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Morgan Shake

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NeilWhaley Neil Whaley
Reinholds, PA, USA   USA
I have a 54 plus 4 four seat roadster and it has the "Morgan Shake". It starts just above 50 mph and goes away after about 60. Anyone experienced with this problem that has advise for me? Otherwise the car is very driveable, reliable and is 100% original. Thanks! Neil

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DuncanCharlton Avatar
DuncanCharlton Duncan Charlton
Elgin, Texas, USA   USA
1931 Morgan 3 Wheeler "Gwenda (Sold)"
1967 Morgan 4/4 "Toly's Car"
1967 Unknown Unknown
1970 Mini Countryman    & more
Neil, this is the well known "St. Malvern's dance." Check the adjustment of the damper blades first. You should be able to reach them from floor level in front of the car (they are a piece of saw blade-type steel that run from just below the main spring to the chassis). They are free to move in and out as the suspension moves up and down but should not be able to move fore and aft at the chassis end. If they are floppy, loosen the bolts holding down the clamp and tap the triangular shims toward the blade and retighten the bolts. Put a little grease in there while you're down there.

If that doesn't fix it, check for play in the steering rod ends first. If they are fine, jack up the car and grab each front wheel from the top and bottom and see if there is wiggle. Assuming the wheel bearings are properly adjusted, significant play indicates that the kingpin and/or kingpin bushings are worn and need replacement.

If there is no play, check the wheels for trueness and balance.

If you do need to replace kingpins and bushings, see if you can find a source for hard-chromed kingpins instead of the original mild steel (rust near the bottom of the kingpin will grind away at the lower bushing) or the replacement stainless steel ones (they wear very quickly). The bronze bushings need to be honed after installation.

Malcmog Malcolm Skirrow
Vienna, Austria, Austria   AUT
Hi Neil
My '56 +4 2 seater had just the same problem last year, between about 80-90kph.
The first time it happened was terrifying. The whole car was vibrating violently.
I had EVERYTHING checked out, - steering, suspension, tyres, balancing, dampers, and so on. But still got the shakes.
I knew my steel wheels were not very true, but they had never caused a problem before. I've had the car since 1972.
My local Morgan workshop spent a considerable time trying to trace the fault.
Eventually he fixed the problem by balancing the wheels with brake drums attached. I cannot remember the exact technique, but it worked and the shake has gone.
I think the fault was initiated by a local (non-morgan) mechanic mixing 2 of the brake drums - exchanging them. I'll never go back there.
If you need further details on how the wheels and drums were finally balanced I will find out for you.
By the way, I have 15 inch discs. Do you have original 16 inch? I wish I did!
Good Luck
Malcolm

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NeilWhaley Neil Whaley
Reinholds, PA, USA   USA
Thank you for the very detailed information! Much appreciated. Neil

Fred Winterburn Avatar
Ripley, Ontario, Canada   CAN
Neil,
Sometimes the only way to cure it is with a steering damper. I used a Mercedes SLK damper. The pictures shown on the gomog site are the pictures I took of the installation on my car. I was not able to cure it using the normal methods on my 56 Plus 4. http://www.gomog.com/allmorgan2.html#Curing
I think there is someone selling a kit now to use the Merc damper. Mounting one end of the damper as close to the pitman arm as possible keeps the damper movement low on bumps an makes the setup a little better. As far as I know I am the first to use the Merc damper. The Volkswagen bus and beetle dampers do not have as long a stroke as the Mercedes SLK damper. Also the SLK damper is slightly stiffer and removed all traces of the shake on my car while there was still some with the VW damper. You won't notice the steering being any stiffer with the damper in place.
If you do install a damper, be sure to mount it such that water can't collect in the protective cover. I mounted the VW damper in the pictures the wrong way around and fixed that mistake when I mounted the SLK damper. Also make sure that however you mount the damper that it does not interfere with any of the steering arms when they turn or on large bumps. Good luck with curing that shake! Fred

In reply to # 11265 by NeilWhaley I have a 54 plus 4 four seat roadster and it has the "Morgan Shake". It starts just above 50 mph and goes away after about 60. Anyone experienced with this problem that has advise for me? Otherwise the car is very driveable, reliable and is 100% original. Thanks! Neil

Cymog Dave Marks
Lemona, Paphos, Cyprus   CYP
You are not alone.... On my 1988 4/4 the only solution is to balance the wire wheels on the car. This is a procedure only a few workshops can carry out, but, as they say in all the best ads, it works for me.

Cymog

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