2018 Mecalac 6MCR

[treemuncher]

That plastic is easy to work with and it will last a fairly long time. If you made it fit tight enough it will keep the grease in and most dirt out.

If your line is straight, I have used rectangular tubing as a guard. Just cut one of the narrow sides off and lay that open end onto the hydraulic cylinder. You can use heavy duty hose clamps for light duty but exhaust clamps are much better. If you weld the clamp base to the guard and wrap the threaded rod portion around the cylinder, it will be easy-on easy-off for repairs. Or lightly weld guard to cylinder with minimized heat.

Like this factory built one that is a welded on unit:

 

[materthegreater]

Great material for spacers! I'm going to copy you when I start doing the work on my backhoe bucket for my old 410B! By the way, this Mecalec looks like a fantastic machine to operate, probably a load of fun. Can you run it like a normal excavator - is that a pin grabber on it - so you can have the bucket face either direction? or is that a special Mecalec connector?

Yes it can be run like a normal excavator. It has a special Mecalac bucket coupler, but it can use attachments either direction like a pin grabber.

 

[materthegreater]

That plastic is easy to work with and it will last a fairly long time. If you made it fit tight enough it will keep the grease in and most dirt out.

If your line is straight, I have used rectangular tubing as a guard. Just cut one of the narrow sides off and lay that open end onto the hydraulic cylinder. You can use heavy duty hose clamps for light duty but exhaust clamps are much better. If you weld the clamp base to the guard and wrap the threaded rod portion around the cylinder, it will be easy-on easy-off for repairs. Or lightly weld guard to cylinder with minimized heat.

Like this factory built one that is a welded on unit:
View attachment 330579

Thanks for the input, but in this case I'm actually looking for a guard for the cylinder rod, not the hydraulic line. Many minis have guards for the boom cylinder because they are most susceptible to damage, but this machine has a very exposed arm cylinder. I don't think it'll be too difficult to make one, but I need to figure out a good rugged way to make a guide for it to slide in. I like your idea of an exhaust clamp to anchor to the cylinder barrel.

 

[treemuncher]

I also use a Band-It tool for fastening some of my custom guards. I have a bulk spool of stainless banding material and hammer-shut clamps that are very versatile.

Tool here: https://www.band-it-idex.com/products/tools/hand-tools/standard-banding-tool/



I have made this particular guard from 4" or 5" ID fertilizer solution hose from Rural King. It is very durable. It might also be sold as Canaflex. It is far tougher than corrugated gutter drain tubing. Cut lengthwise with a sabre saw or skill saw, notch for any fittings and snap over the outer tube. It will allow for some flex when needed and keeps my rod out of the discharge zone.

 

[laidback01]

I went outside and took pics of the very simple setup on my 50ZTS. this is an easy design to work with and straighten with a hammer - as I've had to do a couple times already.
Upper Mount, Lower Mount, example damage that my boom cylinder has been saved from.

So, yeah, this is a useful shield. I'm used to pinning stuff against the boom - my original equipment is a 410B backhoe where the cylinder is enclosed in the boom. so this is a bit more exposed. I may have to come up with a better shield.

 

[materthegreater]

I cleaned all the main power cable connections (including grounds), except for at the starter itself because it's not accessible without removing the exhaust. At -3°F this morning it did the same thing: turned over once slowly and then nothing.

The dealer still has not responded to my request for the wiring upgrade kit for the relay board. I think I need to call a different dealer.

 

[materthegreater]

 

[Columbo]

Nice snow bucket!

 

[laidback01]

You got it running again! did you fix it with a kit or just by increasing the cable diameters from battery to frame and solenoid?

 

[materthegreater]

You got it running again! did you fix it with a kit or just by increasing the cable diameters from battery to frame and solenoid?

It only has the starting issue when it's in the single digits, so usually if I wait until afternoon, or if it's a warm day, it will start.

This morning was 5°F so I did spend a little time troubleshooting. I measured the voltage drop at the control board during cranking and it was 1.2 volts. That seems like a large voltage drop to me, so I'm planning to make my own wiring upgrade to feed the control board and see if it eliminates that problem.

 

[laidback01]

huh. I suppose the oil is that much thicker that the starter uses about 50% more power maybe? their solution is a bigger wire... why not a block heater? since the voltage drop is a symptom, the problem is higher viscosity fluids creating a higher drag on motor internals. I get it that bigger wire is a good call, but.. perhaps fixing the symptom still doesn't alleviate the load on the starter?

