Just been wiping over the Colander with the proverbial oily rag and thought I'd check nuts for tightness etc. I noticed what looked like a small crack in the steering arm. Knowing this to be a problem area I removed it and looked closer. Inspection with a 10x glass revealed a very small hairline crack only noticable because of the dirty oil I had wiped onto it!

I have now started to make a simple brace similar to those commercially available to strengthen this area, and have filed a small amount of metal off the arm in the area of the crack to remove it.

I am aware of redesigned arms available but not sure if they are available in low frame form, and anyway the 19" wheels are eating away at funds at present.

My point is that at the start of the "driving season" perhaps it would be worth everyone checking parts like this? Some people may have many layers of paint or grime on their front suspension and wont spot the trouble till its too late. Research on various website seems to show this can be alarmingly common[:-
|]


Would be interesting to hear anyone elses experiences?

Regards

Steve.

Steve ...... It is very commen to hear of hairline cracks, it is extremely rare to hear of anyone having an accident with one.....

I'm not saying don't worry, your right that we should check and replace as required, I have a spare under the back seat, just in case. But the incidences of cars having a problem are few. Think of all those Trial cars and the bashing their steering gets, but I don't recall many breakages.

I agree about high and low frame steering arms, when I've tried to buy them in the past and asked the seller (ebay or a telephone call etc.) if they are high or low, the normal reply is ".... is there a difference...", yes there is, the high frame rises from the stub axle to the drag link pivot, the low frame drops.

Algie.

PS, lovely pictures of you in this months Cornwall Mag. and agree, 19" wheels will look better on the 'Colander'.

Steve,

Your suggestion that everyone should check their steering arms is very good advice. Naturally I tend to look at a lot of these components, and it horrifies me to see just how many are covered in paint or dirt, thereby making it impossible to spot any problems. In this area, ignorance is definitely not bliss, and doing nothing is NOT an option.

At the very least you should polish it back to bare metal and examine it under a magnifying glass. Even if it looks OK, you should keep an eye on it, but preferably fit a brace or, better still, a new one. The braces are all very well, but they compromise the security of the fixing of the half-nut on the back of the arm, and they have been known to break (so that the steering arm holds the brace together...)

For a better method of checking, refer to John Bowring's procedure at www.austin7club.org/How%20To4.htm. However, the best is to get it professionally crack-tested. Or you could fit a new one and have done with it.

The new ones are not yet available for cars with lowered suspension, but the standard ones do fit (and a new standard one is far preferable to a cracked original). The only thing you have to do is to keep an eye on the neck of the ball-pin because the greater angle of the drag-link means that the bearing cup can cause wear at that point.

Cracked steering arms are extremely common, and many of them have broken. Mike Hodgson had one break on a van only 10 yards away from the garage that had just given him an MoT certificate. The Western Australian A7C called in ALL the steering arms in the club, both on cars and spares. They tested the lot (around 150 arms I think) and found that 93% were cracked. As for trials cars, Barry Clarke saw one break during a Cobham trial some years ago, and Dave Dye (top VSCC trials man) has had one break.

I find it extraordinary that people will go to the expense of buying a new steering arm, or have a good crack-tested spare, and then keep it under the back seat, just in case! Just in case of what, for heaven's sake? Perhaps theirs failing just as one of Mr Sainsbury's big orange lorries happens to be coming in the other direction, so that their grieving heirs can fit it when rebuilding the wreckage...

David
www.ingineur.co.uk/A7C

Thanks for all replies so far.

I made sure that important components like this were not painted, just plated. I have now as previously said cleaned and polished the cracked area, which I think is probably sensible. I am familiar with more scientific methods of crack testing and flaw detection having worked in the tubing industry using ultrasonic testing equipment, BUT in this case I think my basic visual inspection has proved the point.

I guess we all have to make assesments of something safety related from time to time, and I suppose we often come to different conclusions. I decided to make up a bracing device for a bit of piece of mind because I have seen the crack. If I hadnt seen the crack I wouldnt be worried.

Steering probably comes high up most peoples lists of desirable features in a motor car so A bit of caution probably does no harm BUT lets keep a sense of perspective after all there are no seat belt,airbags,roll bars,ABS,antiskid blah blah etc....

We dont want to fall victim to the health and safety police do we
Why not just have a look at your arms at the weekend and make you own choice what you do with them?

Steve

David, the spare under the rear seat is because that is in the list of spares I have had for many years, including half shaft, dynamo, dizzy, etc etc. It's not so my relations can grieve, but so that should something go wrong I can replace it, be it in the next town or in Ireland, Holland, Scotland or whatever. To date it's nearly always been someone else's car that I have helped out, because, THEY had no spares with them.

I was not saying it's not important, but over the last ccouple of years, suddenly steering arms are a problem, people have been told to look for cracks and they have found them. How many broken steering arms have there been in say the last ten years whilst a car has been on the road. Certainly there have been more half shafts broken, how often do people check them, apart from trialist, who seem to get an extra flat on the nut after each outing.....

Much the same goes for wheels, how often do people check the nuts before a journey, sensible people yes, but I've heard of at least a dozen incidents in the last 5 years where wheels have become dangerously loose and two of wheels actually coming off by snapping a wheel nut bolt, following loose nuts - These were all on the road, not trialing..

