458 Brake pedal sinks to floor, no loss of fluid..?

With Ferraris it is usually age not miles that things go bad. The newest 458 is 10 y/o so yeah a MC could die in 10kmiles. If no other maintenance has been done because so low miles the entire brake system needs to be gone through. At age 10 you should have flushed the system somewhere between 5-10 times already. Flushing keeps the system from absorbing water and producing particulates and precipitates that damage seals that kills your MC or shorten's its life.

 

Have you tried just bleeding the brakes?
Can you build any pressure by pumping the pedal?

 

+1

And to add to the above post was anything that preceded it

 

Interesting

 

Yes that or rebuild with new seals...but...everyone tries a system bleed first just to make sure. It makes no sense that a working system would somehow get air in there to cause a spongy pedal, unless very porly maintained, but we do that step first anyway. When there are extremes say a racecar with marginal brakes run hard and put away wet you can get the spongy pedal the next time you just move the car around or do a short paddock drive. That happens when you heat boil the fluid locally and that boils off any absorbed water and that puts air in the system. I can't think of a time that happened to a legally driven street car. But go through the steps. A bleed takes you 10 mins or under an hour if you have to take the wheels off for access.

 

Seems there is minimal hydraulic pressure developed by the master cylinder. If booster is ok, and nothing changes after a bleed, I'd replace the master cylinder This is indicative of a failed master cylinder as everyone has stated. There is internal leakage past the master cyl pistons. Probably sat for years with low fluid in it, rusted/scored master cyl walls, and someone just topped off reservoir with fresh fluid. IMHO.

 

Bleeding is free. Eliminate the possibility that you have air in the system which can come from an over active abs or stability control if the car is overdriven.
Worn pads also can contribute to a spongy pedal as the pistons are further out and more fluid is required. As mentioned someone else might have added fluid.

 

As I stated above, "after bleeding and checking booster".... What we don't know is the maintence history, pad history, tracking details etc. It sounds like its a garage queen. What would be helpful to know is there any braking effect at all when stopping? if none or little,.pads, or master cyl would be my bet.

 

The master cylinder went out on my 488 after about 5K miles, so not so strange. And the symptom initially was a pedal that went to the floor with very little braking ability followed shortly thereafter by no braking ability whatsoever as it dumped all the fluid. I suspect it would not take much of a leak to ruin the master cylinder seal.

 

Has the brake recall been done on it? There was a period of time that the brake reservoir cap was not ventilating properly and starving the master cylinder of brake fluid, If I understand the issue properly. The dealer replaced the cap with another type that had a better ventilation setup in it and adjusted some software to indicate low brake fluid earlier.

Have you bled the brake system yet? There could be air in the system that gives the spongy pedal. IF so, and it still is symptomatic, it is an internal leak in the master cylinder. Ill bet the new booster and master cyl will solve your problem if there are no external leaks in the system. GL.

 

replace master cylinder with new reservoir fluid cap. get some good brake fluid and do brake bleeding using pump at least 2.2 bar pressure and by using official dealer tool or texa to bleed abs system. helped with mine 488.

 

The brake recall was to address (in theory) a booster issue caused by the fluid leaking into the booster; so the symptom of the issue was not a spongy pedal but exactly the opposite (hard pedal, so no braking with normal pressure applied), since there was no booster working anymore.