Clutch issue

[Tokyo-Joe]

Hey all,

I had a nasty surprise this morning while starting to head off to work, my clutch felt very light (did not stick to floor) and gear are hard to engage. I tried all gears and there was much resistance putting any of them in.

The car was parked up for a week (fine before) and left in 1st gear (as I always do).

Any thoughts on what this issue might be? I have had soft clutch's in other cars when the clutch fluid is low but the pedal always stick to the floor in those cases..

Thanks,
Joe

[Kaz-kzukNA1]

Hi, Joe.

If you are having difficulty in engaging the gears and CL pedal feeling light, then it sounds like you are having CL Hyd system issue resulting in CL not being fully disengaged.
If it is something inside the CL case such as torsion spring popping out, release bearing, etc, then normally you would feel sign of failure beforehand such as increased friction through pedal travel, noise, etc.

There are several possibilities but I would first check the CL fluid reservoir under the bonnet.
It’s the small one close to the centre of the chassis near the big black A/C blower motor fan housing.

As your CL pedal didn’t stay at the floor (yet...), you may have just started to introduce the air into the Hyd system.

If the fluid level is almost empty, the main cause is the leakage at the CL master cyl or seepage from the crimped fitting at the CL hose under the engine bay.
The leakage at the master cyl will leak into the cabin just behind the pedal and drip onto the floor carpet so not good.

CL slave cyl can fail as well but master cyl and hose tend to fail more.

If replacing any of them, please replace all three as a set.

If it is indeed Hyd system issue and if you have just introduced small amount of air, you may be able to move your NSX for a short period just to get to the garage but I'll wait for your diagnosis first.

Kaz

[Tokyo-Joe]

I have heard a shrill squeel when engaging clutch from standstill in first gear, it sounds like release bearing. It has been this way for two years with no clutch performance issues or noises in any other gear.

Okay I just checked the clutch fluid bottle is empty and the driver front carpet seems bone dry.

[Tokyo-Joe]

Any ideas what a master and slave clutch cylinders go for on the NSX?

[NSXGB]

From the UK, the master cylinder costs about £220, hose about £50 & slave about £170

Can't remember for sure whether you can source the master cylinder from the USA, got a feeling you can't (LHD vs RHD). The other two parts are ok to get from the US. You could save a bit by sourcing the slave & hose from Rock Auto, who are good. Andy at Vtec is also worth a try.

[Tokyo-Joe]

Thanks mate :)

[paulc]

Try Allmakes

[Tokyo-Joe]

If I refill the clutch res will that give me ten miles worth of clutch action to get it to a garage?

[Kaz-kzukNA1]

Depends on how much air you have already introduced into the CL Hyd sys, where it is leaking from and most importantly, how severe the leakage is.
Please note that the leakage may get worse on the way to your garage so you may need to check and top up the reservoir on the way or have a back up plan.


Just fill up the CL reservoir and squash the rubber hose (covered in cloth) attached to it many times.
Tapping on the hose rapidly will also help.
You should see small bubbles coming up into the reservoir.
This is to prime the master cyl because of the narrow feed hole diameter and higher viscosity of the brake fluid compared to the water.

Once you can no longer see any bubbles coming up, top up the reservoir and close the cap.
Closing the cap is very important otherwise you are going to splash brake fluid all over the place during the next stage.

Now get to the CL pedal, use your hand to floor it and then flip it up quickly to create sharp impact.
This lifting movement will create big vibration to the master cyl body that will help bleeding the air.
Again, make sure to close the cap of reservoir before doing this.

If you managed to spot the issue before introducing too much air into the Hyd system, you may start feeling increased pedal resistance by repeating the above vibration method many times.

If you can't feel any changes in resistance, you have introduced too much air into the system or your leakage is severe and you will need to review other method to take your car to the garage.

Once you have some resistance, just use your foot to press on the CL pedal and pump it more than 100 times.
Please check your fluid level after the first 5 pedal stroke.

If the fluid level has dropped significantly, your leakage is beyond the quick fix and you must find where it is leaking from or flatbed it to your garage.
If the leakage is slow, you should be able to keep pumping the pedal without topping up but please double check the fluid level while pumping it 100 times.

As your pedal didn’t stay at the floor, you may be able to start with the foot pumping and skip the big vibration method using the hand.

If you are lucky, you may be able to bleed the air using the above method and generate enough travel at the CL slave cyl in order to disengage the CL.

Good luck.

Kaz

[Tokyo-Joe]

I had it recovered in the end :)

Kaz you were bang on, the issue was the slave cylinder.

[Tokyo-Joe]

Incase anybody else faces these symptoms here is the outcome- 1hr labour at NW £120 and I imported a slave cylinder from rocky auto for 100 USD. So quite resonable all in. Thanks for the help and advice guys. I really enjoy being a part of this club.