Entered the VSCC Cotswold Trial at the weekend, passed scrutineering, set off to the first section but the steering became alarmingly dangerous. Found the OS kingpin had broken! On removal at home the pin was in three pieces! I changed both pins although the NS pin looked OK so I decided to test it by clamping it in the vice and hitting it with a large hammer. Instead of bending as it should, it snapped like glass and the cross section looked crystaline.

I had this happen once before in the 70s when there was a bad batch of glass hard pins in circulation. Can anyone remember the source of these pins, and perhaps remind us what the metallergy of these pins should be?

Just be warned that if you suspect you have dodgy pins from this era - change them with known good ones!

Sounds like the pin has been hardened all the way through, lethal! I would suggest buying your pins "new" from known traders, unknown stock is exactly that.

Ruairidh

I had exactly the same thing on an MCC Exeter trial a few years ago. The pin sheared into 3 bits. On closer inspection it had been hardened all the way through and the grease hole had wandered so it was way way off centre the other end. The unbroken one was the same. These pins were ones that I had had in stock for years (or at least dad had).

King pins are discussed on page 176 of the Austin Seven Companion, where there is a warning about 'glass' kins pins i.e. those through hardened rather than case hardened. This article was originally written by Mike Eyre in 1977.

hi nigel,you asked who made the glass kingpins!
who did you buy yours from.
and did you buy them because they were the cheapest out there!
or were they recommended.

Hi Tony,
The trials car was borrowed and the the pins were in the car when bought by the current owner so we have no idea where they came from or when they were fitted.

I buy pins from reputable suppliers on the assumption that the rubbish pins only too prevalent in the 70s are a thing of the past.

In those days I remember having to take a micrometer with me when buying pins to measure not only for size but ovality and taper, both usually present. Material used and hardness were a total gamble. But I thought the source of these "glass" pins was identified then but I have forgotten - hence the question.

I do remember a picture on the front cover of 750MC bulletin in about '78 of an original Austin pin that Jack French had managed to bend through 90 degrees without it breaking.

ive heard of pins breaking that have been fitted since the 70s.
even fitted in the last 10 years.
this is from people buying the cheapest they can get.
perhaps there lives are not worth anymore!!!!!
although dont just blame the traders who manufacture cheap pins.(or even many other items)
as mutch of the blame should be passed to the customer who sucks through his teeth when told a quality pin is £10 - £12.
so they go and buy the one for £5.

I personally dont use commercial pins, since breaking one alarmingly years ago. I simply buy a piece of chromium plated Hydraulic piston rod (Marchrome bar ) which is precision ground and of medium or High tensile Quality. You can cut it with a Hacksaw or Part it off in the Lathe. I tend not to drill a hole through it unless it is for a original car, preferring to put a nipple in top and bottom of the stub axle. These pins will never break and are lots cheaper than commercial ones.
Another good trick is to ream and fit the bushes to the pins before fitting them . Machine the O D of the Bushes on a mandrel so that they are 4 thousandths (.1 mm)
of an inch loose in the Housings and assemble the bushes to the stubs with loctite using the Pins as alignment guides, leave them in until the Loctite has cured. Everything will then line up fine with no reaming in situ required. Try it, its much easier than the usual way and does not require a Pilot Reamer. If you are clever on a lathe all the machining can be done before parting off, if you make the whole bush yourself . I have found this method also lasts longer as the mating areas are 100%, giving more bearing area, a real high finish can be given to the pin holes. Hope this Helps. The Hydraulic rod is available from steel merchants and Hydraulic Service agents (forklift Repairs etc.)

Location: Wellington NZ