mx5cartalk.com

Hey all,

slowly settling into my little car and beginning to get the hang of it. One thing I can't live with though is the heavy clutch. The previous owner said he'd had a heavy-duty clutch fitted and I guess he wasn't lying about it! (I asked if the pressure plate had been changed as well and was assured this was the case - often just the clutch plate itself is changed whilst the worn-out pressure plate makes for a pretty heavy action.) Trouble is I split my left kneecap in a bike accident some years ago and it's never going to be 100% again. Just wondered if there's some way of easing the load other than throwing out a perfectly good clutch and replacing it with an original item.

Sounds like it is on the way out.

A HD clutch is not necessarily heay on the pedal.

All the spring pressure is in the pressure plate. The clutch plate is just a spinning disc. There is a hellovalot of mechanical advantage applied through the clutch hydraulic system.

How long since the hydraulics had a check over and a flush with new fluid

MX5 Mania installed a heavy duty Exedy in my MX5 and the first thing I noticed was that it was much lighter than the outgoing clutch by comparison.

Not long afterwards I was looking at buying an NB and went for a test drive and the clutch in the NB was as heavy as the old clutch that was replaced in my NA - with the exact same feel and action, take up point etc. So I immediately assumed that the clutch in the NB was on the way out as well.

Yeah thanks guys, I'm beginning to wonder about the pressure plate. Don't see how the hydraulics can have mich bearing on the matter if there's full travel and no bleed-past.

I got a heavy duty clutch from Direct Clutch in Brissie (it's one the bigger brand one I believe, just can't remember the name on the box though) and it's full face organic yadda yadda and doesn't feel heavier at all than standard... just bits way harder.

Might be a stupidly strong pressure plate or something wrong with it.

davamb wrote:Don't see how the hydraulics can have mich bearing on the matter if there's full travel and no bleed-past.

It can if the hydraulic oil has turned to a somewhat congealed consistency because of mixed oils, water contamination, blocked passages or a combination of all those things. Imagine trying to push clean oil through a plunger as opposed to grease.

Unless it has been done recently, a complete flush of the clutch hydraulics would not be a waste of time, would cost very little and is well within the scope of the home mechanic with a spanner, some plastic tube and an old glass. It's also the only thing you can do without pulling the gearbox off to inspect the mechanicals of the clutch.

Thanks JBT I hear and understand.

Is there anything I can use in the way of a solvent to make sure there is no crap in the system - Isopropyl Alcohol? Or is just a complete drain then refill adequate?

Just pump it through as you would when bleeding and don't let the reservoir run dry. Keep bleeding until just clean new fluid is being pumped into the bleed tube and glass container.

In extreme cases I think metho will help but normally new fluid will do the trick alone. Don't forget to post results when/if you do it.

Waiting for the new concrete in our driveway to set. Will be useable from mid next week onwards. Think I'll have to have a go at this on the front lawn though this weekend. Need an improvement desperately!

If you find that flushing doesn't help, you could always get a mechanic to put in a vacuum booster on the clutch pedal.
That will make it very light.

I hear someone laughing at this suggestion, but they used to use this on the old Nissan GTR's, and it works a treat.
My assistant has a 6-speed HSV R8, and I can't for the life of me understand why the clutch is so heavy.
They have power assisted brakes, steering, seats, windows but no assistance for the clutch.
Bloody stupid if you ask me. Makes it a dog to drive in traffic.

Benny wrote:you could always get a mechanic to put in a vacuum booster on the clutch pedal.

Our 1990 Patrol had a booster on the clutch master cylinder - most unusual I thought at the time.

JBT wrote:

davamb wrote:Don't see how the hydraulics can have mich bearing on the matter if there's full travel and no bleed-past.

It can if the hydraulic oil has turned to a somewhat congealed consistency because of mixed oils, water contamination, blocked passages or a combination of all those things. Imagine trying to push clean oil through a plunger as opposed to grease.

And here's what I found in my clutch master cylinder on Saturday:


Mmmmm.