Clutch Hydraulic Failure

davamb · Postby **davamb** » Sun Aug 06, 2006 10:05 pm

Foot went to the floor just as I was tunring into my street, some prior indication as the clutch wouldn't disengage fully a couple of depressions beforehand. Checked down at the slave and it's barely moving for full movement of the pedal. My guess is the main seal in the master cylinder, there's no sign of leakage from the slave and I've had a whiff of fluid in the cabin for a week or two now.

Question is - can you get a seal kit from Maz or is it a whole new master cylinder? Any idea what either of these alternatives cost? Readily available? (Maybe this is what's been causing the heavy pedal all along.)

I did a bleed of the clutch a couple of weeks ago and used DOT4 as DOT3 was not available. Bottle said it was totally compatible with DOT3 but maybe not?

Thanks in advance.

Andrew · Postby **Andrew** » Sun Aug 06, 2006 10:08 pm

I replaced the slave cylinder on mine with an origional Mazda one for about $100 (parts only) and it took about half an hour for me to install it

Moggy · Postby **Moggy** » Mon Aug 07, 2006 8:10 am

You'll be able to get seal kits for the master and slave cylinders for very little money at Super Cheap. You just need to find the leak... Give the rubber boot on the slave cylinder a squeeze to see if fluid comes out - it shouldn't. Check all around the master cylinder and down the firewall for leaks as well.

JBT · Postby **JBT** » Mon Aug 07, 2006 8:26 am

The only problem with re-kitting a master, slave or any hydraulic cylinder is that there must be absolutely no pitting in the bore or you'll be wasting your time and money. Pitting is usually caused by water in the hydraulic fluid because it hasn't been changed every couple of years.

You can clean up the cylinder bore with fine sand paper if the pitting isn't too bad or get it re-sleeved in stainless steel or just buy a new slave or master as required.

sabretooth · Postby **sabretooth** » Wed Aug 09, 2006 4:49 pm

$100 is a lot to spend on replacing something when it just may need some new seals. Rebuild kits can be had for about $10 and a little bit of time.

davamb · Postby **davamb** » Thu Aug 10, 2006 11:00 am

Thanks for the help guys,

a new seal in the slave did the trick.

My mechanic was a little concerned over how close the take-up was to the floor though, something I've always thought too. As there's no adjustment in the system for this I think the pressure plate may not have been changed at the last overhaul, despite what the seller said. S'pose there's a chance he thought he'd paid for a new pressure plate too!

JBT · Postby **JBT** » Thu Aug 10, 2006 11:22 am

davamb wrote:My mechanic was a little concerned over how close the take-up was to the floor though

davamb wrote:....and I've had a whiff of fluid in the cabin for a week or two now.

You may also have a master cylinder leak.

SuperMazdaKart · Postby **SuperMazdaKart** » Thu Aug 10, 2006 11:42 am

about how much is a new master cylinder anyway? are there exchange ones of them

sabretooth · Postby **sabretooth** » Thu Aug 10, 2006 2:30 pm

I don't know what replacements cost, but the kit to reco it is $14 from a clutch shop. If you can smell the fluid in the cabin, then that's because the end of the master cylinder's piston actually points towards the cabin - so therefore it must be leaking past the piston.

davamb · Postby **davamb** » Fri Aug 11, 2006 11:27 am

Yeah thanks guys,

I'll keep a nose on things for the next couple of weeks, but I think the fluid smell I was getting was from the slave, no sign of it now after 2 days back on the road. Clutch does feel a little better than it used to, now with new fluid and seal, but still not happy with takeup. Mechanic was happy with master cylinder - he tested when the slave was out by blocking the line and checking for any sag in the pedal height under pressure: rock steady.

The bore on the slave was pristine, so just a new seal rather than replace the slave. The price of the parts insignificant compared to the labour cost.