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Thread: Front prop shaft and lift confusion...

  1. #1
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    Front prop shaft and lift confusion...

    I'm so very confused about the next step in trying to sort out my County. The love is still there but the relationship is a bit strained....

    So long story short, purchased car of my dreams, got her on the road and did a 7000 km road trip with some mild/moderate off road. On the last leg home I'm starting to hear rattles and feel vibrations I'm not sure were there before. I can feel them through the steering wheel most of the time at all speeds but with a definite harmonic type hum at exact 104km/h. Also the car wanders a fair bit at anything above 95 km/h.

    On the trip the radiator developed a weep (it was damp but didn't use any water....), in the end made it home without any dramas. No luck sourcing a replacement so this is on the to-do soon list but may be able to get it repaired given how minor the problem is. Only other drama was a leaking front diff seal, gotta love being able to replace a $4 seal on the roadside, very happy with this.

    So the County has a 2 inch lift, just replaced the original OM Emu shocks with the same (can't afford Koni's right now). All uni's replaced prior to the trip, with a little slop in the front prop shaft spline. Changed the tyres to Kumho MT51 (235/85R16), they're half way between a mud and AT pattern....hang in there...I'm getting the point.....

    On inspection after the trip one of the uni's on the front pro-shaft is very loose, no play, just loose.

    So my objective;
    1) Fix the vibrations before things start to break
    2) Sort out the steering at freeway speeds
    OR
    3) Confirm the that this is all a County thing and live with it....

    I've spent a few days trawling through the forum

    I've removed the front prop shaft and the vibrations have dropped marginally I think but not gone away. Discovered a bit of a clunk (backlash?) in the transfer case.... So my dilemma is;

    Keep the lift ?
    - I've fitted cranked rear radius rods to help with articulation
    - Considering fitting front castor correction bushes (I've read this could make the vibration worse. I have a pair of front radius rods, Terra Firma I think, that have a bend in them to suit a 2 inch lift but they are too wide for my diff).
    - Keep the lift, fit a Disco 1 front diff so I can use the modified front radius rods ?
    - Put a D2 double cardan front prop shaft in (I think I only have to change the transfer case flange)

    Take the lift out ?
    - Not sure if I need the lift, the car looks great with it but does it really help with anything else ????
    - Stock handling, stock steering geometry, nice

    However
    - My shocks have slightly different specs to stock and I'm not sure if this is going to cause problems;

    Front Open Front Closed Rear Open Rear Closed
    OM Emu 559mm 339mm 560mm 346mm
    Stock 548mm 330mm 553mm 346mm

    My gut feeling is go back to stock height springs to improve stability and be able to run a stock front prop shaft but I really don't want to have to shell out for another set of new shocks, equally I'm happy to mess around and keep the lift if i can get something that works, just not sure of the right path....anybody help before I go insane.

  2. #2
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    So the County does not have the double carden front driveshaft that the Series 3 Stage 1 had?

    i am sure your vibration will be from the lift you have putting the angles on the front drive shaft either out of UJ specs or close too it (the 101 has this issues built in). A double carden shaft should help but you will need to work out your phasing to ensure minimal vibration.

    garry
    REMLR 243

    2007 Range Rover Sport TDV6
    1977 FC 101
    1976 Jaguar XJ12C
    1973 Haflinger AP700
    1971 Jaguar V12 E-Type Series 3 Roadster
    1957 Series 1 88"
    1957 Series 1 88" Station Wagon

  3. #3
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    County vibrations

    Quote Originally Posted by Zcoota View Post
    I'm so very confused about the next step in trying to sort out my County. The love is still there but the relationship is a bit strained....

    So long story short, purchased car of my dreams, got her on the road and did a 7000 km road trip with some mild/moderate off road. On the last leg home I'm starting to hear rattles and feel vibrations I'm not sure were there before. I can feel them through the steering wheel most of the time at all speeds but with a definite harmonic type hum at exact 104km/h. Also the car wanders a fair bit at anything above 95 km/h.

