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MG MGB Technical - Wiring Loom

I had the grill off last week to tidy up some of the wiring under the slam panel.
The bullets to the lights looked dodgy (48 years old!!), so decided to remake them.
The cables were really oxidised. No amount of stripping back got to any decent wire to solder to.
I looked further at other parts of the forward loom.......all the same, I even delved into the bound loom near the fuse box, still heavily oxidised copper.

This is a '73 factory V8. I know it's been garaged ever since it was bought from BL in 1974.
My roadster conversion which has a loom taken from a wrecked '75 -76 GT, shows no sign of this extensive copper corrosion.
Is this odd?
A sign of badly produced or stored wire, when or before, the loom was made?
OR maybe a product of the cheap copper which this country imported in the 60's & 70's, which led to a lot of plumbing issues? (I had some of those in my first house!)
Allan Reeling

I've experienced corrosion under the insulation in wires running across the front, nowhere else. However I only cut off bullets/spades and solder on new by exception. The wires I found it in were from a harness removed from a 1980 that I wanted to use for something else, other lengths from that harness have not had the problem. They were more tarnished black than anything, the only wiring where I have found green corrosion was a headlight sub-harness without sheathing where the insulation on the dipped-beam wire had been damaged in the past and the conductor strands eventually corroded through.

Unless the insulation is damaged by the bullet I just polish them with fine wet and dry and replace the connectors. Replacements for those are nothing like as good as the originals in a number of areas, Nigel and I both have pictures of the differences.
paulh4

Over these past few years, I have restored three MGB's and replaced the looms/harness's. Because I dislike throwing stuff away, I have kept the old wiring looms, for the simple pleasure of being able to match up the Lucas colour coded wires but more importantly, to reuse the old male bullet connectors and the female sheathing.

Removing the brass connector is as simple as a little heat from a small flame torch and likewise re-soldering the bullet connector to any new wiring. My method to re-solder, is to re-insert the new wire into the now cleaned bullet connector Insert the wire having a small protrusion of wire, bent over at the pointy end, and then upend end it into a small hole drilled about 1/4" inch depth, into the plywood. The idea of the hole in the plywood is to hold the connector upright and also to stop the solder from running out of the opened end. It also allows enough solder to set at the point. Works a treat.

Maurie
R M Prior

Reusing bullets is a bit mean - I thought I was tight! Current (no pun intended) stock brass solder bullets aren't a problem, it's the connectors. Also from the harnesses I have the bullets are crimped, not soldered, as far as removing them from the wire goes.

For soldering new bullets I no longer use a hole in a bit of wood to keep them upright, now supporting the wire pointing upright with the bullet sitting on the top, and apply iron and solder to the head of the bullet, it's easy to see when it has 'taken'.

The conductor strands can't stick out too far or it prevents the bullets being fully inserted into the connector.

But there are myriad opinions on connectors and connections, including whether to solder crimped spades or not ...
paulh4

As Paul knows I've recently had the great 'pleasure' of discovering various mixes of age and types of bullets and connectors. See Paul's excellent website (and I'm not blowing smoke ... as our USA friends would say as Paul and I often disagree on things) for details and photos. - http://www.mgb-stuff.org.uk/bullet.htm#2

As Paul put I'm surprised Maurie about leaving wire much passed the bullet end as with the original style connectors with more pronounced locators this can put the bullet over centre preventing the opposite bullet, depending on its type, from fully locating pass the locating dimple.

I found it was the mixing of bullets to any type/age/style of connector that was more of a problem than the age/type/style of connector.

I connected the bullets to the connectors with the sleeves off and found that how well they seated and need adjustment with a small screwdriver to move then back, or forward with closing tool, varied and I had the use of two different types of closing tool. My summary was that unless you had exactly the same type of bullets it was unlikely that you could guarantee to get both correctly fitted and centred with the sleeves on using either type of closing tool.

As I normally work with the loom in situ on the car and often with very short wire tails or in awkward places crimping is my prefered and only sensible option.

