it's not split for rear and front. Is there a way I could use a splitter in the line or something? I need this car ready for a competition this weekend :hmm:

[Slide Star]

If it says on the side of the master I can check tomorrow!

[72240z]

You'll be ready by just properly bleeding the brakes. I would get the proper master.

http://forums.hybridz.org/topic/102754-a-one-inch-diameter-brake-master-cylinder-for-the-s30-z-cars/

[Slide Star]

Ill read up on it thanks!

[datzenmike]

A single master means that if you get even one leak you loose ALL brakes.

[Mannyvig]

Bleed the brakes better and there is still an issue check the reaction disc.

[72240z]

If the master wasnt messed with its next to impossible that the reaction disk dropped out. 

[Mannyvig]

Could have been an issue before the brakes were swapped, now coupled with air in the system the problem seems way worse. Several of my customers come in wanting a brake upgrade because theirs aren't working well when the reaction disc was the problem the whole time. I read pretty quickly, but I didn't see the OP say the brakes were perfect before.

[72240z]

Hey guys! I swapped the toyota 4x4 calipers onto my 72 Z and now the brake pedal nearly goes all the way down to the floor and can barely stop the car. They are so bad that I won't drive the car on the road being a safety issue. There is no air in the lines at all and I am completely lost. Need this fixed by this weekend if possible! Any ideas??? Thanks!

 

 

Could have been an issue before the brakes were swapped, now coupled with air in the system the problem seems way worse. Several of my customers come in wanting a brake upgrade because theirs aren't working well when the reaction disc was the problem the whole time. I read pretty quickly, but I didn't see the OP say the brakes were perfect before.

 

It's definitely a common issue when people mess with the master/booster but as I said it doesnt seem like it in this case. 

[RedBanner]

Or on "nos" mc's, sometimes get gummy.

[datzenmike]

The problem was saying the Toyota calipers were added but leaving out that it also had a master cylinder added also. And a single master at that. Some set ups are dual single master cylinders side by side and set so there is more bias to the fronts. A single is probably way way too small to work the huge 'Yoda calipers.

 

When one thing is changed and there is a problem it's likely that thing. When two things changed there are now twice as many things to suspect.

[72240z]

Dont think thats right Mike? hes said twice is was stock size and his father had a wilwood master for another project that was a single. Thats how I understood it anyway I could be wrong. 

I agree a single in the oem size would be too small but he says the car barely stops. I dont think any master/booster combo is going to cause that honestly. A missing reaction disk would though 


OP what master booster are you running? lol