Problems with good ground on LT40, help?

[Kelvin]

Howdy all,
I'm working on getting a '94 LT40E15 going thats been sitting awhile.  I can't get the thing to ground very well.  When i jump the spring loaded contacts with jumper cables i can get the hydro pump to run, but not if don't use the cables.  I've sanded the strip on the side.  Wire brushed the one on the bottom of the rail, and took off and cleaned both contactors.  What else would you do?  Where is the usual weak link, other than me.  Any help appreciated,
Thanks
kelvin

[zopi]

Grounds can be a pain to troubleshoot...pull all the connections, clean them and inspect any cables..new cables might be in order..any corrosion in the cables themselves can increase resistance. Electrical connector grease is good...

If I remember right, Bibby had a thing in the mill mods thread on grounds.

[johnjbc]

When trouble shooting ground problems you need a volt meter with a set of long leads, with a good strong alligator clip on the – side.
First step is to remove the battery clamps and clean and reinstall them.
Put the alligator clip on the – side and the + on the POS battery terminal. You should have 12 volts. Now while holding the lead on the battery try to operate the pump. The voltage should not drop more than a couple volts. If it does your battery is bad or needs charged.
If the battery voltage is good leave the – meter lead on the battery and start moving along the ground path toward the pump. Keep trying the pump until you find where the voltage is being dropped. Note you may have to go through the pump and back toward the battery pos terminal till you find the voltage drop.
I'm betting you have a sulfated battery 8)

[bull]

Sand the entire bottom rail to a clean silver shine and repaint it,pull the brass block and soak it in brasso brass cleaner makes a hell of a difference,

[Kelvin]

Thanks for the input guys,
I was buying some more parts from woodmizer today and talked with their electrical guy.  He said leave the bottom rail shiney metal, but wipe with tranny fluid.  I think my old (well newer than this one) LT40 had the bottom rail painted.  How can it ground through paint?  Also the battery is brand new from woodmizer, so it should be good. 

I've got a few steps further.  I worked on the side strip cleaning more, and made shiney spot on bottom rail, and i can get it to work, but it won't maintain very well w/ any movement.  This is a very fussy system.  Would you use Di-electric grease anywhere on this?  The woodmizer guy said it would grab dust so leave side strip bare metal.  I ordered a new contact shoe for the side strip as the one that is on the mill is worn on some funny angles, so i'll start with new.  I think its just dirty, rusty crap that is causing the problems.  I did clean the leads to the battery as well.  They were pretty oxidized.  We'll see how it goes.
Thanks
kelvin

[backwoods sawyer]

I was having the same problem with mine. After checking all contacts with an ohms meter I found the brass shoes had glazed over and were not making contact. I took a wire brush in the drill and went over the bottom rail front to rear. It had some burs from a dead bearing dragging and lots of grime. Then I put new shoes on and that solved that problem. I like the damp trany fluid on the rails method myself.

[Brucer]

To keep my ground in good shape, every spring I polish the bottom of the bottom rail with emery paper -- just the portion near the front where the contact strip is. If the mills been sitting a while, you might need a little more elbow grease. The emery just removes rust -- the rail's too hard to be damaged.

I  once had a problem with the contact strip. Turns out the contact shoe wasn't pressing firmly enough against the strip. On my '06 mill, the whole shoe assembly can be moved in or out. Pushing it in 1/8" gave enough extra pressure to give me good contact. Be sure to disconnect the battery ground before you mess around with this -- you've got a battery positive sitting awfully close to a grounded frame.

When I was running Louis' mill back in '04, we had a heck of a problem with good contact. The closer the carriage was to the front of the mill, the poorer the contact. His solution was to reach down with his left hand, grab the wire that was attached to the contact shoe, and push in while he operated the hydraulics. I noticed the contact strip was badly pitted, so I tried polishing it with a sanding block, but that only helped for a while.

One day when we were down waiting for a load of logs to arrive, I took off the contact strip and the shoe. I noticed the springs on the shoe were installed the wrong way around, so I fixed that. I also reversed the contact strip so the bright side was out. That pretty much fixed things -- at least for that season. The following year when I was running my own show, Louis came by and told me his hydraulics were acting up again -- could he borrow my volt meter. Well, I checked it out for him and discovered the wire to his contact shoe was getting really hot when we tried to run the hydraulics. It turns out that all that pressure he'd been putting on the wire during the previous season had flexed and work-hardened several of the copper strands. These started to break, leading to a high voltage drop in the wire, which caused more heat, which caused more strands to break. Once he replaced the wire, things worked just fine.

This was a case where lack of proper maintenance (fix the pitted strip) led to another problem (someone putting the contact shoe springs in wrong) which led to yet another problem (broken wire).

It's a good idea when you're dealing with a problem on an older mill to check out every component that might be involved, and fix any that are dubious. Otherwise you could get a sequential failure like Louis had.

[Kelvin]

Thanks guys,
I ordered a new shoe as the old one has many bevels on it.  After sanding, lubing, grinding and brushing it works intermitantly so we'll see if the new shoe fixes things.  I'm getting close.  Now i'm off to all the other things to work on!
KP

[Slabs]

If jumping the "hot" seem to fix the problem it isn't the ground.  That new shoe that contacts the copper rail may be a solution.  I think the new shoes are bigger and give more contact.

Good luck

[Kelvin]

I got the wrong type shoe for the siderail from woodmizer, but before i realized it i had taken the old one apart.  Sure enough the wire inside was really burned up and corroded.  clipped it back, cleaned it up and it works well now.  It was the weak link.  I've got the new shoe coming, but i'm not sure i need it now.
thanks all,
Kelvin

[LeeB]

Spare parts. You might not need it now, doesn't mean you don't need it.