The last time I drove the car, as I was coming home I noticed that there was this weird vibration in the pedal as I was at the point of engagement (went along with the movement of the pedal). Drove the car again today and noticed that the clutch was engaging basically on the floor, and made some weird sounds when the clutch was pressed in. By the time I got back home, I could barely even get it into gear when shifting. My thought was clutch slave/master, which is weird because they are both new (less than 5k miles). Checked and no leaking or missing fluid.

Does this sound like a bad throw out bearing? I was a dumbass and didn't replace it when I reinstalled the engine/transmission last year so I'm afraid that's the case, but I don't know if a bad throw out can cause these symptoms.

 

Could very well be the bearing, although usually you can hear scary noises.

My ****-up years ago was not properly tightening the 4 nuts that hold the tube in place that sits over the input shaft. It got tangled in the pressure plate preventing me from full disengaging the clutch.

 

The T/O bearing nor the pilot bearing will not change the pedal travel, the turbo fork is much stronger
than the non turbo, so check fork, but both can sustain a broken pivot ball.

 

Interesting. I didn't realize that there was a difference between the shift forks. So, you're saying that the turbo and non-turbo shift forks are interchangeable? How about pivot *****? There's different p/n's for the turbo and non-turbo pivot *****. Is there any difference between the pivot *****?

 

ok so the pivot ball, is 0603-16-102B for the NA
the S4 turbo uses an N302-16-102 and the S5 is N310-16-102 for the turbo

For the Fork the S4 Turbo is N302-16-520 and the S5 is N310-16-520
the S4 NA is N204-16-520 and the S5 is N302-16-520

Since the Turbo uses the same bell housing, i believe this is why the Throw Out bearing changes, S4 uses FE84-16-510 for the NA, and F853-16-510 for the Turbo and S5 is G561-16-510C for everything

i think all of this would interchange, but you'd probably need to have matching parts

 

Would you know what the differences are between the throwout bearings for all series FC3S, if any?

From the Pineapple Racing website (https://www.pineappleracing.com/heav...n-turbo.aspx):

"This is the Heavy Duty throwout bearing originally used in the 87 TurboII (F853-16-510), but works for all RX-7 applications prior to 1992, both turbo and non-turbo. This thing is REALLY heavy duty and worth the extra cost!"

According to Pineapple, it appears that all FC3S throwout bearings are interchangeable.

 

Just had someone depress the clutch, and it looks like it easy moving pretty well. Moving the clutch in when the engine is off feels normal, but when it's on there's a weird vibration when I gets to where it should be engaging. It was making a noise before, but now it's even worse when I depress the clutch, it's almost like a screeching sound.

I get that the throwout bearing shouldn't cause the clutch engagement to change, but it sure seems like it's jacked up. Dammit.

 

i do not! and i went and looked and it didn't help. if you look up the part by application, 1990 Mazda Rx7, you get a different part number than if you use the Mazda number, even in the same brand.
for example National shows a 614155 for the 1990 Rx7, but if you use the part number G561-15-510C you get 61479...

it does kind of point to these all being really similar

 

Pilot bearing?
When that bearing is shot, the main shaft keeps turning, hard/no shifting.
Have someone hold the clutch pedal to the floor, turn engine and see if the shaft is turning.

 

Huh, that makes a lot of sense. Still requires dropping the freaking transmission though.

 

so this one time, i unbolted the drive shaft, and stuck it up over the diff, and you can push the trans back a bit. then the engine can lean forward a little, and there is enough room to get in there, just

 

I assume you're talking about the throwout bearing? I can barely get the pilot bearing out with the transmission totally out, let alone trying to wedge the tool 3 in a small crevice.

 

yeah i don't think you'd be able to get the pilot bearing, i did get the rest of the clutch and flywheel in though

 

Been quite a while since I've been under one of these, but there isn't any way to inspect the inside w/o
removing the trans? How about pulling the fork boot back and check using mirror/light?

 

I finally got it pulled apart, and the final diagnosis is catastrophic failure of the thrust bearing. Thankfully, I don't think it damaged anything else.

 

Glad you came back with the problem/solution.

 

Of course! I've been here over 20 years, and one of my biggest pet peeves is when there is no solution posted.