ScarboroughSeadog

Howdy folks- my grandfather brought this back from WW2. He said it was from a glider in Sicily. That’s all I know- see the markings. Is it from a Horsa? Or an American glider? Is it from a gunsight? My grandfather is long gone and my Dad is trying to research the gyroscope, without much luck.

Grateful for any thoughts!

Thanks.

1 hour ago, ruxy said:

On LR military vehicles  - the fuel gauge indicated readings show   E  1/2  & F   with a strike mark at 1/4  & 3/4  full.  - there is not a red mark to show low/reserve.   The only difference on the early or late gauges is the position they are mounted within the instrument cluster.  This position is a good indicator on 24 volt FFR vehicles - exactly what tank level indicator you need to be matched .  The starting point is to establish that you have the correct parts for the age of the vehicle and to confirm you are using the correct wiring diagram.

Ruxy-  The TB1114-001W senders as now produced are a multi-fit part, which (correctly) span a variety of vehicle set ups from mine (older, less common, military specific) to a range of other classic civvy landrovers (which do have the red mark on the gauge). It would make sense if they are calibrated to by far the most common application (ie the latter). Fortunately I had a repairable 40 year old TB1114-001W which works perfectly- problem solved. Thanks for your help and advice.

2 minutes ago, john1950 said:

Perhaps the newer ones read to reserve on the gauge in red.

I have to say…..I think you’ve nailed it! These senders cover a few different set ups, and hence supply to different gauge decals etc. My particular (dated, less common) set up is an anomaly as far as these senders go. I suspect your explanation will save a fair bit of head scratching for many with this issue- I bet you’re right!

Always good to finish these things off with a conclusion: replaced a faulty fuel gauge, replaced a faulty Lucas switch. All now working perfectly but there is an interesting issue with the senders. I have 3 senders marked TB1114-001W. This is the correct part number. One is brand new, one is say 10 years old, one is say 40 years old. Only the 40 year old one reads correctly (ie empty at empty). The other two newer ones read 1/8th at empty. I can only think the more modern parts have a different resistance scale? Fortunately with a repair made to a snapped spade connection I was able to use the original 40 year old part and all is working perfectly. Bit of a mystery though.

Thanks Ruxy- will try and decipher all this when back in civilisation (away working in the north of Scotland at the moment). My fuel gauge is mounted at 6 o’clock- as you say, as per a late model fitting. Also have the late model oil and temp gauges and transmitters you describe.

Haven’t had much time to look at the lightweight, but have now replaced both Lucas switches and have one tank reading perfectly. One tank still not registering empty but suspect that is it’s sender- will replace and see. Expecting that will solve the problem, but will see! Will post a conclusion and findings as soon as I can- but don’t expect that that will be in the next few days.

On 3/7/2023 at 10:06 PM, ruxy said:

Both fuel tank sender units & dash level gauges for 24 volt are different to 12 volt.  You should have 560757 senders , No.. should be stampd on and  552616 gauges.  

Hhmm   -  tap in neutral position , somewhere in my office I have a tap/bracket with switches assembly but I can't find it.  IIRC the switches are N.C.  (normally closed).    Fuel tap lever in neutral - you would only do that as a gratis extra anti-theft (expect running for only 1/2 mile downhill - don't ask , I caught the wife out once).  The fused supply is fed white (Ignition control) & you don't leave Ign. on without engine running.  So - yes , I think you would have both switch contacts bridged  & point (cinch) between the control coil & deflecting coil feeding both tank units , not a normal situation - you are not supposed to do this & I would expect a spurious reading on the gauge.

 

Just double checking that the Lucas switches are NC? So the circuit is made when the nipple is NOT depressed/activated? If the nipple is depressed by the tap, that breaks the circuit and therefore stops any reading from the tank connected to that switch, correct? I'm thinking if one switch is faulty and remains closed (or partially closed) when activated, that would mean both switches (tanks) are closed (reading) at the same time, which might explain why the gauge reads 1/8 when the tank it should be reading is empty? Does that all make sense? Feels like a bit of a eureka moment, but not in the shed until Sunday eve.....

