QUESTION
Like many before me I'm undertaking the difficult task of replacing rear hub bearings.
Like many before me I'm undertaking the difficult task of replacing rear hub bearings.
I have some questions regarding the bearings.
My elan S3 (36/6858) has one type 16 and one type 18 hub.
Presumably one has been replaced over the years, and the type 18 hub has been fitted to one side.
However the bearings all look identical, and I've read on the forum that some type 18s actually take the type 16 bearing.
Could you please clear up this mystery?
Presumably if I try to fit the (wider?) type 18 bearing to the type 18 shaft on the right in the attached pic, it will cover the circlip groove?
R.V. - Five Dock, NSW
ANSWER
From the information you have provided, your Elan S3 would originally been fitted with issue 16 wheel bearing housings.
If one housing has been damaged then it could have easily been replaced by non-matching issue 18 housing.
However these housings are subtly different, as detailed below:
Lotus Elan rear right hand alloy bearing housing - issue 16 (Lotus part number 026D0004Z) these were fitted up to chassis number 7761.
Lotus Elan rear left hand alloy bearing housing - issue 16 (Lotus part number 026D0005Z) these were fitted up to chassis number 7761.
NOTE: Both of these housings are fitted with identical bearings 0.625” (15.87mm) wide (Lotus part number X036D6017Z) fitted on both the inboard and outboard sides of the drive-shaft.
The bore size of both bearings is 30mm.
Lotus Elan rear right hand alloy bearing housing - issue 18 (Lotus part number A026D0004) these were fitted from chassis number 7762.
Lotus Elan rear left hand alloy bearing housing - issue 18 (Lotus part number A026D0005) these were fitted from chassis number 7762.
NOTE: Inboard bearing fitted is 0.825” (20.95mm) wide (Lotus part number X036D6003Z)
Outboard bearing fitted is 0.625” (15.87mm) wide (Lotus part number X036D6017Z)
The bore size of both types of bearing is 30mm.
The information you have obtained from "the forum" is not concise and does not appear to high-light the dimensional or bearing differences.
Having a different inner bearing for the issue 18 housing means the circlip groove on the drive shaft is repositioned to accommodate the wider bearing.
Subsequently there are two different drive-shafts, one specific for each type of housing.
It is imperative to install the correct bearings, drive shaft and circlip in the relevant housing.
The circlip plays an important role in preventing the drive-shaft and bearing assembly moving in and out of the housing when subjected to side-loads.
The photograph above appears to show the circlip grooves in identical positions which indicates they are both issue 16 type drive-shafts.
The left hand drive-shaft would appear to indicate the outboard bearing has been rotating on the shaft and is no longer serviceable.
It is recommended the right-hand drive-shaft be bead-blasted, then crack tested and if proven satisfactory be installed in the issue 16 housing.
In addition to this, a new drive-shaft with the correct circlip detail should be purchased and installed in the issue 18 housing.
Lotus Marques manufactures and stocks new solid billet drive shafts if you require a replacement.
Copyright © 2013 Lotus Marques
My elan S3 (36/6858) has one type 16 and one type 18 hub.
Presumably one has been replaced over the years, and the type 18 hub has been fitted to one side.
However the bearings all look identical, and I've read on the forum that some type 18s actually take the type 16 bearing.
Could you please clear up this mystery?
Presumably if I try to fit the (wider?) type 18 bearing to the type 18 shaft on the right in the attached pic, it will cover the circlip groove?
R.V. - Five Dock, NSW
ANSWER
From the information you have provided, your Elan S3 would originally been fitted with issue 16 wheel bearing housings.
If one housing has been damaged then it could have easily been replaced by non-matching issue 18 housing.
However these housings are subtly different, as detailed below:
Lotus Elan rear right hand alloy bearing housing - issue 16 (Lotus part number 026D0004Z) these were fitted up to chassis number 7761.
Lotus Elan rear left hand alloy bearing housing - issue 16 (Lotus part number 026D0005Z) these were fitted up to chassis number 7761.
NOTE: Both of these housings are fitted with identical bearings 0.625” (15.87mm) wide (Lotus part number X036D6017Z) fitted on both the inboard and outboard sides of the drive-shaft.
The bore size of both bearings is 30mm.
Lotus Elan rear right hand alloy bearing housing - issue 18 (Lotus part number A026D0004) these were fitted from chassis number 7762.
Lotus Elan rear left hand alloy bearing housing - issue 18 (Lotus part number A026D0005) these were fitted from chassis number 7762.
NOTE: Inboard bearing fitted is 0.825” (20.95mm) wide (Lotus part number X036D6003Z)
Outboard bearing fitted is 0.625” (15.87mm) wide (Lotus part number X036D6017Z)
The bore size of both types of bearing is 30mm.
The information you have obtained from "the forum" is not concise and does not appear to high-light the dimensional or bearing differences.
Having a different inner bearing for the issue 18 housing means the circlip groove on the drive shaft is repositioned to accommodate the wider bearing.
Subsequently there are two different drive-shafts, one specific for each type of housing.
It is imperative to install the correct bearings, drive shaft and circlip in the relevant housing.
The circlip plays an important role in preventing the drive-shaft and bearing assembly moving in and out of the housing when subjected to side-loads.
The photograph above appears to show the circlip grooves in identical positions which indicates they are both issue 16 type drive-shafts.
The left hand drive-shaft would appear to indicate the outboard bearing has been rotating on the shaft and is no longer serviceable.
It is recommended the right-hand drive-shaft be bead-blasted, then crack tested and if proven satisfactory be installed in the issue 16 housing.
In addition to this, a new drive-shaft with the correct circlip detail should be purchased and installed in the issue 18 housing.
Lotus Marques manufactures and stocks new solid billet drive shafts if you require a replacement.
Copyright © 2013 Lotus Marques
