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Replacing Rear Main Seal questions

Discussion in '365 GT4 2+2/400/412' started by 400iGuy, Apr 17, 2008.

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  1. 400iGuy

    400iGuy Formula 3
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    #1 400iGuy, Apr 17, 2008
    Has anyone replaced their main seal with the engine in the car? I have an oil leak that I am pretty sure is the rear main seal. I'm going to check that out this weekend with a dye. Thanks to Sebastien I have a pretty good idea how to get the auto transmission out but there are 2 areas of this project that I'm looking for some help with.

    1. What do I need to do topside in removing the transmission? Do I need to remove the center console to disconnect the auto shift mechanism from the transmission? If so, how the heck do you get it out. I know there's a screw under the read ash tray. After that???

    2. Replacement of the the main seal. The workshop manual says very little about how to do this (their assumption is you are doing it as part of an engine out rebuild). In either case it says Ferrari Tool AV 811 is needed. Any thoughts on who might have this type of tool or if it's even necessary? I have questions out to Partsource and T. Rutlands about the tool. I expect all of them will have the seal.

    Thanks,
    Al
    Apopka, FL
     
  2. markcF355

    markcF355 F1 Rookie

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    #2 markcF355, Apr 25, 2008
    Make sure its not the half O-ring seal between the rear bearing support and the sump housing. Wash the engine and trans completely and know EXACTLY where the leak is BEFORE you start.
    You'll be surprised how far oil came run along a surface before forming a drop. You don't what to replace a rear seal because of a failed head gasket!

    As far as the seal tool, I use a small block of wood and a rubber mallet. Just make sure the seal is in the right way and fully seated. Work your way around a little at a time and you'll be fine.

    Be careful under the car with the trans out! The motor mounts will NOT keep the engine from flopping over and breaking something like a distributor or your hand!

    If you remove the rear support replace the two little O-rings on the studs before you reinstall it.

    As far as the trans, you can disconnect the auto trans linkage from under the car. Be prepared to spend hours removing the bolts holding the bell housing to the adapter plate. You'll have to lift the diff off its mounts to slide the whole deal back to disconnect the torque tube.

    Don't forget to remove the dip-stick tube. Replace it after the trans is back in the car.

    This process is covered in the service manual.

    Good luck.
     
  3. b3tech

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    #3 b3tech, Apr 26, 2008
    well done Mark, I too have replaced the rear seal. All of what you stated is true and I repeat, plan to spend a lot of time. My suggestion is to do all of this on a lift. I do not see it being a garage type of event, but stranger things have happened with the people on this chat, so.....
    good luck.
     
  4. markcF355

    markcF355 F1 Rookie

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    #4 markcF355, Apr 27, 2008
    A lift would be nice. It's not very funny when you drop a trans only to figure out that you can't roll it out from under the car because its too low. I've had to go buy a second jack in the middle of one of these...
    That being said, I think putting the car up on four tall jack stands works well because it lets you reach the trans with a floor jack.
    If your jack doesn't have a trans plate it turns into a two person event for sure.

    IMO, if you do drop your trans, consider converting it to a Buick Switch Pitch. The two stall speeds let you get up into the higher RPM in normal driving.
     
  5. 400iGuy

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    #5 400iGuy, Apr 28, 2008
    I've been concerned about the height issue (since I do not have a lift available) I have a set of (4) 12 ton 32" tall jack stands which I haven't used yet. If I do my arms probably won't be long enough to work on anything connected to the car!

    Yesterday I did a test with flourescent dye and I am now pretty sure it is NOT the rear main. It's leaking higher than that. I hope to figure out more tonight.

    Al
     
  6. 2NA

    2NA F1 World Champ
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    #6 2NA, Apr 28, 2008
    Last edited by a moderator: Sep 7, 2017
    Plenty of things higher up that can leak.

    Ferraris use a one piece lip seal (as opposed to the 2-piece "rope" seals commonly used on American & British cars). They are not prone to leaking (although it is possible).

    Head gasket, cam cover, distributor drive, oil pressure sender are more likely suspects.

    It is possible that the oil galley plug (#53 on the drawing) is leaking. This would be better than a main seal but would still be a lot of work to tighten up.
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  7. 400iGuy

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    #7 400iGuy, Apr 29, 2008
    For some reason I cannot upload attachments....

