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Spring Damped Trailer Couplings

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Spring Damped Trailer Couplings

Post by wurlycorner » Thu Mar 05, 2015 7:08 pm

Need to get round to servicing some bits on my trailer.
Starting with the tow hitch, which is worn to the limit (still works fine but, you know, it's not something you want to keep risking :lol: )

It's this;
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A Bradley Doublelock Mk3 CU60, which is a spring damped over-run coupling rated at 3500kg, with reverse brake lockout.

These type of couplers (spring damped) are illegal to sell and fit to new trailers within the EU (have been for years) but you can replace like-like on an old trailer.

I couldn't find out anything useful on line from after market places, or from the Bradley website, so I dropped them an e-mail.
They were back within an hour (amazing 8-) ) and we've been e-mailing back/forth quite a bit over the last few days. I have to say, they've been absolutely brilliant responding to questions etc. You don't normally get this these days, IME.

Where I've got to after discussions with Bradley is this;
That coupling dates from at least the 1980's (last time they were made).
They don't do the hitch as a replacement/repairable/serviceable item (bet they used to!)
They've said I can buy this to replace it;
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Which has a different bolt pattern so they sell this adapter plate;
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But then I'd need to relocate the jockey wheel (not the end of the world, but not ideal, because it means the loading on the front of the trailer is then unbalanced onto one side of the frame, which will encourage twisting) but more annoyingly, it means some kind of bracket would have to fabricated to take the handbrake (all that is currently part of the existing head).
:evil:
A bit of a pain. Plus the replacement head is about £200 from what I can see, which is a lot more than I was hoping to pay for repairing it. That's into complete new hydraulic damped head territory.

I've gone back and asked if I can buy the replacement head, unbolt the hitch from it and swap that into my existing head which, looking at this pic on ebay;
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looked eminently possible to me.
I didn't expect they'd 'recommend' doing that (and they haven't) but worse, they've said it definitely wont' fit :evil:

I did also ask which of the modern hydraulically damped couplings would be the nearest direct replacement (and how much of a direct replacement it would be). I'd rather not do this tbh because a) the cost/potential aggro, b) I don't like the new over-centre handbrakes (I prefer the old type, which doesn't have a horrible spring load and isnt' just either 'on' or 'off'). But anyway, they've said they're a completely different fitting system and wouldn't be compatible :cry:

We're still in discussions, so we'll see what else comes up, but just wondering if anyone else on here has dealt with this problem before?

@jjmartin349571 I seem to recall you changed the coupling head on your new trailer when you got it, is that right? What did it have before and what has it got now? BTW are you still excommunicado? :lol: I tried texting you today.

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Post by jjmartin349571 » Thu Mar 05, 2015 7:18 pm

I didn't replace mine but I was considering buying a replacement coupling and swapping the head over, which I believe you can do provided that the shaft diameter is the same?? :?

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Post by wurlycorner » Thu Mar 05, 2015 7:19 pm

Ah, so are you in the same boat as me then?

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Post by jjmartin349571 » Thu Mar 05, 2015 7:24 pm

No I have the opposite problem, I think my coupling head is ok but my coupling is only rated for something whimpy like 1500kgs so I can't use it loaded up atm and I think the damper has failed anyway (plus it has no brakes still :twisted: ).

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Post by wurlycorner » Thu Mar 05, 2015 7:37 pm

Ah, right...
What's on yours at the moment?

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Post by jjmartin349571 » Thu Mar 05, 2015 7:52 pm

Can't remember atm, nothing exciting from memory though. I'll have a look next time I'm up the farm. I'm after a 2700kg hydraulic damped hitch to replace it with, but I don't know what my axle units are rated for so I've been putting off doing the work :lol:

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Post by wurlycorner » Sat Mar 07, 2015 9:30 am

:facepalm:
Self defeating post - guess what comes up now in the top 10 results on google, when you search for "replace bradley doublelock mk3 cu60"
:roll:

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Post by jjmartin349571 » Sat Mar 07, 2015 10:04 am

:lol:

I don't know why, but it seems to be really difficult to find information online regarding servicing and repairing trailers yourself, which I find really surprising considering how many people tow trailers :?

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Post by wurlycorner » Sat Mar 07, 2015 2:10 pm

Yep.

The Haynes manual is jobby too :evil:

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Post by wurlycorner » Sat Mar 14, 2015 7:35 pm

@jjmartin349571 I have done some more research into this... :hurr:
Although it still hasn't got me to a conclusion! :roll: :lol:

Anyway... I noticed that one of the trailers that the other guy I share the barn with has, is fitted with the exact modern equivalent of the coupling on my trailer. i.e. a Bradley Doublelock Mk3 3500kg Hydratow (so the newer hydraulically damped version of what's on mine) :mrgreen: :idea:
Measuring stick needed to come out...

So, length of existing spring damped coupling;
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Call that 17". That's the length of all the gubbins that mounts on top of the trailer frame. So on a spring damped coupling, it's the length from front of the hitch, to the back of the hitch (to the back of the large nut on the back of the head, that operates the brake lever).

Equivalent measurement of all the gubbins mounted on top of the trailer on the hydratow;
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:shock:
Call that 33"!!!

And that's not the end of it... Measuring from front of the hitch, to the back of the brake mechanism on the towing head (so to the point at which you attach the brake rods);
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:o 45"
:suicide:

To put that into perspective, this is roughly where 45" would run back to on my existing trailer;
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:?

Those new things are drokking massive!
In theory, I think it would be do-able, becuase the length of the hydratow would run back to where the existing equalising pivot is;
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But I guess it wouldn't work going straight onto the equalising pivot, so that means arsing about shortening the brake rods and moving the pivot back (which means altering the front rod bracket on the trailer) as well as drokking about with chopping out a structural cross-member at the front of the trailer to accommodate the new long head (ooer).
:evil:

So that's major aggro :evil:

I think I am gonna end up having to go down the route that the Bradley guy suggested (buy the new plain spring coupling, with the adapter plate).
The problem is that all the brake mechanism is integral to the existing coupling head (the pivots and handbrake etc.)
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From underneath (brake linkage pivot on the right)
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Maybe I can cut the pivot part off the existing head and get it welded it to the new adapter bracket, but I'm not sure...

I think I'm just gonna have to bite the bullet, order the new head and then see what I can work out :(

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