P38 Tow bar - my experience

P38 Monkey · Jan 19, 2022

The LR standard towbar for the P38 has a detachable swan neck / ball, but it is usually held in place by a big rusty bolt with an equally rusty nut and locknut. Removing it means getting the spanners out and mucking up your tweeds or pin-stripes. So it stays put and rusts further. I replaced the bolt with a cotter-pin and R-clip, to make the operation much simpler, and clean. A cotter-pin that is exactly the right size is a Massey Ferguson top link pin off one of the old Fergies. It has Imperial dimensions of course, but is a much better fit than the metric bolt anyway.
Note that this is my own experience (750 kg un-braked trailer) and I am doing no more than recounting it - use a cotter pin at your own risk...particularly if you are towing a 20 foot container...
So, with its agricultural components, coil springs, manual seats, no cruise control, is my P38 evolving into a tratter? Obviously without the rust, draughts, noise, oil leaks and total lack of power of course.

Datatek · Jan 19, 2022

P38 Monkey said:
The LR standard towbar for the P38 has a detachable swan neck / ball, but it is usually held in place by a big rusty bolt with an equally rusty nut and locknut. Removing it means getting the spanners out and mucking up your tweeds or pin-stripes. So it stays put and rusts further. But if you replace the bolt with a cotter-pin and R-clip, the operation is much simpler, and clean. A cotter-pin that is exactly the right size is a Massey Ferguson top link pin off one of the old Fergies. It has Imperial dimensions of course, but is a much better fit than the metric bolt anyway.
So, with its agricultural components, coil springs, manual seats, no cruise control, is my P38 evolving into a tratter? Obviously without the rust, draughts, noise, oil leaks and total lack of power of course.

View attachment 257036

Not sure I would like to tow 3.5 tonnes with just cotter pins holding the swan neck, no clamping effect.

P38 Monkey · Jan 19, 2022

Datatek said:
Not sure I would like to tow 3.5 tonnes with just cotter pins holding the swan neck, no clamping effect.

Fair comment.
I towed a 750 kg un-braked trailer for 600 miles and the pin was basically unworn / unmarked.
Nose weight of the trailer is very important but often over-looked, particularly if your towing vehicle (EAS) will adjust itself for a heavy load on the ball.

Datatek · Jan 19, 2022

P38 Monkey said:
Fair comment.
I towed a 750 kg un-braked trailer for 600 miles and the pin was basically unworn / unmarked.
Nose weight of the trailer is very important but often over-looked, particularly if your towing vehicle (EAS) will adjust itself for a heavy load on the ball.

You are supposed to lock the EAS when towing. Yes nose weight is important, but emergency braking with 3.5 tonnes on the hitch will put a considerable load in shear on the pins.

P38 Monkey · Jan 19, 2022

Datatek said:
You are supposed to lock the EAS when towing. Yes nose weight is important, but emergency braking with 3.5 tonnes on the hitch will put a considerable load in shear on the pins.

I see what you mean. The sideways clamping force between the bracket sides and the swan neck does add to the strength of the cotter pin and the bolt across the rear of the swan neck (it's the original bolt at the back of the swan neck, not a pin). A braked trailer will not load the pin/bolt any more than enough to compress the braking mechanism and apply the brakes, so arguably the un-braked trailer will apply more stress on the swan neck than a much heavier braked trailer. But I tow very rarely as the kids pony club days are long passed and I am not fox-hunting these days.

dubbleRR · Jan 19, 2022

If i mind right" the wheel key on a standard p38 ,fits the towbar nuts ,The bolt self locks at the other end ..and use the jack bar for extra leverage ...

..

P38 Monkey · Jan 19, 2022

dubbleRR said:
If i mind right" the wheel key on a standard p38 ,fits the towbar nuts ,The bolt self locks at the other end ..and use the jack bar for extra leverage .....

I am sure you are correct, and that would be fine straight off the production line at Solihull. When I got my tow-bar it was locked solid though, which I think is a more normal state. Mind you, that rust would be a safety feature to counter incompetent driving, overloading the trailer, incorrect nose weight and/or faulty trailer brakes. Or if you want to pull a 20-foot container like that old tratter pictured on this group a while back.

Datatek · Jan 19, 2022

dubbleRR said:
If i mind right" the wheel key on a standard p38 ,fits the towbar nuts ,The bolt self locks at the other end ..and use the jack bar for extra leverage .....

Just checked, the wheel nut spanner does not fit the tow bar nuts or bolts on either of mine, more like 17mm or could be 19mm.

dubbleRR · Jan 19, 2022

Datatek said:
Just checked, the wheel nut spanner does not fit the tow bar nuts or bolts on either of mine, more like 17mm or could be 19mm.

AH my nuts are bigger than urs

Mines 27mm just went n checked

.....and also my towbar

..

Datatek · Jan 19, 2022

dubbleRR said:
AH my nuts are bigger than urs Mines 27mm just went n checked .....and also my towbar ..

Not an OEM swan neck tow hitch then?

dubbleRR · Jan 19, 2022

Datatek said:
Not an OEM swan neck tow hitch then?

Maybe its heavy duty

....its a swaneck and it goes in the jack tray in the boot, The hole the bolt it goes through is about 19mm ,and is a snug fit in the mounting , ,

...so my wheel key fits ....others may differ ....answers on a post card ,too,.... as long as it dint fall off

Datatek · Jan 19, 2022

dubbleRR said:
Maybe its heavy duty ....its a swaneck and it goes in the jack tray in the boot, The hole the bolt it goes through is about 19mm ,and is a snug fit in the mounting , ,...so my wheel key fits ....others may differ ....answers on a post card ,too,.... as long as it dint fall off

Put a 19mm hole through the swan neck on mine and there would not be a lot of metal left

dubbleRR · Jan 19, 2022

Datatek said:
Put a 19mm hole through the swan neck on mine and there would not be a lot of metal left

Sad i know ,but i looked up 27mm nut .n it says m18 shaft so its m is metrics ,but ranges are old school imperial.... but m18 is 18mm shaft ....so my nuts are bigger and my shaft

myfirstl322 · Jan 19, 2022

S'not a cotter pin...that's a pin with an R-clip.

A cotter is a wedge.

tomcat59alan · Jan 19, 2022

Think my towbar nuts are 15/16.AF

pete12345 · Jan 19, 2022

I’m sure mine fitted my tow bar but it was years ago I used it

flat · Jan 19, 2022

That looks like a clevis pin setup to me. Not sure I would use that on a tow bar setup to be honest. I doubt it will have the same strength as an 8.8 bolt etc.

kermit_rr · Jan 19, 2022

R clips and split pins are forms of cotter pins.
A wedge is just another form of cotter

A cotter is used to hold a clevis pin in place. A clevis pin is designed to withstand shear forces

That said i think I'd rather use a nut and bolt to clamp everything tight in this scenario

Datatek · Jan 20, 2022

So I did a proper check on the swan neck bolts today, the bolt heads & nuts are 19mm, the bolt shank is 11mm.
Maybe early cars used imperial I don't know.
The bolts are impossible to remove, I think they would have to be drilled out.

Mark Piercy · Jan 20, 2022

@P38 Monkey Don't forget, any movement brings on wear... When bolted it is clamped also and there's no risk of shock jerking that snaps stuff cleanly away.
I'd bolt it back together...

Some towing hitches are designed to have play as they also designed to deal with it!
These aren't unfortunately

P38 Tow bar - my experience

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