My New 456 and clutch prob I need help with

attached are pics of my new 1995 456. Verde Silverstone;beige. 15K miles. Completed 30K service and put on new shocks to replace the leaky rears and then Drove it home about 500 miles- and it drove great.unbelievable. even handled I-75 stop and go ( more stop than go) traffic for 20 miles without overheating in 100 degree weather.

but the more i drove it, the more free play in clutch pedal, so that by the time I was home I had 4-5 cm free play, then the clutch would disengage as I pushed pedal to the floor. Managed to limp home in second gear ( afraid to take any route that would require shifting!). This AM, cannot get into gear as clutch will not disengage as I push pedal. Is this a bad master cylinder or a problem with air? If its the master ( its original), is this an easy replacement for someone like me who has rebuilt engines, replaces shocks, AC units, etc, on american cars? Many thanks!
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

1 check is to see the fliud level in the reservoir. IIRC the inlet for the clutch is higher than the min line on the master. But if the fluid is lower than the clutch inlet line you have sucked some air. once you top it off then you can try bleeding the clutch but you have to get the car on jackstands and do it two man style. This may have been done on the 30k service and perhaps they got an air bubble in there. also check for leaks around the bellhouse or drips on the undertray indicating a hydralic leak. If a clutch plate is worn out it will slip under power and pedal in makes it worse. A clutch that will not release means you can't get the finders to bend in far enough to release the pressure on the plate. That means broken or bent pressure plate fingers, too thick an installed height on plates, t/o bearing not moving or destroyed, hydralics not working. I vote for hydralics until you give us more info.

 

reservoir filled appropriately. car ran fine till I hit stop and go traffic and had to use clutch pedal. doubt its the clutch or thrust bearing. It reminds me of what a brake master does when it goes. It looks like an easy replacement and fairly inexpensive part so Ill do that this week. any one else have any thoughts.?

 

Michael- Yes. Before you do that, bleed the master cylinder. A trick learned from Brian Crall.

Taz
Terry Phillips

 

lol

 

my guess. unknown fluid in system. air drawn into system from worn pistons/seals. does this car have a slave cyl. as well as a master cyl.? pressure bleed the system. Auto zone will loan a free tool system for that procedure, at least they do here. i would bet $$ this is a fluid problem. not the first time i lost a bet

 

I think I may be able to help you here..

My car is a UK '96 456GT. Probably be easiest to describe my symptoms to see if they coincide with yours. I drove the car down to Le Mans one year, no problems, enjoyable weekend etc then on the way back after c 1 hour on motorway pulled in for fuel to find no resistance on clutch pedal travel until 75% down, quickly gave pedal a few pumps and the resistance point went to normal. Headed off, drove for a bit then went for the clutch pedal to find no resistance on pedal (flat to the floor). Attempted bleeding at roadside to no avail and had to drive back Rouen to Calais, on/off ferry etc without a clutch, cranking in first gear on starter motor to get going (not funny!)

Once home bled the system and normal service resumed for a mile or two then resistance point started dropping - I was having to pump the pedal every few miles to keep the pedal. There was no fluid leak, reservoir to max and no fluid from bell housing. First thoughts were master cylinder (easy to replace and cheap to buy - same as Alfa GTV I seem to remember - I have AP part no somewhere if you need) and had new hydraulic hose made up (cheaper than the OE by a mile) - made no difference. Fitted new clutch plate and cover (same clutch as Testa Rossa by the way) - made no difference. Bit the bullet and bought new concentric slave cylinder (from Hill Engineering - beautifully made), pulled the gearbox again to fit and bingo, problem solved and still going strong - never really got my head around what was going on as there was no fluid leak, assume it was bypassing seals then returning on pumping.

Jeremy

 

I re-read the thread and to clarify, the clutch slave cylinder is not conventional on your car, it is a concentric hydraulic clutch release bearing, the clutch release bearing and slave cylinder are one and the same thing.

 

And usually when those annular T/O bearings go they leak a witness trail of fluid which will point right to their letting fluid bypass the seals. Heat/cold makes problems worse. Seals in a traditional slave like on a QV mondial cabriolet will leak internally "sometimes" and fail just like yours did. In fact I had that exact failure once. Interestingly, there is an upgrade for those on 348/355 by Hill Eng. The OEM ones can actually blow out the metal while the seals stay intact. How's that for great Ferrari part sourcing?

 

On the 456/550, the bearing by Hill Engineering is quite similar to the 348/355 one, but it is not identical:

http://www.ricambiamerica.com/product_info.php?cPath=600_100033&products_id=335955

 

tonight we bled the clutch. initially I got some fluid out, then no matter how much pumping of the clutch, no more fluid came out. Wife was in drivers seat, I was under car handling the bleeder nipple. she said "the pedal is all the way to floor without resistance" so we kept bleeding, but then We stopped. I checked, and Sure enough, pedal all the way to floor. figured the master had to be shot. Had dinner, went back to garage, and did nothing else to car in between. lo and behold, the clutch is back to normal with normal engagement. But while The level in the main reservoir seems the same (see pics) ,the level in the front drivers side segment of the reservoir is lower than the max line in the other chambers, and its this chamber that feeds the master. I am confused as to why it is now working, and what I could have done to make it better. When I bled it, the fluid that cam out ( a few squirts) was junky and dark, but then amber and normal. I am also confused about why that small chamber isnt filling up like I think it was before, even though the fluid next to it is above the max line as recommended by the manual.
Image Unavailable, Please Login

 

you need to look inside the reservoir to see how it is baffled and how fluid goes into the chambers. You could have 1 giant tank, front/rear seperation and even clutch feed separation. Sometimes you could bleed the clutch dry and suck air and still see you got plenty of fluid for brakes because of the baffling of the tank. This is actually a safety feature so that if you loose clutch hydralics you will still have brakes. If you look at your picture the hose off the tank is the clutchline. The tank around the clutch line looks dry from the photo relative to the brakes. You need to bleed the clutch carefully and watch it when you bleed because everytime you bleed it down too low you suck in new air and have to start all over. So you need to add more fluid as you bleed. Also, bleed technique is important. The technique you should use to clear the line getting the old cr@p out is two man where the guy at the bleeder says down and the guy in the car pushes the pedal to the floor through a count of about 1/1 thousand. If you suspect that there is air difficult to remove trapped air after you have done this standard bleed you can agitate/bleed the fluid by having the in car guy pump the clutch pedal fast and full travel about 6 times and when he says 6 he hold the pedal to the floor and the guy at the bleeder cracks the bleeder open and a massive rush of fluid flys out. This tricks works very well on 348's which trap air all the time. Do the agitate/bleed until you get no air coming out then once more with no air then a slow up/down bleed once seing no air and you will have the best pedal you can get. If you really have master cylinder seal issues those need to be fixed and no amount of bleeding is going to help. This two man bleed is more effective than any motive or pressure bleeder.

 

OK, its working fine now. Appreciate everyones help. With the car started, some electric switch or pressurizer must have caused fluid transfer, so now all sections of reservoir are filled, including clutch section. We drove car and it drives great. No problems.Thanks to Taz for pushing me to flush it as that is all I did, and its working fine. So hopefully I avoided a CRB replacement. mibi

 

was noman able to help ?

 

didnt need to - did a two man clutch bleed without the machine. Ill drive it to work tomorrow and stop by on the way to work and thank him for offering.

 

Michael

Have you got to the bottom of this yet?

 

yes. my master clutch cylinder was 15 yrs old and the seal failed. Thats all it was,; replaced it and all is fine