Does anyone on here know what the usual “sympton” is when these go? And how do they go?
Usually the trailer doesn’t follow you.
i honstely dont know but if you have any doubts get it checked!
if its your 5th wheel you normally get some slapping when braking etc before it goes or i did!
If there is wear, then the play will show when you move the tractor unit forwards or backwards. Normally you can feel it, otherwise get someone to look at what is happening from the side when you rock the tractor unit forwards and backwards.
I’m guessing the OP means the king pins on the front axle, not the trailer pin…
Paul
repton:
I’m guessing the OP means the king pins on the front axle, not the trailer pin…Paul
Good point. Abnormal tyre wear, play in the steering and a tendency to wander then.
jack the front axle up, grip the wheel at top and bottom and try to rock to check for any play in the kingpin, if they have been lubricated regularly its rare for them to fail. do not mistake wear in the wheel bearing for worn kingpins if possible get someone to assist by looking where any movement takes place
Yeah it’s front axle rigid cheers guys
repton:
I’m guessing the OP means the king pins on the front axle, not the trailer pin…Paul
+1
was wondering why all replies was about the 5th wheel pin. 
gezt:
repton:
I’m guessing the OP means the king pins on the front axle, not the trailer pin…Paul
+1
was wondering why all replies was about the 5th wheel pin.
Because the trailer pin is also known as a kingpin.
A road tractor coupled to a semi-trailer is often called a semi-trailer truck or semi, or in the UK an articulated lorry. The fifth wheel on a truck connects to a semi trailer Kingpin. Kingpins come in many guises, however the most common within the UK market is the 2.0" (50.8mm) EEC approved type. This Kingpin is fully interchangeable and given strict maintenance is adhered to, it should last the life of a trailer.
Harry Monk:
gezt:
repton:
I’m guessing the OP means the king pins on the front axle, not the trailer pin…Paul
+1
was wondering why all replies was about the 5th wheel pin.Because the trailer pin is also known as a kingpin.
A road tractor coupled to a semi-trailer is often called a semi-trailer truck or semi, or in the UK an articulated lorry. The fifth wheel on a truck connects to a semi trailer Kingpin. Kingpins come in many guises, however the most common within the UK market is the 2.0" (50.8mm) EEC approved type. This Kingpin is fully interchangeable and given strict maintenance is adhered to, it should last the life of a trailer.
we live and learn harry,always known it as 5th wheel pin 
green456:
jack the front axle up, grip the wheel at top and bottom and try to rock to check for any play in the kingpin, if they have been lubricated regularly its rare for them to fail. do not mistake wear in the wheel bearing for worn kingpins if possible get someone to assist by looking where any movement takes place
As greeny + Harry has said above,
Jack axle up + slip a long tyre lever through gap of rim to get a good leverage and bite at checking for play up + down.
To eliminate wheel bearing wear/play → 
- apply footbrake - this grips hub solid and allows check of steering axle kingpin/bushes and components.
You can get away with a "minimal " kingpin wear - providing - it will “grease out”.
Sometimes a wear giveaway is a light thud/knock sound when going over uneven road surface or pothole,+ uneven tyre wear.
If your getting one shoulder wear on tyre , get it flipped 180` on the rim to wear even again and get its life usage (providing tyre is legal + not one directional … 
olde skool ).
Recheck tracking adjustment .
Dont forget to check the other steering + suspension components + bushes + pins also, and steering locks (full locks adjustment ) – relube as appropriate.
Road test 
I ve never heard of a trailer pin being called a king pin before!!
gezt:
Harry Monk:
gezt:
repton:
I’m guessing the OP means the king pins on the front axle, not the trailer pin…Paul
+1
was wondering why all replies was about the 5th wheel pin.Because the trailer pin is also known as a kingpin.
A road tractor coupled to a semi-trailer is often called a semi-trailer truck or semi, or in the UK an articulated lorry. The fifth wheel on a truck connects to a semi trailer Kingpin. Kingpins come in many guises, however the most common within the UK market is the 2.0" (50.8mm) EEC approved type. This Kingpin is fully interchangeable and given strict maintenance is adhered to, it should last the life of a trailer.
we live and learn harry,always known it as 5th wheel pin
I assumed he was talking about the 5th wheel pin as I’ve always known it as a kingpin, thought everyone did 
Never heard anyone refer to a kingpin as a ‘‘trailer pin’’ before tonight looks like there is a split camp on this one 
jimmy2loads:
I ve never heard of a trailer pin being called a king pin before!!
You have now
Semi trailer King pin - connects to fifth wheel
The steering axle king-pin' is another story, or rather this one :wink: . The OP added it was a :arrow_right: rigid ’ in question.
merc0447:
Never heard anyone refer to a kingpin as a ‘‘trailer pin’’ before tonight looks like there is a split camp on this one
Well no there isn’t, because we were calling them “Kingpins” fifteen years before anyone had ever heard of the word “internet”.
Harry Monk:
merc0447:
Never heard anyone refer to a kingpin as a ‘‘trailer pin’’ before tonight looks like there is a split camp on this oneWell no there isn’t, because we were calling them “Kingpins” fifteen years before anyone had ever heard of the word “internet”.
well always been 5th wheel pin in my yuff. never called em “kingpins” even before bbc 2 came on air.kingpins was always steering wheels stuff 
PRODUCT DETAILS
The Bulldog heavy duty King Pin lock easily locks onto the fifth wheel of the trailer to prevent the coupling of the tractor unit to the trailer, it comes complete with Bulldogs highly developed lock bolt.
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Bulldog KP100 King Pin Lock
PRODUCT DETAILS
The Bulldog heavy duty King Pin lock easily locks onto the fifth wheel of the trailer to prevent the coupling of the tractor unit to the trailer, it comes complete with Bulldogs highly developed lock bolt.
The Bulldog King Pin lock is
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Simple to fit
-
Heavy Duty and fully portable
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Drill and pick resistant heavy duty lock
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Attack tested and approved by SCM
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Complete with a PVC carrier for clean, grease free handling
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Instruction [King Pin.pdf]
File Size: 230.63KB
Fitting Video [KP100.mpg]
File Size: 2.64MB
Data Sheet [King Pin Lock.pdf]
File Size: 3.02MB