Posted by Tony P. on March 22, 03 at 11:44:04:
In Reply to: 2/0 AWG Battery cable replacement details (really, really long) posted by Fat Boy on March 22, 03 at 00:21:16:
I ordered the mil-spec battery terminals last week... from powerStride... anyway, after sitting on the order a week, they sent me a note saying that the parts are out of stock and that they will have them in about another week.... ggrrrrr. Once they are in then I can get the new batteries and start working on the cables... I've got a local guy who has heavy guage cable and will let me have enough to do the job... so the cost should be fairly low. hhmmmm while I'm thinking about it and the weather is good, I think I'll go measure clearences... be rough to buy batteries, install them, close the hood and arc-weld the whole mess...
Tony
: So here it is! A total list of what I did to rid myself of the slow crank of death in my '94 K2500 GMC 6.5L Turbo-diesel.
: The stock setup:
: I've got two batteries... One behind each headlight in the factory trays. I have replaced both batteries with Group 75 Red Top Optima spiral-cell sealed gel batteries (950CA/725CCA). I did this a couple years back and have never regretted it. Each battery has both top and side-post terminals. Until the overhaul, I had been using the side-posts with the factory battery cables. I've had to jimmy rig new terminals on the cables a couple times as they corroded a little more month by month. I finally got sick of it and decided it was time for new cables...
: With the stock cables, if each cable connection to each battery were separated (i.e. not crimped together in the battery connectors), there would have been four 2 AWG cables and three 8 AWG cables. Here's the old layout...
:
: Note DSB = "drivers side battery", PSB = "passenger side battery"
: 1) DSB positive to alternator (8 AWG w/ 12 AWG fusible link)
: 2) DSB positive to PSB positive (2 AWG)
: 3) PSB positive to starter (2 AWG)
: 4) PSB positive to firewall power distribution block (8 AWG w/ 12 AWG fusible link, runs down with starter, back up behind engine)
: 5) DSB negative to block (2 AWG)
: 6) PSB negative to block (2 AWG)
: 7) PSB negative to body (8 AWG)
: Thus far, I have created 8 new 2/0 AWG cables, each with 3/8 inch tinned copper lugs at both ends. These replaced all the 2 AWG cables and the one PSB neg to body cable, plus added three more grounds. I have not yet replaced the PSB to firewall or DSB to alternator wires, but I will be doing that soon. For now, I re-used the stock wires with new 3/8 lugs on the battery terminal end. Both batteries are now wearing Premier Power Welder military spec battery clamps with stainless steel hardware (1/2" nut/bolt holding clamp to battery, 9/16" nut/bolt holding cables to clamp).
:
: Finished cable lengths:
: Here's the list of cables I made, and the function of each. Note that these lengths are eye-to-eye (measured at center of eye). When cutting cable, the unterminated cable was about an inch and a half (1.5") shorter than the finished length. Each lug adds about 0.75" from the end of the cable to the center of the lugs eye and another .375" to the end of lug, but we're not counting that anywhere, so don't worry about it... Point is, if you're trying to get the lengths below, cut your cable an inch and a half shorter. For the first cable listed, you'd need a 29" length of cut cable.
: Passenger side battery...
: Neg to Block - 30.5"
: Neg to Frame - 31"
: Neg to Body - 16.25"
: Pos to Starter - 47.25" / 0.375" (see details for info on funky measurement)
: Driver side battery...
: Neg to Block - 25.375"
: Neg to Frame - 27.625"
: Neg to Body - 12.75"
: Battery to battery...
: PSB Pos to DSB Pos - 66.125"
:
: Details on each cable:
: Passenger side...
: Neg to Block - 30.5": This runs from the negative terminal on the passenger-side battery to the stock stud on the block (right behind/below the feed pipe on the upper intake manifold). The stud has a 15mm nut on it and could be reached without taking anything else off. I used a deepwell socket and a 6" extension. This cable replaces stock cable (6).
: Neg to Frame - 31": This snakes down from the negative terminal on the passenger-side battery to a stock bolt on the top of the front upper-A-arm mounting bracket. This was accessed by removing the splash-shield on the inner fenderwell and using a ½” deepwell socket on 3/8” drive ratchet. This can be done with the tire/wheel in place, though I had the tire/wheel off anyway to get to the starter (more on that later). The only thing this bolt holds is a small bracket which locates the lead-wire to the ABS sensor. I was able to back out the bolt, scrub everything down with a wire brush, put the lug on top of the bracket, and put the bolt back in. I think I could’ve used a ¼” lug here, but the bolt head is plenty wide to hold the 3/8” lug in place. This does not replace any factory cable.
