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MG TD TF 1500 - TD rewire

I am about to start a complete rewire of my 1953 TD.
Existing wiring done in early 1980's and is a mess, nothing like what I have seen as original routing etc.
I am buying a complete loom from autosparks.
Any recommendations where to find info on routing and fixing? Anything I need to be aware of particularly?
Any held much appreciated.
Mike TD29330
M Lees

Cut out all the old wiring and bin it. The Autosparks loom has all the correct original colours and terminals. Using the wiring diagram in the WSM, label up every wire end. There will be a few that you are not sure about until you get it in position, then it will become clear. The loom runs down the inside face of the LH chassis member and goes between the pedal box and the chassis on LHD cars (you don't say what yours is). It then branches with one section going forwards and another up to the voltage reg, fuse box, etc. There is nothing difficult about fitting it. For exact positioning its best to look at the gallery in Chris Couper's The Original TD website.
Dave H
Dave Hill

M Lees

The main problem I found was to get the main loom through the bulkhead - probably because the modern wiring has pvc as well as fabric insulation. A good solution is to wrap this section tightly with insulation tape and maybe lubricate with vaseline.
Tim Wilkinson

There is a coloured & coded wiring diagram on T Talk which you'll find is a great aid. I enlarged it to A3 size & stuck it onto a piece of stiff board. The colours at this size make it easy to read from a few feet away. Cheers
Peter TD 5801
P Hehir

Thanks Peter, I knew there was a colour diagram somewhere, but couldn't find it.
I need to find out correct routing to front.
M Lees

See for the wiring diagram. I had a problem with an Autosparks loom for a 53TD. The wiring for the turn signal relay would not reach the original, under the cowl, location. I had to move the relay to the outside of the firewall. I'd suggest asking them about this when you place your order. Other than that their quality was excellent and well priced. Bud
Bud Krueger

Don't know abut Auto Sparks loom, but the Moss loom I used the wires were color coded and the ends were tagged for placement, which really helped. As Dave suggested, label everything that isn't labeled. The tub wasn't mounted when I ran the main harness, which made it easy, the inside harness was a little more demanding. PJ

Thanks Bud. I spoke to autosparks, they do not have a pattern for a loom with footswitch and relay on back of bulkhead! They have done a modification on 2 recently returned looms, explained the difference and I have gone with that - sounds correct
M Lees

Mike - One further suggestion - once you get the wiring all complete and are ready to test it by turning the ignition on, either put a 10 amp fuse in line with the battery cable, or use a trickle charger in place of the battery to protect the very expensive loom and your hours of labor in case of an inadvertent short. You sure as hell don't want watch the new loom go up in a cloud of smoke - it would ruin you whole day. Cheers - Dave
DW DuBois

I agree with Tim. Getting the new harness through the bulkhead was a challenge. If I had to do it again I would open the hole a tad wider and get a larger grommet to fit. I also added a ground wire between the front fenders and frame as painting the parts separate tend to increase the resistance. Mike
Mike Hart

"I also added a ground wire between the front fenders and frame as painting the parts separate tend to increase the resistance."
Good idea Mike, I have been meaning to run a ground wire to both the headlight buckets and the side light enclosures - just haven't gotten one of those round tuits yet. Cheers - Dave
DW DuBois

I asked the question re conductivity & painted surfaces a while back & also asked a few gurus here but never really got a satisfactory answer. Obviously the bare metal to bare metal contact produces the ideal from a conductivity POV but as corrosion just loves bare metal... Has anyone solved this conundrum? The point where the battery cable earths to the tub is a case in point. Cheers
Peter TD 5801
P Hehir

I've wondered about that, too. The only solution I see is to smear those connections with dielectric grease.
David Littlefield

The dilemma Peter describes is the main reason that TDs inevitably have ground problems. The conductivity between painted, bolted-together surfaces depends on random metal-to-metal contacts where the screw, nut, or washer breaks through the paint. If you remove the paint, you have a surface that can rust. I suppose that, if you use an eyelet on the end of the wire and clamp it down well, you minimize the chance of rusting of the contact, but still, eventually...

My solution, since I made my own wiring, was to use a return from each load to a common ground point. You can see it in the top left corner of the picture. It's under the dash, so it's protected. The negative (ground) terminal of the battery runs to the frame, not that skinny sheet metal battery box. I don't depend on the frame or body for conductivity, though; a heavy wire runs from the common-ground point to the battery connection on the frame.

Some people have criticized this, saying that the wire will have greater resistance than the frame and body path. I don't think this is true. I suspect that the spreading resistance through the sheet metal of the body and the haphazard joints between the metal body and frame parts is a lot higher than people think. On the other hand, I can size the wire so the voltage drop is insignificant.

S Maas


There is a pressure pak blue colored product that most car servicing companies use to spray battery terminals, am sure a Google would locate it. Your concerns with originality may deter you using it. The old trick is to smear these terminations with vaseline which is fine until you degrease your engine bay.

If you want to boost your cars reliability run earths to both the engine and the chassis, you might be astounded how ignition and starting problems disappear when you do this.
G Evans

Funny how none of the pre-made wiring places use pre-tinned copper wire. I'm talking the copper wire inside the insulation being (each strand) pre-tinned, as in the original wire.
D mckellar

Great comments - many thanks for help.

I need to buy the wire clips and straps:
NTG S001 and S002
anyone know how many of each are needed?

btw: Autosparks supplied loom with 1 wire incorrect colour and one spade connection for footswitch connecting feed and dip together! No wiper wire, no clock wire, no coil CB to distr. wire. They are correcting errors without any issues.

Mike TD29330
M Lees

This thread was discussed between 21/10/2015 and 29/10/2015

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