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T/O Bearing Failure w/pics

Discussion in 'Technical Q&A' started by ShanB, Apr 25, 2004.

  1. ShanB

    ShanB Formula Junior

    Jul 9, 2003
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    shanb
    While on my way home from a short run last night I went to take off from a stop and the clutch pedal went to the floor. I managed to get to a nearby gas station, leaving a trail of hydraulic fluid behind me. I flat-bedded the car home and called it a night. Today I raised the car and pressurized the brake fluid reservoir then watched and listened as brake fluid started streaming from under the bell housing. I removed the rear wheels, bumper, exhaust and bell housing to find my T/O bearing had blown apart. Mine was the updated one shared with the F355. I know that the seals do fail from time to time, but was wondering if any experienced F-chatters have seen this kind of failure happen before?
     
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  3. vincent355

    vincent355 F1 Veteran
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    Woe, looks like major failure. Can you tell what it was rubbing on.
     
  4. ShanB

    ShanB Formula Junior

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    Vincent - Before I pulled it off the shaft, I examined the bearing as it sat on the assembly. I really couldn't find anything rubbing or binding against the area where it failed. The closest object was the spring on that side. There seemed to be enough clearance from the spring.
     
  5. vincent355

    vincent355 F1 Veteran
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    I'm just trying to figure out how something like that could happen. I mean, it doesn't look like just the seal, but th whole assembly is tweaked.
     
  6. ShanB

    ShanB Formula Junior

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    Yup - you're right it is odd to my eye too. On the bright side, I'm getting pretty good at taking things apart. Once I realized where the leak was coming from it took me less than 45 min to get the T/O bearing out while listening to NPR. Everything has a positive side. Ha-ha!...

    Hey, how's the F355?
     
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  8. Ryan S.

    Ryan S. Two Time F1 World Champ
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    Mar 20, 2004
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    I dont know really anything regarding ferraris and their mechanical tid bits. Butttttt, is that part under any kind of pressure. It looks like it was blown out, not ripped. Anyways, good luck on fixing it. And on a side note, I cant wait till i have my own ferrari to play around with. Fixing a ferrari sounds like so much fun.
     
  9. ShanB

    ShanB Formula Junior

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    Ryan - definitely yes it is under some high hydraulic pressure. I suspect it did blow out, but not sure why.
     
  10. ernie

    ernie Two Time F1 World Champ
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    OH SNAP!!!!!!! Dang Shan that looks ugly. Looking at the picture, it apears that it could be a bad casting of the part. I don't see why it would just come apart like that. Didn't you just finish working on that a couple of months ago? I would look into have the parts place you got it from give you a new one. It has to be under some kind of warranty. Oh wait, duuuuuuuu, warranty on a Ferrari part, what am I stupid or something. Hahahaaaa. Anyway hope you get it all worked out.
     
  11. khayes

    khayes Formula Junior

    Nov 1, 2003
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    Hello Shan, quick question for you? What brake fluid do you use?

    FoSA just recommended Dot 3 to me. I need to top off my reservoir.

    I thought I was having the same problem you had this weekend. I was excellerating HARD while going uphill and lost my clutch to the floor for a moment. It came right back and everything works fine now. The fluid is between Min and Max and I guess the combination of going up a steep incline and a HARD excelleration between 2cd and 3rd were just enough to slosh the fluid around the reservoir and cause me to lose pressure momentariy. Just guessing.
     
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  13. ShanB

    ShanB Formula Junior

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    Hi Kelly. I use Valvoline SynPower DOT 4 brake fluid. Glad yours is okay. Wierd feeling suddenly losing the clutch, isn't it?

    Ernie: When I rebuilt the flywheel a few months ago I didn't replace the t/o bearing as there was no apparent need. The slave cylinder update was already done and the bearing looked fine after 10 years in service. I even had a mechanic eyeball my work and everything looked good. Goes to show you can never really tell by looking when things are going to wear out.
     
  14. tbakowsky

    tbakowsky F1 World Champ
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    Sep 18, 2002
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    This a actually quite common. I don't know why Ferrari went to this style of slave. The 348 units which are cast are much mor reliable. I have never seen a cast one do this. The part is expensive to replace though as it come in a complete kit about 1200 buck if I remember right.
     
  15. jakermc

    jakermc Formula 3
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    Jan 17, 2004
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    This exact thing happened to me on my 355 about 1 month ago. Picture looks identical to my blown out part. I didn't have time to do the job myself so I brought it to Norwood's. The part was $1000 or $1100. James Patterson at the shop said he had seen this a few times on the 355 and in every case the part had a 1997 manufacture date. My car is a '98 but sure enough the part had a '97 date stamp on it. He said the part it was replaced with has been updated and should be a little more robust. Casting seems to be a weak link in the original design. Sad to see a TO bearing blow up after only 12,500 miles.
     
