Front axle/steering wobble

[Hugh Barnes]

When I suffered this many years ago, it manifested itself once on the brake/road test during the MOT. As you can imagine, the tester (who was well used to Austin 7s) jumped out in alarm saying 'I'm not going to pass THAT!'

[Dennis Nicholas]

"Did the king pins" 
Were the axle and stub axle eyes checked for being square to the pins?
Presumably stubs and axle shimmed out so no vertical clearance?
  Passed abuse wears these surfaces so that they can become V shaped i.e more weare on the outside than on the inside faces.  This can be tested for by checking any gap with feeler gauges.  Try the outer part first (maybe about 0.001 to 0.004 inch)then try to put the same feeler that goes in into the area between backplate and kingpin.  

   

   

The top picture shows the surface round the kingpin eye blued all over and square to the kingpin.  Prior to grinding there was only bluing on part of the surface.
The bottom photo shows the pilot in the kingpin eyes with the cylinder fixed between the eyes.....this was used firstly with bluing to show the wear, then with grinding paste on the cylinder end to grind the faces true and square.  Note the smaller diameter on the end of the pilot so it fits a drill chuck.  From memory it needed 0.002 off top and bottom eyes, then there was the axle eyes so just add that lot up....say 0.001 on axle then 2X 0.001 + 2 X 0.002 = 0.006 wear.    Shims may take up initial space at the least worn faces but there is still 0.006 wear at the worst faces.

Dennis

[Ray White]

Nice to see such attention to detail. It should pay dividends.

[Dave Wortley]

Hedd,
I use the rad arm spring as a spacer,ie it’s coil bound!

[Hedd_Jones]

The axle even needed twisting to get it all correct Dennis.

Using a modified domestic tap valve face cutter gets away with fannying about with grinding paste. Gets it flatter too.

That said, Ive driven a few cars where the king pins were atrocious and never had the problem I describe.

I will report back once I've had another look.

[Dennis Nicholas]

Using a modified domestic tap valve face cutter gets away with fannying about with grinding paste. Gets it flatter too.

That said, Ive driven a few cars where the king pins were atrocious and never had the problem I describe.

I will report back once I've had another look.

Hedd   What is the size of the cutter you used (presumably on standard 7 axle with 1/2" pins)? 
The problem with using a tap valve face cutter was that I could not find one large enough dia for the BIG 7 axle thrust faces.  I needed 1 1/16' (27mm) for underside recessed axle eye and slightly different size for stub axle eyes.
I would like to know if you or anyone else has found one that size (5/8 king pins).

[Chris KC]

Using a modified domestic tap valve face cutter gets away with fannying about with grinding paste. Gets it flatter too.

That said, Ive driven a few cars where the king pins were atrocious and never had the problem I describe.

I will report back once I've had another look.

Hedd    What is the size of the cutter you used (presumably on standard 7 axle with 1/2" pins)? 
The problem with using a tap valve face cutter was that I could not find one large enough dia for the BIG 7 axle thrust faces.  I needed 1 1/16' (27mm) for underside recessed axle eye and slightly different size for stub axle eyes.
I would like to know if you or anyone else has found one that size (5/8 king pins).

Mine came from Wickes a few years back and goes up to 1" diameter I believe. The cutters obligingly came threaded 5/16 BSF so can be bolted directly onto the end of an old kingpin as a 'pilot'.

[Hedd Jones]

I believe fathers is a very old unbranded cutter. I have it now and its in a biscuit tin!