Head tube bearing in my 1960s Carlton

[midlife]

The OP needs to check the races for Brinelling (OK I know it’s fretting) but if all smooth don’t think there’s a need to replace unless the chrome has rusted etc and wants it to look better.

 

[Ajax Bay]

Could do, but (see the OP) the symptoms of brinelling (in the case of a headset a notchiness when turning the bars with a preference for staying 'straight ahead) are not described. That's what I meant by "checking the races" recognising that the OP was a (self-confessed) "reasonably competent engineer" so would know what to look for.

 

[rogerzilla]

They usually die from either rust pitting (water ingress) or the dreaded false brinelling, most common on road bikes (by which I mean any bike used on the road). If a headset on a vintage bike still has smooth races, it's a real survivor!

 

[Johnsco]

There was no evident brinelling of the upper bearing races when I checked them over.
Having renewed and greased the bearings, and adjusted as-said in post #29, there is no notchiness or tightness at any point of the steering.
I gave the bike another good run today over the rough roads of Leeds.
The "clacking" that was the original head problem is cured.
When I unscrewed the upper bearing, I was expecting to see the grease dried out and the bearing in a real mess.
There was still quite a bit of good grease there .... Just a shortage of balls.
I've a few other issues to attend to before I return to the question of the lower bearing.
This bike was used by a "friend" for some time 30 years ago before it was returned to me in a very poor state.
He was something of a hooligan !
I may be asking for technical advice on sorting out lateral run-out of the chainwheel before too long.
Also, the old steel rims are pitted (front and back), which means that braking is a bit rough.
So - I'm looking to replace with a couple of alloys.
I think that's the next job.
At the moment, the bike rides well - So I'm enjoying being back in the saddle after many years away.

 

[Ajax Bay]

Braking on wheels with alloy rims will feel like a step change from steel rims - attractive on Yorkshire downhills.
Sheldon worth a read. Likely your wheels are 630 and you'll replace with 622 (so make sure your caliper brakes have enough drop to reach down the extra 4mm) but that would allow you to fit wider/deeper tyres (eg 622-32 if you wanted to.

 

[Johnsco]

Thanks Ajax Bay.
I'll check out your Sheldon link.
The bike has always run on 27" x 1.1/4".
Originally alloys and then, in more recent years, steels.
(Times were hard !).
I may open up a new post re. my intended alloy wheels, as I don't really understand the 630 or 622 references.

 

[Ajax Bay]

ETRTO (SI) sizes are 27" = 630 and normal road wheels are 622 (aka 700). The latter are much more available, and tyres to fit, likewise.
Enjoy the Sheldon Brown link and the detail should be clear.