Hydraulic clutch issue

[Kozy]

I have an issue with the hydraulic clutch on my 2002 Honda Accord Type R that I am having trouble diagnosing.

When sitting in traffic, or trying to park, the pedal seems to get stuck down, the bite point goes very low and sometimes the clutch seems to engage just enough to load the gearbox to make getting it out of gear impossible without stalling the car.

Last night I clamped off the hose to try and detect which end of the hydraulics was faulty, but couldn't detect any leaks. With the clutch pedal depressed, and the hose clamped off, the slave cylinder held it's position suggesting there were no leaks there.

Clamping the hose off before pushing the pedal to test the MC didn't really work as there was clearly enough pressure to overcome the clamp, and the slave cylinder moved out but then didn't return. Pulling the pedal up and pushing it again threw the slave out some more until I presume it topped out, as the pedal then went stiff. It had some spring to it which I might assume was the elasticity in the flex hose, but returned as normal and didn't creep downwards with constant force. This would seem to suggest that the hydraulics are all fine, but I am no expert.

Has anyone had anything similar before? Could this be an issue with the release bearing/arm/pressure plate instead?

[DaveL485]

Sounds like it needs bleeding (if its not a sealed system), and/or the fluid is getting hot....do the hydraulics run over or near to the exhaust?

[Kozy]

Nowhere near the exhaust. Forgot to mention it was recently bled to see if that was the issue. Made the pedal slightly better but then it just got worse.

[Bennachie]

Master cylinder fault.

[stevieturbo]

Seen similar before on Toyota jeeps, it was the master cylinder was the problem.

Although not really any way to test for it.

[DaveL485]

If bleeding makes it better and then it gets worse it suggests air getting in. Check the footwell for fluid leakage.

[Kozy]

The fluid has been fully flushed through this morning, absolutely no sign of leaks anywhere in the system either. The pedal isn't sticking now but the clutch still begins to bite after about 10 seconds, making getting it out of gear impossible without stopping the engine.

[stevieturbo]

Kozy said:

The fluid has been fully flushed through this morning, absolutely no sign of leaks anywhere in the system either. The pedal isn't sticking now but the clutch still begins to bite after about 10 seconds, making getting it out of gear impossible without stopping the engine.

I assume your last statement means if you hold your foot on the clutch for 10 seconds it starts to bite ?

Simple test. Pump up the clutch and clamp the hydraulic line somewhere. If it still bleeds down, the slave isnt holding. If it holds, your master isnt holding. ( ie it is leaking internally past the seals )

[Kozy]

stevieturbo said:

I assume your last statement means if you hold your foot on the clutch for 10 seconds it starts to bite ?

Correct.

I will try that test again with the engine running to see if it bites, I was only looking for movement in the arm but it may not be that obvious.

[Steve_D]

If it does bite then it must be the master cylinder internally leaking.
If it were the slave you would have reported the evidence of the leak.

Steve

[Kozy]

More home diagnostics today, it would seem that the hydraulics work fine with the engine off, no pedal sticking at all. With the engine running and a gear selected, I can hold the pedal down fine, and select and unselect gears without hitch. The problem comes once the clutch is allowed to bite slightly, after that it will catch and pull the pedal down, then continue to bite until the car stalls.

Seems more like something in the gearbox that's gone, still none the wiser as to which bit really so I think it's going to be a box out job to diagnose it properly.

[stevieturbo]

Did you do the test exactly as I said ?

[Kozy]

No, haven't got round to it yet (requires airbox removal to access the flex hose on the clutch line) this was just an observation on the driveway today.

It feels more like an internal issue more than hydraulic now, maybe the release bearing or something breaking up on the clutch plate. There are a few cases on the owners club of the spring retainers snapping which can cause intermittent issues with gear selection.