Dumbing Down a 1997 773 C-series

[SirThadious]

So, just before Christmas I picked up a 97 773 C-series Bobcat that had an unfortunate accident with either the battery or one of the relays catching fire and roasting out the left side (when looking at it from behind) of the motor and associated components in the area. The motor (v2203) had also injested water into #1 & #4 cylinders (causing heavy pitting). The motor has been sleeved in these cylinders and all cylinders rebored 0.020" over.

Since then, all plastic parts have been replaced, all seals replaced, oils, greases etc redone. Everything cleaned, stripped and the entire machine repainted (with the exception of the main chassis lower pan). I've since run up the motor and started breaking it in.

Now... the fun stuff... The machine had the old B.O.S.S. system in it. The only parts that were salvageable was the instrument panel inside the cab and the seatwall B.I.C.S. panel. A large chunk of the wiring in the engine bay was burned out in two sections, the connector area for the main cab harness and the computer itself was roasted. That being said, most say to just swap to analog gauges (since you aren't going to be able to replace the roasted parts and even if you could, the system was troublesome and unreliable at best).

I've picked up a replacement gauge panel (right side) and all the new gauges and hourmeter to go with it. Started rewiring all of it (have the schematics) and figuring out which wires to run where. This is essentially "dumbing down" the machine, I know. I have a '91 743 with a lot of the same sensors and guages, minus the electric brake interlock, the control body lock solenoid and the auxiliary solenoids. I am looking to just wire most of those to 12v illuminated switches for overrides and such. This should allow the use and safety of all of them. The sensors have all be removed and such. Yes... I know I'm pushing it back to the ages before computers and such, but not a lot of options, not without a ton of costs to revamp the entire system to a newer B.I.C.S. system... yes, I priced that out too. So, analog gauges, switches, replacement relays and solenoids and new base sensors have all be assembled.

Keep in mind that this isn't for a company or business, just a homeowner that works his property.

Anyone have any thoughts or considerations when going this route?

Cheers!
Ted.

 

[Tazza]

Never done it, but doable all the same.

Starting the motor, hook the pull coil power to the starter motor terminal that gets power to crank. Hook the hold wire to the keyed power.

Park brake, push button to unlock it with a switch that turns the switched power to the hold coil.

The hardest bit will be the aux hudraulic controls. I don't know if they are 12v or lower.

You will also have a lift lock solenoid, it is 12v or so as well, you can hook up a switch to turn it on and off too.

Do let us know how you go.

 

[ianmcolo]

I just worked on a 753C series machine that was in an underground coal mine. This machine did have the BOSS system and a mechanical brake, The wiring was a disaster and had a "G" series cab, this thing is mess. I just ran a fused push start button to the starter and a pull kill cable on the engine, just like your 743 and it works great. As far as your breaking system you can always pull the brake parts out, a lot of the older New Holland, Case and John Deere's had weak braking systems that failed years ago. The person that owns this machine only uses it for yard work and to move trailers around, so they do not care about the gauges.

As far as the aux hydraulic the solenoids are 12v for your era of machine, you can wire in a separate switch block and should be fine.

Good Luck.

 

[SirThadious]

So, I did manage to get it all set up and running. The key still has all the functions that it orginally did, even the hydraulic drain down position. The glow plugs have their own momentary rocker switch as does the parking brake (keeping in mind that there is a lift signal line and a hold. The hold is wired to the key switch (low amperage) and the lift to the momentary rocker via a relay. I have individual front light (with rear tail lights) and rear lights on their own switches. One for a rotary beacon and one for a window wiper. As well, I have installed the power switch (rocker) for the hydraulic solenoid and another rocker on the other side for the Aux solenoid (stays on). The thumb rocker on the right joystick still operates the aux solenoids as well, just on/off, nothing proportional.

The on position of the key sends power to all the relays in the engine bay for all the auxillary power and the glow plug and start relays are much more robust (think the relays that are used on a the glow plugs for a 7.3 diesel pickup). New sensors for oil pressure and temperature were installed and everything seems to work like it should... just no computer and you actually have to pay attention to the gauges and the warning lights if they go off!

A lot of splicing, solder, heat shrink, new switches and such went into this, but it works great (and I would think much more reliable than the BOSS system).

 

[foton]

I am all for using the KISS system, I wish we could do it with cars again.

 

[SirThadious]

One of the reasons I like the OLD trucks. No computers, thicker sheet metal and simple wiring!