1 hour ago, ruxy said:

You know  ,  many bread& butter car manufacturers went off this style of sender unit because they are useless for accuracy.   Take  Fiat Group  ,  small cars  £ cheap   Uno Mk1  ,  Uno Mk. 2  Punto  - they had a plastic tube down the tank from the top (a little larger on dia. than a toilet roll tube )  inside is a tubular float (giving variable resistance)  about the size of said toilet roll card tube , this has a small coil spring at each end.  This design probably went back to the 500D of the 1960's  + earlier  ?     Land Rover could have introduced similar but didn't, you have to work around what you have if you want originality,  probably ndividuals would had done better operating modifications if it were not for fuel safety and insurance cover.

That said, I’ve owned mine for nearly 25 years and until recently the fuel gauge readings have been spot on. The problem I’ve got is resolvable- just need to figure out the fault. 

1 hour ago, osiford said:

I've just scanned this thread, and from what I can gather, the gauge in question reads OK, except at the critical empty end of the scale, so the basic system seems to be working OK. I've had to fit a number of new sender units and gauges on various vehicles, and none of them are exactly precision calibrated instruments. I have dealt with most as follows. Remove sender unit, and drain tank. Next put in a known quantity of fuel, say a gallon. This is, if you like, a "reserve", as it should have this amount available still, when the gauge reads empty.  If your gauge was reading too high a level when the tank ran out, bend the float arm slightly upwards. Reinstall and check reading on gauge. If still not showing empty, remove sender and re tweak. Some folk may not agree with this approach, but I can't see any problem, and I've always been happy with my fuel level readings on the road. Why make things complicated, if a simple solution is available? Just my thoughts, for what they are worth.

Thought of that- but the 1/8 reading is at absolute minimum on the sender arm (bent or not), so doesn’t work.

It would be really useful to have a 'print thread' option for reference purposes, which prints the text in a suitable (concise) format without all the banners etc. Is that possible? They have just that on the Lightweight Forum and its very helpful.

New Lucas switch about £30. Mine are over 40 years old so don't mind renewing speculatively. Chain spray probably good preventative idea.

Yes- PRC1789 and 90560612 fitted.

Have cleaned the various connections. I'm going to replace the second Lucas switch on the changeover tap. This should be NC (normally closed), but if it has deteriorated and is remaining partially open when not activated, I wonder if that could explain my bogus reading......

1 hour ago, ruxy said:

You need to know for absolute certain.   Starting 1977 - there were lots of electrical & mechanical  'change points'  , only a few such as axles are given to/from Serial numbers.  Defender was complex with civvy - but at least normally the change points were stated with chassis/VIN  number. 

I think you will have a single ammeter on the shunt box between seat-back squabs  ?

--------

 Your   20HF63  -  I think built very early 1979  ,   Contract  FVE 22A/87  Item 1 

I have  23HF63   but not much help because it is  12 volt.  FVE22A/87  Item 3   - and I know this Item were built between March and June 1979  ,   having said that - they could have gone down thje lines alongside each other , because as daft as it may seem  Item 1 and 2 vehickles  were built as late as  November  1979.

Yes, I have a single ammeter on the shunt box- which is located in the rear tub behind the drivers seat. Correct, contract FVE22A/87. First entry on the VHC is 27/11/79. Chassis 95105646A.

8 minutes ago, ruxy said:

Then with PRC1789 - you must use tank sender unit   90560612   - the only one suitable  (and in fact suitable for 12 volt vehicles - but only with gauge  (panel)   PRC1768

Understood- that's the sender I have.

12 hours ago, fv1609 said:

It presses up on the inside of the metal case onto an extrusion that is the weld point for the earth thread the other side. So it is important there is no internal or external corosion and there is a good earth connection

Thanks Clive- my cluster is a later part I think. The gauge fits directly into a common cluster housing.

12 hours ago, ruxy said:

Yousay your LWT is  1979,  but what is the VRM  - is it a HF  ?      I have some very accurate Solihull records for build up but nearest FFR is  GJ  (1977)  I do have records for most Contracts of  1979 and 1980 - unfortunately these are only for 12 volt GS.

So - I have to go to the next best 'definative'  Fiche   RTC9968FA   dated  June  1993  ,   I have found a few errors but at least it is official  Land Rover Parts Ltd.

fiche 1   page  O8

PRC1789   Fuel gauge   24 volt

PRC1788   Fuel gauge   12 volt   Printing is a bit blurred but  think correct.

