Jack McNamara Salisbury Air locker.
Posted: Fri Aug 20, 2004 10:23 pm
I fitted a Jac Mac Airlocker to a FC101 today, This is the second one I have done,Nice diff but a pig of a job.
First up, it comes assembled with all the bolts high strength loctited and tightened up.What for?
You would have to be extremely lucky to fit the correct value of shims behind each carrier bearing first time. if you are unlucky, and I was twice, despite having a surface plate and height measuring equipment to measure the old carrier, you must completely dismantle the carrier assembly to facilitate removal of the carrier bearings to alter the shim value. They have machined the carrier in such a way that you cannot use a bearing puller unless you pull on the roller cage with the very real risk of damaging some very expensive bearings, so they drilled two 6mm holes through the bearing shoulders on each half of the carrier so you can drift the bearings off after dismantling.
The carrier is very substantial and I can see no reason why they couldn't machine a decent chamfer on each side to allow the use of a bearing puller, I was almost tempted to do it myself, but its not my diff and I may have voided any warranty by doing so.
What I am getting at here, is that this oversight costs heaps in extra labor charges for installation, so if you buy a Salisbury difflock from Jack McNamara, do not even think about fitting it yourself unless you have the correct knowledge, equipment, and the patience of a saint.
If you do take it to a specialist to fit for you, expect to pay for anything up to 8 hours labor to get it right, particularly if pinion bearings need attention too. These comments apply only to the Salisbury diff. Jac Macs Rover type diffs set up quite easily for the UNF diffs, The spot facing for the crownwheel bolts is a bit small for the earlier Series 2a BSF bolts.
there is also a bit of clearance grinding required on the pinion housing.
Bill.
First up, it comes assembled with all the bolts high strength loctited and tightened up.What for?
You would have to be extremely lucky to fit the correct value of shims behind each carrier bearing first time. if you are unlucky, and I was twice, despite having a surface plate and height measuring equipment to measure the old carrier, you must completely dismantle the carrier assembly to facilitate removal of the carrier bearings to alter the shim value. They have machined the carrier in such a way that you cannot use a bearing puller unless you pull on the roller cage with the very real risk of damaging some very expensive bearings, so they drilled two 6mm holes through the bearing shoulders on each half of the carrier so you can drift the bearings off after dismantling.
The carrier is very substantial and I can see no reason why they couldn't machine a decent chamfer on each side to allow the use of a bearing puller, I was almost tempted to do it myself, but its not my diff and I may have voided any warranty by doing so.
What I am getting at here, is that this oversight costs heaps in extra labor charges for installation, so if you buy a Salisbury difflock from Jack McNamara, do not even think about fitting it yourself unless you have the correct knowledge, equipment, and the patience of a saint.
If you do take it to a specialist to fit for you, expect to pay for anything up to 8 hours labor to get it right, particularly if pinion bearings need attention too. These comments apply only to the Salisbury diff. Jac Macs Rover type diffs set up quite easily for the UNF diffs, The spot facing for the crownwheel bolts is a bit small for the earlier Series 2a BSF bolts.
there is also a bit of clearance grinding required on the pinion housing.
Bill.