How to clean a cloth wiring harness

I am reusing a newer wiring harness on my BT7 ... fabric covered. Not greasy or oily - just dirty. Any ideas on getting it clean without damaging it?

What about spray carpet cleaner? The kind that foams up then when dry you brush it off.

steveg said:

What about spray carpet cleaner? The kind that foams up then when dry you brush it off.

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I'd be leery of anything that leaves a residue you have to brush off as I'd be worried the residue would get caught in the weaving and be impossible to get out. I haven't done it so you'd have to test it first, but maybe wiping with alcohol would work?

HealeyRick said:

I'd be leery of anything that leaves a residue you have to brush off as I'd be worried the residue would get caught in the weaving and be impossible to get out. I haven't done it so you'd have to test it first, but maybe wiping with alcohol would work?

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I'm thinking that wiping alcohol on/off would have the same issue. Also, alcohol might affect the colored thread. I would probably try Windex or something where wiping isn't required to soak it and let dry.

You'd need something that would release the dirt and float it away. The carpet cleaner would release the dirt, then dry to dust; perhaps it could be blown off with compressed air. I'd think spray upholstery cleaner would be similar.

I'd be worried about alcohol and the paint.

I used alcohol on my wires once. Wiped off the color coded stripes! That was the wire not the cloth.

I used Scotch guard on my new cloth wiring harness to protect it. A carpet guy gave me the industrial strength stuff. Though I haven't driven the car enough to know if it worked.

Boy Racer,

When considering how to clean the fabric, remember that the fabric was used to allow a wet harness to drain and dry. Depending on the condition of the fabric (over time the heat and cold, wet and dry cycles take a toll and the treads grow brittle so would never consider physical adjuration). I would use a detergent like Dawn mixed in hot water and sprayed it on the harness. I would then rinse it with and water spray and allow to dry. If you want to take a chance, I would use a small amount of washing bleach in the washing mix to brighten some of the lighter colors but I would first test on a small section. Keep in mind that the threads of the woven cover are either strong enough to sustain the wet/dry cycle or not and, if not, the cover (not the harness) will need to be replaced. I would never expect it will look new.

Good luck,
Ray(64BJ8P1)

To be clear, the harness is out of the car. And, the cloth fibers are in very good condition. Based upon what Ray just said, I think I should be able to put the entire harness into a bathtub with a mild detergent and gently agitate to get it clean? I was originally concerned that there might some kind of plastic wrapping under the cloth that could trap water and not completely dry out.

Steam works wonders
White Terry cloth to wipe it dry

Richard, here's what an old timer who ran a motor rewind shop told me once. When I was restoring my Healey the original starter was i terrible condition but still worked. I disassembled it and the innards were just coated with grease and grime. I took the field winding out and the cloth fabric wrap and insulation was just disintigrating. I asked the old fello if the winding could be saved and he told me to go home and gently wash them with soap and water, let them drip dry in the sun for a few days then paint them with automotive enamel. I told him I didn't have any enamel but I had some clear coat. He said then use that. I did exactly as he told me. That was 18+ years ago and the starter is still in the car and working today. A lot of hard summer driving every year.
If your harness is in good shape, you could assist the drying with some low air pressure from the air hose.

BoyRacer said:

To be clear, the harness is out of the car. And, the cloth fibers are in very good condition. Based upon what Ray just said, I think I should be able to put the entire harness into a bathtub with a mild detergent and gently agitate to get it clean? I was originally concerned that there might some kind of plastic wrapping under the cloth that could trap water and not completely dry out.

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Yep I think U got it right , use a bit of Dawn no bleach N the grease will be gone, I asked a baby duck---LOL

You could always have it re wrapped. I believe auto sparks will rewrap it, or sell you the wrap to do it yourself. https://www.autosparks.co.uk

BoyRacer said:

To be clear, the harness is out of the car. And, the cloth fibers are in very good condition. Based upon what Ray just said, I think I should be able to put the entire harness into a bathtub with a mild detergent and gently agitate to get it clean? I was originally concerned that there might some kind of plastic wrapping under the cloth that could trap water and not completely dry out.

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This is how it has been done for decades. While it is out, take the time to closely examine all of the end connections and replace any that look questionable. Be careful not to cut back any of them if you do not know how much "spare" length you have to work with. While most can easily accommodate a half inch cut back, some cannot.

Richard - when you do the cleaning, would apprectiate hearing back on how it went.

So far, very good. I took the smaller rear harness, put it in a 5 gallon bucket with some warm water and laundry detergent. Then, using a toilet plunger, I agitated it for about ten minutes or so. I then rinsed it thoroughly, I used a bath towel to blot up as much moisture as I could. I then used compressed air to blow out the connectors and the two wires that were encased in a plastic sheathing. Then I hung it up to dry. Its nice and clean and no damage was done to the cloth. The main harness is larger so I will do that one in my shop sink ( a laundry tub).
Thanks for all the ideas. I love this forum!