0 deg. caster - what affect of front braking

[Tom Bellfoy]

The Les Andrews book states the Model A Ford should have a 5 degree caster.
A couple of us guys are trying to diagnose a model A problem with a friends car, we all have a fair knowledge of the Model A and its workings.

problem is when the stock brakes are applied the front end goes absolutely volatile by jumping all over the place.

We are likely looking at some loose parts and steering box in need of rebuild, however we also believe the front axle may be bent.

I've read a few posts on the bent axles so far but was wondering how to check the caster angle while the axle is attached to the car and if there was no caster at all what affect would this have on braking.
We'll als be checking the camber angle

thanks for your input