Brian James Minno trailer owners heads up: worn Knott hitch coupling (these are old trailers) Knott-Avonride, Type 2, 2700Kg

[anthonym]

My BJ Trailers Minno Shuttle is nigh on 20 years old, unused for at least five years so in preparation for use an mot (called an Expertise here) is required. In fact rather glad it is because:

the hook/coupling rattled a bit as usual, since I have two of these so can compare, a bit of rattle seemed perfectly normal. 

Turns out in this case it is not.

I will add a video link shortly to show how you can test it with one hand, but suffice to say the coupling itself is apparently worn.

Must say I have begun to wonder about the life of this one before I bought it, totally hammered springs to mind. That said given it's age I was expecting to renew ALL moving parts, just that the coupling I never thought of, the lock yes, but the head itself no.

Anyone else had this? Suggest you check first...

It's a Knott.

Testing a good coupling

https://www.dropbox.com/s/nwllq1e9u7jugxb/IMG_2377.MOV?dl=0

and the bad:

https://www.dropbox.com/s/tjnoz7rle081sb0/IMG_2375.MOV?dl=0

there is no movement possible pushing with one's hand, with the bad one there is a lot. 

Having something to compare makes a big difference in determining if there is a problem.

Anthony

 

for younger viewers these now obsolete trailers were designed specifically around the 7 and to fit in a single domestic garage.

and

 

these two trailers are the same vintage, the "bad" I bought used quite some years ago now. The good I have had from new.

edit to add:

The first one, with snow in the background, is the "good" hitch and when you press the back of the inside of the coupling, with the mechanism closed as if for towing, so the default position, there is no movement whatever when you push backwards

The second one is the "bad" coupling where doing the same thing you will feel and even hear if you do it fast enough much movement in the back of the inside of the coupling, also the handle goes up and down, but that's just a bonus because it always does that if you pull it anyway.

When you put your hand in you will feel the correct bit to push.. (i.e. you need to be there ;-)    )

 

 

SOLUTION:

The BrianJames Trailers item code is S-COHD-5104-P-N and commodity code is 87169090 £83.74+vat and carriage will be expensive because it is heavy.

For Coupling-Head, Knott-Avonride, Type 2, 2700Kg, 12mm bolts. It includes the integral lock and key.

[SM25T]

Do you have to grease the towball regularly, to reduce wear when cup fitted. Just remembering the days of getting trousers dirty if the cover or half tennis ball wasn't fitted.

[anthonym]

I never have. 

[SM25T]

Maybe that's the answer for the future ?

[anthonym]

I don't think so. My other trailer has no such problem and I have had it since new, and covered tens of thousands of miles with it. This one has done about 3,000 with me only. Anyway, the question is about the rattle experience. I haven't yet considered whether it is avoidable or what caused it. 
 

When you see the video it's not just a bit of wear. It's like a bit is missing. Maybe it is. When we fit the new one I will disassemble the faulty one and see... I might need some help ;-)

In any case this is a heads up to other owners where in the UK you have no periodic tests and owners will be blisssfully unaware, like I was. 

[anthonym]

It's a Knott.

Testing a good coupling

https://www.dropbox.com/s/nwllq1e9u7jugxb/IMG_2377.MOV?dl=0

and the bad:

https://www.dropbox.com/s/tjnoz7rle081sb0/IMG_2375.MOV?dl=0

these two trailers are the same vintage, the "bad" I bought used quite some years ago now. The good I have had from new.

edit to add:

The first one, with snow in the background, is the "good" hitch and when you press the back of the inside of the coupling, with the mechanism closed as if for towing, so the default position, there is no movement whatever when you push backwards

The second one is the "bad" coupling where doing the same thing you will feel and even hear if you do it fast enough much movement in the back of the inside of the coupling, also the handle goes up and down, but that's just a bonus because it always does that if you pull it anyway.

When you put your hand in you will feel the correct bit to push.. (i.e. you need to be there ;-)    )

[nutty7]

Tow balls should not be greased, better with more friction especially if using a stabilizer.

[SM25T]

Not sure the differerence between the videos ?

