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+--- Thread: Front wheel bearing play (/showthread.php?tid=3541)
Front wheel bearing play - morrisminor - 15-11-2019
Hi all, what wheel bearing play is acceptable to Mot testers(I know it doesn't need a mot) if I apply the brakes then rock the wheel there's slight play in it
RE: Front wheel bearing play - Bob Culver - 15-11-2019
With the brakes applied the hub is locked more or less solid so actually observing kingpin movement. (perhaps outer race which seldom at fault)
The Seven races are very generously proportioned and actual wear is normally insignificant so the play should remain as new, almost none. But movement of the bearing in the hub is common thru having not been clamped at some time due thick gasket, ommitted steel seal washer etc. Remedies of varying crudity, including centre popping, solder, fibregalss smear etc. Not prudent to loctite race into both halves. If properly clamped needs only be tight in one. Depths and protrusions can be measured.
Modern testers are accustomed to moderns with no play. Older taper rollers, often/normally loose on the stub axle, upset them. On my 1960s car to avoid inevitable argument I maladjust tight for every test. Otherwise would have replaced umpten times. if a tester thinks the car has taper rollers he should accept considerable play, but will likley accept little if knows they ball races.
RE: Front wheel bearing play - morrisminor - 15-11-2019
Thanks Bob, I've a moggy 1000 and that wheel bearing can be tightened up to a spacer to eliminate play, but I believe you can't tighten 7 ones ? If I understand you correctly with the handbrake fully on and there's movement its the kingpins slightly moving ?
RE: Front wheel bearing play - Tony Press - 15-11-2019
As you suspect the Austin Seven front bub design is such that there is no adjustment for the ball bearings.
Ball bearings must have internal clearance so there will always be a slight movement.
If tested with the handbrake on the hub should be 'clamped' and as Bob notes the movement will be in the kingpins.
RE: Front wheel bearing play - squeak - 16-11-2019
As Tony and Bob have said it's likely the kingpins at fault, but can also be loose a wheel due to worn wheel nuts bottoming on their threads. Easy fixed by grinding off the sharp edge of the nuts.
RE: Front wheel bearing play - Bob Culver - 16-11-2019
Various makes have a variety of arrangements and judging from ruined bearings encountered on trailers and old cars many mechanics do not grasp the sublties.
I suspect in the Morris 1000 both bearings are constrained and the spacer length is critical. Overtightening can preload the bearings and eliminate play. With Sevens only the large bearing is fully constrained; super tightening the nut unnecessarily collapses the spacer and acheives nothing. Close scrutiny of the cross section diagram which appears in handbook reprints reveals all. The large bearing must be clamped by the two halves.
Because the kingpin bushes are so closely spaced very little wear allows movement. Again modern inspectors accustomed to no movement get paranoid about this but harmless. The pin must not move in the axle (or be in two pieces! Regualr shaking of the wheel when greasing can detect the latter).