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Cracks in steering components....

I received an email tonight from a new A7 owner who is diligently going through his car before returning it to the road, he writes:

several photographs of cracks I have found in the steering components of my 1936 Mk 1 Ruby, to alert others and encourage them to inspect everything regularly, I am asking for them to be posted on this forum.


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Re: Cracks in steering components....

Thats quite a common crack in a hub. Ive weighed a few like that in.

Re: Cracks in steering components....

I've experienced cracks in my own and a friend's Austin 10 hubs.

Time to be thinking about new ones machined from solid?

Re: Cracks in steering components....

The top picture is a stub axle.

Re: Cracks in steering components....

Some years back I think it was David Cochrane who had a load of original steering arms tested and found a very high percentage had a crack developing on the inner radius of the bend. Most could not be seen with the naked eye.

I did also hear last year of an instance where the drop arm had sheared - luckily at a time when the car was moving very slowly.

Worth making very regular checks on these components as 80 odd years of 'push/pull' is almost bound to have weakened them

Location: North Herts

Re: Cracks in steering components....

Despite the considerable publicity this vital topic is still new info for newcomers. It really needs a six monthly bring up.
Probably the best overview is on the A7 Components site.

It is dangerous to presume that cracks will be visible before failure. Many 1/3 of the way through are not. If the centre dot represents the visible end of the unusual mid arm crack, someone has had a close escape! The steering arms also crack at the shoulder, a tendency which better shaped new arms may not avoid. The shoulder must seat appropriately and the nut kept tight to pretension.
Hauling on the steering wheel should be avoided. If wedged in a tight park better to pull the wheels lock to lock by hand. (Tugging on the wheel does have the merit of often ensuring failure at low speed!)

Stub axles I have tested seemed headed to fail across the diameter, a more dangerous situation than the photo. The cracks were only apparent with magnetic detector and would probably have been OK for thousands of miles. Left stub was cracked at 100,000 but that included very many miles of corrugations and broken edges seldom encountered now. Curiously the Big 7 stubs seem the same despite extra weight.

I have told the story before but it may bemuse some. My father experienced a failed arm over 65 years ago. The car was negotiating a tight sweeping bend at 30 mph but did not respond. The wheel was instinctively wrenched causing the drop arm to cut through the horn wire and open the throttle. The car hit a deep gutter at a tangent and continued until abruptly stopped by a vehicle crossing bridge. The horn was blaring and the engine running full tilt! A firm was persuaded to weld the arm so could drive home. A good replacement was difficult to find. We took a keen interest in the topic of metal fatigue ever since. At the time few had heard of but the Comet crashes later introduced to all.

Axle beams also crack where the H section starts.
It is also prudent to eye the rear main spring leaves occasionally as a complete break at the wrong moment can be exciting.

My father had great faith in his Seven and trusted it to go anywhere. He had never heard of a failed crank and would have been horrified to learn of the similar tendency (although the original survives).

Location: Auckland, NZ

Re: Cracks in steering components....

I looked at the steering arm on my RK and it seemed alright, it even rang true, but when I gave to my friend,who prepares historic F1 for racing, he had it crack tested. It failed across the knuckle. I bought a new one. Therefore when I do finally get the little treasure back on the road I can feel safe i won't be exploring the hedgerows. Alf

Location: Hampshire

Re: Cracks in steering components....

i think for simplicity and safety this swap is a given.. just done mine the original seemed ok and came out easily and its replacement fitted just as easily.. peace of mind for 30 minutes and 75 quid.

Location: pennines

Re: Cracks in steering components....

Ruairidh Dunford
The top picture is a stub axle.


In what plane is the crack on the stub - in other words is it vertical and thus possibly caused by a frontal shunt?

Location: Farnham

Re: Cracks in steering components....

Under the stub. Along the line of the thrust face of the bottom king pin bearing.

Thats where all mine cracked

Re: Cracks in steering components....

David
Ruairidh Dunford
The top picture is a stub axle.


In what plane is the crack on the stub - in other words is it vertical and thus possibly caused by a frontal shunt?


Hi David - I only have the picture you have seen so I am assuming that it is horizontal, as are the ones I have seen fail like this.

As has been stated, to many of us these types of failures are well known, to newer owners finding such will come as quite a shock for sure.

The purpose of the post is not to find how many know about such failure but to alert those who know nothing of them to check.

Re: Cracks in steering components....

the stub axle crack is quite common.

like hedd ive scrapped plenty.

the crack will run horizontal.

it you turn the stub round for a view from the rear.

austin made a small mistake of useing a standard cutter. so the corners are square instead of having a small radius in them.

this seems to be the fail point for the crack.

sorry pearl but when there are still plenty of good stubs about for around £10 to £20 i dont see anyone stoopid enough to make new ones at ill guess around £150 each.

and even if they were in short supply, i can hear alot of HOW MUCH coming

always felt if i could spell, or even read. i would right a book called the CRACKING little car. as there are plenty of others to look for.

tony.

Location: huncote on the pig

Re: Cracks in steering components....

Hi Tony

Always enjoy your straight shootin comments, but the crack about cracks would have got me excommunicated! (again)

Admittedly based on a small sample but the stub axle cracks I detected definitely started on the wheel side, slightly further out and were headed straight up through the tubular section. Both on Girling stubs and previous. Probably would have been visible well before failure, but it is unwise to assume that all latent failures will become as obvious and be as benign as the photo.

Location: Auckland, NZ