Disco vibration under load/acceleration

Hi guys.

I've got an odd problem at the moment on my Disco, which started at the
same time as I noticed a hole in the exhaust where the bracket behind
the second box had worn through the pipe, but I guess the two problems
are unrelated.

When I accelerate, I get a heavy vibration shaking the entire vehicle,
it's worse in 4th/5th and it's exacerbated by increasing the load on
the engine such as going uphill or accelerating harder. It stops as
soon as I ease off on the accelerator. It almost feels as though a
wheel of some sort is out of balance and is wobbling while turning, but
it's incredibly forceful, and the engine feels like it's working hard
and getting nowhere - it's almost like some kind of harmonic.

Anyone have any ideas what's going on here?

Cheers,
Aled.

On 2006-04-28, [email protected] <[email protected]> wrote:

> When I accelerate, I get a heavy vibration shaking the entire
> vehicle, it's worse in 4th/5th and it's exacerbated by increasing
> the load on the engine such as going uphill or accelerating
> harder. It stops as soon as I ease off on the accelerator.

I had similar when my prop shaft UJs were shot, causing the prop shaft
to wobble around especially when it was being twisted hard, e.g. when
going uphill or accelerating. Also not quite so bad but still there
when using severe engine braking, e.g. down a steep hill.

Pop underneath with a pry bar and shove it in the prop shaft UJs for
both front and rear and give them a bit of a levering to see if they
move much more than a millimeter. It's fiddly but easy to fix, I had
a hard time getting the needle bearings back on without dislodging
them even when I packed it all with grease, but managed it in the
end.

I'd suggest you check this first as it's easy to check, if it's not
prop shafts then it's probably something hard to find and expensive
;-)

While you're under there, have a prod around and see if anything else
looks out of kilter.

--
Blast off and strike the evil Bydo empire!

On 2006-04-28, Ian Rawlings <[email protected]> wrote:

> I had similar when my prop shaft UJs were shot, causing the prop shaft
> to wobble around especially when it was being twisted hard, e.g. when
> going uphill or accelerating. Also not quite so bad but still there
> when using severe engine braking, e.g. down a steep hill.

Forgot to mention, prop shaft issues can also be down to prop shaft
imbalance, e.g. if you've clouted them while off-roading or have been
having this shaking problem for a long time without correcting it. It
can also be down to the sliding section of the prop shaft not sliding
any more due to insufficient lubrication. There's probably other
things that you can do to the shafts, humans are an ingenious lot ;-)

--
Blast off and strike the evil Bydo empire!

Ian Rawlings wrote:

> Pop underneath with a pry bar and shove it in the prop shaft UJs for
> both front and rear and give them a bit of a levering to see if they
> move much more than a millimeter.

If they visibly move is closer to the correct tolerance - any UJ that
moves a mm is well overdue for replacement.


--
EMB

"EMB" <[email protected]> wrote in message
news:[email protected]...
> Ian Rawlings wrote:
>
>> Pop underneath with a pry bar and shove it in the prop shaft UJs for
>> both front and rear and give them a bit of a levering to see if they
>> move much more than a millimeter.
>
> If they visibly move is closer to the correct tolerance - any UJ that
> moves a mm is well overdue for replacement.

Indeed. Also worth checking engine and gearbox mounting rubbers while you're
at it, if a mount splits you will experience similar vibes.
Badger.

If it turns out to be a problem related to unbalanced propshaft may I
suggest you contact Scorpion Racing and ask about the active balancer they
will be introducing very shortly?

I have had those fitted to several vehicles here in Greece with vibration
related problems coming from their propshafts (even on vehicles with +2"
suspension lift) and they did a very good job on cancelling the vibrations.

Take care
Pantelis


"Badger" <[email protected]> wrote in message
news:[email protected]...
>
> "EMB" <[email protected]> wrote in message
> news:[email protected]...
> > Ian Rawlings wrote:
> >
> >> Pop underneath with a pry bar and shove it in the prop shaft UJs for
> >> both front and rear and give them a bit of a levering to see if they
> >> move much more than a millimeter.
> >
> > If they visibly move is closer to the correct tolerance - any UJ that
> > moves a mm is well overdue for replacement.
>
> Indeed. Also worth checking engine and gearbox mounting rubbers while
you're
> at it, if a mount splits you will experience similar vibes.
> Badger.
>
>