550 clutch: losing pedal travel

Ferrari warns against using silicone brake fluid (DOT 5) in the brake or clutch circuits. You sure you do not mean DOT 5.1, which is OK?

If you are using 5.1, it is possible the seals in your clutch master cylinder are bad, and I surely hope it is not the seals in the annular throw-out bearing, which act as a slave cylinder in late Ferraris.

Are you losing brake fluid from the clutch circuit?

The other possible problem is your clutch is worn. Symptoms are a much harder pedal as the linkage goes over-center, but your dealer can check that visually with a borescope on the throw-out bearing pin to see if you still have travel remaining.

 

In addition to what Taz has suggested, check the plastic elbow and hose that feeds the clutch master cylinder from the brake fluid reservoir. Often that plastic elbow is cracked and admits air into the circuit.

 

Car is 13 years old. You could have leaky master cylinder seals which is what I would suspect if shop just changed fluid and problem back so fast. It is possible shop error too but this is so simple. It is likely shop used right stuff. Almost no one uses dot5. Storage, maintenance, and use will influence the life of those seals.

 

I forgot, one other thing. There are two bleed screws on the master cylinder. Probably worth bleeding the master cylinder to ensure that is not introducing air into the system. Normally affects braking, too, but you never can tell.

 

I know of 3 550's that have had that cracked elbow; if yours has it too, that will be #4. It must have seemed like a good idea at the time, to save some space and not have to have dual reservoirs, but 13-15 years later, the plastic parts are getting brittle. Ferrari didn't improve on this system for the 575M, so it's something to watch for on those cars too in the future.

For reference, it's #14 in the illustration below, and if it is cracked and must be replaced, its grommet #15 ought to be replaced too. They're P/N's 184497 and 175189 (same for the 575M) and cost around $90 and $30 respectively, here in the US, and probably less if you source it on the other side of the pond.

For that kind of money, I'd be tempted to replace it with a SS barbed elbow, or something similar that would never require replacing again. That, or try to fit the clutch master with its own reservoir, which is something I had looked into awhile back, and I think there is a Fiat or an Alfa that uses the same or similar clutch master as our cars, but has its own integral reservoir. Could be a tight fit in there, as the brake master & clutch master are very close to each other.
Image Unavailable, Please Login

 

While separate brake and clutch master cylinders are easily to achieve the Ferrari method at first glance seems dumb. It is especially dumb when you consider the clutch inlet is so high up the reservoir. Then when you think about it if you has a failure leakage in the brake circuit it is likely that you would loose drive control at the clutch first. Voila an attempt at a safety feature. I like the Ferrari design. It has been like this since at least the late 80's. I would rather loose the ability to move the car first instead of the ability to stop the car.

 

Definitely have him bleed the master cylinder. If your annular throw-out bearing seals were bad, you would be leaking brake fluid into the clutch housing and the fluid level would be going down fairly quickly, with the possibility of brake fluid getting on the clutch itself. The fact you are not losing fluid points to air in the system, and the master cylinder is the only thing you have not bled.

 

You almost have to trust your techs on stuff like that, but you might as well put in a new clutch and clutch position sensor if you are changing the throw-out bearing or seals. Changing those seals uses almost as much labor as changing all the clutch components.

 

My bet is on the clutch control pump. Number 4 in the diagram. Mine went bad and the symptoms were that the pedal had about an inch of "free play" in it before I started really "doing anything" to move the clutch. The warmer it got, the worse it was. I never got to the point where I was having difficulty shifting.
Of course I had bled, checked my elbow, and done a pretty thorough scoping into the bellhousing looking for fluid leaks. None were found.

 

Great news! I'm glad to hear all went well. Mine has started acting up again so I'm going to take my own advice and go in a stepwise fashion. This is 1.5 years and about 1000 miles after I replaced the clutch control pump so I hope it just needs a bleed.

 

Funny thing is that you can get marginal to failed parts right from Ferrari new out of the box. 1.5years and 1000 miles is just unacceptable! I happen to be fighting a brake master cylinder right now. The cost new was about 150 bucks over re-sleeved and was faster to obtain. So stupid me went new and I'm having a devil of a time with it. So I'm going to re-sleeve my old MC and put that back in. I know it will work then I will nicely plead with the vendor to take this new POS back. I can't imagine that be successful but I'll try.

 

Sooo...I have had the same issue. I was convinced at first that it was a bad clutch control pump (which I had replaced last year). So I replaced it again with a new OEM pump, and bled the hell out of the system. I found that I was not able to get ALL of the air out of the clutch hydraulics until I positive pressure bled with a Motive Power Bleeder with the car's front end jacked up as high as I could get it. I was able to get a bunch more air out by doing that.

Thought I had the problem solved, and then after three pumps of the pedal the spongy feeling was back. Boroscoping the pumpkin revealed no leaks at the thrust bearing and adequate clutch plate thickness. Going back to basics, I triple checked the hose clamps on the hose connecting the brake master cylinder and the clutch control pump. They were tight, but not COMPLETELY tight...my guess is that I was entraining air through these incompletely clamped ends. I tightened them up to where you couldn't physically turn the screws anymore and rebled, and my problem appears to be solved. I've put 100 miles on since, will report back if this continues to recur.

 

Factory always put them in dry and the gear box always needs to be removed regardless of a stuck shaft.

 

Same here when I was removing the transmission for a failed C-clip on reverse. Couldn't get the shaft out where it inputs the transmission until I had the torque tube and tranny on the ground together. Then only with real difficulty they came apart. The splines then need to be cleaned of any and all remaining rust until they come together easily while still ON THE GROUND. Guess how I know.