    On the trip the radiator developed a weep (it was damp but didn't use any water....), in the end made it home without any dramas. No luck sourcing a replacement so this is on the to-do soon list but may be able to get it repaired given how minor the problem is. Only other drama was a leaking front diff seal, gotta love being able to replace a $4 seal on the roadside, very happy with this.

    So the County has a 2 inch lift, just replaced the original OM Emu shocks with the same (can't afford Koni's right now). All uni's replaced prior to the trip, with a little slop in the front prop shaft spline. Changed the tyres to Kumho MT51 (235/85R16), they're half way between a mud and AT pattern....hang in there...I'm getting the point.....

    On inspection after the trip one of the uni's on the front pro-shaft is very loose, no play, just loose.

    So my objective;
    1) Fix the vibrations before things start to break
    2) Sort out the steering at freeway speeds
    OR
    3) Confirm the that this is all a County thing and live with it....

    I've spent a few days trawling through the forum

    I've removed the front prop shaft and the vibrations have dropped marginally I think but not gone away. Discovered a bit of a clunk (backlash?) in the transfer case.... So my dilemma is;

    Keep the lift ?
    - I've fitted cranked rear radius rods to help with articulation
    - Considering fitting front castor correction bushes (I've read this could make the vibration worse. I have a pair of front radius rods, Terra Firma I think, that have a bend in them to suit a 2 inch lift but they are too wide for my diff).
    - Keep the lift, fit a Disco 1 front diff so I can use the modified front radius rods ?
    - Put a D2 double cardan front prop shaft in (I think I only have to change the transfer case flange)

    Take the lift out ?
    - Not sure if I need the lift, the car looks great with it but does it really help with anything else ????
    - Stock handling, stock steering geometry, nice

    However
    - My shocks have slightly different specs to stock and I'm not sure if this is going to cause problems;

    Front Open Front Closed Rear Open Rear Closed
    OM Emu 559mm 339mm 560mm 346mm
    Stock 548mm 330mm 553mm 346mm

    My gut feeling is go back to stock height springs to improve stability and be able to run a stock front prop shaft but I really don't want to have to shell out for another set of new shocks, equally I'm happy to mess around and keep the lift if i can get something that works, just not sure of the right path....anybody help before I go insane.

    IMO if you have removed the front prop shaft and the vibration is still there then its not the prop shaft.
    With the prop shaft on is the vibration present all the time (may be the diff), on deacceleration (may be the transfer box output shaft/bearings) or under load (may be the gearbox)?
    Do you have the V8 or the 4bd1?

    Regards,
    Phil B

    Custodian of:
    1974 S3 swb wagon (sold)
    1978 S3 swb canvas
    48 749 '88 4x4 Perentie
    1985 County with 4BD1T

  4. #4
    JDNSW's Avatar
    JDNSW is offline RoverLord Silver Subscriber
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    As above, if the vibration is still there with the shaft removed, it is not the front shaft.

    In my view, very few people have any reason for lifting these vehicles, and doing so only invites this sort of problem.

    If you are certain that the vibration is too high a frequency for it to be wheel related, you need to look at the engine and transmission. I would be looking for a loose engine or gearbox mount, or some part of the engine/transmission touching the chassis or body, especially if it is an Isuzu - these engines vibrate a lot, and the engine mounts insulate you from this. Also, do not discount the possibility that it is the rear prop shaft, even if you feel it in the steering - the steering is not insulated from the chassis.

    There is also the possibility that it is a high frequency shimmy related to an out of balance wheel or free play in the suspension or steering or insufficient swivel preload, although this is usually too low a frequency to be confused with a prop shaft issue.

    Note, when refitting the front prop shaft that the universals are not aligned as you would expect them to be. There are marks on the sliding joint to show the correct alignment. If you get this wrong it will vibrate, even without a lift.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

  5. #5
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    Quote Originally Posted by Phil B View Post
    IMO if you have removed the front prop shaft and the vibration is still there then its not the prop shaft.
    Hmmm missed that bit - agree it is not the prop shaft so my comments are not relavant .

    Garry
    REMLR 243

    2007 Range Rover Sport TDV6
    1977 FC 101
    1976 Jaguar XJ12C
    1973 Haflinger AP700
    1971 Jaguar V12 E-Type Series 3 Roadster
    1957 Series 1 88"
    1957 Series 1 88" Station Wagon

  6. #6
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    Cranked arms or caster correction bushes are used to correct caster from 0 degrees or a little less to about the stock 2 degrees, usually for a 2" lift.

