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Jan 03, 2018 11:57 am
Jan 03, 2018 11:57 am
Subject: Re: Leaf Spring Bodge Buttons
Happy New Year Barry
As leaf springs wear the ends of each leaf tend to create a ridge on the underside of the leaf above. This effect is more noticeable when springs are used dry but can still occur to some extent even when well lubricated and protected by gaiters.
These wear ridges stop the leaves sliding over each other as the spring is compressed and if bad enough makes the main leaf carry all the load possibly resulting in a bent or broken main leaf or possibly even damage to the chassis when a pot hole is encountered!.
When assembling a leaf spring you can reduce the wear by grinding a small chamfer on the upper edge of each end of each leaf to eliminate the sharp edge wearing the leaf above.
I have come across these buttons on other cars, forget what now many years ago, probably a prewar Austin... I guess they were an attempt to prevent wear...I do recall at least one worn spring I took apart with these buttons having quite badly distorted leaves. Suggest these buttons are neither use nor ornament!
When the springs are not lubricated, some manufacturers fit thin pure zinc sheet interleaves between each leaf, this makes much more sense and seems to work well as it eliminates wear on the leaves and helps to prevent rust sticking the leaves together as this can also result in the main leaf taking all the load and failing.
If ridges are present but not too deep I have in the past polished them out with a soft disc on an angle grinder but one must take care not to remove too much material and weaken the spring.
On several occasions I have found that simply stripping down the springs, cleaning them up and removing any ridges has returned them back to serviceable condition without need for re-tempering.
A reputable spring maker / repairer will have a press with a load cell so they can measure the amount of load required to deflect the springs a given amount.
Whatever you do, I would take the springs and have them checked out like that, if you tell them the weight of your car they should then be able to make a good guess at whether the ride height will be within acceptable limits and whether each pair of springs are approximately equal. You can then decide if they need re-setting or perhaps some new leaves...
Hope that helps
Bill
Happy New Year Barry
As leaf springs wear the ends of each leaf tend to create a ridge on the underside of the leaf above. This effect is more noticeable when springs are used dry but can still occur to some extent even when well lubricated and protected by gaiters.
These wear ridges stop the leaves sliding over each other as the spring is compressed and if bad enough makes the main leaf carry all the load possibly resulting in a bent or broken main leaf or possibly even damage to the chassis when a pot hole is encountered!.
When assembling a leaf spring you can reduce the wear by grinding a small chamfer on the upper edge of each end of each leaf to eliminate the sharp edge wearing the leaf above.
I have come across these buttons on other cars, forget what now many years ago, probably a prewar Austin... I guess they were an attempt to prevent wear...I do recall at least one worn spring I took apart with these buttons having quite badly distorted leaves. Suggest these buttons are neither use nor ornament!
When the springs are not lubricated, some manufacturers fit thin pure zinc sheet interleaves between each leaf, this makes much more sense and seems to work well as it eliminates wear on the leaves and helps to prevent rust sticking the leaves together as this can also result in the main leaf taking all the load and failing.
If ridges are present but not too deep I have in the past polished them out with a soft disc on an angle grinder but one must take care not to remove too much material and weaken the spring.
On several occasions I have found that simply stripping down the springs, cleaning them up and removing any ridges has returned them back to serviceable condition without need for re-tempering.
A reputable spring maker / repairer will have a press with a load cell so they can measure the amount of load required to deflect the springs a given amount.
Whatever you do, I would take the springs and have them checked out like that, if you tell them the weight of your car they should then be able to make a good guess at whether the ride height will be within acceptable limits and whether each pair of springs are approximately equal. You can then decide if they need re-setting or perhaps some new leaves...
Hope that helps
Bill