So  -  supercession ,  I would say change in contractor supply not change in specification.

 

 

Thanks- yes correct fuel gauge is PRC1789.

It's FFR  20HF63......

2 minutes ago, fv1609 said:

How should the earth point shown be correctly earthed? With direct earth from the ‘to fuel tank’ bolt (in addition  to the fuel tank connection)?

7 minutes ago, ruxy said:

Both fuel tank sender units & dash level gauges for 24 volt are different to 12 volt.  You should have 560757 senders , No.. should be stampd on and  552616 gauges.  

Hhmm   -  tap in neutral position , somewhere in my office I have a tap/bracket with switches assembly but I can't find it.  IIRC the switches are N.C.  (normally closed).    Fuel tap lever in neutral - you would only do that as a gratis extra anti-theft (expect running for only 1/2 mile downhill - don't ask , I caught the wife out once).  The fused supply is fed white (Ignition control) & you don't leave Ign. on without engine running.  So - yes , I think you would have both switch contacts bridged  & point (cinch) between the control coil & deflecting coil feeding both tank units , not a normal situation - you are not supposed to do this & I would expect a spurious reading on the gauge.

 

Late model (1979) 24v models with enclosed cluster gauges can use the 12v sender units- checked this with Blanchards. I have the correct 24v gauge.

Thanks for the detailed response which I will try and decipher tomorrow. 
 
As you say, mid point on the tank lever is useful anti theft measure, but can catch you out!

I did read (on hmvf) the gauge should read empty at the tank lever ‘neutral’ position- hence the query.

Thanks for this detailed response. Looks like the red arrow point is electrically connected to the right bolt (as it appears in the photo). There are 3 earths attached to the cluster securing bolts- perhaps one of them should be connected to the right bolt of the fuel gauge (it hasn’t been for many years- 20, probably). 

The oil and water temp gauges aren’t earthed directly.

It’s the correct 24V part- direct part number replacement for the old one. 
It has (and should have I believe) only 2 connections to the gauge itself- the cluster housing is earthed.
I’ve just noticed that the gauge reads full when the tank switch is in the middle (selecting neither tank). Pretty sure it should read zero. Any thoughts if that points to a particular fault?
pic shows the gauge

Thanks all- and good point ref the compression gland. Will be permanently wired.

This has become a niggle.....

Late model (1979) 24V- no voltage regulator on these models. Just replaced fuel gauge and one of the lucas switches and now I have a fuel reading at least. BUT both tanks read 1/8 full when empty (they read full when full). Its not to do with the position of the sender float (which is at the bottom of the tank). The gauge returns to empty when the ignition is switched off.

Any thoughts on what the prob could be? Both tanks are well earthed.

Thanks

I’ve dissembled the unit and C is clearly earth. A goes to the switch. B goes to the bulb. Any thoughts which is live? Consensus seems to be that B is usually the live pin, but there appear to be different protocols. Any thoughts? I’ll be wiring it permanently to a plug.

2 minutes ago, 64EK26 said:

Hi

I see what you mean, just the light...

These are designed for a 24V DC supply only.  I didn't think there was a mains version.

Cheers

Richard

Yes- there is a 240v version, stamped as such (like mine)

4 minutes ago, 64EK26 said:

Don't think I have seen one of those, a photo would be good

Cheers

Richard

4 minutes ago, 64EK26 said:

Don't think I have seen one of those, a photo would be good

Cheers

Richard

37 minutes ago, G8RPI said:

Technically those mains connectors are illegal. They are certainly unsafe. This is because the earth connection does not have a positve means (e.g. long pin) to ensure it makes first and breaks last. Ideally they should be replaced with a modern mains connector like an IEC 60320 C13/C14 type as used on computers etc.
If you must use them NEVER plug or unplug them with the supply on. Pull the 13A plug first.  Put a label next to it saying this and if possible wire lock then in the mated position.

The issue is if there is a fault as you can end up with a live box in one hand an a earthed metal plug (or vice versa) in the other as you mate or un-mate them.  This is likely to be fatal so while the chance of a fault is low, the consequence is exreme.

Robert.

A very sobering thought! My proposed connection would be permanently made direct to the lamp (same issue with equal length pins though), but many thanks for pointing this out!