Any tips for cleaning up wiring harness connectors?

[colonel mustard]

As per the title, I have an existing wiring loom that Justs needs the connectors cleaning up? Any tips?

[Spider]

I've always found with old harnesses, it's the connectors that let them down. There are a few ways to clean them, but before long, the are corroded again and giving trouble.

The corrosion will also be between the crimp and and the wire as well as in the copper of the wire too.

Usually too, when the harness is of this age, many wires in the engine bay have become hard and even on some brittle.

The Multi Pin Connector Bodies also get brittle and the clips that hold them together either break off or are no long effective at holding the two parts together.

I'd suggest you replace the harness.

[colonel mustard]

Thanks Spider
The harness has come off a car that has done circa 15k miles since new and has been stored out of the car for the last 10years, most of the wiring looks in good condition. Will have another review of the loom.

[Andrew1967]

We have used Cillit Bang household cleaner with good success.

[Nick W]

You could blast clean them with bicarbonate of soda.

[Southwest]

White vinegar works well on brass

[Rusty old S]

Brown sauce overnight, wash off with hot water.

[Dearg1275]

Before you spend time “renovating” the connectors, strip some covering of some wire and see what it looks like. If it looks black then it’s time to replace. Once the copper corrodes it increases the resistance and you will have poorer performance and hotter cables. Not a good combination.

D

[colonel mustard]

Thanks all,
Dearg1275 - thanks for the advice, cut back a couple of wires throughout the harness and all look shiny copper
I have gone with the brown sauce method first this evening, as it’s something we have to hand albeit I hate the stuff! T
Let’s see tomorrow evening the results, might try the Andrew and Nick’s suggestion as a comparison!

[Polarsilver]

Why not just replace the original end Terminals & re-crimp with new items .. the crimp tool & terminals are cheap // ok you do shorten the cable to do this.. but in that process as you strip back the insulation cover you will see what condition the original copper wire is ?..as said if its dark copper in colour it needs to be cut back to the bright copper wire as you need to get electric reliability .. another option If you are set on cleaning any Electrical Terminals today there are Rattle Can Cleaning Agents on the market specific for that type of job.

[850man]

Dip them in zinc chloride ie. Bakers soldering fluid or equivalent.

Glass bead blasting also works well, its great for Lucas fuse boxes.

[Gary Schulz]

I like the bead blasting approach better than chemicals in this case. I have spent years trying to recover corroded connectors and the biggest problem I always face is due to the effects of capillary action drawing the moisture (and resultant corrosion) up into the cable. This is one serious drawback for stranded wire.

I also spend a great deal of time working on restoration of vintage/antique radios and they can suffer from the same issue if seriously neglected. I have seen capillary action draw moisture up several feet from the connector end in serious cases!

I would gently bead blast and then take a crack at soldering the ends to see if you can join the connector to whatever clean copper gets exposed. Those crimps are the biggest point of failure.

EDIT: Saw you verified wires are good adjacent to the existing connectors. In that case just put new connectors on the marginally shorter wires. I am a big believer in soldering all these connections however. I hate crimps!

[snoopy64]

Brown sauce overnight, wash off with hot water.

Ketchup is good too

[MiNiKiN]

I also suggest to just renew the crimps if the copper braid is not corroded.
Fine sand blasting is what I do, but it doesn't reach and clean the 'insides'.
The ONLy contact cleaner that really works is "Kontakt 60", which removes the oxides chemically.

http://www.kontaktchemie.com/KOC/KOCpro ... NTAKT%2060
OR
http://www.kontaktchemie.com/KOC/KOCpro ... 060%20PLUS

I buy that at my local electronics DIY shop.

[mk1]

Most of the suggestions in this thread will clean a terminal so it looks shiny & bright for about a week, after that they will increase the corrosion issues. Using any sort of acid or salt to clean the terminals without thoroughly neutralising them afterwards is a recipe for years of wiring loom grief.

The best suggestion for cleaning is Nick's, blasting with dry soda or similar. But this can still cause issues if all the soda isn't removed afterwards, once a bit of damp gets in, its party time for corrosion.

I totally agree with Spider, the best thing to do with an old wiring loom is stick it in the "spare wire box" & buy a new one.

If you are determined to use an old loom, I would suggest NOT trying to remove the existing oxide apart from where the terminals touch each other, you can do this with a file or sand paper. Then using a little copper grease on each terminal as you connect them up.

Personally, I'd replace it.

[Spider]

I found exactly what Mark has said when cleaning them up, no matter how it's cleaned, they corrode again and it seems in ever short time frames. Cleaning corrosion off no matter how never removes the corrosion totally, most methods only remove what's on top and what can be seen and not where it counts inside crimps etc. and it travels up under the insulation too as Gary mentioned.

Given the cost of a new harness and how easy it is to fit during a build vs coming to the realisation that it's a loosing battle at a later point, makes an easy job a real fiddle, especially the rear harness where it runs through the roof channel.

[Catmint]

I use this stuff now if the teminals are exposed or outside (progression from vasaline )

https://www.12voltplanet.co.uk/dynatex- ... -tube.html

Expensive, but not compared to future issues of it all going wrong - Great for new terminals as well if you squeeze a bit on the wire before crimping

With regard to soldering, if the terminal is in a high vibration area, like on an engine, the solder can cause the wire to fracture as it can't move