Stiff King Pin

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shep289
Posts: 16
Joined: Sat Jan 15, 2011 7:44 am

Stiff King Pin

Post by shep289 »

Having trial fitted the front suspension ( Gerry's ) to check where everything goes, I removed the king pin / stub axle assemblies for final painting. After final cleaning of the king pins I noticed that one will not rotate through 360 degrees due to resistance to rotation. there is no play in the king pin just stiffness for about 60 degrees of a circle. Could this be resolved by greasing ? Rebuilding king pins appears a specialist area, shall I just exchange for a recon unit or have it rebuilt ?
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clive
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Joined: Thu Mar 01, 2007 1:18 am
Location: Perth

Re: Stiff King Pin

Post by clive »

Is it the king pin or the hub assembly? Try swappiong them round with the other side just to confirm. If it is the king pin, talk to Gerry for advice. I recall many Morris Minors, MGs etc lying at the side of the road with collapsed front suspension due to king pin failure.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
shep289
Posts: 16
Joined: Sat Jan 15, 2011 7:44 am

Re: Stiff King Pin

Post by shep289 »

Hi Clive,

It is the King pin, one side rotates freely through 360 degrees ( off the car obviously ! ) while the other will only rotate about 300 degrees. I don't want any future problems and am a bit aprehensive using the secondhand parts.
shep289
Posts: 16
Joined: Sat Jan 15, 2011 7:44 am

Re: Stiff King Pin

Post by shep289 »

Just dropped in to see a mechanic friend who injected grease with air powered grease gun, has released some of the stiffness. We've come to the conclusion it's stiff only in a local area which should not affect performance since the pin rotates only approx 90 degrees on the car, the stiffness being where the stub axle would face into the engine - hopefully not a situation that will arise ! Will keep spinning the pin a few times to hopefully ease the stiffness further before fitting to the suspension.
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Roger King
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Joined: Mon Mar 19, 2007 10:29 pm
Location: St Ives, Cambs

Re: Stiff King Pin

Post by Roger King »

clive wrote:Is it the king pin or the hub assembly? Try swappiong them round with the other side just to confirm. If it is the king pin, talk to Gerry for advice. I recall many Morris Minors, MGs etc lying at the side of the road with collapsed front suspension due to king pin failure.
***anorak alert***

The Morris Minor collapse syndrome has a very different cause - they used a soft metal threaded trunion at the bottom of the kingpin, on a link arm connected to a torsion bar (no conventional springs on the front end). If incorrectly lubed, or not lubed at all, the thread would strip allowing the link to thrust downwards with the full force of the torsion bar. I always thought it was a bit weird that the thing actually turned up and down a thread for the steering to work, changing the geometry slightly.

Sorry, what does 'pedant' mean again?

Edit - Just for your peace of mind, I can't see a kingpin failing in the same way. It would have to become very seriously seized to snap the pin itself - I think it's far more likely to go very tight on the steering, followed by very loose on the upright once the bush has failed. Also, just wiggling a stub axle by hand will not give you a very accurate picture of its tightness. With the full weight and leverage of the wheel in place you will tell better. All usual disclaimers - don't follow this advice whatever you do, etc.
I'd go with it as it is, just make sure you keep it well greased and that it doesn't get tighter.
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