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Hi guys,

I noticed this morning that my clutch pedal has suddenly become very soft, the pedal goes in a long way before you feel pressure but it does come back up off the floor.

It was behaving a little odd the last few days (it's a button type) but this morning I crunched a few gears before heel/toeing it home.

I checked the fluid level and it's full but it's black in colour. I've had the car 12 months so no idea how old it is.

My question is whether or not the dirty fluid could cause this or does the problem point towards the slave cylinder? It's happened very suddenly if that helps?

My car is an NA6 btw.

Thanks guys
Luke

definately fluid, it shouldnt be black!!!

Change it out and bleed it well, that should fix it.

Dave

Also check for fluid leaks at the rubber boot on the slave cylinder by squeezing the boot. I'm thinking you have a slave or master cylinder problem caused by old fluid.

Brake and clutch system should be flushed every 2 years. Flush the systems more regularly if you live in a humid area or use the car in motor sport.

JBT wrote:Also check for fluid leaks at the rubber boot on the slave cylinder by squeezing the boot. I'm thinking you have a slave or master cylinder problem caused by old fluid.

Brake and clutch system should be flushed every 2 years. Flush the systems more regularly if you live in a humid area or use the car in motor sport.

how do you bleed the clutch system??

same fluid as brake fluid correct??

irwin83r wrote:how do you bleed the clutch system??

same fluid as brake fluid correct??

Almost the same way as you do the brakes, Miata Net link

Yep same fluid

Andrew wrote:

irwin83r wrote:how do you bleed the clutch system??

same fluid as brake fluid correct??

Almost the same way as you do the brakes, Miata Net link

Yep same fluid

thanks dude

Thanks for you help guys, really appreciate it.

Yes the slave cylinder is leaking upon closer inspection, the master cylinder appears to be ok.

Further attention has also revealed a seeping brake master cylinder, the fluid is in need of changing as well.

I should have done all this when I bought the car, ow well you live and learn!

I've been told that you can't buy a replacement brake master cylinder for an NA, you need to rebuild your own one which needs to go into an oven for 12 hours to set, anyone done this before? I can't be bothered dealing with it all so I've booked it in at ABS.

From memory a new Mazda slave is around $100

hot rod wrote:I can't be bothered dealing with it all so I've booked it in at ABS.

Excellent decision

Take it back to them every 18-24 months for a hydraulic system flush and you should be fine for many years.

you need to rebuild your own one which needs to go into an oven for 12 hours to set, anyone done this before?

Oven? Whats that about Mine never went near an oven when I rebuilt it and it was still working fine when I sold the car.

Bizarre. No oven usage here...

Maybe getting things confused with stainless steel re-sleeving process. New MC is available from the UK http://www.mx5parts.co.uk/index.php/cPath/65_66

JBT wrote:Maybe getting things confused with stainless steel re-sleeving process. New MC is available from the UK http://www.mx5parts.co.uk/index.php/cPath/65_66

Thanks for the link, I'll save that for next time, a lot more expensive than just rebuilding my current one ($220).

Yes that's it, the master cylinder required a new sleeve which had to be drilled out. ABS refilled it with green brake fluid, cheap stuff at a guess, any idea what they might use?

I might flush it out again and refill with some of the Martini product (I've heard some good reports here?) as I'd like to take it to Winton once I replace my A/C pump in the coming weeks (it's very noisy). With the hard top on she's starting to heat up inside at this time of year!

The clutch slave was also replace so the clutch pedal is back to normal. The fluid is still looking very dirty though, they pumped nearly 2-litres through the system and it was still coming out contaminated so the master cylinder is probably corroded inside. I might track down a new one before that fails as well.

hot rod wrote:ABS refilled it with green brake fluid, cheap stuff at a guess, any idea what they might use?

Don't know what it is but it hasn't let me down under any conditions, including track days.

Brand new ones are still available in Aus from PBR and also I think Protek, but a hell of a lot more expensive then just getting it sleeved, and a sleeve is probably the best way to go to not have to do it again. One drawback of a alloy cylinder I guess.