QUESTION
I have been told its not worth installing shrouds on the coil-over shock absorber assembly for my Elan +2.
Does installing the road-spring shrouds cause a noise problem?
N.W. - Mordialloc, VIC
ANSWER
The advice you have been given regarding noisy spring covers is an unqualified comment by someone who has limited knowledge about the Lotus Elan +2 front suspension.
There are several circumstances where the front suspension components can produce unwanted noise, for example-
1) Corroded spring cover and road spring, where the rusty components abrade against each other
2) Collapsed/worn road spring, where the spring lateral distortion causes it to rub against the shock absorber body and/or spring cover
3) Incorrectly installed road spring, where it is not centralised on the spring perch
4) Anti-friction sleeve missing from shock absorber body (prevents spring from making contact with shock absorber body)
5) Incorrect top shock absorber mounting rubbers
From experience these items can be a source of problems and noise.
There is an inherent design problem where inadequate rubber bushes are expected to support 1/4 of the weight of the vehicle.
When the coil-over shock absorber assembly is initially mounted to the top front suspension tower, the bushes locate correctly.
Once the bushes are subjected to the full vehicle weight, they will compress to half their original thickness.
This allows the upper bush (on top of the suspension tower to disconnect itself) to move upwards away from the fixing point
Once this happens the shock absorber mounting spindle will rub against the location hole in the suspension tower.
This is a common problem and if left unchecked causes the location hole to be elongated by the constant sawing action on the threaded spindle.
This hidden problem is the most common source of noise originating from the front suspension.
Checking for this problem is a simple matter of reaching up under the wheel-arch to feel if the top bush and spindle are located in the top of the suspension tower.
Assembly advice-
DO NOT apply grease to the road-spring or shroud as this will attract dirt and grit that will act as an abrasive grinding compound.
If a lubricant is to be used, then apply a dry lubricant such as Molykote 557 that is available from Dow Corning.
This is a dry-film lubricant that is available in a convenient aerosol container.
Dow Corning supply a range of specialised coatings which are described as "lubricating paints"
"Molykote antifriction coatings (AFCs) provide a dry, slippery film that improves surface roughness and optimises friction on the wear surface, even under extreme loads and operating conditions"
To prevent the top shock absorber threaded spindle from damaging the chassis, harder duro urethane bushes should be fitted to eliminate this problem.
Copyright © 2015 Lotus Marques
I have been told its not worth installing shrouds on the coil-over shock absorber assembly for my Elan +2.
Does installing the road-spring shrouds cause a noise problem?
N.W. - Mordialloc, VIC
ANSWER
The advice you have been given regarding noisy spring covers is an unqualified comment by someone who has limited knowledge about the Lotus Elan +2 front suspension.
There are several circumstances where the front suspension components can produce unwanted noise, for example-
1) Corroded spring cover and road spring, where the rusty components abrade against each other
2) Collapsed/worn road spring, where the spring lateral distortion causes it to rub against the shock absorber body and/or spring cover
3) Incorrectly installed road spring, where it is not centralised on the spring perch
4) Anti-friction sleeve missing from shock absorber body (prevents spring from making contact with shock absorber body)
5) Incorrect top shock absorber mounting rubbers
From experience these items can be a source of problems and noise.
There is an inherent design problem where inadequate rubber bushes are expected to support 1/4 of the weight of the vehicle.
When the coil-over shock absorber assembly is initially mounted to the top front suspension tower, the bushes locate correctly.
Once the bushes are subjected to the full vehicle weight, they will compress to half their original thickness.
This allows the upper bush (on top of the suspension tower to disconnect itself) to move upwards away from the fixing point
Once this happens the shock absorber mounting spindle will rub against the location hole in the suspension tower.
This is a common problem and if left unchecked causes the location hole to be elongated by the constant sawing action on the threaded spindle.
This hidden problem is the most common source of noise originating from the front suspension.
Checking for this problem is a simple matter of reaching up under the wheel-arch to feel if the top bush and spindle are located in the top of the suspension tower.
Assembly advice-
DO NOT apply grease to the road-spring or shroud as this will attract dirt and grit that will act as an abrasive grinding compound.
If a lubricant is to be used, then apply a dry lubricant such as Molykote 557 that is available from Dow Corning.
This is a dry-film lubricant that is available in a convenient aerosol container.
Dow Corning supply a range of specialised coatings which are described as "lubricating paints"
"Molykote antifriction coatings (AFCs) provide a dry, slippery film that improves surface roughness and optimises friction on the wear surface, even under extreme loads and operating conditions"
To prevent the top shock absorber threaded spindle from damaging the chassis, harder duro urethane bushes should be fitted to eliminate this problem.
Copyright © 2015 Lotus Marques