On the other hand, you can get those clamp style ammeters fairly inexpensively and you can test your starter current draw on cold days vs the machine being warm. it'd at least help with the basics - high current, low voltage, low crank speed = bad starter. Low current, high voltage, low crank speed = high resistance in wiring. So, if you are only testing voltage, you need to change that to get your answer as to what the problem really is. If it's the second choice, then bigger wiring is the right solution as they under-specced the wiring system for this rig in cold environments. Cold rigs obviously take way more current to start than warms ones do.

 

[laidback01]

huh. I suppose the oil is that much thicker that the starter uses about 50% more power maybe? their solution is a bigger wire... why not a block heater? since the voltage drop is a symptom, the problem is higher viscosity fluids creating a higher drag on motor internals. I get it that bigger wire is a good call, but.. perhaps fixing the symptom still doesn't alleviate the load on the starter?

On the other hand, you can get those clamp style ammeters fairly inexpensively and you can test your starter current draw on cold days vs the machine being warm. it'd at least help with the basics - high current, low voltage, low crank speed = bad starter. Low current, high voltage, low crank speed = high resistance in wiring. So, if you are only testing voltage, you need to change that to get your answer as to what the problem really is. If it's the second choice, then bigger wiring is the right solution as they under-specced the wiring system for this rig in cold environments. Cold rigs obviously take way more current to start than warms ones do.

by the way, this may have come off wrong. I was trying to look at both sides of the problem - is it an under-powered starter for the cold oil days, or is it small diameter wire not supplying current to the starter. I know very little about any equipment - just apply the same knowledge to different rigs because they are often very similar. Oh, and i recall you saying you can't get to the starter in an earlier part of the thread - you can use those clamp on meters at the battery - current flow is the same no matter where it is. voltage measurement at the battery won't help though. too bad the starter is hard to get to.

 

[materthegreater]

by the way, this may have come off wrong. I was trying to look at both sides of the problem - is it an under-powered starter for the cold oil days, or is it small diameter wire not supplying current to the starter. I know very little about any equipment - just apply the same knowledge to different rigs because they are often very similar. Oh, and i recall you saying you can't get to the starter in an earlier part of the thread - you can use those clamp on meters at the battery - current flow is the same no matter where it is. voltage measurement at the battery won't help though. too bad the starter is hard to get to.

It's always good to have more perspectives on the problem. Helps me think through everything and question things that I may have made assumptions about. And much of what I've posted is just my speculation, not necessarily confirmed diagnosis.

While the oil is a little thicker at colder temps, I don't think it's the problem. Lots of machines start just fine in much colder temps than this (my other excavator, for example). I also don't think the starter is the problem, and I'm doubtful that the wiring to the starter is either. Most times I've experienced issues with those, either the starter won't turn at all, or it will continue to turn slowly, but not fast enough to start the engine.

The problem here (in my current understanding) is that the control circuit that energizes the starter solenoid is getting cut off due to low voltage, therefore stopping the starter from turning as if I had let go of the key. When the key is turned to the start position, it activates a relay which supplies power to the solenoid, which connects the starter to battery power. Relays require a certain voltage to function. And if the voltage drops 1.2v below battery voltage during cranking, the relay can no longer function.

 

[laidback01]

if they put a relay in that won't operate below 10.8vdc, that's a screwup. Most cars/trucks battery voltages will drop to 10.5 and as low as 10.0 in extreme cases of sustained cranking. Relays can be designed to operate at any voltage - and I'd like to point out that contrary to everything else, resistance drops when it's colder (not by a lot, but it's notable) and resistance rises when heat rises. Relays in particular are sensitive to this.

I'd like to point to a reasonably well documented page on relays - What is the minimum voltage required to run a 12v relay? This guy tests generic relays, but the principals are the same. roughly 60-80% of nominal voltage is what it takes to activate a relay. I'm not sure who told you it takes a bit more than 85% of nominal voltage to run a relay, but they are wrong.

Now, the control board... that's a different animal. Could well be that Mecalec actually uses a computer to control a relay. That computer will be a lot more sensitive to voltage variation. However, were that the case, I'd expect the gauges and everything to flicker or reset if the computer itself is rebooting.

anyway, it's impossible for me to do much to help. so, I'm just offering generic knowledge. hope it's useful.

 

[materthegreater]

The problem is that the voltage to the control board drops 1.2v below the battery voltage during cracking, not the nominal voltage. So if the battery drops to 10.5 or 10.0 as you suggest, the control board is only getting 8-9v. Which, depending on the relay, may not be enough to activate. I didn't say it took more than 85% of nominal voltage, I said it takes a certain voltage (which can obviously vary based on the specific relay).