[anthonym]

ok I'll edit just a sec, in fact text in here first:

 

The first one, with snow in the background, is the "good" hitch and when you press the back of the inside of the coupling, with the mechanism closed as if for towing, so the default position, there is no movement whatever when you push backwards

The second one is the "bad" coupling where doing the same thing you will feel and even hear if you do it fast enough much movement in the back of the inside of the coupling, also the handle goes up and down, but that's just a bonus because it always does that if you pull it anyway.

 

[anthonym]

The BrianJames Trailers item code is S-COHD-5104-P-N and commodity code is 87169090 £83.74+vat and carriage will be expensive because it is heavy.

For Coupling-Head, Knott-Avonride, Type 2, 2700Kg, 12mm bolts. It includes the integral lock and key.

[7 wonders of the world]

Think this is the same one only cheaper for you Anthony..

https://www.towingandtrailers.com/product/trailer-parts/trailer-couplings/trailer-coupling-spare-parts/knott-avonride-coupling-spares/knott-kf-7-5-pressed-coupling-spares/2700kg-coupling-head-avon-50mm-ball-2/

 

[anthonym]

lovely thanks - problem was I didn't know for sure which one it was pre purchase; now we know :-)

[paul richards]

Greasing tow ball prevents the wear you have experienced with a regular tow hitch.

Conversely if towing a caravan with an Alco stabiliser the tow ball must be grease free. The tow hitch has pads that clamp onto the tow ball and will wear in time and need to be replaced rather like brake pads. 

[anthonym]

that's interesting, I was planning to disassemble the old one to see what we can see so I'll add some pics here, assuming I can get it to bits.

[Bricol]

That was my understanding, so my ball gets regular new grease (get rid of the grit in it) and thoroughly degreased for towing damped couplings.

You can get hitch grease in the US specifically for it from one of the hitch manufacturers - so they must think its a good idea.  But interestingly I can't find any official recommendations either way over this side of the pond.

Certainly not worn my hitch - I couldn't persuade a US ball (2") into as I thought I might after 20 years . . .

[anthonym]

Hang on, paul and bricol you are not saying the same things.. one says damped couplings (which a BJ Minno is) and the other says "Alco stabiliser" which (my) BJ Minno does not have.

Please agree between yourselves? :-)

 

edit: BJ Minno is a double axle braked trailer, the brakes are actuated by a damper arrangement at the coupling. 

 

[garybee]

Your coupling only provides a moveable link between the car and trailer.  It doesn't try to slow the rotation of the joint with friction (the damping that Bricol is referring to).  You're fine to grease yours, it should reduce wear and corrosion making it last longer.

They're not disagreeing with each other at all.  I think you're just misinterpreting what Bricol means by a 'damped coupling'.

[anthonym]

Aha! So damping the coupling itself does the same as the Alco Stabiliser and my brakes' damper is unrelated to the damping of the coupling.

Right? 

[paul richards]

Right. HERE is an example of a stabiliser (damped) hitch. It has pads which grip the ball and are activated by the big red handle that pushes down over normal handle which opens the hitch. 

I've covered many thousands of miles with a "normal" greased hitch and never a sign of wear. Best advice is to cover the ball when not in use. Not only does it stop grease getting on your trousers it stops grit contaminating the grease. Also good practice to clean the ball and hitch occasionally and re-grease it, again to stop grit causing wear. If using the ball with a "stabiliser" hitch it is again good practice to clean it regularly as ironically the lack of lubricant can cause the build up of corrosion which can cause wear. Pads on the stabiliser hitch need to be replaced occasionally as they do wear. Normally there are markings on the handle and hitch which help identify the wear and the need for change. 

[anthonym]

Here's the official response direct from BJT (the manufacturer of my trailer) a few moments ago:

Grease?

Just a light smear on the ball
 

Thanks to everyone.

Anthony

 

edit to say extra thanks for that Paul.

[7 wonders of the world]

or use a normal greased hitch with a Bulldog stabiliser

[SM25T]

All tallies with my understanding !

[anthonym]

New coupling now fitted :-)