Unless specific preload is given, Aristides - the endfloat, bearing play should be used. In any case; having used preload, the play should then be verified as well…
The play is changed by mowing the inner race along the axle to vary the distance between the inner and outer race - the play. When computing shim thickness it’s important that the inner race is moved to a position where the shim makes an accurate displacement of the inner race. That the play changes after assembly implies that this was not done…?
Yes that could very well be the case.
I tried my best to be sure that the races were fully inserted to the hub, but it was done by hand as I have no press.
I actually re-thought the whole matter and went back and removed some of the preload by adding a 0.1mm shim.
This gave me a drag torque of about 2 lbs.in., almost identical with the seal drag torque and no play, so I think I am very close to 0 preload / end-float.
I am happy with that.
I also revised the original post to avoid confusion.
[quote=“Aristides, post:39, topic:378381”]
“My hubs were a mess, someone was there before me and one side had excessive play but the other side had zero.”
“The manuals for early cars calls for 0.10mm (0.004”) End-float but for later cars they changed it to Preload…[/quote]"
I have read this several times on the JL E-type list over the years and I believe this is incorrect.
The series 3 XJ manual specifies end float… not pre load for the hub carriers. The later XJ40 manual specifies preload for the hub carrier with outboard brakes. Perhaps this is the source of confusion.
Wheel bearing end float on the classic irs is set via a thickness spacer which resides between the oil seal track and the inner bearing, inner race. The method for achieving the desired end float is clearly explained using the special tool in the workshop manual.
Yes indeed, but the principal of operation and bearing arrangement are exactly the same.
What is more confusing is that on the XJ40 with outboard brakes there are much greater temperature differences involved and one would expect end-float to be called for as to compensate different expansion rates.
Maybe because of the presence of the disc brake, a no play arrangement was needed?
It must also be noted that preload is specified at the output shafts bearings, and it’s the exact same tapered roller bearings configuration.
My guess is that end-float was chosen because it’s so much easier to set-up and measure, much more forgiving at mistakes either by the factory either by the service mechanics, and the minimal reduced bearing life was not much of a concern.
It’s a matter of convenient access for measuring, Aristides - and indeed convenience of altering bearing play. With shims adjustment some dismantling is required to change shims. Like the diff’s pinion axle bearing requiring major, and possibly repeated, dismantling if shims were used…
Both methods aim for the proper clearance for adequate lubrication between be fixed and moving pars of the bearing - without excessive axial and lateral movement.
With shims generally; play is independent of nut torqueing - which arguably is better for keeping assemblies together…
Endfloat measures play directly, when possible - and is very exact with proper tools. While preload uses resistance to turning - relating to overall ‘friction’. Which relates to bearing size and lubrication type - and other factors like masses involved involved and other friction elements. More possibilities for errors…
Plugged center vent hole and drilled two holes outside the bearings, as suggested in Kirbert’s book.
Now new grease will have to go through the bearings before it comes out from the vent holes and will actually lubricate the bearings.
Hole distance from edge of Hub: 7mm
M3 x 5 screw
Chamfered the holes and added a small O-ring.
I would be inclined to replace those bearing cups and cones while you are in there. Due to the action of the suspension there is very little rotation and you can see where the rollers have been working.
I thought long and hard about it Robin…
The marks you see it’s only discoloration.
Actually they are double marks, i.e. from two different positions of the rollers as I had taken it apart a couple of years ago and very few miles since. So the two sets are almost identical but with a big difference in time and miles.
And as the races are as smooth as glass, I figured that they will be fine.
I will also try to position the rollers in an unmarked area in the races when I put them back together.
I am afraid Robin is correct both with the advice and partially with his description of the track damage.
The damage might appear as discolouration but in fact it is called “Brinelling” and although you cannot (yet) feel indentations it is plastic deformation of the surface caused by extreme and repeated shock loading. Re-using these tracks risks transverse cracking across the track, and you do not want to know about that !!
I would suggest you replace the bearings whilst it is easy to do so, ensuring you purchase from a trusted bearing agent.
Until two years ago when I sold the business I was spending over £25k per year on tapered bearings and I had been for the last 25 years, I fitted a lot of bearings and hypoid gears and I could tell you the next two sequences, you would like neither !!
You are looking at the warning signs, you know the bearing history but the choice is yours.
Spacer ring and extra ring made from 1.2mm wire.
The lip seal (6.3mm) is thinner than the original felt seal so the extra ring is needed to bring the seal at the right height.
Also works very well for the grease vents as the hole is inbetween the gap.