My 348 Just expired

Merrily driving along, I depressed the clutch. There was sort of a bang and a lurch and then no resistance under the pedal. As I was still going I found somewhere safe to stop and got out to find fluid leaking from the pumpkin. I reckon its the slave cylinder seal. The next 3 hours were very dull. They couldn't get it on the first rescue truck they sent and the second took 2 hours to come. At least its back home safely now. I think I have read of a few slave failures recently. Is it an age related thing? (The rubber, not me)

I'm just looking for sympathy.

 

Yep it sounds like the thrust/slave bearing seal or alloy case has bust. On the plus side its a small fix There is shed loads of imfo and how tos on this forum.
MB: When mine went the alloy case bust open under the pressure, this pushed the seal through. I fit the Hills uprated unit.
Hey any pictures of ya car broken down, i took a couple of mine while i was waiting for the truck Good to look back on

 

Phil, I won't be able to give you much mechanical advice, but I can give you some sympathy! Sorry to hear about your troubles. It's never good to learn about one of our Brothers having to get picked up by a flatbed.

 

Not too big of a deal, it's a relatively straight forward job and there are threads on here detailing the whole job...pull that pumpkin off and see what gave...sounds like a seal...although I did see a pic one time of the actual slave unit had cracked...the hardest part of the whole job is figuring out WHICH of the 3 slave units you have! Once you know that, get the replace seals is easy and cheap...and while you have the pumpkin out, might as well measure the clutch plate thickness...7mm is what it starts at with 1.5mm tolerance but I am going by memory so don't quote me on that! Someone please correct me if I am wrong....if you catch the plates before they are actually burnt, I believe you can just add material onto them which is cheap to do....

Good luck and keep us posted....

 

Thanks all. I know fixing it's not a big deal. I'll take some pics as I pull it apart.

The real pain is the inconvenience of it letting me down and the subsequent waiting about and recovery.

In some ways its not too bad. The clutch had just started to slip a bit if I really provoked it, so that'll get done too. I probably would not have bothered doing that until the slipping became more obvious. Doing that sooner rather than later has got to be a good thing. Thanks for the sympathy.

 

I wonder if the slipping clutch was due to fluid getting sprayed onto the plates....

 

If the seals were weeping before the seals just blew out or the housing has cracked, then clutch fluid could have caused the slipping clutch.

You can also upgrade to a Hill Engineering/355 T/O bearing. Really really good apparently.

 

I wondered about fluid leaking onto the plate, however the clutch has done 20K miles. We'll find out later. I'm going to pull it apart this morning. I'll put some pics up later.

Oh, I forgot to mention the the recovery was made MUCH more difficult because the towing eye was missing from my toolkit. It expired going up a hill. If you dont have one, order one NOW. Hills do one.

 

No mysteries here. The plates are worn to the rivets - way past spec. The pressure required to operate this sort of diaphragm spring increases as the plates wear. Ferrari did not leave a great deal of overload tolerance on the slave unit so it went pop.
There were no other significant problems. A hint of oil past the triple seals. No oil or fluid on the plates. No grease leak. Just plain and simple worn out.

Lessons

1) have a towing eye
2) Dont ignore a slipping clutch even if its only a tiny bit.

I'm surprised its a 2 plate clutch. I thought they were only on early cars and mines 1994.

BTW Chaa, no pics of it broken down. no camera with me. Your diagnosis was spot on.
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Glad to see it wasn't any more serious. When that noise and symptom happened in my TR this past summer, it was first gear splitting in half
(a much costlier repair).

 

wow,

I believe that is the same T.O's that are on the 355's right? Thats the second one i've seen split like that. The cast iron ones (the old ones) seem to me IMO, to hold up better...

Also didn't know that Hill made an upgraded unit, if you get one, please advise us on your thoughts...

 

tmobileguy.

Yep, it looks like a 355 Valeo slave and measures up the same. I have ordered one from Paul Hill which he sells as a 355 part, and a towing eye. The other bits are on the way too, so should be back together by the end of the week. I took the old slave apart on the lathe to measure the thickness of metal. The thinnest part was 1.85mm and the bore was not machined centrally in the casting - and guess where it broke. I'm surprised it lasted this long, made this way in soft cast alloy. VERY poor engineering. If this is the standard of OEM I dont feel bad about using aftermarket parts.

Paul Hill's stuff is worthy of Ferrari. This Valeo junk isnt.

 

Exactly what happend to mine last year. Heres the link to my posting http://ferrarichat.com/forum/showthread.php?t=94880&highlight=355+slave+cylinder
Also here is a picture although bad, of my original slave cylinder compared to the Hills unit. Notice the very same alloy "burst" pushing the rubber seal through.
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All is well. Paul Hills 355 slave fits perfectly, Triple seals and o-rings done. I got the friction plates re-lined at a cost of £105. The pedal is much lighter in operation and there is no judder or harshness about it.

I have read of people having problems bleeding the clutch. The following worked with no problems for me. I was on my own and hadnt got a pressure bleeder to hand. The system was empty so I filled it before fitting the slave. After a few minutes fluid starts to leak from the hole in the flange. Open the bleed. Push the slave on as far as it will go and fit the guide. After a minute or so fluid starts to leak from the bleed. Close the bleed and pull the slave out as far as it will go. Wait a minute or 2. Open the bleed and push the slave as far as it will go. Air bubbles out of the bleed. Do this a few times until no air comes out of the bleed.
Reassemble clutch and refit pumpkin. Most of the air is now out of the system. Loosen the bleed ever so slightly and put a pipe on and into a bottle of fluid. Pump the pedal a few times. If the bleed is just cracked open you will feel air going out through the bleed. Keep the reservoir topped up. When there is no air. Tighten the bleed. Mine took about 5 or 6 pumps of the pedal. No Jacking up. No spongy pedal. If anything there is less drag and gears are easier than before it went bang.

Job done. Easy.

 

Did you need to buy Paul Hill's flange, too?? Or did his 355 slave/throwout fit correctly on your OEM flange?

 

Well I guess I have this "issue: to look forward to...... But then I can have "kevlar" installed on the friction disc!!

 

Nice work.

 

ND,

Paul Hills slave fits the OEM 348 flange as long as the spring centres are the correct distance apart. I think the later models which are prone to the cylinder bursting have the same flange as the 355. I'll post up the important dimension after I've been to the workshop and measured the old one.

 

Gothspeed.

Unless you have a good reason to go for kevlar,dont. Organic plates make a much smoother, nicer, less prone to judder clutch. Kevlar doesnt seem to last longer either. I had one on my Grinnall and it was horrid for its entire 7000 mile life!

 

Thank you!