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Wales
by Joske Vermeule, September 1
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Jun 14th, 2026
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Joined: Jan 2011
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OP
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Hi All, hope somebody can help!
I have a 1987 4/4 with a 1600cvh engine, when i get to 50mph the front end shakes quite hard. Past 65 the shaking stops. It starts to shake again when slowing down between the same speeds. I'm no professional mechanic just a very enthusiastic amateur. Not sure where to start to look for the most likely source of this problem - I have checked wheel balance and it seems fine.
Any ideas?
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Joined: May 2009
Posts: 2,190
South Wales Correspondent Talk Morgan Expert
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South Wales Correspondent Talk Morgan Expert
Joined: May 2009
Posts: 2,190 |
Hi All, hope somebody can help!
I have a 1987 4/4 with a 1600cvh engine, when i get to 50mph the front end shakes quite hard. Past 65 the shaking stops. It starts to shake again when slowing down between the same speeds. I'm no professional mechanic just a very enthusiastic amateur. Not sure where to start to look for the most likely source of this problem - I have checked wheel balance and it seems fine.
Any ideas? If you have wires fitted, and especially if you have sticky weights, have any of them come off. If there is the slightest lack of 'true' in the wheel, this is very common. As a related point, if they ARE wires, are they still true or do they need tuning? Also, check that your tyre supplier/fitter has fitted the right size weigts for the rim G
GLLHG
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Learner Plates Off!
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Learner Plates Off!
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Complimentary to what G advises, check the steering damper blades (those flat spring steel blades mounted from the stub axle to the side member of the chassis). They should have no radial movement and slide inwards and outwards only. To adjust losen the two nuts which clamp the blade to the chassis. The nuts lock shims in place which you can adjust.
Frank
1967 4/4 1500 Comp.
1935 Super Sports Barrelback
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Learner Plates Off!
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You have what is known as Malvern dance.
Rather than one specific thing it may be a combination of smaller issues.
You say the wheels have been balanced, also get the tracking checked.
Damper blades as suggested by Frank are the next choice.
Then check the wear on the King pins
Brian
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L - Learner Plates On
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L - Learner Plates On
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Vibration associated with a specific road speed will be tire/wheel balance.
'65 +4 four seater
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Talk Morgan Regular
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Talk Morgan Regular
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Could also be a flat spotted tyre from heavy braking/standing stationary for long period,
John
Morgan 4/4 Sport Competition
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Roadster Guru Member of the Inner Circle
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Roadster Guru Member of the Inner Circle
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Try swopping wheels front to back - see what happens.
(in addition to everything else....)
DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4
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Salty Sea Dog Member of the Inner Circle
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Salty Sea Dog Member of the Inner Circle
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And if all those fail, check the chassis for cracks and that the gusset plates just ahead of the bulkead are not being pushed away from the chassis by rust.
Been there with my '76.
Cheers,
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly
'11 MINI Countryman Cooper D All4
'90 LR 90 SW
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Vibration associated with a specific road speed will be tire/wheel balance. ...except on a Morgan where it may be oscillation of the coil springs (hence the damper blade connected to a brass/bronze plate below the main spring)
1967 4/4 1500 Comp.
1935 Super Sports Barrelback
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Joined: Apr 2009
Posts: 462
Learner Plates Off!
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Graham, do you know when the gusset plates were introduced? My '67 didn't have them.
Frank
1967 4/4 1500 Comp.
1935 Super Sports Barrelback
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