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Re: Front wheel wobble

Using depth micrometer etc, the spacer between the bearings is 0.007" less than the gap between the inner races of the 2 bearings and not giving the bearings the pre-load that they should have. Although the bearings are 20 years old, they have only done 8,000 miles and I would not expect well greased SKF bearings to have packed up in that short lifetime. I had a 0.005" shim (Stub axle diameter), so thought reducing the gap to 0.002" was better. As one can imagine, over the last 85 years or so, even the stub axle may have worn in its chequered history.
Another thought is that the gasket is too thick, but its one provided by one of our suppliers some years ago.

Probably the correct answer is to replace axle, hubs bearing and all - BUT that isn't going to happen. The wheel won't drop off so there isn't a safety issue. I was wondering what others had experienced and what the MOT guy would accept.
Bob

Location: France Dept 46

Re: Front wheel wobble

If you have a carte grise "collection" on your RN then it's exempt Contrôle Technique, Bob.
Bruce

Re: Front wheel wobble

Interesting Bruce. When I spoke to the guy at the CT, he said it was still required. I later spoke to a guy at a rally and he said "Not necessary, but may be an insurance requirement".
I will update as to what happens tomorrow at the CT.

Location: France Dept 46

Re: Front wheel wobble

Hi Bob

There should be no preloading in the accepted sense. There is a clearance between outer ring of small race and the enclosing hub so the race is free to locate itself endways in the hub.
With any gasket in place, the outer ring of large race should be lightly gripped sideways. Metal shims are tedious to make; stiff card probably adequate.
Assuming the small race is a good fit, once the large race is loose radially in the hub the wheel will wobble; a side shim may disguise but wont prevent on the road. If cannot obtain a good hub (or even half of) remedies of varying crudity; pop dots, knurling, tinning, Loctite etc. The appropriate grade of latter nowadays accepted as OK by some, perhaps assisted by dots. I would try fixing in just the inner hub flange; the hub will then remain dividable.

Seven wheel bearings are very generous for the size of car and should and normally do last forever.

Location: Auckland, NZ

Re: Front wheel wobble

Are you sure that it is the wheel bearings and not axle eye wear/elongation. Your king pin and bearings may be perfect but the eye in the beam may be out of shape ( a common problem with Austin Sevens)

Re: Front wheel wobble

All ball bearings have internal clearance even when new. A two ball hub as with the Austin 7 must always have some slack and as Bob says the outer bearing should be free to float endways in the hub, with the inner bearing doing the locating.

If you can find two new good quality bearings with reduced internal clearance (SKF C2, R&M/RHP two dot)), which is unlikely now, then the movement could be reduced slightly.

If the bearings are loose in the hub or on the stub axle this will exaggerate the wobble.

The inner bearing must be a snug fit in the two parts of the housing and on the stub axle, the outer bearing a sliding fit in the hub and on the stub axle. I wouldn't suggest Locktite which will give problems later when dismantling.

If sealed bearings are used (recommended) then the felt plate must still be used.

Originally a paper gasket was used between the two hub halves- any thicker will lose the side retention.

I believe race scrutineers often complain about Austin 7 front wheels, being used to two taper roller assemblies but as noted a front hub with two ball bearings will always have a slight slackness.

Chewers, Tony.

Location: Melbourne, Victoria, Australia.

Re: Front wheel wobble

Thanks to you all - a pretty comprehensive answer. I reckon its Loctite on the inner bearing to start with. At the same time I will take the opportunity of replacing the wheel studs as the old ones are the originals.
Bob

Location: France Dept 46

Re: Front wheel wobble

Bob,
Your tester unfortunately is mistaken. The exemption which came into force in February this year relates to all cars with Carte Grise Collection first registered before 1/1/1960. Later cars still have to have the 5 yearly test.

If there is an insurance requirement that's a private matter between the owner and the insurer and in any case it's voluntary. My classic insurer certainly has made no contact regarding this.

If you need documentary proof there is a link to the legislation on the FFVE.fr website.

Good Luck
Bruce

Re: Front wheel wobble

Turned up for the CT this AM, and the tester was surprised to see me. He checked the docs and as Reckless said. No requirement for the test as it was pre '60 and a "light Vehicle". It was his boss that had said the test was required. So I went home with a smile having saved 59 euro - then my wife said the dish washer had packed up. On inspection, the computer was burned out and as it was over 12 years old, so it was off to buy another one. Some you win and some you loose.

Location: France Dept 46