Three photos, two questions. First, can anyone tell me what the little inverted dome is that's stuck to the roof of my F40 interior (1st photo)? Is it a dome light with the bulb broken? A sensor of some kind? I can't figure it out... Also, notice the cracks around the drilled holes in my front and rear rotors (2nd and 3rd photos). How serious is this? My dealer pointed them out today - I was surprised that the dealer who did the PPI on the car when I bought it last month didn't catch this. Were the stock F40 brake rotors drilled AND slotted like this?
Cracks are common on drilled rotors. Its nothing too bad. These cracks seem to still be minor compared to what I have seen on some pcars. I think as long as you are not too aggressive (ie no track days) you will be fine for a few miles still...but still recommend changing them ASAP. I have no idea what that dome is.
I am no expert, but these cracks are pretty common on drilled rotors. It is my understanding that you just have to keep an eye on them and avoid from the hairline cracks extending from one to another. All drilled rotors have this happen to them, even the ones that the holes are cast into the rotors. Sorry could not be of further help.
I don't think drilled AND slotted were standard, but could be wrong. Cracks don't look that bad to me. The thingie on your ceiling is a temp sensor for the A/C system, I believe.
I don't think it's a temp sensor. The manual says nothing about it, and the system is "old school" like my 328, where you turn the knob to red for hotter and blue for cooler. Any other F40 owners in here have this in their car? I'm wondering if it might be a sensor for the aftermarket Halon fire system.
The dome is the cabin temp sensor for the A/C. I've got a 308 in at the moment with big brakes fitted to the front. It's turns out it's discs are F40 and they too are slotted and drilled. I needed to replace them due to cracking, and the new ones are not slotted, but the drillings are better spaced and are nicely radiused like Porsche parts.
Standard F40 brake discs are drilled only, there were slotted discs available which were mainly for track use. Heat cracks are very common on F40, and from experience they are usually very shallow. The inverted dome is an a/c sensor. MW
cracks around the drilled holes are common and will not adversely affect braking. We generally keep an eye on them, when they go all way between holes or to the edge, we will change them. Slots are a help to keep surface swept, most manufacturers of performance rotors are offering rotors with both now.
There is no way to prevent cracks on drilled rotors that are used hard. (period) It is not a question of the machine work quality, nor is it a question of the quality of materials usd in the rotor. Drilled holes in a differentially heated and cooled item will crack. simple as that.
Yes! Generally accepted rule Rotors to be replaced when cracks between holes meet or you have to beat a friend in his Ferrari and you need 100% braking effiencecy to beat him with the truest rotors and race pads.
Shouldn't be a problem, generally they are only surface cracks, which dissapear after only a few thou is ground off the disc. MW
Time to change is when the outermost drilled holes crack to the outer diameter. At this point, you most likely also have 0.010 inch of lateral runout too, and you'll have a violent pedal vibration. Check each session, order spares. Common Brembo racing rotor size, however, a few years ago, Brembo changed the dimensions in the area of the mounting flange. To utilize the racing Brembo, you must remove the small "lip" on the mounting brake hat. Very easy on a milling machine. Rotor's the same size as common Nextel Cup (a.k.a. Winston Cup) stock cars. For track days, run slotted only, not drilled. Change the mounting screw nuts after a few rotor changes. Those are not the original brake rotors, nor dealer replacements. Best regards, Rob Schermerhorn
As I am sure you are aware of now, the thingie on your roof is an A?C sensor. I believe you will find one by your feet also. The rotors should be replaced. The ones to get are the steel Brembos as you will stop faster. You should keep your hats and on the new rotors drill out the rivets and refit you old hats to the new rotors. I believe that OEM rotors became unavailable about 4 years ago. gary
Huh? You mean cast iron. I've seen motorcycles run steel brake rotors, but not cars. There are no rivets. Are you refering to the hat to rotor screws? No need to drill, just unscrew. As stated previously, modification to the lip on the aluminum hat will be required when running a Brembo motorsport rotor. Best regards, Rob Schermerhorn
The little dome on the roof is either the A/C temp sensor or it's a the factory satellite linkup to make your slow down lights come on any time Maranello needs extra revenue
Hi Rob: I met you several times at Mancuso's when Richard was restoring his glass 308. I am Richard Messersmiths best friend. I was the one on the Ducati when we all used to ride together. He sends his regards and ask how unpleasant was it to have Jeff around? Richard was sure he has no screws on his rotors and politely disagrees) Unfortunately Richard can wrench on his F40 but can't log on to the itnernet. Is that something?
Hi Gary, nice to hear from you and that Richard's still fooling around with Ferraris. Send my regards, Rob BTW, if you (or Richard) look at the nice rotor photo posted at the top of this thread, that fastener you see is the head of a specialzed rotor-to-hat retaining screw. Remove the rotors, and one will then see the nuts on the other side. I can now see how one may think that's some kind of rivet.
Thanks for response Rob: Richard thinks the world of you and your abilities. I will refer him to the picture which I printed of all of the threads to send to him. Can you give me your opinion regarding 550's and 575's please. I am shopping for one now and I am using Richard as my go between negotiator. I figure if it can pass his inspection along with a dealer check I know I will have as close to a perfect car as possible. Richard and I are discussing whether it is worth moving up in dollars to get into a 2002 575 versus a 2000/01 550. Either way I am looking for a low milage perfect car. Richard feels they will both look the same over the hood. What is your thoughts on this? Thanks again gary