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Mon Oct 27, 2008 3:53 pm

Why are the ground straps bare, unsheathed copper? I am talking about the Transmission one and the battery one.

Is there any reason why these are not covered? I would think that having them insulated would help protect them from corrosion... There must be a reason.

Mon Oct 27, 2008 4:49 pm

Is that the tranny/body strap?
Gave me problems cause I had the ends sparklin shiny, but it was corroded through the middle.
Not being too clever about these things, I can't figure it, unless someone was just trying to save money. :roll:

Mon Oct 27, 2008 4:55 pm

You know, I've wondered about that too. Could you replace the original braided copper straps with some generic battery cables?

Mon Oct 27, 2008 4:59 pm

If you wanted a protected cable could you use the super duper heavy duty Monster Cable??

Mon Oct 27, 2008 5:00 pm

hiram6 wrote: You know, I've wondered about that too. Could you replace the original braided copper straps with some generic battery cables?

I replaced mine with a $4 strap from autozone/pepboys.

Mon Oct 27, 2008 5:04 pm

Any copper wire of sufficient gauge will do.

Never knew why they preferred uninsulated braid, but it was probably just a cost savings.

Mon Oct 27, 2008 5:11 pm

I've been looking around and the standard seems to be 2 gauge or 4 gauge braided, uninsulated copper (and sometimes stainless). I can't seem to find any reference as to why it is uninsulated though. Cost saving I could buy if it was just for a Ford or Chevy, but Porsche also uses uninsulated. Could it be for either flexibility due to the heavy gauge, or heat dissipation?

Does anyone know off hand the lengths of the battery ground and the tranny ground?

Mon Oct 27, 2008 6:20 pm

Don't really know why they use unsheathed cable. I doubt that it has much to do with cost, couldn't be more than a couple of cents difference. Being unsheathed probably doesn't make it more prone to corrosion, but would surely make corrosion easier to spot.

I do like bare braided cables as they are more flexible and since they often don't use a terminal on one end have one less joint to give problems.

Mon Oct 27, 2008 7:07 pm

I'm curious, my van has got a bit of a rough idle, and my mechanic said I should try replacing the ground strap going from my engine to the van body. I can't remember whether he said it looked corroded, or too light of a guage. I haven't changed it yet, but was planning on using a large guage amplifier cable to do the job.

So my Q:

Has anyone changed this ground cable and actually noticed a difference in the performance of their van?

Mon Oct 27, 2008 7:49 pm

shorepig wrote: I'm curious, my van has got a bit of a rough idle, and my mechanic said I should try replacing the ground strap going from my engine to the van body. I can't remember whether he said it looked corroded, or too light of a guage. I haven't changed it yet, but was planning on using a large guage amplifier cable to do the job.

So my Q:

Has anyone changed this ground cable and actually noticed a difference in the performance of their van?

I had a van that was running pretty crappy, just off idle. As far as I remember the idle was fine, but in gear, give it a little gas, and it would just bog down. Ran ok if I got the rpm up. Did that very consistently till I replaced the tranny/body ground. Never happened once after that.

Mon Oct 27, 2008 8:29 pm

I just replaced the strap on mine with a big honking wide insulated copper cable from autozone. My idle is definitely a bit better and my tired starter is not quite so tired. I had to bang on it a couple of times to get it to click over before replacing the strap. Since replacing it, I haven't had the problem. Though, I'll probly have to replace it fairly soon anyway as it's pretty slow to crank. Replace your strap.

Mon Oct 27, 2008 10:20 pm

I'm intrigued! I will be replacing it soon! I'll let you know what happens.

Tue Oct 28, 2008 5:01 am

Several yrs ago i chased a slo cranking problem to a batt cable with too small wire inside,cut open and had a really thick insulation/small wire,was a 12v sys also. Since i have replaced any bad/worn /corroded cables with ones rated for "6-VOLT",heavy wire size and improve cranking in all. my 2cts.

Wed Oct 29, 2008 8:36 am

Here's a more detailed approach from motogiro:

http://www.thesamba.com/vw/forum/viewtopic.php?p=3376770#3376770

"Something that is really easy to do and solved the same problem for me was to pull all of the grounds from where they connect to both the engine and the engine compartment, spray with engine, or preferably electrical contact cleaner, and wire brush while they are wet, clean them off with a rag. Do the same thing with the bolts/screws that ground the wires. Spray the bolt holes and clean-out with a q-tip. If possible, buy a battery cable of sufficient length and replace the main engine ground on the driver side of the engine with it.

It was like a miracle after that. It took an hour and cost less than 10 bucks."

Wed Oct 29, 2008 8:57 am

To assure a good connection when you are bolting wire eyelets to bodywork or engine/trans casings, sand off any paint or corrosion around the attachment point so there is a patch of clean metal. Then use a stainless star washer under the eyelet (or stack of eyelets in the case of the left-side harness grounds). Coat everything with dielectric grease or Vaseline as you reassemble. The star washer bites into the base metal and assures a good low-resistance connection. In fact it should bite right thru paint or rust to base metal, but to be really sure I always sand the area clean and bright first. The grease should ward off corrosion.

You'll notice VW actually used star washers under the bolt head where the engine ground strap attaches to the left cylinder head, at the grounding rosettes up above the fuse panel, and in some other places. They liked to put the star under the bolt head and rely on the contact at the threads. What we see with age is that corrosion attacks the threads first since moisture is retained there. That's why I like to put the star washer directly between the eyelet and the bare metal.

Thu Oct 30, 2008 12:58 pm

I added an additional ground cable that runs the length of the van. I used a big (Probably 2AWG) insulated wire. It runs from the neg terminal of the bat, out of the bat box and along the frame rail to the trans. It's connected to the trans at the same point as the factory ground. A short run connects at this point to go to the ECU. From the trans connection it runs to the grounding point in the engine bay next to the coil. All of the stock grounds are also in place and in good order. I know this is probably overkill but since I added it I have had zero ground problems.

Fri Oct 31, 2008 6:30 am

What a range of prices, wow!
Price range for the same ground strap part # 251971237:
Low: $ 8.84 - from one of our regular on line suppliers
High: $ 78.00 - local VW parts counter

Fri Oct 31, 2008 6:47 am

The best way I've found to protect an open ground cable from corroding is spray it liberally with aerosol wax oyl.

It's goes on easier than di electric, or vaseline finger brush stroking it, and penetrates deep into the open wires, then forms a bees wax protective barrier.

Same stuff that VW coated the whole undercarrage's of the type 2 Buses, and some of the Vanagon's.

Simple solution.

Works real good.

Fri Oct 31, 2008 6:50 am

Terry Kay wrote: The best way I've found to protect an open ground cable from corroding is spray it liberally with wax oyl.

It's goes on easier than di electric, or vaseline finger or brush stroking it, and penetrates deep into the open wires, then forms a bees wax protective barrier.

Same stuff that VW coated the whole undercarrage's of the type 2 Buses, and some of the Vanagon's.

Simple solution.
Is this stuff still available?
Can you get it in a spray bomb?

Fri Oct 31, 2008 6:53 am

<<Is this stuff still available?
Can you get it in a spray bomb?>>

Yep--sure is---

How much do you need?

The stuff works real good to load up the inside of the door & side panels with, load up the bottom side of the Van too----no more rust problems.

It's like VW used to do the undercoating job.