: Neg to Body - 16.25": This runs from the negative terminal on the passenger-side battery to the stock stud on the inner fender, right between the battery and the air-box. This was easily accessed with a 10mm shallow socket on a ¼” drive ratchet. This bolt holds the old body-ground wire (stock cable (7)) and shares the bolt with the ground for the head-lights. This is another case where I could’ve used a ¼” lug, but stuck with the 3/8” anyway. It works. I made this cable longer than really needed so I could run it off the battery and loop it back to the bolt. The distance between terminal and mounting bolt is only about 5”, but I didn’t want any sharp bends in the cable.
:
: Pos to Starter - 47.25"/.375": This runs from the positive terminal on the passenger-side battery to the stock stud on the starter, and it was a B1TCH! This is the only cable that took more than three minutes to mount. Actually, it took about four hours to mount because I’ve never dropped the starter on this truck and wasn’t quite sure how to go about doing so. With these pointers, redoing would only take about an hour.
: First, jack up the truck and take the front passenger-side tire off. Remember to drop the truck back down on jack-stands for safety, and keep an extra jack stand close by… It’ll come in handy later. Next remove the splash shield on the inner fenderwell (if you haven’t already done so for the neg-to-frame cable). Now crawl under the truck with a 15mm socket and a 9” extension (I stacked a 6” and 3”) on a 1/2” drive ratchet. Loosen the two bolts that hold the starter in. Now crawl out, locate the extra jack stand right under the starter (it wont’ likely fall until you start moving it, but just in case…) and get comfortable in the open wheelwell.
: In the wheelwell there are two brackets holding battery cables in place along the frame rail. Remove the two bolts on these brackets (1/2” deepwell socket on 3/8” drive). Remove the brackets from the cables (keep them around, you’ll be putting them back later). Now pull the whole cable down from the engine compartment so the battery-end is sticking out through the fenderwell. As much as possible, separate the two cables (2 AWG starter lead and 8 AWG power distribution lead). They’re held together with about four layers of split-loom and electrical tape. Once you get them split apart as far as you can, pull them off to your left. This will make getting to the next bolt easier…
: Now disconnect the two glow-plug harness connections at the back of the starter. Tuck these up out of the way (I looped them back on themselves).
: At the front of the starter is a bracket holding it the starter to the block (bolt threaded into block). This is barely accessible with a ½” deepwell socket on a 3/8” drive ratchet. Be ready to catch the start once you get this bolt out. Once out, pull the starter forward and guide it down onto the tranny cooler lines underneath it. You may be able to get to the wires at this point. I dropped the starter down past the tranny lines and onto the waiting jackstand. This way, the wired end of the starter was pointing up a little so I could see it better.
: Now push the heat-sheild up and out of the way. This will expose the mounting stud for the starter lead. Separate the two leads all the way up. Using a 15mm deepwell on 3/8” drive ratchet, remove the brass nut on the starter cable mounting stud. At this point, you’ll want to do the re-routing mentioned in the “Power Distribution Block” section below. Done with that? Good. Now put the new cable in place. Be sure to put new split-loom on it. From here on out, “installation is the reverse of removal.” HA HA HA!. Seriously, now put starter back in. I put the starter back up in the flywheel hole and started the two bolt on the bottom side. In hind-site, I think I would’ve put it back in and started with the front bolt, then two bolt on the bottom side. Make sure you’ve got all your wires routed properly!!! You don’t want anything trapped on the top-side of the heat shield!!! Once the starter is back in place, reconnect the two orange glow-plug harness connections. Now put the locating brackets on the cable (remember, the wire for the rearmost glow-plug also went through the back bracket) and bolt them back to the frame-rail. Run the battery-end of the cable up to front of the truck. Now you’re ready to put the splash-guard and wheel back on (assuming you’ve already put on the neg-to-frame cable).
: Note on funky length (47.25"/.375”): The lug on the starter end of this cable is bent over at a 90 degree angle. The 47.25” measurement represents length from normal lug (center of eye) at the battery end to the bend on the lug at the starter. The extra 3/8” (0.375”) is the length from from the bend to the center of eye on the starter lug. I used a pair of pliers and my fat man-hands to bend it. It seems solid, though I did scratch the tinning a little on the lug in the process. If you’ve got a vice and some rubber protectors, I’d use that to bend it… Or just get a bent lug to begin with. This cable replaces stock cable (3).
: Note on glow plugs: While you’ve got the wheel/tire and splash shield off, you might want to replace the front three glow-plugs… They’re a bear to get at from the top, but easily accessible through the fenderwell.
