Lagondaforum

Subject: DB3L Rear hub serrated drive

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Have just removed the RH coupling and found the serrations fatigued.
Only half of the serrations have failed because only half of them transmit drive torque.
Help!
Is a repair feasible ?
Are there any spares available?
Ken

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Subject: Re: DB3L Rear hub serrated drive

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Hi Ken,

I have the parts, but will need to dismantle to check the condition of the teeth.

Will do so in the next day or two,

Regards,
Mark

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Subject: Re: DB3L Rear hub serrated drive

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Hullo Ken,
I have dismantled the hub carriers that I bought from Ivan Forshaw (Aston Service Dorset) in 1969. the offside inner flange is perfect, the outer is missing one half of an inner tooth.

Having never mastered the art of putting a photo up on this forum - despite Peter Schirg telling me how to years ago - I will send photos if you wish to your email address.

Regards,
Mark

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Subject: Re: DB3L Rear hub serrated drive

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Thanks Mark
I know what you mean about photos; 200 K is smaller than usually taken and either you photo-reduce or set the camera to a small frame size and hope it is a small enough file
About serrated drives, I wonder how many DBLs are about to fail
At wheel lock up or wheel spin a torque of about 1000 lb-ft is transmitted. For a 1.575 OD 0.75 ID shaft this calculates to 15.45 KSI
A spline has 50% area and the serrated version 25% area so the stress can reach 62 KSI . As the hub appears to be a low carbon steel this is asking for problems even under normal driving conditions
May be we should advise our co-owners to check the tightness of their 3/4 bolts!
Ken