Brake lock-up

[IanS]

Rear drum break cylinders probably are the same as still fitted to the latest small cars that still have drums at the back, if it works well dont redesign.

[Snapperpaul]

Just a thought if all else fails swap front break pipes on the master cylinder, if the other side locks up it’s the master cylinder 

most master cylinders have two outlets for the front, 1 for the rear which goes to a T piece near the back

[Peter Bell]

Hi Andy, I have a DTi (dial test indicator) if you wish to borrow it. I would check the caliper/sliders that is not locking first, may be that that is slightly siezed causing the other side to lock.

[AndyW]

Hi Peter, many thanks for the offer, but I'll defer that one for now.  Since I cleaned up the front calipers and sliders, and replaced the seized rear drum cylinders, the overall braking balance is vastly improved, and I'm not seeing the front lockup now. So maybe I've fixed it. I'll drive it for a bit and see how it feels before I get into checking disc runout.