How Can A Clutch Master Cyl Wear Out? And Minor Clutch Annoyances

[ausdrift]

In what situations would you need to replace the clutch master cylinder?

I just ask this as I have a few imperfections in my clutch use/pedal that I'm hoping to iron out.

I had the clutch replaced recently for a heavy duty one and while the clutch works fine, I've had to adjust the nut on the master cylinder rod out to almost nothing left now to get it to work without sticking. It almost feels like it slowly, over the month its been in, had needed to be adjusted more and more, little by little (ive adjusted it numerous times to get it acceptable) to keep it in the sweet zone (the clutch maker suggested only 1 turn would do it)

Also recently the clutch pedal sometimes gets a strange feel to it. Hard to describe, almost like it wants to stick to my foot when I release it. Im probably going to have a quick look on the WE as ill be installing other stuff, but was hoping for any heads up o my situation, and could it be related to the master cylinder itself?

thanks

[Hadouken]

Air

[jiffo]

Do I read it correctly, you've been extending the push rod to such an extent there's not much rod left in the clevis?

Air doesn't magically appear, not unless the fluid level dropped and then where would it go?

So no free travel and 99% will need a master cylinder, but to be 100% positive I'd remove the boot and check the throw out lever isn't broken.

Master cylinder is not expensive and always best to sort out before it leaks fluid onto your carpet.

Heavy clutch will soon show up any weaknesses, either in the hydraulics, the actual pedal or the throw out lever.

[Hadouken]

Air could have been introduced when clutch was done.

[Hadouken]

Why not do the easy shit first and bleed it see if that sorts it out?

[ausdrift]

It did have a braided line installed and new fluid at the time of installation, and the clutch action itself is otherwise fine...

And yep, very little more thread left on the rod so soon I would run out of rod to adjust the nut onto

[jiffo]

Braided line install would presume the system was bled?

By extending the push rod so far, you've eliminated free travel.

Then the piston doesn't expose the inlet ports to get a gutfull of fluid, so eventually everything comes to a halt. (In most cases this is due to wear in the master cylinder's initial bore and you're chasing better bore further down)

Your pedal take up point can be set via push rod length and the pedal's "up" stop, so long as the master cylinder is operating properly.

When finished setting ensure your pedal has free travel.

But first pop off the dust boot, give the throw out lever close inspection.

Be aware the pedal's return spring will go over centre about half way down without clutch pressure to return it. Watch the fingers when the master cylinder push rod is off.

[Dale FZ1]

I'm backing Hadouken.

Check that the hydraulic unions for the new braided line are tight, not leaking or allowing air into the system.

Bleed the line properly. This really sounds like there's air in the system. Hopefully the big loop that Nissan saw fit to use has been deleted, and there's a straight run down from M/C to slave. That type of setup makes the line virtually self bleeding simply by cracking the lower nipple and letting gravity do most of the work.

You're still going to need to bleed it in the conventional manner though.

If there's any cylinder going to be needing love, the slave would be first port of call. It's the one subject to most contaminants and internal corrosion/pitting. If you're handy, it's possible to recondition with new internal seals. Generally this works for a while, so the cost of a new slave makes better sense if you don't like spannering.

Listen to Jiffo's advice

[blind_elk]

The pivot socket on the throwout lever may have cracked. When this happens, the cracks open up and effectively lengthen the throw required to disengage the pressure plate.

[ausdrift]

Thanks all, sorry for the slow follow up; other car related issues have jumped the queue for this.

The braided line is just a straight line and that big loop piping is gone (I was surprised to see it when they pulled it out, to be honest) of which the shop annoyingly chose red when the WHOLE engine bay is black. When they did the clutch I got them to fit a Nismo pivot ball also which I bought for $10, 5 years ago.

I have fit a Nismo Clutch pedal bracket about 6 months ago as I was getting a squeak that wouldn't quit, so that part of the set up should be ok. The little plastic U on the pedal which I had to keep had split in half and isn't something you can buy, so now part of the mechanism is metal on metal.

So, moving forward...

* The fluid level is still high (slightly over the high mark) 6 weeks after the clutch being fit, so although I will give it a visual check later, I don't think there is a leak.

* I will get under and inspect the rod and mechanisms for wear and anything obvious

* I don't think I will have a go bleeding the line. While I've done for brakes before I'm parked up a hill in a carport and cant afford to f**k something up where I cant limp to a workshop.

* Assuming nothing is obviously wrong I might just bite the bullet and have a shop replace the slave and master. This way everything along the line is new and there should be no reason for any malfunction. Don't want to but I'm getting tired of the age related issues I'm getting with this car.

Just lastly though, a crack in the pivot socket; this would be inside the clutch housing isn't it, and therefore not something that can be easily looked at, right? Lets hope its not that.

Hoping to get to that over Easter