How can i tell if this is 26mm or 30mm

[KiDoZ]

How can i tell if this is 26mm or 30mm
i need to install new seals and or get replacement.
how can i tell from the outside what size this is.
car is 1990 300zx NA.
thanks

[Ace2cool]

Most N/A's in 1990 came with 26mm. If you need to know for sure though, pull the rotor off, and measure across the back. It should be 280mm in diameter.

Well, actually all N/A's from 1990 came with 26mm, but some have since been upgraded.

[KiDoZ]

Most N/A's in 1990 came with 26mm. If you need to know for sure though, pull the rotor off, and measure across the back. It should be 280mm in diameter.

Well, actually all N/A's from 1990 came with 26mm, but some have since been upgraded.

measure how so? not sure i get it

im buying the caliper repair kit, does that fit both sizes???

[Ace2cool]

Measure the diameter of the rotor. Not sure I can make it any clearer than that.

[itsa300zx]

Measure the diameter of the rotor. Not sure I can make it any clearer than that.

Wrong measurement, you need to measure the thickness. All z32 have same diameter rotors, only difference is the thickness in the '90 NA.

[Ace2cool]

Oh crap. You're right. For some reason I was thinking the TT and 91+ N/A had 300mm rotors. Guess I should fact check before I post from memory on stuff I "learned" like 4 years ago, lmao.

The thickness of the rotor will be 26mm instead of 30mm wide.

[KiDoZ]

So most likely these are 26mm then. ?

[Ace2cool]

Did you measure them?

[KiDoZ]

Did you measure them?

In morning. Will do. Thanks.

[t.mcginley.jr]

It's probably 26mm, but you'll have to measure it to really know. They sell full pad & rotor kits on ebay for both the 26mm and 30mm so that's probably what someone bought.

[KiDoZ]

I Measured, it came out to about 26mm. The seal rebuild kit that z1 sells. Do they fit both or not. I need ASAP. Thanks fokes.
Don

[t.mcginley.jr]

Yeah the rebuild kits fit both sizes, I don't think the calipers themselves are any different between 26mm and 30mm, but even if they were the pistons inside of them would be the same so the seals are the same. I've installed the Z1 rebuild kit and I also have 26mm rotors so no worries.

[KiDoZ]

Man i just drove car for a few minutes and afterward notice the brakes were smoking hot. Is that because of the brake fluid burning up or am i missing something. kits on the way.

[BlackWidowZ]

Man i just drove car for a few minutes and afterward notice the brakes were smoking hot. Is that because of the brake fluid burning up or am i missing something. kits on the way.

ya dont drive anymore till you figure it out. I would try and bleed the brakes make sure there is no air in the lines make sure brake fluid is getting to the calipers. Did you use anti seize when you changed the pads? Sounds like your break is locking up and your driving around with the breaks on. make sure u didnt kink or twist the break line.

[t.mcginley.jr]

Does it sound like the pads/rotors are rubbing when you drive around? If so then your pistons are stuck and yes you will need to rebuild them. It isn't too hard to do. Your supposed to use compressed air to push each piston out, but mine were stuck SO bad that I had to use channel locks. Get your caliper off, put it in a vice, spray around each piston with some WD-40/PB blaster and let it soak a little. Then take some channel locks or whatever big pliers you have, put a rag around the piston and work them back and forth until they pop out. Just make sure you are grabbing the very edge of the piston and not the smooth/shiny part or else you'll scratch it (and it won't be able to seal right).

Your supposed to be able to use like 20 or so psi to pop them out, well mine weren't coming out with 120 psi so that should put things into perspective on how stuck mine were. When you get all the pistons out, soak them in something to clean them up and then just take out the old seals and put in the new ones. Also I forgot to mention taking off the dust boots around each piston, but they are only held on by little metal rings nothing hard to do. Make sure to clean the caliper fluid passages out with break cleaner too. Mine had some hardened crud in them that I'm sure was messing my fluid flow.

[KiDoZ]

Does it sound like the pads/rotors are rubbing when you drive around? If so then your pistons are stuck and yes you will need to rebuild them. It isn't too hard to do. Your supposed to use compressed air to push each piston out, but mine were stuck SO bad that I had to use channel locks. Get your caliper off, put it in a vice, spray around each piston with some WD-40/PB blaster and let it soak a little. Then take some channel locks or whatever big pliers you have, put a rag around the piston and work them back and forth until they pop out. Just make sure you are grabbing the very edge of the piston and not the smooth/shiny part or else you'll scratch it (and it won't be able to seal right).

Your supposed to be able to use like 20 or so psi to pop them out, well mine weren't coming out with 120 psi so that should put things into perspective on how stuck mine were. When you get all the pistons out, soak them in something to clean them up and then just take out the old seals and put in the new ones. Also I forgot to mention taking off the dust boots around each piston, but they are only held on by little metal rings nothing hard to do. Make sure to clean the caliper fluid passages out with break cleaner too. Mine had some hardened crud in them that I'm sure was messing my fluid flow.

i saw the video online that shows how to do this, im cool with that, i have compressor. the brakes i don't think are sticking, i here them pop when i let go of pedal. it hurts so bad not being able to drive this car,, beautiful weather today and couldn't drive it, don't want to mess anything up. but that's only for a day or two. i drive it but now far and i don't brake hard. being careful. thanks

[KiDoZ]

I just realized. I thought I mention. At about 63/65 mph. The left wheel vibrates like crazy. I mean bad. Any ideas??

[Ace2cool]

Tie rods most likely. Only way to figure that out is jack the front up and grab stuff and shake. Look for busted bushings as well.

[KiDoZ]

Tie rods most likely. Only way to figure that out is jack the front up and grab stuff and shake. Look for busted bushings as well.

Ima give you props on that. Cause that I knew already. It's shot bad. Lol. I wanted to see if someone would confirm this. I saw tie rod when I had caliper out and it was beat bad. Rattles. Ordering now. They aren't costly so I'll get new ones.

[Ace2cool]

Don't forget to get an alignment afterwards. That'll eat your tires up otherwise, unless you get 100% precise measurements.

[KiDoZ]

Don't forget to get an alignment afterwards. That'll eat your tires up otherwise, unless you get 100% precise measurements.

thanks