It seems like a simple thing to do but it gives me problems with the Foretravel.
Every time I look for a grounding point I try for the chassis, this does not always work. My thought is that anyplace on the chassis would be a good ground, NOT.
I have tried scrubbing the surfaces with abrasives to ensure a good contact but that does not work.
Where have you found the best ground areas are?
Then check the chassis metal to battery ground connection. All steel in the coach welded "framing" should be reasonable ground except for high amp loads.
I have always found that an extra engine to chassis ground strap plus an extra battery ground cable from a negative post to the chassis a very short distance away keeps a lot of problems at bay.
Finding an existing bolt on the chassis, removing it and then placing the ground under the fastener will usually work well.
The water pump ground wire is frequently a problem. Just remove it, splice in a few inches extra and then use a ground location like the compartment light ground works well. Easy to check after that.
Pierce
I was eyeballing the bolt the holds the lower shock mount. It is in a great spot for an additional ground for the batteries.
Good or bad?
Lower shock mount? You mean on the axle carrier that moves constantly with every bump in the road? Not an ideal spot... also the shock mount bolt is probably close to ¾" in diameter (as I recall the bolt head takes 1-⅛" wrench) and it is a "top locking nut" (the kind that have deformed threads on the top and lock by jamming). These can be a bear to remove, and the largest lug size commonly found for cables up to 4-0 has a ½" hole. There are several of the rolok type self thread screws (just like the bulkhead bolts only short) holding various brackets and such to the heavy framing in the area around the chassis batteries. These are 5/16"-18 and if you run a tap through them, you will have some clean threads to make a good connection. Use some corrosion X on the bolt and you should get a solid ground out of it. I added several chassis grounds when I redid the chassis battery cabling. The most important one is to the starter. I made a new 4-0 cable for that, and that goes to a heavy duty bus bar to which several other grounds go to as well. The more the merrier :D
Don :D
Good point Don, I will tear my eyes off the shock mount.
After rebuilding the 6 pack in there, installing a new Parker 790R pre-filter, and re-cabling the 3 batteries in that compartment, I have spent a lot of time looking at that shock absorber.
I have never tracked the chassis battery's ground point, where is it located?
On our coach, the original 3-0 chassis battery cable went to a insulated post mounted on the vertical angle iron that forms part of the chassis battery support frame, just inboard of the batteries. Multiple small gage ground wires were grouped together along with several larger gage cables on that post along with the battery negative in-line cable lug. The 3-0 negative cable continued from there and went directly to the starter case where it was held by one of the starter mounting bolts. Here are a couple of pictures, one before with the insulated post (circled in green) where the battery negative cable interrupts its path on the way to the starter chassis ground, and one with the bus bar set up while I was in the process of redoing it. The positive cable was similarly done...
Don
Why is it, every time I see a photo of Don's craftsmanship, I think to myself "I'd like to hang that up on the wall in my living room"?
Lon, when you find the common ground post, follow the negative cble from your start batteries, you may find like I did that time had corroded it to the point where the nut is locked in place. I was going to add another cable on there when I discovered that ir was locked up. No way to tell if it is secure or not so it is getting replaced. A bus bar makes a nice connection point, use whatever anti-corrosion product you like to keep it from getting stuck.
I am not sure whether or not it was the new clean grounding connection, new 4-0 negative and positive battery cables, but now with the same chassis battery (a 4+ year old single Oreilly 8D AGM), but the engine spins much quicker without boost than it did with boost before the changes... about the same now with or without boost actually. In fact with the heavy duty Blue Sea magnetic relay in place of the boost switch, I discovered by accident :o (having left the chassis battery disconnect switch in the off position), that the coach starts easily with just the house bank routed through the boost relay. Though I didn't notice any negative consequences from running it that way for about five minutes, I don't plan on repeating that experiment! Still, it is nice to know that I can start the coach with no help from the chassis battery if I ever have to...
Don
Thanks for that tip, It is right under my nose. Looked like it snaked away under the coach, must just turn around and come back to where it originated.