FWD Front Wheel Bearing

This job came up as a result of an MOT fail for excessive play.  the bearing felt smooth and, once stripped, was clearly servicable but mis-adjusted when it was fitted.

The front bearings on these are taper roller type and adjusted for play when fitted by adding spacers to the end of the driveshaft.  Replacement or adjustment requires a fair amount of dismantling and the manual calls for several special tools.  In fact, Mr Haynes suggests that it should only be done by a Triumph Dealer.  Only the last of them closed around 20 years ago, so ......

 

First, remember to loosen the hub nut before jacking the car.  It's tightened to 100 - 110 lb/ft torque and it's not worth risking pulling the car off the stands!

Loosen hub nut

 

 

The flexi brake pipe mount to the top balljoint needs to be removed so the caliper can be hung out the way:

Undo brake pipe mount

 

The caliper is then unbolted and hung out the way, so that the top balljoint can be disconnected from the spring strut and the top suspension arms:

Disconnecting top balljoint

 

The manual directs you to remove the hub, carrier and driveshaft as a unit then dismantle on the bench using various special tools.  There is a lot less dismantling involved by applying a normal 3-leg puller to the hub and "pushing" the driveshaft back through the centre:

Separating driveshaft

 

In this case, the hub came free from the vertical link (carrier) at this point.  Note the outer bearing race fitted in the centre of the hub.  Doing it on the bench "by the book" would have pushed the driveshaft out, leaving the hub and link joined by the bearings.  In that case, it would be neccessary to push the hub out of the vertical link after removing the link at the next stage.

Hub removed

 

To remove the vertical link, the manual tells you to separate the lower balljoint and the track rod end from the steering arm.  It's far easier to leave the balljoints in place and undo the two bolts holding the steering arm to the vertical link!

Disconnect steering arm

 

Once the link is free, the inner bearing can be checked for smooth running and removed through the grease seal if required for inspection.  In this case it was well greased and smooth so I left it in place to avoid risking seal damage.

Vertical link removed

 

The spacer (possibly with extra shims) fitted to the driveshaft can also be removed now:

Driveshaft spacer

 

Measuring the bearing endfloat the "right" way requires Triumph Special Tool S325.  Never seen one except in pictures so this was the alternative.  Place the spacer in the centre of the inner bearing (where it will sit in use) and put a straight-edge across it.  In this case I used 2 inches sacrificed off the end of a 6 inch aluminium rule that had cost 79 pence.  Apparently, other (richer) people use credit cards.

 

Whatever you use, measure the gap between the straight edge and the inner bearing race using feeler gauges.  If you have two sets available, use one feeler under each side to make sure everything's sitting level.  In this case, the gap was between .010 and .011 inches.  It's supposed to be between .002 and .005 inches - hence the play in my wheel!

Measuring bearing end-float

 

At this point, you should select from your available spacers and shims to make up a set that will bring the play within tolerance.  My selection of spacers was the one on the car or the one on the car.  So the alternative was to make the one on the car thinner.  Reducing it by .008 inches would bring the play down to between 2 and 3 thou - nicely at the bottom end of tolerance.

 

Time for a little lathe work.  Unfortunately, the spacer is hardened so normal lathe tools wouldn't touch it.  But where there's a will (and a diamond cutting disc) there's a way!

Thinning the spacer

 

With a gentle touch on the Dremel-a-like, it took less than a minute to reduce the thickness from .148 to .140inches.

 

Reassembly, as they say, was the reverse of removal with one exception.  At some point in the past, someone had stripped the inner half of the hub nut and then only tightened it to half it's proper torque.  I really wasn't happy to put it back like that (yes, I do have standards where it matters) so I had to find a new nut.

 

It measured as 5/8" x 18 thread per inch which makes it a 5/8 UNF.  It also had to be a "nyloc" self-locking.  In North Wales.  At short notice. I didn't hold out much hope to be honest but, to my surprise, Brunswick Fasteners in Caernarfon had them in stock at a very reasonable 50 pence each.  It meant a 50 mile round trip and about a fiver in fuel - and they only had "full height" instead of the half-height I needed but that was just a bit of hacksaw work to correct and it was well worth it to avoid having a hub come loose!

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