Hello thank you for reading this and giving me any advice you may have I’m super new to rotary’s and replacing clutches this happend to be my first clutch change


so to start off I let my brother drive my rx7 and he then subsequently blew the clutch up on it or at least I thought he did ( the clutch grab was on the floor and it slipped also there was very little resistance on the clutch


i ended up floating it home from where it was parked the clutch although had very little preasure still grabbed and would engage and disengage to a point

so where I’m at now

I dropped the tranny put a stage one excedy clutch kit in it and put it all back together then I bled the clutch system to the point where only dot 3 was coming out of the bleader valave and still nothing the clutch goes to the floor and barley builds any pressure after that I replaced the slave and master cylinder along with the flexible clutch hose still nothing the clutch will barely engage and it won’t go into any gears unless the car is off



side note if I put it in a gear push the clutch in and hit the starter the car feels like it wants to lurch forwards but then it sits there and doesn’t move in Gear with the car running




Thanks for any input I’m kinda at the end of my wits with this but I really do love my rx7 and want to see it on the road again

 

Sounds like the jam nut that controls the friction point got loose and allowed the threaded rod that goes between the pedal clevis and master to thread in. Ie lowered the friction point below the floor.

Look under the dash, follow the clutch pedal up to where the master linkage is and you’ll see a threaded rod. Unscrewing this rod from the body of the clevis (add distance between the pedal and the master) raises the friction point. Holding the rod still and torquing the jam nut against the clevis body is how to lock the new friction point you set for good.

edit: btw, the addition of the rotary engine doesn’t change anything from the flywheel back, when compared to a piston engine of the same era. Sounds like you did all the right things to refresh the clutch hydraulics. I drove without a slave cylinder a couple times for a week or so each time. It’s strange when you start to get the feel for how much force you can put into going into first when stopped and can feel first gear working (complaining) as It moves the car forward (partially engaged mind you). Once it’s moving, you can shift with just rev matching and no clutch; once you are used to it. Not advisable, but absolutely doable.

 

How's the pedal feel? Any resistance at all or is it just a limp noodle? Ideally, you should have a slight free play when first pressing the pedal until that threaded rod engages the master cylinder piston. Then you should have some pedal resistance as the fluid actuates the slave cylinder to move the clutch arm to compress the pressure plate springs.

When you depress the pedal, does the clutch arm move at all, at the bell housing?

 

Hey guys thanks for replying I honestly didn’t think anyone would so I checked on the clutch pedal I really had to contort myself to get under there you were right that push rod had backed all the way into that bolt and it wasn’t pushing all the way

I pulled the push rod out and it’s kinda bent does that matter?

also how do I go about putting back in properly

And when I push the clutch the fork does move a little bit back but not enough to fully disengage the clutch

note: there is almost no play in the fork when the clutch is disengaged is this a bad thing?

 

Is the slave cylinder push rod installed correctly? They can be put in backwards.

 

Yea so the clutch pedal feels realllly soft but it will kick back after I push it all the way in and the clutch fork does move a little bit but the slave cylinder looks like it’s not moving it far enough

 

I believe so honestly the end with the ball and point is on the outside

 

The clutch pedal has a return spring which returns it. you should feel the resistance of the pressure plate spring, not just the return spring on the pedal arm. Not exactly sure how much the clutch arm should move, guessing around an inch or so.

Once you get the push rod to the master adjusted correctly, to remove the slop (freeplay) it should work as long as the circuit is fully bled. A "slightly" bent push rod shouldn't change that. The push rod at the slave normally has a small locating pin on one end that fits into a hole in the clutch arm at the bell housing. That should tell you if it's installed in the right direction.

 

So I did what you said and freed up the slop with the clutch master cylinder and the push rod but it was still lose so I losened up the push rod some more and it sees the clutch is starting to come back only problem is I have maxed out the push rod and the clutch is still not working properly

im Starting to think mabey I either bought the wrong clutch master cylinder and the throw is to long or my clutch fork is bent

 

You mean you removed the slop, so that there is a minimum of freeplay?