Incidentally all my steering arms have one thin coat of paint and the rest is light oil.

Algie.

I for one am very glad that I spent £75 on a new arm, with a 93 percent failure rate, that leviathan coming in the opposite direction would look even more menacing than it already does, and you only need drive a mile before you see one!!! I am amazed at some peoples thought pattern when this subject is raised again and again. When the new arms first came out I didn’t waste any time convincing myself that it was a good idea to get one. Keep in mine that of the 90 odd arms that I checked, at least 30 were cracked around the boss, so a brace would be no use whatsoever.

All good stuff. If you go to sales and wants 2nd page . the guy who does the new arms has an ad.I have fitted a couple for others,but still run my original,which I check every year now. mac

The man who does the new steering arms is the second response , David Cochrane .

Just a few thoughts !

If the 'cracks' in the steering arms were possibly due to the manufacturing process of the component then it is more important to make sure that the 'crack' is not getting worse than the fact that the 'crack' is there!

The highest strain on the steering arm, when the steering is being turned, is at zero speed; the faster the forward movement of the car the less force on the arm.

If 93% of all arms are cracked ( or some similar failure rate ) but the failures can be counted on the fingers of both hands then that is a failure rate of 0.001%

I repeat my first point, if the crack is not progressive then is it a failure ?

Yes I would consider using the new steering arms if mine were 'cracked', or I could fit a big Seven arm which were a little stronger in design. By the way, one of our club members had an offside, frontend impact in their Seven, the steering arm was bent like a safety pin BUT DID NOT BREAK !

Happy thoughts

.

That's it chaps - keep on shouting about it!!!!

If the DtP get a wind of this we will all be off the road en masse.

If you are happy to take the undoubted risk then for goodness sake keep it to your self.


Mike

Malcolm says..

By the way, one of our club members had an offside, frontend impact in their Seven, the steering arm was bent like a safety pin BUT DID NOT BREAK !

In the early 60's when I was into cycle road racing, I hit a tree and bent the front forks back to the extent that turning them through 180 degrees I had the same caster angle offset, they lasted me for the rest of my racing days (3 competative years) and showed no signs of cracking at all, although I admit the first road race or two was undertaken with some degree of trepardation.

Now at some rallies I see bent radius arms, drag links, etc etc, I wonder what effect some of these may have under 'pressure'.

When I bought a Seven a few years ago, I did the normal run it around for a week or two to let things settle and find out it's handling traits, then I started to clean off the grot from the nearside radius arm. I found it was visibly split (vertically) for at least 50% from one edge about halfway between the axle and the ball joint. That one I replaced immediatly - there seems to be a shortage of sound pre Ruby radius arms, especially with sound threads at the 'front end'.

Like Algie, I too carry a spare steering arm, half shaft etc - we had a directive in the Cornwall Club of spares to carry - and most of my spares seems to end up in other peoples cars........

Sandy

The percentage given of cracked arms is surprising as well as frightening. For those who read John Bowring's article as suggested above, one added thought. The arm in question that he quoted had already been crack-tested by a reliable professional firm and pronounced OK. Question, as the car had not been used since, was the arm cracked before John started belting it with a hammer? Cheers, Bill

Algie,

I too carry a good selection of spares under the back seat - probably too comprehensive (do I really need to carry a complete gasket set?). However, the steering arm is rather different from most of the other fragile parts of our little cars - if a halfshaft breaks or a distributor packs up, then all that happens is that you subside gently by the side of the road. However, the potential results of suddenly having no steering could be fatal, and whilst not having seat belts, air-bags et al will make any accident less survivable, the lack of these won't actually cause one. The steering arm is a safety critical item, the halfshaft is not.

Since I started looking into remanufacturing these arms nearly four years ago, I personally heard of around 20 people who had had them break - I have recorded 10 of these instances, but there were many more that I didn't make a note of.

It is very unlikely that the crack in the arm is due to the manufacturing process. It is a design problem. The worst cracks are located in the area of greatest stress (see the stress charts in my article at www.ingineur.co.uk/A7C). The failures at that point are a classic case of fatigue failure. The point about fatigue failures is that they become more and more frequent as the vehicles get older, so we can expect more of these failures as time (and mileage) goes on. With the re-designed arm there is a reduction in stress which effectively takes the stress below the recommended endurance limit for EN16B steel. These cracks are obviously progressive, varying from the small cracks in many arms through the one that Steve Jones had (for instance) which was cracked halfway through, to the complete crack (i.e. break). However you calculate the failure rate, any failure is potentially fatal and is therefore too many.

Just an update to let you know the "brace" is completed and has been road tested.
It bolts to the steering arm retaining nut and also direct to the drag link ball joint stud, thus being independent of the arm, there is also an aditional mounting bolt replacing the 5/16 grease nipple for the kingpins (Girling stub axle). I have of course drilled this bolt and tapped it to take a smaller grease nipple to allow the passage of grease to said kingpin. It effectively "triangulates" the steering arm and I think will reduce "flexing" of the arm. If this is true and it does reduce the amplitude of the flexing then I suspect this will help the life of the arm with respect to fatigue?

regards

Steve

p.s With regard to spares I am guilty of not really carrying any apart from some electrical cable,spark plug and distributor cap!!