Play in the front wheel

[ndevans]

I have a little play when I try to twist the front n/s wheel from top to bottom. Is this a worn trunnion, worn wheel bearing (unlikely as it's only 2yrs old), or loose hub nut?
Cheers N

[BLOWNMM]

If you can get somebody to do the twisting then place your finger between the brake drum and backing plate. If there is no relative movement between these then the problem is probably trunnions. If you are able to feel relative movement between the drum and backing plate then possibly loose wheel bearings or loose hub nut.
Bob

[ndevans]

Thanks for that.
Should have mentioned it has discs, and I did it with the car raised. I presume the same principle applies with discs?
Cheers Neil

[philthehill]

What type/make of disks have you got fitted to the front?
Normally there should be slight play in the wheel bearings if fitted with disks as disk braked hubs are usually fitted with taper roller bearings.

[BLOWNMM]

I have tapered roller bearings with Wolseley brakes and have adjusted them as per instructions from most car manufacturers - with slight pre-load and no play. This is also as done with diff pinion tapered roller bearings.
Bob

[philthehill]

Bob
With the Marina brakes fitted to the front of my Minor the wksp man specifies that the wheel bearing nut is torqued to 5lb ft - then slackened off and re-tightened only finger tight. It also states that the bearing should not be pre-loaded and there will be discernible play at the wheel.
The diff pinion taper roller bearings are torqued high for a different reason - that being to keep the bearings together under high pressure loading.
I asked in my post as to what brakes were fitted so as to determine as to whether the bearings are pre-loaded or not though most of the conversion kit supplied by the usual suppliers have tapered roller bearings which I suspect do not require pre-loading.
Phil

[BLOWNMM]

Phil
I based my recommendation on my long practised proceedures which have generally recommended a slight preload. There may be particular installations which recommend otherwise. See link.
Bob
http://www.rwmcasters.com/technical_inf ... stment.cfm

[ndevans]

I've got Ford based discs, I believe the hubs are taper bearings, but can't remember. What got me asking is that there's no discernible play on the o/s.

Cheers N

[philthehill]

Bob
Many thanks for the link.
Whilst the link recommends bearing preload (not specified as far as I can see) I will continue to set Marina taper wheel bearings as per the manual. I will also continue to set all taper wheel bearings as I have always done - that is the nut firmed up to make sure that the bearings are set fully home then wound back (loosened), then tightened finger tight so as to give some discernable play at the wheel rim.
Phil

N.
Whilst it is your car and you can set the front taper roller wheel bearings as you see fit - my preference would be with your Ford disc brake installation to set the bearings as described above for the Marina hub bearing - that is with just a discernible amount of play at the wheel rim which at the bearing is negligible.
Having excessive preloading of the wheel bearing can lead to early bearing failure.
Phil

[les]

I've had this dilemma with a mini taper front wheel bearing, the issue there was a solid spacer between the inner and outer race, the preload or play was determined by said spacer, it appeared to rely on all tolerances being spot on.

[ndevans]

Ok. So if I understand you correctly, Phil, I shouldn't worry too much about a little play on the n/s, but perhaps ought to back the hub nut off slightly on the o/s?

Cheers N

[philthehill]

Les
Only the Cooper S and 1275 GT had Timkin taper roller bearings (with different hubs) with a predetermined spacer between them to give the correct preload with the spacer having to be replaced when the bearings are replaced - if I remember correctly Les you used to own a Cooper S. All other variants had ball bearing wheel bearings with a high preload which they were designed for.
Both the Ford Cortina and the Ford Escort (both the old rear wheel drive types but with taper roller front wheel bearings and disc brakes) Wksp Manuals give similar instructions to those given for the Marina only the pre-set torque is at 27 lb ft before slackening off - allowing the wheel to rotate freely with just discernible play at the wheel rim.
Phil

[philthehill]

N
I would prefer to have a little play at the wheel rim than have a pre-loaded front wheel bearing - so yes I would check both sets of front wheel bearings and set them both so that there is just discernible play at the wheel rim.
Phil

[firehor5e]

Have an assistant apply the foot brake while you test for play,if there is play with the brake applied the problem is with the suspension/steering components.

[BLOWNMM]

Can somebody explain to me in simple terms why a front wheel fitted with roller bearings which are adjusted with a SLIGHT preload, can be subject to premature failure when compared to diff pinion bearings with a much higher preload regardless of the reason for this adjustment. It is not unusual for pinion bearings to last for 200,000 miles or more without failure. One must assume both bearing sets were chosen to safely offer a satisfactory service life as far as loading. That being so then the number of revolutions of each should have some effect on their life. The much higher preloaded pinion bearings do considerably more revolutions than a wheel bearing: something between 3.5 to 5.0 or more dependent on the diff ratio.
Bob

[philthehill]

Bob

The diff pinion taper roller bearings run in a bath of oil so are constantly lubricated for longer life under pre-load.

Front hub taper roller bearings run in grease which is not fluid until a certain temperature is reached and which may never be reached if the vehicle is used for short runs.

If the front taper roller wheel bearings are pre-loaded (even slightly) and the grease is not fluid the grease may not be able to circulate throughout the bearing rollers and roller faces and the bearing could be considered to be running dry which will or may cause the rollers to skid so damaging the rollers by creating flats on them and subsequently damaging the roller race faces which invariably leads to bearing failure.

Whilst the above may take some time to happen and that time period is dependent upon the pre-load applied - it does shorten the life (premature failure) of the tapered roller front wheel bearing.

Having that slight play allows the grease to circulate between and around the bearing rollers and roller race faces even when not totally fluid so providing that much needed lubrication.

Therefore unless special provision is made to run taper roller bearings under pre-load it is better to have some discernible play at the wheel rim (as describes by the manufactures wksp manuals) to allow that cold grease to circulate so that the bearing is able to achieve its predicted life cycle.

Phil