456 manual clutch adjustment or clutch replacement?

Sounds like you have air in the clutch line. Get a trusted tech to rebleed the system and check for leaks while he's at it.

The rubber hose that feeds fluid to the clutch master cylinder from the reservoir, and the plastic nipple on top of the clutch master can get brittle with heat & time and crack.

Also check the clutch master for leaks. It has a rubber bellows wiper on its actuating rod, so you may not see a small leak, but if you can get up under the dash with a flashlight and have a look at that rod, and feel it to see if it's wet, that may tell you something.

It's either the master or the slave, and the master is a LOT easier to change. The slave requires the bell housing to come off.

 

Stu- You can download a workshop manual for free from ferraridatabase.com.

 

There are some handy one man bleeding tools around now. Motive Products makes the one that I like & use, but be sure to get their 1109 "Black Label European Adapter" so it'll mate up with your master cylinder.

You might want to have the 2nd person there to keep an eye on the fluid in the Motive Product jug as you're bleeding. You don't want the pickup tube in the jug to pick up any air at all, else you'll be compounding your problem.


There are also Speed Bleeder nipples, which require you to change the OEM bleed nipples out for their special ones with built in check valves. I have used them on other cars and liked them a lot, but haven't heard/read much about them being used in the FCar community.

 

I had similar effects on my 550 and at the same time observed slowly lowering clutch fluid level. By occasion of a large service with a main dealer I indicated to the workshop guys to check the clutch system for leaks. They returned the car to me with the comment that no leaks had been found.

I then looked by myself and found out in minutes that the clutch hose heat shield material was soaked with clutch/brake fluid. It obviously leaked a little, but enough to result in the effect.

I exchanged it myself, actually an apparently simple and quick job, just two hose ends to unscrew and fitting of the new hose. It however turned out to be a mayor job, since the lower end of the hose ends on top of the clutch bell and the only way to get there is to remove at least one cat (and the related probe). An initial try through the wheel arch made me see the joint, even reach there with the end of the wrench, but no chance to apply the necessary torque for removal. I hope that this is somewhat more easy in the 456, in case that the hose is indeed faulty.

 

Bernhard, that's interesting; did you locate where exactly the clutch hose was leaking? Was it from one or the other fitting, or had the line itself simply fatigued and failed?

 

Sorry, I did not take a really close look at it and simply discarded it. But I was surprised how much fluid was taken up by the heat insulation material. As I recall, it was wet right from the top, so that it might be that the upper fitting went bad. But this may also be a result of capillary forces in case that the line itself had failed.

 

I replaced the cluch on my 456. If your clutch is not worn out,if the shifter is properly adjusted,if the combined slave cylinder/throw out bearing is functioning,bleeding this sistem can be a PITA. I eventually bled mine with positive pressure thru the bleed opening from the bottom of the clutch. Why did ferrari put the bleed nipple on the bottom of the housing when air rises? got me.

 

When removing the hose to the slave cylinder,get a proper line wrench on it. The fitting strips easily.

 

The last clutch bleed that I did, was initially done with the master on the car, however, it was a custom sleeved master that was poorly done, so no amount of bleeding would help it.

I trashed it for an aftermarket master in the bore diameter that I wanted, which I initially bench bled, then I mounted it and finished bleeding the system after that.

On the procedure, yes if you choose to do the 2 man operation, it's still the same as it's always been. Don't forget to put the 2x4 to limit the pedal travel

 

I ran positive pressure up thru the master by attaching a pressurized syringe to the bleed nipple at the bottom of the slave.. It takes a little time,one below pushing on the syringe and one above seeing when the bubbles stopped. Worked first time we tried it after endless tries to bleed from below. No brake pumping needed with this method. Still holding hard clutch 1 year later.

 

Every car manufacturer in the world does it that way. Brake systems are really no different. Master at the top and bleeders at the bottom. It does work but some systems are more trouble than others. It requires a method that insures high fluid velocity.


Unlike brake systems, clutch systems are so simple I bleed many by just pumping the pedal. The movement of fluid makes the air rise back to the master.


There is actually a method shown in old Mercedes manuals. Hook a hose between a brake nipple and the clutch bleeder nipple and pump the brake pedal until the clutch system is full.

 

There is only one reservior. If the clutch feel suddenly changes and bleeding the clutch fixes it you have addressed a symptom but fixed nothing. In my experience slave cylinders only leak externally so if that was an issue fluid would be comming out of the bell housing. If the master cylinder is bad it will usually leak where the push rod enters, usually under the dash. Air can also enter there. It is a really simple system so should be easy to figure out. There are some more exotic systems with magnesium cylinders and standard fluid will create gas in the fluid but a 456 is not one.

 

Stu, is it possible that you let the fluid in the reservoir drop close to the level where the clutch hose picks up?

If you did, then if you happened to do some fairly high-G driving, the fluid could have sloshed around in that reservoir and introduced some air into that line. Doubtful, but possible.

Your system will bear some watching now. Leaks rarely get better and fix themselves

p.s. Where did I mention a 2nd reservoir in the transmission? AFAIK, there's only the one reservoir that feeds both the brake & clutch systems. I'm not a big fan of this system as I've seen that hose and plastic nipple fail on several cars, and plus, it doesn't take much of a fluid drop in the reservoir for air to get into the clutch circuit.

When my car goes back together, I'm going to investigate using an Alfa clutch master cylinder, which will have its own fluid reservoir.

 

I have yet to see a hose failure and the only plastic nipples I have seen fail were damaged from people trying to remove them.

It is one part of these cars we have never needed to fix.