Not sure what you are trying to say here either, maybe that you see the clutch arm moving?

From the top again, when you push the pedal, you should have just a fraction (small) amount of freeplay where you only have the return spring resisting the pedal arm movement. Then the push rod comes in contact with the master cylinder piston and you start exerting hydraulic pressure through the system where you encounter added resistance from compressing the pressure plate springs. From here, you should have enough pedal travel move the clutch arm and fully engage the clutch.

If the arm isn't moving enough, I'd first suspect that the system is not bled properly. I like to use a vacuum blender to suck the fluid from the reservoir to the slave bleeder. One person job, no pedal pumping, easy / peasy.

 

Yea I loosened the bolt until there wasn’t any free play in the clutch and it still feels really lose and won’t disengage the clutch fully


I losend it all the way and the clutch was still partially engaged even though the fork had moved back probably a inch and a half

 

did u install the disk in the correct orientation? i've never put one in backwards so i wouldn't know how it would act.

 

This might make things worse… but I have bled the slave cylinder with it removed from the trans bell housing. That makes it the highest point in the system and much easier to bleed. Just make sure the bleed valve is cracked so you don’t over travel the slave piston.

I’ve recently learned from bleeding my NA miata clutch that a bike pump attached to a fernco coupling and an air fitting is a really easy way of un powered pressure bleeding without moving the pedals. A few questionable connections but it works great.

With either method, go slow and don’t let the tiny reservoir drain completely. Otherwise you’re back to square one. Try that before going around and checking other things.

also… you can remove the rod from the pedal clevis and straighten it out with a vise. The thing I didn’t see mentioned is that there should be a locking/jam nut on there to maintain the rod to clevis position that you set. If that’s not there, the threads in the clevis may have become damaged. The jam nut prevents the threads from getting loaded by the high forces in that little rod and m6x1 (i think) threads.

re: putting the rod back in properly. A little grease on the spherical tip that goes into the master doesn’t hurt for some future proofing. From there you pull the pedal up, insert the threaded end into the clevis (with the jam nut already in place on the rod). Then thread the rod in and use the jam nut to lock that position… I bet the FSM, find a copy at foxed.ca, has the official method of setting the clutch engagement height. You can start at the threads on the rod end even with the inner part of the clevis (full thread engagement) then work the friction point lower once you know the clutch is being fully released.

 

I love a ginned up thing that makes life easier. Got a picture of that?

 

Bad lighting/old pic.
Used one of those thick hoses from an HF fluid transfer pump, a random pump fitting that fits into that id and hooks up to the pump. The fernco side is a leftover female air fitting and a male fitting that magically threaded over the od of that thick hose. Then the pvc pipe and fernco to attach to the reservoir. It mostly holds pressure; it leaks around the threads of the reservoir, so I just have to keep pumping which makes controlling the flow very easy. Using it on the miata clutch, I bled that in about 10 minutes with this thing. New slave, master and flex pipe.

 

Awesome, I probably have most of those parts in my garage full of random stuff! I'm a bit of niche hoarder :P

I like the idea of a pressure bleed vs vacuum...when using a little HF vacuum hand pump, I always get bubbles sucked into the exiting fluid from air leaks around the threads of the bleed screw.

 

You could probably simplify the reservoir attachment a great deal if you had an old cap that you could tap an npt fitting in to. Then some epoxy around the threads on install to seal the fitting to the thin plastic.

 

You could probably simplify the reservoir attachment a great deal if you had an old cap that you could tap an npt fitting in to. Then some epoxy around the threads on install to seal the fitting to the thin plastic.

I did exactly this years ago and it has worked fine. I had a spare pressure regulator laying around, so I set it up with a quick disconnect to the cap and on the other end to a compressor (actually air tank for use at the track). I set the regulator to about 2psi and it worked fine. I do like the idea of the bike pump though. A lot harder to screw things up by accidentally overpressuring.

Carl

 

I use mine with the motive power bleeder, added the air fittings for quick disconnect. When I use it I still ask myself what in F was I doing all those years pumping the pedal.