is there really ANY way to repair the casing on the wire harnesses that has worn off? i keep hearing "no, dont use THAT..." and no one seems to know what you can actually safely use. i did read somewhere that the brush on rubber stuff works ok, but im looking for more of a wrap... is there such a thing that can withstand the temps? sure a couple years down the line (when im sure oil leaks and rust are a thing of the past) i might replace the whole shebang, but until then, what are the options?

handsome greg

See http://www.brickboard.com/RWD/?id=673372

Don Hodgdon's photo shows gray connector with cover plate popped off allowing one to work on the wires individually.
--
1980 245 Canadian B21A with SU carb and M46 trans

Just for the good of the order, I think I've discovered where the saleman who sold the bad wiring harnesses to Volvo went after Volvo kicked him out in about 1988. I'm buying my sister-in-laws Mercedes. In researching this make I found that many Mercedes wiring harnesses from the early 90's are going bad. Sounds like a very similar problem although I haven't seen one yet. Fortunately her model , 1986 300E, is not one which has bad wiring, at least that is what seems to be the case.

fyi-art b. alerted me to this thread, so here goes.

the wiring came from a vendor in texas, trying to increase the domestic content in euro cars. that's why some cars have a mixture of ok and rotting wires in the same harness. mercedes tried to increase their domestic content in 91 or so, but it only lasted until sometime early in 93.

the salesman's name-uncle sam.

the reason for the rot? not biodegradation like it's been said AND appears in the landfills. poor plastic and it's reaction to heat. seems the polymers line up like magnetized particles when they are heated. as they line up, they detach from their neighbor and that's when the grip to each other is lost. and eventually enough grip is lost and we've all seen the results. as translated from an ex-vcna electrical engineer to me in the past. and so it goes, chuck.

Interesting, the plot thickens. Except for a 1934 Checcy, my first car, I've never had the insulation on a domestic car go bad. Connectors, sometimes, but not the insulation.

i've never seen the texas stuff on a domestic car, either. but, i'm not under the hoods of those like i have been with volvo, mb, etc. i guess the domestic content in the big is enough not to warrant outsourcing to texas. after all, gm put delco-packard in the wire business during the 20s or 30s. everybody here's been set.

like i said, the saleman was uncle sam and them furrin' ones were the ones needed more u.s. content. and so it goes, chuck.

As someone has already stated, the peace of mind is worth the time to replace the bad wires. But, from my experience with two 83's, it is not the entire harness that needs to be replaced (see the harness photo in one of the other post, only some of wires have biodegradable insulation). Only the six wires coming out of the grey plug at the firewall (see photo in one of the other post) need replacing. This also agrees with one of the other post that referenced a problem with the alternator and oil pressure gauge (see below). The hardest part of replacing the wires is tracing out those six wires but I'll pass that on to you: black=oil pressure sender, yellow=temp sender, red=alternator, yellow/blue=starter solenoid, brown=coil temernial 15, red/blue=not used. Unplug the grey plug, cut the wires about 2" below the plug (the wires on the plug going to the main harness, not the wires on the other half of the plug going through the firewall). Solder on new wires and heat shrink tube the solder joint. Each wire needs to be about 6' long and then cut to length later. Use 14 or 16 gauge stranded copper wire with oil and heat resistent insulation. The insulation can be the same color on all the new wires as long as you keep track of which wire is going where. Ues crimp on spade connectors on the other end to connect to the devices (match the old spade connectors). DON'T try to remove the old wires from the main harness. You can remove the intake manifold to get better access to the starter solenoid and temp sender. I re-routed the new wires along the firewall and around the inner fenders. As you can see, this job requires alot more time than it does money. jp

The wiring harness in my '86 245 is crumbling, particularly around the big gray plug at the firewall.

I carefully separated the (then bare) conductors near the plug and coated them with "liquid tape." I used three layers of the stuff. (I think I bought it at Radio Shack.)

The solvent in that goop is MEK, so this should be done in the open, good ventilation, no flames.

That repair was in '96. So far, I've not installed my (good used) Dave Barton harness because my liquid tape repair is still holding up.

--
Don Foster (near Cape Cod, MA)

...but it illustrates Kane's point. The wires really need to be replaced.

There is a special place in hell reserved for the Volvo exec that signed off on these wiring harnesses...



