Crankcase Front Bearing Housing Repair

It is possible to repair a crankcase when the front bearing retaining lip has broken away allowing the crankshaft to ‘float’ in the crankcase, often evidenced by a heavy rattle/knock when you press in the clutch. The crankcase design is similar to all Austin Sevens except the Big Seven.

Like all things Austin Seven there are many ways to achieve the same objective, this repair is no exception. This is the method I use.

Lip repair 1

First the old lip needs to be removed together with a ring of metal from the crankcase so that a new retaining plate can be bolted in so that it replicates the lip.

Lip repair 2

I use a home made tool, which is rotated by hand with downward pressure in a set of dummy bearings as in the picture (right).

It does take a little while but eventually the metal is cut away.

Lip repair 4

Lip repair 3

Next a cone tool is inserted into the front bearing housing so that the replacement ring/lip will be central.

Lip repair 5

The plate is marked so that the screws will be where the metal is thickest, i.e. where there are strengthening webs in the crankcase. I don’t like the pre-drilled plates.

The plate is then drilled and used to mark the positions of the holes in the crankcase which will be threaded ( horror!!!! I used ‘metric’ socket screws, 5 mm. which are readily available ).

Lip repair 6

Once the crankcase holes are marked, drilled and threaded then the plate is screwed into place using a little Loctite on the threads just to make certain.

You could use slot headed countersunk screws but socket headed with an Allen key can be made really tight.

The original article, written by Malcom Watts, appeared in CA7C Seven Focus in Feb 2014 pp16-17.