    I saw there was an oil galley in the block with that plug but it is not leaking from there. I've managed to get up in there and clean it off and the fresh oil is not comming from that plug. There is what appears to be a drain tube (that I would show if I could upload a JPG!) that runs in the vacinity of that plug down to the oil pan. I don't think that tube itself is leaking at what ever connection it has since no fresh oil runs down the tube. I can reach the back of the cam covers and they are dry. It's leaking in that one area behind the driver side cylinder head that I cannot get to or see from either the bottom or the top. With everything cleaned off the oil is running down the rear of the block where it bolts to the trans.. right by the #58 in your attached diagram.

    I'll plug away on it tonight. Also I have to go figure out why I can't get the JPGs uploaded.

    Al
     
  8. 2NA

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    #8 2NA, Apr 29, 2008
    If I recall correctly the cylinder head dowel pin at the rear of the block is hollow and is an oil passage. I have seen oil leaks from head gaskets in this area (I've seen engines assembled without the dowel).
     
  9. 400iGuy

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    #9 400iGuy, Apr 29, 2008
    Does that dowel pin show up in the parts manual somewhere? Is that it right below the upper rear head stud?
     
  10. 2NA

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    #10 2NA, Apr 29, 2008
    Yes, IIRC that is the main oil feed to the camshafts in the left cylinder head. It is at nearly full oil pressure when running (obviously) and is typically sealed by a little o-ring molded into the head gasket. If it's leaking there you can try re-torqueing the head but it probably won't help (there is likely a little channel or split in the gasket there). To fix it the head has to come off.
     
  11. 400iGuy

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    #11 400iGuy, Apr 29, 2008
    I gave up trying to figure out what's going on in that area below the cam covers and above the plug in the oil gallery (now I'm not positive it's not that plug but it seems unlikely). I ordered an inspection scope. When it arrives I'll get back to it. Thanks for all the input.
     
  12. 2NA

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    #12 2NA, Apr 29, 2008
    Try a $10 inspection mirror and a flashlight.
     
  13. 400iGuy

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    #13 400iGuy, Apr 30, 2008
    I tried that. To get it to work I need arms 6" to 12" longer with 2 more elbows and better vision. Maybe a convex mirror may have showed a little more. an additonal problem with the mirror and flashlight is the tube that runs from the back of the engine (I'm guessing the cyl head) to the sump.
     
  14. rebirthauto

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    #14 rebirthauto, Apr 30, 2008
    Now that's a definite number 2 on my top ten worthwhile elective surgeries.

    Seb
     
  15. 400iGuy

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    #15 400iGuy, May 11, 2008
    Last edited by a moderator: Sep 7, 2017
    I guess the title of the thread should change to just "Find the Oil Leak"

    So far I have found a lot of places the oil is not leaking from and I'm homed in on the area below the water hose outlet (inlet?) on the rear of the left cyl head. It's a tough place to see even with the video scope I got (Testo 318-V). There are 2 units (see photo) that clearly were not on the car when it left the factory and are in my way big time. Each are connected to a vacuum hose and are grounded where their brackets are bolted to the cyl head. The purple wire runs from the top of the passenger foot-well to (or from?) the units and goes back into the passenger compartment just below the water heater valve cables in the firewall. I've looked under the dash and in the fuse box and see no sign of this wire connected to anything.

    Anybody know what purpose these serve? I'm going to remove them so I can gain better access to the rear of the cylinder head and would prefer not to put them back on if they aren't performing any useful purpose.

    Al
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  16. Steve Magnusson

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    #16 Steve Magnusson, May 11, 2008
    Can you tell where/what the vacuum lines go to? Does each electrovalve have only a single vacuum line and a port to atmosphere or is there another vacuum line (or more) on each?
     
  17. 400iGuy

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    #17 400iGuy, May 12, 2008
    I took them off to give myself access and found that there was only one vacuum line..... they were connnected to each other and nothing else!!!

    Al
     
  18. Steve Magnusson

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    #18 Steve Magnusson, May 12, 2008
    Well, that made it an easy decision (and explains why it looked plumbed a little odd for any useful functionality) -- yours is probably not the only 400/400i located here in the US with some questionable "added" emission equipment to baffle the inspector ;)
     
  19. Ashman

    Ashman Three Time F1 World Champ
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    #19 Ashman, May 14, 2008
    At first I wondered why anyone would install something like that, but you have the right answer I'm sure!

    Car owner: "Emissions equipment, sure it's there! Just look at all that stuff!"

    Inspector: "Pass! Here's your sticker."

    LOL
     
  20. 400iGuy

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    #20 400iGuy, May 14, 2008
    Thank goodness Florida doesn't have any inspections of any kind so no problem with emissions here!
     

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