Replace it, the peace of mind is worth the effort.

--
don hodgdon '89 744ti, '81 242t, '71 D-35...just waitin' for the glue to dry :-)

That image was my very first impression of a Volvo- first hood I looked under, an 83 244DL, rest its Nordic soul. First thought was short circuit, fire. But couldn't find the smoke! Then came the Brickboard and lots of sympathy.

That's a nice photo!
--
Art Benstein near Baltimore

OOh that's ugly. And all too common in pre-88 cars.
However, if the harness is NOT that bad, and just has a split (kinda like the crack visible in the upper left of that picture), there IS some electrical tape that can help.
We use all kinds of tape where I work and I've done a lot of work in materials, testing electronics, etc. The best regularly available commercial electrical tape is Scotch (by 3M) "33" black tape. no relation to Rolling Rock by the way... The stuff sticks and stays stuck in some very adverse conditions. CLean off oil before using, but it's good to over 200°F, and very water and chemical resistant. We use it to help keep things watertight, and I work in a lot of wet locations. I've also used it for this specific repair, wiring harness sheaths. Extra wrap at the end of the repair helps keep it stuck down.

For very high temp applications, there are alternatives: for toughness, use 3M's fiberglass tape, or for better electrical and some waterproofing, use self-vulcanizing silicone tape. The stuff we have is yellow and while not adhesive, sticks to itself after a minute and is hard to separate. High electrical strength (>1000V/ mil). THere is also a brownish tape called Kapton that will withstand very high temps- not extremely tough however but very thin and strong.

Hope all this does some good!
--
Rob Bareiss, New London CT ::: '87 244DL/M47- 230K, 88 744GLE- 220K, 82 245T-181K Also responsible for the care and feeding of: 88 745GLE, 231K, 87 244DL, 239K, 94 855GLT 189K

Like you, I'm pretty fortunate in the electrical junk box. Not all the striping combinations are handy, but I've quite a stock of solid color automotive wire in common gauges, vinyl sleeving and shrink tubing selection. But that day I just grabbed my precious roll of 33. For just about what a discounted new harness would cost you, Waytek can supply you with enough automotive wire, terminals, fuse blocks, tubing and specialized connectors to rewire a couple cars. I didn't use it, but the vinyl tubing looks to be identical with the original harness covering, save it is new and supple.

Never had any troubles with heat on the intake side of the motor, but I did melt a bit of that polyethylene corrugated split loom between the alternator and the exhaust manifold. Nothing affecting the function, just a spot of ugliness. Now, Kapton -- that's jet plane stuff! Lots of flex circuit boards made of it, but I can't think of any in the 240.
--
Art Benstein near Baltimore

Thats just like my turbo harness was. The worst area was not visible until I cut the black sheathing off the bundle. The wire insulation was gooey mush on the whole bundle of wires where it was against the block. Definitely replace the harness if there are visible signs of deterioration. You might get away with patching the harness, but I like to be able to rely on my car. If you have time and patience you can build your own harness.

Good points. At first I patched the one in this picture for the obvious problems with the alternator D+ lead and the oil pressure sender -- back around the passenger fender to the gray plug. In fact you can see the gray sheathed cable in the upper right along the firewall.

Then about a year later, when this pic was taken, I'd just set about changing the manifold gasket and cleaning up that side of the motor after doing the cam cover gasket. That's when I exposed the rot you see in the picture. I just pulled everything out that wasn't sound and replaced it wire by wire, using Scotch 33 as a harness maker, just as Aye Roll suggests. I learned to buy nothing else 30 years ago when I used this stuff outside in cold midwest winters (pardon me for saying it can get cold down here, Jessie) and it is pretty good at staying glued under the hood too.

Good electrical tape (read: 3M) can stand the underhood temps, but having done a wire harness swap myself ('86 245GL), and aided my cousin ('85 244GL)in doing their's, the wires were further disintegrated than just what's visible. Both the alternator oil pressure wires were especially bad - neither were intact until nearly where it branches off under the intake manifold.

Both were done last year, about 140k miles.

Get a used one (or get on his waiting list) from Dave Barton. He includes very helpful diagrams.

-- Kane

--
Blossom II - '91 745Ti/M46 ... Bubbles - '74 144GL/BW35 ... Buttercup - '86 245GL/AW70 ... The Wayback Machine - '64 P220/M40