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Wierd Vibrations

G

Guest

Guest
Morning All,
OK, here's something for you to get your teeth into...
Mid last week we started getting vibrations in my 80 and I am part way
to pinning it down, but would be interested in people's views here.
The vibration seems to occur when travelling at speed for example
70mph, but only when you put your foot down and accelerate, if you
maintain a constant speed or are decelerating you don't notice it.
It is difficult to pin down exactly where the vibrations are coming
from, it isn't coming specically from the front or the rear of the
vehicle so I get the impression it is coming up through the chassis.
The car has had a history of problems with the rear axle so over the
weekend I drained the diff oil and checked that, but it was all OK.
I also checked all the wheel bearings and they are fine as well as
checked all the brakes and none of them are rubbing.
The engine appears to be running fine, with no hesitation or loss of
power.
I have checked the front and rear prop shafts and the UJs appear to be
fine - because of the lift on my 80 (heavy duty 2.5" but with no load
so sits around 3-4" higher than normal) it tends to eat UJ on the back
of the rear propshaft.
I know that the CVs are on their way out, but apart from some clicking
on very tight left and right turns there doesn't seem to be any more
difference there and they appear to have plenty of grease in them.
The oil levels seem fine in the auto box and transfer case, although I
may change those just in case.
Another thought occuring is to check the engine mounts, in case one of
them is getting loose.
The problem started suddenly when my wife went off to pick up the
children from school - it hasn't been progressive.
I would have checked more, but ran out of time.
So, what do you think?
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
I'm literally heading off out so will think as I use public transport in
London.
All I would say is it can often pay to think like a doctor - 'common things
occur commonly.'
Sorry can't do better than that Julian but I'll check in when I get back to
a computer.
Jeremy
On 9/10/06 09:00, "Julian Voelcker" <[Email address removed]> wrote:
Jeremy Llewellyn-Jones
Mob: 07831 458 793
--
 
Julian
| The vibration seems to occur when travelling at speed for
| example 70mph, but only when you put your foot down and
| accelerate, if you maintain a constant speed or are
| decelerating you don't notice it.
Worn shock(s)? Possibly on the rear as acceleration will load them
more. Maybe get someone to trail you at speed looking for wheel bounce?
Christopher Bell
____________________________________________________________
Electronic mail messages entering and leaving Arup business
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On acceleration torque is generated, also the power output of the engine
increases.
An increase in engine torque would unevenly load the engine and the
gearbox mountings so I would check if these are worn.
Extra power, as well as the extra torque tends to move the exhaust in
relation to the chassis - it's not touching the chassis on acceleration
is it?
Just a couple of thoughts. I'm off out for the day as well now.
Pete
 
Julian,
Only two things spring to mind. One, of course, is the wheel
balance. Two, not so common, is an overgreased propshaft joint. If you
put too much grease in the joint becomes solid and has no slide on the
splines, this will cause vibration.
Regards, Clive.
 
Blocked injector?
When I was selling Lexus years ago, we had an LS400 with a slightly blocked
injector. The motor in this is so smooth, the only way you could see it was
a slight fore-aft rocking of the gear selector and what felt like a rear
wheel balance issue at certain speeds. I swore blind it was a transmission
fault until one of the real good techies we had pinned it down.
He went on to be a WRC mechanic running Sainz and Kankkunen.
Just a thought.
Neill Watson
On 9/10/06 9:00 am, "Julian Voelcker" wrote:
 
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Hi Christopher,
No shocks are fine. With the HD suspension it hardly moves unless well
loaded.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Clive,
The wheels were OK, although knowing the wife she might have knocked a
weight off one of the wheels.
As for the propshaft, that's fine, took it off, stripped it down and
cleaned it over the weekend, just the right amount of grease in it.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Neill,
Interesting, hadn't considered it, although as I said the engine feels
as smooth as always up to the higher speed. I would have thought a
blocked injector would have an effect throughout the speed and rev
range.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Just to add further:
Unlikely to be wheel balance issues since it goes away when not
accelerating.
Also, I have run the car up to around 95mph on axle stands and no
apparent vibration then most likely due to lack of load.
Tried to introduce load using the brakes, but difficult to do it evenly
- interesting to note how much the brakes are biased towards the front
- could do with some adjustment there.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
If your wheels are tight I'd put my money on prop shaft UJ or balance.
Jon.
 
Hi Jon,
First thing I checked - Prop shaft UJs are OK, and it doesn't look like
the weights have come off or sustained any damage to the propshaft to
cause it to suddenly loose balance.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Julian
Got my Hardy Spline or whatever you call it changed recently and that
stopped a similar vibration.......
Niall '95 HDJ80
 
Hi Peter,
As I said, on the list of things to check.
Exhaust is fine.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Jon,
Wheels are fine - checked them all when I checked the wheel bearings.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Niall,
Did they re-balance the prop (guess they must have done)?
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Julian,
Had this problem on several auto cruisers over the years, top gear is a lock
up gear which locks the torque converter, but when ATF gets old/dirty the
gear slips and causes vibrations exactly like you describe. You need to
change the oil at least 4 times as you can only get an average of 5 litres
out each time so you need to keep repeating the oil change - do not put
synthetic ATF in only Dextron II- If this doesn't work you can get an
additive to help with lock up or at worst you need a new torque converter -
(I've never had to put in the additive yet or changed the torque converter )
Hope this helps,
Chris Cutting HDJ60/80/100
----- Original Message -----
From: "Julian Voelcker" <[Email address removed]>
To: <[Email address removed]>
Sent: Monday, October 09, 2006 9:00 AM
Subject: [ELCO] Wierd Vibrations
 
Thanks one and all for the input, however I have the feeling that you
are all wrong ;-))
It turns out that I have a slow puncture on one of my rear tyres and it
was down to about 2psi !!!! but because it is on the passenger side and
I approach it from the other side I didn't notice it, also it wasn't
that obvious when jacked up.
So simple, yet so annoying!
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Julian
2 psi? That's flat isn't it?? Well at least you found a probable
cause. I had a similar vibration issue years ago and it too was the
rear tyre nearly flat but it was very very noticeable and you felt it
when going round corners so I pulled over and the tyre was falling apart
you could see the fabric coming thru!!
Take care
Simon Hughes
93 80 tlc
Tel: 020 7549 3663
Mobile: 07973 288061
Mail: [Email address removed]
 
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