Thetford Cassette Door

[Albertslad]

Ok: Eurovision is not holding my attention: so :

My Thetford Cassette Door doesn’t lock properly. I turn the key, but it has no effect. Anybody else out there having similar problem?

Gaffa tape just doesn’t look good., and f the door opens on the move,chances are it will fly off, maybe causing damage to following traffic

 

Cheers

[Alanb]

There have been several models of Thetford toilets over the years, and I suppose there have also been changes to the cassette doors and latches.

 

On my 2006 PVC, the cassette door has two sprung latches which are released by pressing individual buttons. One of the buttons is lockable, with the lock barrel occupying the place of, and functioning as the button. The lock function only prevents unauthorised access. The door is front hinged, so even if left unlatched, it should not blow open when the vehicle is moving. (Checking that the door is secure, is part of the check list.)

 

Perhaps your vehicle has a different locking system, whereby inserting the key allows rotation of a locking lever, which engages with the door frame? If this is the case, is the lever securely attached to the locking mechanism?

 

Alan

 

[Albertslad]

I’ve just been out to the van and I’m even more puzzled.

The top, non-locking latch locates correctly in the frame, and holds the door closed.

The bottom lock, functions as a locking latch, but does not appear to locate correctly in the frame.

It’s interesting that the lock slot( for want of a better term) has a red plastic indicator strip, which I’m assuming I should be able to see when the latch is locked, ie the slot is vertical.

If I could swap the lock and latch it may solve the problem, otherwise it looks like I have a distorted frame to sort out.

Thanks for the suggestions

 

[Brian Kirby]

Albertslad - 2022-05-14 8:48 PM................... I turn the key, but it has no effect. .............................Cheers

The usual effect of turning the key in the single locking latch on a Thetford cassette access door, is to prevent the unlock button being depressed. The second, non locking, latch can be opened freely at any time. I have never noticed the "red plastic indicator strip" you mention on any of the Thetford access doors on vans we have had. Is this access door actually a Thetford item? Could you post a picture of the trap, possibly open, and of this red plastic strip? It may help identify if the converter has fitted an alternative item.

[Keithl]

Brian,

 

My Thetford doors also have red strips in the locks, they are the shutters to keep dirt out. Well actually the lock cylinders are ZADI but still fitted to Thetford doors. You may not have noticed the shutter as more commonly they are black or metal.

 

Keith.

[Alanb]

Albertslad - 2022-05-15 4:43 PM

==================================================================================

==================================================================================

The bottom lock, functions as a locking latch, but does not appear to locate correctly in the frame.

It’s interesting that the lock slot( for want of a better term) has a red plastic indicator strip, which I’m assuming I should be able to see when the latch is locked, ie the slot is vertical.

If I could swap the lock and latch it may solve the problem, otherwise it looks like I have a distorted frame to sort out.

Thanks for the suggestions

 

On my PVC I have two Thetford doors. The second door is for our gas locker. On receipt both doors had the locking catch at the bottom. I considered that they would be more convenient, and less likely to suffer from road dust, if the locking catch was at the top. I rebuilt the latches to achieve this.

The only red bit is an anti dust flap, and is visible with the lock in either state (key slot either horizontal, or vertical). I suggest that you investigate, as to why your lower locking catch is not engaging with the door frame.

 

Alan

[Brian Kirby]

Keithl - 2022-05-15 6:03 PM

Brian,

My Thetford doors also have red strips in the locks, they are the shutters to keep dirt out. Well actually the lock cylinders are ZADI but still fitted to Thetford doors. You may not have noticed the shutter as more commonly they are black or metal.

Keith.

Oh, that bit! :-D I just didn't recognise that as "the red indicator strip" - probably because I think all the ones we've had have been black, and I hadn't seen them as indicating anything!

 

As Alan suggests, a bit more investigation might be instructive. It looks a fairly simple job to remove the internal lock covers and Alan's comment regarding swapping the locks top to bottom seems to indicate that removing/re-fitting the locks wasn't difficult. I wonder if the actual catch on the locking latch may have broken? Both locking and non-locking latches on ours are identical in size and shape. If so, I'd imagine that replacement locks should be quite readily available.

 

Failing that, the "latch plates" are incorporated into the outer, fixed, frame. It seems improbable (though not impossible if, for example, someone has tried levering the door, - but really, cassette theft? :-)) that these would have broken so, if the actual latches are intact, it seems there must be some mis-alignment between latch and latch plate.

 

The doors do need a firm push to compress the edge seals before the latches can be heard clicking onto their plates. Not enough push?

 

Also, have all the fixing screws been tightened? There will be a sealant bead between the frame and the van body, which relies on the frame being tightened sufficiently to slightly compress it to the point at which a little of the sealant exudes around the frame to ensure a water tight seal (but don't over-tighten, as both components are plastic). If someone omitted to tighten all the screws to about the same extent during assembly I guess it might have created a mis-alignment between door and frame that might prevent the latch "finding" its "plate" (actually just a moulded rebate on the back of the frame).

[Albertslad]

Thanks for the benefit of your experience.

I’ve removed both the latch and the lock; we’ll actually, the lock removed itself, despite my delicate attempts to remove the internal cover plates, the bits just fell out.

I’ll have a lie down and then see if I’m prepared to devote the time to reassembling all of the springs and plastic components: or maybe I’ll get my friendly van converter to fit two new locks. If I decide to “have a go” I’ll remove the door so that I can reassemble the plastic components and springs on the bench

Getting the “plastic “ hinge pins out intact might be a risky thing to do, so I think I’ve decided to pay an expert.

Yes,It is a Thetford door assembly, but if a superior product was available I’d look into it. Until it’s sorted I’m the white pvc with gaffa tape holding the Thetford door shut??

Regards

Alan Bell aka Albertslad

[Derek Uzzell]

A GOOGLE-search on "Thetford cassette locker door", and selecting images for the output!, retrieves lots of useful stuff - including the fact that repair kits are available for the locking mechanisms.

 

(I'd do the search for you, but I'm using an IPad in a French hotel bedroom that constrains me somewhat!!)

[Brian Kirby]

Albertslad - 2022-05-16 4:09 PM.................................Getting the “plastic “ hinge pins out intact might be a risky thing to do, so I think I’ve decided to pay an expert.........................

Alan Bell aka Albertslad

The hinge pins can be a little tight to start, Alan, but I found a little gentle levering under their heads with an electrical screwdriver got both started, and once started they withdrew quite easily. I'd suggest getting both started before fully withdrawing either. Sliding them back was very easy.

[Alanb]

If my memory serves me correctly, I romoved the doors when I "rebuilt" the catches.

 

I extracted the hinge pins by gently tapping them, out with the aid of a small pin punch.

 

Alan