    Either option points the snout of the front diff downwards, increasing the angles that both UJ's on the front prop shaft operate at.

    The only way to deal with the issue is to use slotted swivel balls with non correction bushes and normal arms.

    Not sure where the vibes are coming from in your case........... with the prop out.

    DL

  7. #7
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    Front prop shaft and lift confusion...

    I agree withe the above.

    In particular check if the gearbox mount bolts are loose. This makes a hell of a racket when very loose.

    Having done a Dobinson spring lift which resulted in vibration and vague steering, almost instantly.

    Gave up the idea eventually and reverted back to my factory 130 springs which I kept, without any impact on my moderate adventures.

    So my advice is stick to around the factory specs. JLR probably tried a couple of different spring variations all of which cost about the same and settled on the best allrounder. I did end up replacing the unis both front and back prop shafts from memory. They probably already needed replacing. The extra angle probably finished them off.

    Just my perspective. Here’s the visual comparison between the two. There’s not much height change in it, but it changed handling considerably and impact on unis.

    L322 tdv8 poverty pack - wow
    Perentie 110 wagon ARN 49-107 (probably selling) turbo, p/steer, RFSV front axle/trutrack, HF, gullwing windows, double jerrys etc.
    Perentie 110 wagon ARN 48-699 another project
    Track Trailer ARN 200-117
    REMLR # 137

  8. #8
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    Front prop shaft and lift confusion...

    A vibration at 100 is a wheel speed vibration. Almost certainly a tyre. Propshaft speed vibrations are at a much lower speed.

    In addition to getting the wheels balanced I would do a full front end inspection and adjustment. This is a two hour job well spent. It never gets done properly so every used Defender needs it.

    Hub bearing preload, swivel preload, steering box free play, check all tie rod ends, a check all link bushings and their bolts.

  9. #9
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    Quote Originally Posted by Red90 View Post
    A vibration at 100 is a wheel speed vibration. Almost certainly a tyre. Propshaft speed vibrations are at a much lower speed.

    In addition to getting the wheels balanced I would do a full front end inspection and adjustment. This is a two hour job well spent. It never gets done properly so every used Defender needs it.

    Hub bearing preload, swivel preload, steering box free play, check all tie rod ends, a check all link bushings and their bolts.
    Agree with this particularly the wheel balance. It could also be a tyre delaminating- check for bulges and cracks in the treads.
    Phil B

    Custodian of:
    1974 S3 swb wagon (sold)
    1978 S3 swb canvas
    48 749 '88 4x4 Perentie
    1985 County with 4BD1T

  10. #10
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    Wow! Thanks for the advice guys, I'm really liking this forum.

    I have the 4BD1 and yep, it seems to shake a lot (compared the the petrol Cruiser I've just come out of. I've checked the gearbox mounts and there are some cracks there so I'll swap them out.

    I've noticed the vibes are there at different times so I suppose I could be chasing a few different things. There's certainty the speed related one but also under deceleration and occasionally coasting.

    I did have to mess with the swivel preload before the trip (8,000km ago) and there was no vibration then so I suppose it could be the swivel bearings. Next thing to check.

    I couldn't find any markings on the pro-shaft but did put it together 45 degrees out of phase so hopefully thats ok. The very front uni is loose but no noticeable play in it. With the diff there's about 30 degrees backlash. But if anything I think the propshaft may be a contributor but not the sole source to the vibes as they are still there with it out.

    The tyres themselves look ok and were brand new before the trip. That said I recently drove a Triton with some Coopers with a horrendous front end vibration at all speeds, we changes the tyres and all gone.

    Thanks guys, I'll work my way through the list.

    Any thoughts on the OM Emu shocks being suitable with stock springs given the slightly different open and closed lengths ?

    Front Open Front Closed Rear Open Rear Closed
    OM Emu 559mm 339mm 560mm 346mm
    Stock 548mm 330mm 553mm 346mm

    Cheers,

    Mark

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