:
: THE MYSTERY WIRE!!!! Pos to power junction block on firewall (no length info yet): In it’s stock location, this cable runs from the positive terminal on the passenger-side battery to the power distribution block on the firewall. It’s routed down by the starter, then comes up along the firewall behind the passenger-side valve cover. I did not replace this cable. Rather, when I had the starter off, I snaked this cable up from behind the engine and re-routed it from the battery to the distribution block by going under the air box along the fender. It’s in split loom, and the split loom is zip-tied to another wire behind the engine. I couldn’t get a razor in there to cut the two apart, so I opened up the loom and pulled the wire up through it, then trimmed back the split loom as much as possible. To slide it up through the loom, I had to cut off the fusible link… For now I reused this wire (unfused) with a 3/8” lug on the battery end. I did not have to remove the wire at the power block to pull it up and out. I will be replacing it shortly, but I think 2/0 AWG is too big for this application. Of course, that’s never stopped me before. When I do replace this cable, I’ll post an update. Note that the power distribution block has a cover held on by two or three nuts. I took this off about a year ago and never put it back on (yeah, I’m a slacker), but if memory serves, the nuts can be pulled with a 10mm deepwell socket.
:
: Driver side battery...
: Neg to Block - 25.375": This is mounted on the stock stud on the block (right behind the alternator). The stud has a 17mm nut on it and could be reached without taking anything else off, though I did have to squish the upper radiator hose a little to get the shallow socket (on 6" extension) onto the nut. I have the HO cooling mods… If you’ve got ’92-’96 with stock cooling system, the hose won’t be in the way. This cable replaces stock cable (5)
: Neg to Frame - 27.625": Just like the passenger-side neg-to-frame, but on the drivers side… I did indeed leave the tire in place whole doing this one. This does not replace a stock cable.
: Neg to Body - 12.75": This runs from the negative terminal on the driver-side battery to a mounting bolt for the ABS proportioning unit (accessible with ½ socket on 6” extension). The ABS unit is right behind the battery so not much cable is needed. This cable does not replace a stock cable. Note that in ’95 they changed to a different ABS proportioning unit, so check cable length and mounting location before making cable…
:
: Battery to battery...
: PSB Pos to DSB Pos - 66.125": This runs from the positive terminal on the driver-side battery to the positive terminal on the passenger-side battery. The stock cable goes down to the side of the radiator into a bracket held in place by the screw that holds the upper fan shroud to the lower fan shroud. Then it runs up the side of the radiator, across the top through three clips, down the other side through another bracket, and finally to the other battery. This was necessary because of the side-post batteries. Wanting to simplify installation and keep the cables as short as possible I opted to cut this cable considerably shorter than stock and run it through the top three clips only. With the top-post mounts, this isn’t a problem, but I put split loom on the cable where it passes under the upper radiator hose for some extra protection. I wish I would have cut this cable about six inches longer than I did fo just a bit more slack under the hose and a little more “wiggle room” at the passenger-side connection. As it is, the wire has to make a pretty sharp bend to come from the same direction as the starter lead. Note that the clips on top of the fan shroud are too small to hold 2/0 AWG cable. For now I have it wire-tied to the stock clips, but I picked up some hose-clamps and push-pins to replace the stock clips. This cable replaces stock cable (2).
: Pos to Alternator (no length available at this time): This runs from the positive terminal on the driver-side battery to back side of the alternator. I think it’s about 30” and held in place with a 10mm nut, but don’t quote me on that… I’ll be replacing this shortly, and will post an update shortly after.
: Tools:
: A good socket set
: Hammer crimper
: Big hammer (I used the back side of an axe, but a 16oz claw-hammer would do)
: Razor knife
: Propane torch (for melting heat-shrink tubing)
: Scissors (for cutting heat-shrink tubing)
: 12” Wire cutters (you could probably use the wifes chicken shears if you have strong hands and a comfortable couch to sleep on). I was also told you could use a band saw…
: Supplies:
: 25ft roll 2/0 AWG (you only need about 22ft, but it’s nice to have a little extra)
: 16 3/8” tinned copper lugs for 2/0 AWG cable (I got three boxes of 10)
: 5ft split loom to fit 2/0 AWG cable
: 3ft black heat-shrink tubing
: 2ft read heat shrink tubing
: 2 pair Premier Power Welder mil-spec terminal clamps
: 12 push-pin panel retainers (to put the splash shields back in)
: 3 T-shaped push pin panel retainers (for top of fan shroud)
: 3 insulated hose clamps (for top of fan shroud)
: 72oz favorite iced beverage.
: I’ve got a lot more pointers, but it’s late, and I’m tired (coming off a 65 hour work week). I’ll post pointers, cable-making instruction, and more later this weekend. I will also try to have all the pictures online by the end of the weekend as well… If you would like a specific picture/angle, please ask now as I will be taking more pictures tomorrow and Sunday.
: Of course, I’d be happy to answer questions on anything I missed.
: Fat Boy