I can't remember the ratio of originally crimped to soldered bullets on the loom and replacement part looms and wires but the wiring on my car isn't original and a 25w soldering iron used in the UK outside on a hilltop location requires a still warm day, in which case why farting about with the car when you should be driving it.

I was given a load of connectors by a mate I threw out any that were pre-used or too much effort to clean, life's too short for me, a couple where so rusty they might have contaminated others.

I do save some old wires with bullets on to use as test wires and connects but I've got enough of them now.

I will add the modern connectors even with less locating indents and no rear locating indent do seem to well very well (I struggled with getting some bullets out of modern connectors I'd fitted years ago) but I wouldn't risk reusing them if you remove a wire/bullet, I'd replace the whole connector too.





Nigel Atkins

Might as well post the other two photos to finish the set.

First image shows only the 'original style' connectors has a centre bar indent to the rear.

Second image shows the tapered ends to the 'original style' sleeves and the more plasticy feel and wider sleeve of the modern connector.

I've never had a problem with the modern sleeves staying on but that may be a combination of the car being permanently outside, building up muck or dirt by standing or use, lack of static show displays and owner being generally scruffy.





Nigel Atkins

I think thrifty is more appropriate than mean, but no offence taken. It wasn't so much as being tight, but here in Australia, there was a time when the bullet connectors were simply not procurable. That may have changed in recent years and since I have never needed to buy them from new, I am not aware that they are available here now?
Following on from the availability issue of most parts for MG's in general, we are sadly, not served very well, as the prices of everything new, is loaded up to the hilt, by a few suppliers. It wasn't always the case, but I have noticed lately that the prices on parts are through the roof and as a consequence, I am sourcing most if not all, of my restoration parts from the USA and the UK. There are numerous examples of identical parts that are offered for sale in Australia, than can be purchased in the US and the UK much cheaper, and even with high international shipping costs added, the US prices are way below those here in Australia.
Obviously,when one is restoring a car, it is more practical to make up a decent order so as to spread the shipping costs over each item, but I am miles in front when buying from overseas.
R M Prior

No insult intended, Maurie. Availability is always an issue in different parts of the world, as per my comment elsewhere about so much interesting stuff being available in the US but not in the UK short of extortionate postage. I did subsequently wonder if the harnesses like so much of Aussie built cars was also locally made, hence may have been soldered and not crimped. FWIW, spades are spot-welded to the conductors here in my experience.
paulh4

Maurie,
be very careful of modern made parts as many have been of piss-poor quality for decades with the race to the bottom of price and quality. As many classic vehicle are tight-fisted, I can assure you of this as I've met many at national and local shows over the last 30 years, and as they don't actually use their vehicles parts functioning didn't matter so much to them.

The situation got so bad with some parts that the suppliers had to sort some of them and there were some improvements. The cheap parts were so cheap they must have bought-in huge stocks, certainly enough to send free replacements for those that didn't fit or immediately fell apart. But still you will see for offer the cheap crap parts and sometimes next to an alternative of a higher quality higher priced part but even with this choice the cheap crap part outsells the higher quality alternative, I know as I have spoken to suppliers about this.

Some/many MGB are particularly very noticeable at spending lots on bling or upgrade parts but wanting cheap functional/service/replacement parts.

It's all very much of a gamble of what parts will be how bad and when. "NOS" is a gamble too as its age could just mean it was produced when the part was poorly made.

There are some good replacement and upgraded parts that can be superior to original parts, like fully electronic dissy, some polybushes, battery, starter, oils, tyres, but the list isn't as long as it should be.

As the legal profession has it, buyer beware.

Nigel Atkins

Is this odd?
A sign of badly produced or stored wire, when or before, the loom was made?
OR maybe a product of the cheap copper which this country imported in the 60's & 70's, which led to a lot of plumbing issues? (I had some of those in my first house!)

I wasn't inviting views on soldering.
Just maybe views on possible reasons for corroded copper encased in PVC. I'll just settle for copper wire produced in unsatisfactory conditions, or impure copper.


Allan Reeling

This thread was discussed between 06/04/2021 and 12/04/2021

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