Vintage steering boxes

[galfredus]

Evening all,

I'm seeking some reassurance from more experienced members re the steering boxes on vintage ACs. In one of the docs in the members area the AC steering box is described as a close copy of the Marles of the period. (Interesting note, if my researches are correct, John Weller's brother was involved in the design of the Marles box).

Im also an Alvis enthusiast, and a Marles box was used on later vintage Alvises. A few years ago there was veritable panic among the membership of the Alvis register regarding hidden cracking of the shaft inside the steering box.

My (obvious) question is: Is the AC steering box known to have similar problems?

All guidance gratefully received.

Geoffrey

[Old Crock]

The company's adverts of the late-20's talk of the 'Weller box' and motoring publications of the time refer to the 'Marles steering' on AC's. It may be that John Weller's brother designed the AC box as he patented gears used by AC in the mid-20's. His first patent on helical gears for Marles was not until the 1930's.

The vintage box on AC's is not one of Marles usual designs; it is similar, works on a worm and roller principle (though, unusually, the roller sits parallel to the worm, not at 90°) but the casing is different, there is no makers name on it, and it may be unique (so it is not quote 'a close copy' unquote). Maybe the build was subcontracted to Adamant Engineering (the manufacturers of Marles boxes) or it is very possible they were made, at least assembled, in-house. The owners' booklet does describe it as 'the AC patent steering'. 

It is prone to leaking after so many years and much debate has centred on the use of modern semi-fluid grease to limit leakage. Do not use ordinary grease, the recommended oil was Price's Amber 'B' (now Castrol D140 is commonly used). There is only one seal inside and there are two adjustments possible. A worn worm could be a serious problem - not least getting acceptable tolerance when working with hardened steel with a newly-made one, let alone the cost. The easiest removal on the vintage AC - although it may not sound it - is through the floor by removing some of the wooden sections inside the cabin. Some boxes, like on Lagonda and Alvis are visible and easy to get to, unfortunately not so on the AC.

I have never heard of an AC suffering from cracked worm, and think it would be most unlikely considering in-house design and possible manufacture. 

Postscript: should add, the above refers to the six-cylinder.

[administrator]

John Spencer's 'Archive' in the August 2018 ACtion covered the Marles-Weller steering box.

[Old Crock]

John Spencer's 'Archive' in the August 2018 ACtion covered the Marles-Weller steering box.

I believe that the Marles-Weller steering box was a specific design introduced for the 1930's. The question from 'galfredus', above, refers to the vintage period.

I have not seen this article but does it refer to AC's cars of the 20's? I thought that John Weller's brother's steering patents, used by Marles ( = Marles-Weller) were later.

If the article by John Spencer does indeed refer to the 1920's could someone please give a summary here (or include attachment)? Thanks!

[galfredus]

Hello, and thank you for your responses.  The quote came from David Wakefield's "Vintage Buyer's Guide" in the ACOC members area: "Steering by Weller patented box (but actually a close copy of the Marles design)."

It sounds like that may be incorrect - and in any case, that no steering box used on an AC was sufficiently similar to the Alvis 12/50 for it to be of concern in the matter of cracked shafts - so thank you for your reassurance; we will be leaving well alone (but checking for leaks!).

I tentatively hope to see/meet some of you at Audley End on 16 June.  It'll be a bit of a rush as the engine's not in yet, and needs running it, but fingers crossed.

Geoffrey

[jonto]

I am also a 12/50 owner, last year at Shelsley Walsh a technical adviser to the 12/50 register was admonishing me for not replacing the steering box shaft, its noticeable as the new ones are machined with a tell tale on the visible end. Talking to other owners some had had there's crack tested with cracks showing in the results.