  16. ShanB

    ShanB Formula Junior

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    Thanks guys you are exactly right. I asked around and apparently this does happen more often than you would suspect. You would think a recall would have been in place by now. Hopefully this info will help another 348 or F355 owner out there. Yet another example of what makes this such a great forum. I traced and flushed the hydraulic lines and removed the bearing mount and O-rings. It all looks good. A new t/o bearing is on it's way from Sodacom's. I'll be up and running in time for the weekend. Here's what I figured:
    AAA flatbed home: $0.00
    SynPower brake fluid: $3.85
    New t/o bearing: $417.00
    The understanding gained by working on the car myself: PRICELESS...

    Thanks,
    Shan
     
  17. Husker

    Husker F1 Veteran
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    Dec 31, 2003
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    Shan, my 348 is having the T/O bearing replaced right now. Only mine hadn't yet failed completely. I heard a high pitched squeal coming from the engine area. I was sure it was the water pump (or worse) so I shipped it to my trusty Ferrari mechanic near Dallas and he called me and said "throw out bearing". That was good news from a labor standpoint but the darn part was $1100-ish.

    Funny thing was, he said he just sent another 348 on its way with a new T/O bearing, so there must be something in the air with the T/O bearings, huh?
     
  18. fatbillybob

    fatbillybob F1 World Champ
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    Aug 10, 2002
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    I have never seen one fail nor heard on one failing like shan's. In fact even the early 348 series had no problem. I'm not really sure why it was ever changed. Is it confirmed that the 355 T/O bearing and the 348 bearing are the same? What about the single 355 clutch plate and pressure plate? Do they both use the same anular t/o bearing housing?
     
  19. ShanB

    ShanB Formula Junior

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    Howdy Billybob - The updated 348 t/o bearing (the 348 update kit includes the new flange) is the same as the F355. The updated t/o bearing (part #176560) can apparently be purchased seperately (I'll know for sure after UPS gets here on Friday) It is a cast thrust bearing with four teflon seals, one being a split-ring. While not listed in my 348 parts book my handy F355 parts manual says "valid from gearbox #2439" which makes me wonder if there was an upgrade in between?
     
  20. ShanB

    ShanB Formula Junior

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    By the way - forgot to add that the metal walls in the areas where the seals seat is deceptively thin. There are black (look like Nitirile rubber) rings that sit behind the blue teflon seals. You can see where the one is fragmented and pushing out of the cracked metal in the photo. That area where the casting split the metal was only 2.1mm thick compared to an average thickness of 2.7-3.0mm around the rest of the wall. Maybe this was a bad casting?
     
  21. fatbillybob

    fatbillybob F1 World Champ
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    Aug 10, 2002
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    Well shan,

    You'll have to tell us if that 176xxxx fits. My 348 94 manual stops at 16xxxxxx in that part number series. My T/o bearing for the "last" twin disc unit looks like your T/o bearing. It is unknown if after a certain time 4re when to this t/o bearing for twins singles and 355's
     
  22. ShanB

    ShanB Formula Junior

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    Just got back from a business trip. Billybob - yes, it appears the #176xxxx fits the 348. Same part, different number - taken from the F355 parts book. Here is the old vs new one, as well as a pic showing the four internal gaskets/o-rings you have to buy seperately.
     
  23. ShanB

    ShanB Formula Junior

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    Just to update - installed the seals tonight, placed the new bearing on the shaft and reinstalled the bell housing. The new seals are a very tight fit at first. It then took a while to bleed the clutch. The pressure bleeder couldn't get all the air out of the master so I had revert to the two-person method. Reconnected the battery, warmed 'er up and went for a test drive. All is well.
     
  24. ernie

    ernie Two Time F1 World Champ
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    Sweet Shan. Glad to hear it's back on the road were it belongs. Nice pics too.
     
  25. vincent355

    vincent355 F1 Veteran
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    Awesome.

    Thanks for the pics.
     
  26. SteelFlint

    SteelFlint Rookie

    Aug 17, 2006
    10
    My '91 just went after 26K miles... Ferrari Maserati dealer local is charing $2,400 in parts. And it was exactly the same scenario; short jaunt on the freeway, stopped at the light, and nothing.

    No pleased, considering I've only owned the car for like a couple of months..
     
  27. PAP 348

    PAP 348 Moderator
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    Dec 10, 2005
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    Um, do you still have the car at home? Or is it at the Ferrari dealer getting fixed? What parts are they replacing for $2400????!!!!!:D Dont do it! :D
     
  28. PAP 348

    PAP 348 Moderator
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    Dec 10, 2005
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    I know where you are coming from there. I had my 348 for 3 months and the clutch pressure plate fingers broke. No 348 action for pap for nearly 2 months as I got me a race clutch made. :D Fustrating though isnt it?

    http://www.ferrarichat.com/forum/showthread.php?t=86136&page=7
     

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