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328 Knocking Noise

Discussion in 'Technical Q&A' started by F328, Aug 12, 2004.

  1. F328

    F328 Karting

    Jul 7, 2004
    65
    Midlands UK
    Full Name:
    Graham
    I have a noise from rear of car and its now driving me mad. Is there a simple test I can do to see if I have a shock on the way out. The noise is like a small thud noticable at low speed (just as though the jack is banging up and down in the boot).Seems to go at speeds above 40 mph - it may be the sound of my exhaust covers it!!. If it is a shock it is a post ABS - Bilstein - shock. Can they be repaired ? Should I replace both? One of my friends thought it may be an engine mount so i am really confused.

    Help appreciated
     
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  3. dwhite

    dwhite F1 Rookie

    When my shocks were going bad they had a thud at low speed. However, as I drove the car in time it would go away. I changed all 4 and replaced every suspension bushing, as the car had 50K+ miles on it. Drives beautifully.

    I believe there are 4 engine mounts on the motor, if one were bad, I'm not sure you would hear a sound.
     
  4. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    1,527
    UK
    Full Name:
    Malcolm W
    Does the noise go after a few miles driving - if so it's more than likely the shockabsorber, basically it's air in the shock that "hydraulics" causing a knock, once the air has been disbursed the knocking stops untill the car has stood for a few hours.
     
  5. F308 MAN

    F308 MAN F1 Rookie

    Jan 19, 2004
    2,907
    Isle of Man
    Full Name:
    Dave S
    Hi Malcom....."gina" suffers from the same symptoms, but only on the rear offside.......should the shocks be replaced ? (now 25 yrs old)......or, once the noise in question disappears, do the units suffer no longer ?
    cheers, d
    ps...need to have a chat re winter service and carb rebuild stuff
     
  6. Skindiver

    Skindiver Karting

    Apr 22, 2004
    203
    JHB SA.
    Full Name:
    Greg
    Its the bootlid.
    Mine did the same. Even the PPI said it was shocks.. wasnt.
    Press down on the edge of the closed lid. If there is the slightest down movement.. typically on one side...

    You wont hear it at speed cos of all the other noise, and dont try look for an impact point or reason that the rubber stops should deaden the noise ..
    Its inside the catch where the upper U bolt 'clonks' on the lower catch when closed.

    Skin.
     
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  8. 308 GTB

    308 GTB F1 Veteran
    Rossa Subscribed

    Feb 7, 2002
    9,884
    New Jersey
    Full Name:
    Barry Wolinsky
    Graham,

    Another possibility is a failed stabilizer bar bushing (#26).

    Barry
     
  9. F328

    F328 Karting

    Jul 7, 2004
    65
    Midlands UK
    Full Name:
    Graham
    Thanks everyone for your replies.

    Skin - there is movement in one side of the bootlid and when you press it down it does 'knock'. How did you do your adjustment?

    Only got home late last night (away for the weekend) so couldn't take her out to test the bootlid theory so will look at this one first tonight.

    Keep you posted
     
  10. Skindiver

    Skindiver Karting

    Apr 22, 2004
    203
    JHB SA.
    Full Name:
    Greg
    I had mine adjusted because it was difficult to close. One side closed but the other usually needed two or three bangs to get it to close.
    I didn't manage to adjust it myself ( although i tried but i seemed to run out of thread on the upper lid U bolt. , The agents did at an annual service. It now closes first time and there is no downward play at all. As a spin off i found my Clonking right rear shock was totally cured. :)

    Skin.
     
  11. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,687
    North shore, MA
    Full Name:
    THE Birdman
    I have the same noise in my 308 and I drove another 308 a few weeks ago that sounded EXACTLY like mine. Last winter I did a complete rebuild on my entire rear suspension to try to get rid of it because I was so sure it was a suspension issue. Had the shocks rebuilt, replaced all the bushings, etc. and it made no difference. I think it's either an engine mount that allows something to hit something else, or maybe like skindiver says, the engine lid. I'll try that next! Just be careful adjusting that thing, because as one of our other Fchatters discovered, if you adjust it wrong and lock yourself out of the engine compartment, it gets tricky/expensive to get that thing open again.

    Birdman
     
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