Bedford MJ Steering Shake

Discussion in 'REME' started by freddiestaratemyhamster, May 18, 2013.

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  1. Hi all

    Some here might remember I drove my MJ from UK to Cape town in 2011 and did the 19,500kms with not a single breakdown, not even a puncture! Since then Bob has been stored in Gordons Bay and I've just been out to move him up to Zambia as the South African Customs only allow a foreign registered vehicle to stay in the country for a limited time.

    The truck is in great mechanical condition now that I have resolved a number of issues that I would describe as teething problem (only done 78,000kms now, although 25 years old). However there is one I just can't fix! The ride is very smooth up to 73kms/hr and sometimes you can get up to 80 - 85kms and it is still smooth as silk, except for the slight rumble and vibration from the knobbly Michelin XZL tyres. But then the steering starts to shake. This is quite violent and very tiring for the driver. Slow down to 60 - 65kms/hr and it goes away. Speed up and it will probably come back at 73km/hr, but not guaranteed.

    I've had the front wheels professionally balanced so that's not it. Made no difference at all. Also I've had the tracking checked by laser - it was toe out by 1.5cm and we adjusted to the recommended toe in which is slight. Again, no difference.

    One clue might be the wear to the front tyre on the drivers side. When I had the wheels balanced in South Africa they couldn't balance this one because it had worn in a peculiar way (I now use it as a spare) - the individual blocks of the tread pattern are scuffed and worn on one face. But it did this shaking when I had the bar grips - before I got the Michelins from Vass & Co.

    My guess is that something is misaligned. Any ideas what to look for and check? Any advice most welcome.
  2. prop shaft out of balance, usually happens when universal joints get worn. vibration usually starts at around 40 mph then stops as you slow down. worthwhile getting them checked out.
    • Like Like x 1
  3. Could be tyres that are worn unevenly, mine did it with the bar grips until they wore a bit.
  4. How long has it sat for? Tyres develop flat spots when the vehicle isn't moved for a year or two. Had this problem with my Commer Q4, never did cure it due to the expense of new tyres.....
    Sometimes you get lucky and the flat spot goes away after a while, sometimes it's there forever.
  5. prop.jpg

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  6. check the canvas on the rack and pinion there is should be a canvas gasket, IIRC. If that goes its cause vibration, also if one tyre is below 2 pound you get vibration at forty, that was a common fault, also have at the grease nipples on the rear of the wheel, if that gets low has the same effect. Look at the drop arms as well they can get bent and its hard to spot.

    You need to get it sorted as convoy cock, diesel dick will lead to impotence. Also you can be prone to white finger.

    Good luck and let us know how you get on,

  7. Yes, this is worth checking out, but I have checked the UJ's recently and they are all good. I've painstakingly greased all of them (9 grease points) every 10,000kms. Question - can the prop shaft be out of balance WITHOUT the UJ's being worn? Next question, how do you balance a prop shaft??

    Can't really go for the answer suggesting a flat spot - the shake was there from day one when I had different tyres.
  8. sometimes there is rectangluar balance plates on them , similar to wheel balance weights. these can sometimes fall off if not properly stuck on. check for signs of where thes may have been , to check the balance you would need to go to a engineering shop. they would be able to check them for you,
  9. Two of the biggest causes for the type of vibration you mention are flat spots on the front tyres caused by not moving for a while and the metalastic coupling between the steering column and steering box. If it's flat spotted tyres, as long as the tyre wear and pressures are ok and the steering geometry is good then it should disappear through regular use. If it's the coupling you need to change it before it shears.

    Two other things it could be, and I've seen both many times, the steering box mounting bolts need torque tightening and the front swivel hubs need re-shimming (similar problem to the old Land Rover Mk 3).

    Edited to add:

    You should also check all the cab mounting bolts, particularly if you've had wheel wobble for a while!
    • Like Like x 1
  10. All of above but best bet is tyre flat spots or distortion . These occur for loads of reasons. Standing for a while, hard breaking (even only once). Kerbing and tons more.
    Just a guess but new tyres might be the easy option you never know they may be cheap out there. Then at least you know.

  11. I don't think I go for the tyre flat spot theory, for reasons already stated but I'll certainly check the metalastic coupling on the steering, especially as I've been carting a spare one around with me for the last 2 and a half years!
    And I'll check the steering box mounting bolts while I'm at it. Thanks.
  12. If you find the balance weights have come off the prop (easy to spot as there will be a different coloured square) put a jubilee clip round it with the bolt part where the balance weight should be..take it for a run and then add a couple more if necessary. It's not a perfect method but it'll give you an idea as to the weight that's needed.
    • Like Like x 1
  13. Wish I'd posted this question whilst I was still out in Zambia, now I have to go all the way back just to check... Yes' I've seen those balance plates on the prop shafts, so I know what to look for. But surely the steering shake wouldn't happen unless 4 wheel drive was engaged, or is that crooked thinking...

    Impossible to have prop shaft balancing done in Livingstone, Zambia - had trouble finding even a bicycle pump and a tarpaulin!
  14. It's probably parkinsons disease, put the old **** down.
    • Like Like x 3
  15. shaking would happen in 2 wheel drive also, just the same with rwd cars, if prop shaft lost balance you would feel it througr the steering.
    • Like Like x 1