R12 Vibration
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Thread: R12 Vibration

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    Default R12 Vibration

    Any ideas on an R12 with a "periodic" vibration - about half a second on, half off; perhaps worse when cornering relatively hard? Have checked cv joints, inboard universals, spline joint into diff and front wheel bearings for slack; also wheel balance front & rear plus rear bearings. Wondering whether it might be the rubber/steel damper block things at the front of the motor (the rubbers do seem a bit less than 100%), but don't really want to replace unless some chance of improvement. Anything else I should check (or dismantle)?

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    Quote Originally Posted by cootafrog View Post
    Any ideas on an R12 with a "periodic" vibration - about half a second on, half off; perhaps worse when cornering relatively hard? Have checked cv joints, inboard universals, spline joint into diff and front wheel bearings for slack; also wheel balance front & rear plus rear bearings. Wondering whether it might be the rubber/steel damper block things at the front of the motor (the rubbers do seem a bit less than 100%), but don't really want to replace unless some chance of improvement. Anything else I should check (or dismantle)?
    How were the wheels balanced? Dynamic or Static? If Static, is it possible a wheel is buckled?

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    Actually, I didn't balance them! Just swapped all four wheels & tyres (Michelin) from my other R12 which doesn't vibrate (no difference)! It sort of feels like an out of balance tailshaft (but tailshafts weren't a standard fitting on R12's, were they?!).

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    1000+ Posts schlitzaugen's Avatar
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    It may be those dampers, it may be any of the other engine/gearbox mounts, two on the sides of the engine, oen at the back of the gearbox. Exhaust supports might be worht a check too.

    If the vibration is accompanied by a deep rumble like gears meshing, you might have a worn satellite/sun gear pair in the diff.

    If the problem is with the engine mounts, don't change them, and you will have a worn set of gears in the diff.
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    Quote Originally Posted by cootafrog View Post
    Any ideas on an R12 with a "periodic" vibration - about half a second on, half off; perhaps worse when cornering relatively hard? Have checked cv joints, inboard universals, spline joint into diff and front wheel bearings for slack; also wheel balance front & rear plus rear bearings. Wondering whether it might be the rubber/steel damper block things at the front of the motor (the rubbers do seem a bit less than 100%), but don't really want to replace unless some chance of improvement. Anything else I should check (or dismantle)?
    Hi Cootafrog

    Can you explain your vibration a little more, at what speeds does it occur? is it going around left or right corners? is there any noises with the vibration? can you feel it in the steering wheel? does it feel like its coming from the front or rear?

    I little more specific information will help the experts on here diagnose your problem.
    Regards Col

    1973 Renault R12 Station Wagon
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    Can occur on straight at as low as 70km/hr, but most likely when enjoying (but not floogging) the car around corners (right hand possibly worse than left) at, say 90km/hr. Vibration is perhaps more noise than anything else - a deep rumble (mostly coming and going as though it is a rotating balance problem of some sort, but does seem to get closer to continuous on cornering). No feel of it in the steering wheel. Perhaps coming from front, but seems to be resonating throughout the body. And, it seems to get worse when the car is warmed up! (?) From that description, you might think the car is undriveable - but my (very non-technical) Wife can't hear or feel it at all - but then, I'm no good at gardening! And maybe Schlitzaugen's suggestion that the diff could be the problem is correct - car on hoist, spin front wheels by hand, and there is a bit of clicking/meshing noise in gearbox department. Oh, dear!

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    1000+ Posts schlitzaugen's Avatar
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    Yep. That is it.

    If you have leaking driveshaft seals (I know they all leak but this is a bad leak) it's another piece in the puzzle.

    On my car the leak is one side only. The side with the problem. And I think the problem is that the outdrive on the sun gear has become worn badly so it wobbles around. keep in mind, these cars have the diff supported by bearings, not the outdrives. Any vibration is more likely to affect the wear in the outdrive shaft or the bore it goes through the diff carrier (or both). Mine I guess is really bad. Has the same symptoms and it wobbles so much, if I replace the driveshaft seal it will be destroyed immediately, so I don't replace it anymore. The car drives very well with absolutely no problems up to a tested 130km/h (indicated) sustained speed.

    My strategy is to wait until it carks it and swap the 'box with a good spare I have.

    All that said. If there is no driveshaft seal destroying wobble, it may be the bearings rumbling on their way out. Which by the way can take your diff and/or crownwheel/pinion out too.
    Last edited by schlitzaugen; 10th September 2012 at 08:05 PM.
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    Hi Cootafrog

    Well that clicking noise should not be there. It may be a worn differential bearing with the differential moving side ways as you corner making the noise worse when cornering right.

    I think will need to remove the transaxle and strip it down which is an easy job and find the exact problem.
    Regards Col

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    Well, I have a bit of trouble thanking you both for the outcome (I was hoping for a quick fix!) - but certainly thanks very much for your time. (I'm tempted to go from 80 oil to 90 and keep driving!)
    Regards,
    Paul

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    and half a shed full of stuff from the other side of the Channel!

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    If you find the problem is indeed with the diff conic group (planetary/satellites) I have a spare good one here with diff and crown and matching final drive with pinion clusters which can be yours for postage costs. Swap your crown over or use the whole shebang!
    ACHTUNG ALLES LOOKENPEEPERS

    Das computermachine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitssparken. Ist nicht fur gewerken bei das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets-relaxen und watch das blinkenlights.

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    Hi Cootafrog

    Should take Schitzaugen up on his offer, they are easy transaxle to work on. Only need basic tools to set them up.
    Regards Col

    1973 Renault R12 Station Wagon
    1976 Renault R12 Station Wagon
    2002 Renault Laguna V6
    1973 Alpine A110

    http://alpine-a110.weebly.com/

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    1000+ Posts schlitzaugen's Avatar
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    Quote Originally Posted by COL View Post
    Hi Cootafrog

    Should take Schitzaugen up on his offer, they are easy transaxle to work on. Only need basic tools to set them up.

    Yes and no.

    The g'box is simple enough to pull apart, but the speedo worm drive nut is done up to 200Nm and it only has two (narrow) flats to grip by (normal open end spanner won't work). That is a lot of newton-meters! You don't normally need to undo that, but if swapping final drives/cw, you will need to adjust the endfloat (i.e. axial play) and protrusion of the final drive to get the final drive/cw mesh right (which is critical or you'll wreck the lot). This adjustment is achieved with shims at the back of the pinion cluster (under that worm drive nut and double tapered bearing).

    If I were you I would just drive it into the ground and then get another 'box or the innards I'm offering.
    Last edited by schlitzaugen; 11th September 2012 at 12:37 PM.
    ACHTUNG ALLES LOOKENPEEPERS

    Das computermachine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitssparken. Ist nicht fur gewerken bei das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets-relaxen und watch das blinkenlights.

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    G'day Cottafrog
    we had a very simalar sound coming from the r12 we were trying to fix and we replaced all the bearing and other things to no avail then we relised that the backingplate of the disc was rubbing on the inside of the rim only in one spot and only al speeds over 70km/ph
    so i sugest that you have a look at that before you go getting new stuff
    Kind Regards
    Ryan

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    "Speed has never killed anyone, suddenly becoming stationary... thatís what gets you"

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    OK, I've looked. And realised that somebody in a past life has already bent the backplates over to prevent this happening. Good thought, anyhow.
    Thanks,
    PB

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