apex1

I have searched various threads, but could still use help from experienced owners.

Just bought an 04 8 with 72k. The clutch pedal grabs right off the floor. Sometimes it is hard to get into 1st or reverse. It doesn’t slip or burn But feels like it does not disengage fully.

Currently there is zero free play in the pedal. The clutch pedal has smooth resistance through the travel. There is some wetness where the pedal meets the clutch master but that could just be grease. My guess is once I set the free play correctly the clutch will not disengage at all.

My thought was to bleed it fully and set the free play. After that not sure on if it’s hydraulic or the clutch fork, throw out or disc/plate. Any thoughts?? Thanks

Loki

iTrader: (1)

I would adjust the pedal and see where that gets you. If you raisw the friction point you also give it more room for full disengagement right?

I do wonder how long it has been like that and of the clutch has glazed from not disengaging fully. Do rpms drop/car start to roll if you put it in 1st but not engage the clutch?

apex1

Maybe the better way to describe it is, it is like the master piston has been pre-loaded if that makes sense. If I release the the pedal by adjusting the free-play correctly, I think that will reduce the total piston travel. This is just my theory.

i want to get it through emissions first, as it still drives now. I will do that in a few hours.

But you can shift into gear without the rpms dropping. You just have to make sure your foot is 100% to the floor. I can also confirm there is a small seep of brake fluid coming from the master piston area. I cleaned off the grime and rust and can check going forward.

the good news is my motive brake bleeder adapter from my c6 vette fits the rx8! One less tool to buy...

apex1

Adjusted the clutch to add some free play.... no change. Bled about 3 oz of new dot 3 through the slave.... no change.

Pedal feels solid and smooth all the way through. Still grabs right off the floor, maybe 1/4 inch the tires start turning. Maybe the fork or bearing? Not sure on this one.

Loki

iTrader: (1)

How did you adjust the pedal?

apex1

Shortened the rod going the clutch master. Created a small amount of free pedal travel before the master piston starts to move.

apex1

So more research has yielded little clarity. Judging by the mileage I would say it needs a clutch but the typical symptom is grabbing high, not low. I can't find an explanation for a worn clutch and grabbing low.

But the bottom line is the master and slave provide solid resistance all the way through the stroke, however the pedal travel does not create enough clutch arm travel. Is this hydraulic or some mechanical issue? I did find this post on clutch adjustment.

https://www.rx8club.com/series-i-do-...0worn%20clutch).

If I follow this out, everything is fine. I would just adjust the rod out until the clutch grabbed a little higher and be done. However this is not what the factory manual recommends.

Loki

iTrader: (1)

I would adjust the friction point where you like it to be (within spec), and then validate that it's engaging fully (no slip) and disengaging fully (no rolling/rpm drop going into 1st). Who knows what the previous owner did to make it this way, let's get it back into the desired position first. You've already bled it, so that's the only remaining action you can take without replacing parts needlessly.

After that see if the friction point creeps back to the floor or if the clutch slowly engages while you hold the pedal down. Either of those would indicate loss of pressure in the hydraulic system. If all is well then you're done, it just needed adjustment.

I don't see how a worn clutch could grab lower (sooner) than its original setting.

apex1

So I adjusted the friction point and it seems to grab a bit higher now. Now that I have some premix in the car I was able to go take it on a shake down run and beat it up a bit. The clutch definitely engages well and does not slip. I was able to launch hard, spin the tires and then chirp 2nd and 3rd. So no issues there.

What I did notice about the clutch is it is stiff feeling overall. It takes a good push to get it down and it seems to get stiffer the further down it goes. I wonder if the clutch arm isn’t binding or something is just off with the hydraulics. I will have to do more research.

Loki

iTrader: (1)

Any chance you can test-drive another RX8 to compare? Or an NC Miata? Is it notably stiffer than RX8s you might have driven?

apex1

I have only driven two RX8's recently. I cannot say for sure the clutch in those felt different. It might just be typical for the RX8. Its also been a while since I had a legit standard so maybe I just need to man up. My plan is to drive it for a while and loosen it up.

RastaRx-8

sounds like a bad pressure plate or throwout bearing to me. i dont see any way to bend a fork and if its still working everything must be in place just worn.

"Clutch pedal feel is compromised" :As the issue progresses, the bad throw-out bearing can cause your car’s clutch pedal to become stiff feeling as you press down on it. This should be a red flag for any driver, and should be addressed right away."

dcfc3s

Is it possible a previous owner put an "upgraded" clutch with a heavier pressure plate in the car?

A heavier pressure plate with heavier springs requires more work on your leg to press down. That also means you are putting a lot more load on the clutch hydraulics.

On the FD RX-7, it's common if you upgrade to a heavy pressure plate to install a stainless braided clutch line. There is enough flex in the stock rubber line that it will swell instead of press down on the pressure plate, resulting in a low engagement point, sometimes so low the car is basically undriveable.

All that said, it's worth getting a braided stainless clutch line. Banzai Racing has them for $25. If your clutch hydraulics are old and tired they may have to be replaced, that additional load on the hydraulics can blow them out.

