Front bearings

[Tony Press]

Thanks for all the great replies, I was under the impression that if I got a set no further fettling would be needed. 

Guess I need to have a look for some shims, the mini suggestion returns a few on Google so will look into that.

Tony- they were RHP MJT1.1/8M. They came 2 to a "set".
I've attached a picture of the box.

My list of bearing suffixes indicates:  M- a pair of bearings with medium preload - no memtion of the pre load so could be 8-10 thou. 

Your box has suffix MB which is listed as: MB- solid brass cage ?

In any case I believe the old Austin Seven 'matched pair' of angular contact crankshaft bearings BB68 would have no more that 2 thou maximum preload.

I would think stock of these would be long gone.

[bystander]

If you are fortunate enough to find any old stock, the special part numbers are:
RHP  2/MJT1-1/8
SKF  400648
Hoffman N1919


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[Bob Culver]

With used in place of worn I can endorese the "do not discard worn bearings". As with many amateurs I have tossed out many ball races over the decades, including a.c. Some cars are known for failure of certain bearings but often life is infinite. But if not pitted, rust or debris damaged often a waste of money. Reversal of the a.c races in diffs should hugely extend life. Seven wheel bearings are very generously sized, esp in modern ratings.

[dannyteal1990]

Thanks for all the great advice, I've got a set of shims from a classic Mini on order so will have a play around with those when they arrive and see where we stand.

The bearings are indeed brass caged.

I've also heard that old bearings can give years worth of service but since they are a bit of a pain to get in and out I thought it proved well to change them for new while I had the engine in pieces.

Cross fingers I can get past this hurdle...and will then probably very quickly hit the next one

Thanks again everyone!

[Parazine]

I've also heard that old bearings can give years worth of service but since they are a bit of a pain to get in and out I thought it proved well to change them for new while I had the engine in pieces.

They can but it's worth taking them apart to check for rust pitting first. To do this, I put the bearing in the palm of my hand and tap the thrust side smartly with a copper hammer to force it apart. You can then inspect the tracks with a loupe to check for rust pits, also the balls, which can be renewed for little cost. When you are satisfied, the bearing can be tapped back together again.

Any rust pits, discard the bearing. I ran one years ago with a few small pits, after 5000 miles, the bearing tracks were completely gone.

[dickie65]

I make sure that I buy ground matched bearings its more money but they are available.

[Tony Press]

I've also heard that old bearings can give years worth of service but since they are a bit of a pain to get in and out I thought it proved well to change them for new while I had the engine in pieces.

They can but it's worth taking them apart to check for rust pitting first. To do this, I put the bearing in the palm of my hand and tap the thrust side smartly with a copper hammer to force it apart. You can then inspect the tracks with a loupe to check for rust pits, also the balls, which can be renewed for little cost. When you are satisfied, the bearing can be tapped back together again.

Any rust pits, discard the bearing. I ran one years ago with a few small pits, after 5000 miles, the bearing tracks were completely gone.

Unfortunately knocking angular contact bearings apart can indent the balls causing later problems.

Using unmatched balls defeats the purpose of the original set of carefully matched balls.

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I make sure that I buy ground matched bearings its more money but they are available.

I would have thought that a matched pair of Austin 7 SKF AMS 9 or RHP MJT 1 1/8  angular contact bearings (imperial size) would be very difficult to find.  

Especially the later narrow outer ring pair.

Where do you get these ?

[Bob Culver]

Many do come apart very easily. but in strong sun can usually inspect all parts of assembled races although it is tdious. Do Seven mains properly fitted ever fail by classic pitting? Most of the very old ones I have have worn due corrosion, evident from grey colour. I gather balls are selected within their tiny range to give exact clearances but if shimming probably no matter. I question the notion of signifiacnt preload containing the crank rigid. Seems to me desirable to just eliminate radial movement. I have fitted with, but car had steel lip.

[Tony Press]

The angular contact bearing  balls are matched for size so all take the same load.

The deep groove bearing balls are matched for size and to the track diameter to set internal clearance.

[RossV]

The pair of AC bearings should be fitted with the wide side of the outer ring touching each other. This means that the faces of the inner rings will be a few thou apart and you get the required crush and the retainer on the crankcase has no extra force on it. T