There is a computer also, which as you mention is likely more sensitive to voltage drop, but even under normal conditions when it cranks and starts normally, the screen goes black during cranking and boots up after the engine starts. So I don't believe the computer controls the starter circuit.

As mentioned, much of what I'm presenting here is based on what I've learned of this system during my troubleshooting, and speculating based on that. As I do more testing and research, hopefully I will gain a better understanding of how this system is designed and what the actual problem is.

 

[Willie B]

It's always good to have more perspectives on the problem. Helps me think through everything and question things that I may have made assumptions about. And much of what I've posted is just my speculation, not necessarily confirmed diagnosis.

While the oil is a little thicker at colder temps, I don't think it's the problem. Lots of machines start just fine in much colder temps than this (my other excavator, for example). I also don't think the starter is the problem, and I'm doubtful that the wiring to the starter is either. Most times I've experienced issues with those, either the starter won't turn at all, or it will continue to turn slowly, but not fast enough to start the engine.

The problem here (in my current understanding) is that the control circuit that energizes the starter solenoid is getting cut off due to low voltage, therefore stopping the starter from turning as if I had let go of the key. When the key is turned to the start position, it activates a relay which supplies power to the solenoid, which connects the starter to battery power. Relays require a certain voltage to function. And if the voltage drops 1.2v below battery voltage during cranking, the relay can no longer function.

Do you have a solenoid relay? Is it accessible? It is mounted somewhere along the heavy cable to the starter. Some machines, it is mounted on the starter. Typical layout is battery negative connects to the frame. Iron serves as a conductor to starter & most everything else. Power flows from this through the frame of the starter motor. It flows through the starter frame, the starter windings, & out to the solenoid. Solenoid is a relay, if open, no current flows through it. If closed, current flows through it, back to the battery positive terminal.
A solenoid may have two smaller terminals, or one. If one, the other end of the magnet winding makes connection through its mounting bracket. Positive connection passes through any number of controls connecting battery positive to this terminal. You may be able to follow this circuit to find the point of resistance.
No doubt there are points of the circuit you can't get to. A schematic can be very helpful.

 

[materthegreater]

Do you have a solenoid relay? Is it accessible? It is mounted somewhere along the heavy cable to the starter. Some machines, it is mounted on the starter. Typical layout is battery negative connects to the frame. Iron serves as a conductor to starter & most everything else. Power flows from this through the frame of the starter motor. It flows through the starter frame, the starter windings, & out to the solenoid. Solenoid is a relay, if open, no current flows through it. If closed, current flows through it, back to the battery positive terminal.
A solenoid may have two smaller terminals, or one. If one, the other end of the magnet winding makes connection through its mounting bracket. Positive connection passes through any number of controls connecting battery positive to this terminal. You may be able to follow this circuit to find the point of resistance.
No doubt there are points of the circuit you can't get to. A schematic can be very helpful.

There is a solenoid on the starter. I haven't been able to find if there is a smaller relay that controls the solenoid, or if it's simply the key switch that activates it. The schematic in the manual is in French, which is Greek to me.

 

[Willie B]

There is a solenoid on the starter. I haven't been able to find if there is a smaller relay that controls the solenoid, or if it's simply the key switch that activates it. The schematic in the manual is in French, which is Greek to me.

Will not be easy without speaking the language, but wires are multilingual. Get a clean sheet of paper, draw your own schematic of only the parts of the diagram you need.
It won't be simple if you have no access to the solenoid. I'd sure be curious if your problem is in the high current circuit, or the low current control circuit. With safety devices in series there are a lot of links in your chain, any one could stop current flow.
If you had access to the solenoid, you could narrow it down.

 

[materthegreater]

Will not be easy without speaking the language, but wires are multilingual. Get a clean sheet of paper, draw your own schematic of only the parts of the diagram you need.
It won't be simple if you have no access to the solenoid. I'd sure be curious if your problem is in the high current circuit, or the low current control circuit. With safety devices in series there are a lot of links in your chain, any one could stop current flow.
If you had access to the solenoid, you could narrow it down.

 

[Willie B]

High current circuit seems very simple. Coup batterie I presume to be a master disconnect. Demarreur I believe is the starter & solenoid Rectangle with a slash is electromagnet. Relais Demarrage (relay starter) J2-30 Receives battery positive from unclear source to J2-87 when magnet is powered. I can't read terminal numbers on relais demarrage.