Also there is zero reason to put an "upgraded" clutch on a stock or near-stock RX-8. The stock clutch holds great and lasts a very long time and is also easy on your leg.

Dale

RastaRx-8

agreed on all that . also check to make sure your clutch pedal isnt actually broken like is very common with an rx8... im installing my new oem clutch atm! act streetlite and SS line

apex1

Its possible, the owner I bought it from had it for 14 years, but most of the mileage came from the previous owner. I know that the engine was replaced 3k miles ago and the clutch was not done. He paid 6k for the engine, so the only reason I can think that the clutch wasn't done is that someone determined it wasn't needed.

The only other thing to note about clutch performance, is this clutch does grab hard. I was able to chirp 3rd gear by just driving fast. the only thing I can compare it to is my S2000 which would never chirp 3rd. The clutch was just not as snappy as this RX8.

RastaRx-8

well if there is no noise and its consistent im betting on either not bled all the way somehow or pressure plate worn out. bad throwout bearing, pilot bearing, or broken clutch pedal would all make some kinda squeak at some point and get worse over time... if you are positive on the bleeding (may not be bleeding because of the adjustments on the rod) then its gotta be pressure plate issue. also put a camera on the rubber hose just for ***** n gigs to see if it flexes while you press the clutch

apex1

So I adjusted the rod to raise the engagement point. it was grabbing about an inch off the floor. I say was because after driving the car fairly hard for 100 miles I have noticed the engagement point is coming farther off the floor. It now grabs about half way through the travel. It is still smooth and the clutch grabs hard.

Something in the system changes with heat. Either the hydraulics or the pressure plate. I know this car has been sitting a lot for the last 5 years so I am still kicking off the dust.

RastaRx-8

the only thing that could possibly change your engagement point during driving is a fluid/bleed problem maybe you have one of the screws a little loose and when it heats it expands in seals better .. did you check the flex on the hose?

Loki

iTrader: (1)

If it's moving I would guess hydraulics.

apex1

A couple of updates on this..

I did confirm the clutch and pressure plate were replaced about 6k miles before I bought the car. The clutch still does not function correctly. If I over tighten the adjustment rod, the pedal is very stiff, and the engagement point seems to move around with temperature. If I adjust is correctly, with correct free play, the clutch grabs close to the floor and shifts into reverse are harder. Clearly there is not enough “throw”.

i inspected the slave and fork. The slave rod can easily be pushed into the cylinder creating free play between the fork and rod. This allows the clutch pedal to fall to the floor when pressed. I unbolted the slave and let it hang down. When the pedal is pressed the piston pushes out, but then it seems to retract a bit. Not sure if this is normal.

i can say with the slave out, the clutch fork travels about 1” loosely, not sure if that is normal either.

My guess is air in the system still but the clutch slave looks original and I am thinking I should just replace it.

apex1

I replaced the slave because of the original tsb. After some more testing, I noticed the master started seeping fluid, so I replaced that too. With a speed bleeder and motive pressurizer I was able to get a good pedal. While the travel was smoother it still grabbed low. I took some videos of the slave pushing the clutch fork and all seemed fine.

I read the factory spec sheet on clutch adjustment and came to the conclusion my clutch pedal was set about 3/8” lower than max spec. After raising it accordingly and setting the adjustment rod, the engagement point came off the floor. It grabs about 1” off the floor which I believe is in spec. So now the clutch is smooth and grabs in the right spot.

So either this is 100% normal or the replacement clutch requires some more clutch throw.

apex1

Update…

clutch started acting up again. Grabbing low and then when very hot started not releasing all the way. Pumping it up helped a bit. I expected a hydraulic issue but had already replaced the master and slave.

Clutch aside, there was nothing left to replace…

Nothing but the flex hose. Replaced with Goodrich, bled and now works better than ever. This is part that made the most difference by far. I am guessing the original was expanding, especially when hot. No surprise considering the age.

this was suggested above by several members, thank you.

Vague clutch issues like described above? Replace your clutch hose, trust me.

apex1

So unfortunately, while the clutch hose did raise the engagement point to the highest ever, it still moves closer to the floor with use. The soft flex hose, was just “one” of the issues. The dynamic nature has not really changed. I have bled it the following ways:

pump and bleed
gravity bleed
MC pressure bleed
vacuum bleed
pump and bleed with speed bleeder
reverse bleeding through slave

From the standpoint of a firm, consistent pedal pressure, from first bleed on all methods above have worked well. No method has changed the feel of the pedal. Must have bleed it a dozen times. This makes me think air is not the issue. I have two theories:

1). There is a mechanical issue with the fork, pivot, bearing, clutch or pilot. That issue is pushing back on the slave, or binding, creating the need to pump up the clutch back into position.

2). The MC i installed is bad. Holding the pedal down exasperates the lower engagement issue. Makes me think the system is not holding pressure and there are no external leaks. Only thing that could do that would be the MC

any thoughts?