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(18-12-2017, 10:23 AM)Alan Wrote: The reason I asked the question in the first place is that there appears to be a need among certain forum members to portray our cars as fragile, unreliable and dangerous. In truth, they are none of these and such an attitude is not helpful to anyone thinking of taking up seven ownership, or even using the one they already have.
Here,here Alan
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(18-12-2017, 11:14 AM)Ron Hayhurst Wrote: Of all A7 components, whether deemed fragile or not, the steering arm has for many years been one whose condition needs to be checked. The problem of cracking and its solution was well described in A7CA Mag 2004B. This can be seen on line at A7 Components web site where the article is reproduced. I would strongly suggest any viewer of this thread who has not yet picked up this article to do so now.
At around 2000 when this was a hot topic, about twenty steering arms were located in the Bristol Club Spares Shed and were carefully examined for cracks. All but two were shown to be cracked when subjected to magnetic particle inspection -i.e. it is not always easy to spot by cursory examination. The racing fraternity have been hot on this for years. It is subject to scrutineering. No used steering arms are now sold out of the Bristol shed.
The point about fatigue cracking is that the component continues to give "normal service" while the crack propagates. If you are lucky, as happened with the failures experienced by a few BA7C members, it will finally fail under the stress of slowly going lock to lock when parking. Not so lucky if you are hairing round a corner and hit a pothole!
Thank you Bob for again raising this thread. The topic needs airing now and then if only to bring it to the attention of those who are new to austinneering.
Ron
I used to run a chummy with a performance engine in the sixties and was timed by a following car at 70 mph on an interstate border run. The car was then put into storage whilst I was overseas for some years. On my return I trailered the then unregistered chummy to a local rally and rolling it off the trailer the steering arm totally collapsed at the elbow.
I now use David's new replacements and am on my fifth, with no failures. Call me overcautious but I am also thinking of getting in a supply of brake pedal rods. cheers Russell
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Ooh now I've had one of those go on me for sure. Caused a few anxious moments on a rather steep hill in Paignton many moons ago...
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Car type: 1927 Chummy, 1938 Big Seven 1/2 a Trials Chummy
The only time I've had a steering arm fail was at the other end of the drag link, the arm on the steering box. This was on an hourglass type box; they don't get so much publicity but are just as weak if not weaker.
The car (a late Ruby) failed to turn right after the arm snapped and I hit a stationary Vauxhall Viva HB, waiting to turn out, somewhere around the front N/S wheel. The whole front of the Viva was shifted over by a couple of inches toward the O/S, quite a wreck!
I was upset; the collision had bent my starting handle and broken a perfectly good, original headlamp glass. As my only car, it was back on the road later that day.
That was 1979, the car was only forty years old. Should have taken it back under warranty................
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Now that is something I have witnessed, the late steering box arms (the detachable ones) snapping.
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Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
Don't tell him or we'll never hear the last of it!!!!
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(18-12-2017, 11:01 PM)Alan Wrote: Don't tell him or we'll never hear the last of it!!!!
RAFLMAO!
Black Art Enthusiast
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19-12-2017, 09:08 AM
(This post was last modified: 19-12-2017, 09:09 AM by Ruairidh Dunford.)
(18-12-2017, 11:14 AM)Ron Hayhurst Wrote: it is not always easy to spot by cursory examination. The racing fraternity have been hot on this for years. It is subject to scrutineering.
Hi Ron,
out of interest - how is the scrutineering of this part done please?
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Hi Ruairidh,
There are plenty of readers who can better answer this one, but I understand that when submitted there should be no paint on the steering arm and that it should be polished, particularly in the inside radius where cracking commences. It is then given a close visual inspection - if you can see a crack at this stage it will almost certainly have some depth to it!. It follows, I think, that having done such preparation, the intending driver will have "heaved the offending arm out into the night" rather than refit it!
The brief method described was the case a few years ago and it is probably more demanding now. A check with the VSCC will provide the latest requirements.
Ron
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19-12-2017, 10:45 AM
(This post was last modified: 19-12-2017, 12:14 PM by Alan.)
I always present my car for scrutineering with the steering arm clean and polished, but there is no formal requirement to do so. I've been competing for almost 40 years and I'm not aware of a scrutineer ever having looked at it.
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