I just picked up the car last week. Currently at 69,910 miles. Its got an aftermarket clutch. I do not know the brand or what type, but its quite a heavy clutch and when it grabs, IT GRABS.

The car runs fine but I ran into a problem with the engagement point. I will drive normally and come to a complete stop and have the clutch pedel FULLY pushed in and out of no where the engagement point is literally right when I lift my foot off from the very bottom. Also noticed that when this happens, there's a distinct sound. It sounds like the clutch is grabbing (Duh), but its a low rumbling noise and you can hear it in the cabin. This continues until I let off the clutch fully. The clutch isn't slipping or anything its just that the engagement point will randomly change from very top to dead bottom.


Could some one tell me whats going on? I search for about 2 nights and only stumbled across one thread but there was no fix on what it was, only people with the same problem.

My guess:

Clutch Master Cylinder dying/dead?

Any Ideas?



Update:

Previous owner installed a Tilton Type 86 CMC. Which was slowly dying and loosing pressure.

 

I've read that the clutch restrictor pill can cause that. there is a diy for removing it somewhere on here. Maybe someone can post the link


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If you have no leaks (esp. at the slave), then you probably have a seal in master that is going out. If the PO put in a big, macho clutch and didn't rebuild or replace the master, the master might not be up to maintaining the pressure required to keep the clutch disengaged.

I doubt it's the pill. The pill only restricts the rate of flow in one direction; it is not (usually) a source of lost pressure.

 

Where is the location of the clutch master cylinder? Right on the firewall?

I m also confused about these CMC kits, MAPerformance sells one but it asks if I would like to purchase and OEM part along with the kit? I thought the kit was to replace the OEM part?

 

You can select either an OEM master cylinder or an aftermarket replacement that we have found to work well.

 

Yes, the CMC is on the firewall, right next to the BMC. They share a reservoir on Evo Xs. If the current CMC is the original, you might as well replace it with a stronger one, since the OE CMC isn't going to last long with a macho clutch. If it has already been replaced with a better one, rebuilding it isn't all that difficult.

 

they sell a kit to adapt the stock evo 9 CMC to the evo x, you gotta provide your own CMC

 

Aside from the clutch master cylinder, which if you find that you have the stocker you will no doubt need to replace it with a non plastic upgrade.

I have encountered some weird issues if there is air in the system and not bled properly. I suppose air can move around and with temperature change, run into expansion variables.