GT4 - where does this hose go? | FerrariChat

GT4 - where does this hose go?

Discussion in '308/328' started by dstacy, Oct 29, 2007.

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  1. dstacy

    dstacy F1 World Champ
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    #1 dstacy, Oct 29, 2007
    Last edited by a moderator: Sep 7, 2017
    So I'm changing the oil an I see a braided hose that goes from the rear left carb, past the ignition coils, over the gas tank, then forward through the bulkhead.

    Here are 2 pictures:
    The first shows where it leaves the carb.
    The second show the inner fender removed. You can see the filler neck hose to the right. You're looking forward from the rear wheel.

    I couldn't find it in the 1975 parts book. Old braided hose so it has to go. The question is where is the other end?

    Anyone want to fill me in? Or take a guess?
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  2. 208 GT4

    208 GT4 Formula 3

    Dec 27, 2003
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    I'm not sure if it's the same as my 308 GT4, but on my car the fuel is sucked from the tank, then fed through the carb plumbing with any excess returning to the other tank. By continuously flowing fuel through the carbs, it prevents fuel evaporation. But I'm pretty sure mine returns it to the top of the tank, not the bottom???
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #3 Steve Magnusson, Oct 29, 2007
    Last edited by a moderator: Sep 7, 2017
  4. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
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    91TR has it. It's the vacuum hose for the brake servo. It goes through the body and is fun to change. Enjoy
     
  5. dstacy

    dstacy F1 World Champ
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    Thanks Steve for solving the mystery. I appreciate it.

    So now for the $64,000 question; "Ok, who is the idiot who thought routing this THROUGH the body, rather than under it, would be a good idea?"
    Oh this is going to be fun to change :(
     
  6. jimshadow

    jimshadow F1 Veteran
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    Can you affix the new one to the old and pull through, or are the hoses going thru the body all twisted up??

    Jim
     
  7. dstacy

    dstacy F1 World Champ
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    I'm not sure Jim. It looks like the hose enters the passenger compartment behind the rear seat. Take a look at the picture. See how it goes through the rear firewall? Where else could it go? The only thing in front of the firewall is the rear seat.
     
  8. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Dave -- see this thread:

    http://ferrarichat.com/forum/showthread.php?t=119549 (has some photos from Peter doing this project on his 308GT4)

    and do some searches on "brake booster hose" or maybe "heater hose". You need to shift, or remove the LH side gas tank and there is a small removeable access cover in the front LH wheel well (that might be hidden by undercoat) - then you'll have a straight enough shot where you can pull the new hose(s) thru using the old hose(s).
     
  9. dstacy

    dstacy F1 World Champ
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    Holy Crap! What a PIA!
    I'm starting to think, "It isn't broken, leave it alone."
     
  10. Timj27

    Timj27 Rookie

    Sep 7, 2007
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    Hi Dave, have you determined it to be the Brake boost yet? Is there also vacume assist with the heater system vents? could this be for both? Not sure just learning.
     
  11. Hans

    Hans F1 Veteran

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    Is it broken??? ;)

    Then the OTHER $64K question: what happens if it breaks while driving the car? In other words: pull the hose and try what that does to your car. If it leaves you with no brakes, then just maybe, it's worth the PIA after all. If it doesn't affect safety, I'd just leave it there and wait until it really breaks - in 30 years probably. And WHEN it breaks, just plumb a new stainless steel tube underneath the car after all....

    Just some thoughts....

    Hans
     
  12. 360gtracer

    360gtracer Formula 3

    May 18, 2004
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    If you do have to replace it, I've heard of people putting a dual male hose barb into the end of the old and the end of the new, lubing it up GENEROUSLY, and pulling through the body. Once the joint is through, seperate the hose barbs and discard the old.

    BTW - I have some Gates Greenstripe hose for this very purpose - was on my list of things to do before I sold the 308. PM me if you need any. Also have a larger size, I think for coolant.... Again, PM if interested, and I'll let you know what I have....

    Thanks and good luck.

    gp
     
  13. eurogt4

    eurogt4 Karting

    Apr 15, 2006
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    You really should use hose made for vacumm boosters. It usually is reinforced so that it does not collapse under vacumm, particularly when it has a few years on it in contact with fuel vapor.
     
  14. Steve King

    Steve King F1 Rookie

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    The dual barb is the way to go with a lot of silicon lub. But unfortunately you still need to pull the gas tank. Usually when someone does this they replace all of the hoses on that side which is the main water hose and the heater hose and the vacuum hose. Then you can replace the fuel tank cross over hose while you're at it. And if you are in the mood you can pull the other fuel tank and do the AC hoses . Then again if the hoeses look good and everything works then you may want to let it go.
     
  15. miked

    miked Formula Junior

    Feb 7, 2001
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    #15 miked, Oct 30, 2007
    Last edited by a moderator: Sep 7, 2017
    There is a sheet metal clip inside the fender (below the side window, just in front of the wheel well) that may or may not be tight around the hose(s). If you are lucky the hose will slide through. If the hose seems to be caught somewhere in the dark abyss, this is the likely spot. Accessed by removing the side panel/pocket and the sheet metal access panel riveted over the hole. Once this panel is off changing the hoses is a snap. It is also a good time to lube those engine cover and trunk lid cables, they are right inside the hole.
    IMHO, it is often easier to just open the panel in the first place rather than fighting a stubborn hose.
    Here is my passenger side, ie. AC hoses. The driver's side is similar. The dark metal is the inside of the rear fender. Note the additional US spec "firewall bulkhead" frame tubing just behind the hoses.

    With the panel removed you should be able to avoid removing the gas tank. You can easily grasp the hose as it comes through the firewall and also where it goes into the rocker panel under the door. With a helper outside to work the hose in the engine bay and the front wheel well (remove the small panel there too) the hoses can be easily managed.
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  16. Brian Harper

    Brian Harper F1 Rookie
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    Oh sure, now you mention this! I'm doing this right now. The gas tank is free, but not out. I have removed the transfer gear cover and studs and am in the process of removing the brake disc to get the tank out. Hopefully removing the suspension won't be necessary. I knew there was a panel in the backseats but I haven't looked in there yet.
    The "while I'm in there" list grows constantly. I need to replace the heater hose. So I might as well replace the vacuum hose. Well, the fuel tank is coming out and I really need to replace the transfer pipe rubber lines that I was putting off so I just cut it off. I removed the transfer gear case and I already knew about two stripped holes, so I'll helicoil those this time. I'll have the brake disc off, maybe I should get those resurfaced. Oh and the brake lines are original, definately time for those to go away and the caliper will already be off...

    Oh, and I wasn't under the car tonight when we had a heckuva 5.6 earthquake!
     
  17. dstacy

    dstacy F1 World Champ
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    #17 dstacy, Oct 31, 2007
    Last edited by a moderator: Sep 7, 2017

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