my machine, 7753, drove and operated fine other than a lot of play in the left steering lever. so, due to (i guess) normal wear, i recently replaced left steering bell crank and bushing on top of the hydro pump. i then adjusted the creep out of both sides. now, when using the machine and pushing both levers forward, it wants to bog down or stall and the belt starts to squeal. does the same thing with a hard steer, mostly to the left, the side with the new parts. no change in boom operation. it's like driving the family car with your left foot on the brake and your right foot on the gas. all was good before the routine repair. seems like something got overly tight. what could have happened? what could i have done? could it be something new, unrelated?
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it has the mechanical foot/parking brake on the floor (middle) that has never worked. if if it did work, it would lock. it also has he traction lock button that still seems to work. not real sure what or how that works but i think it operates a solenoid. i also think it would either be off or on and not be partial to cause a drag. but, i'm open to any possibility. again, all was ok before, just sloppy left steering lever. thanks
bobbie-g
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- Mar 15, 2004
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Well, the bogging down is beyond my experience and expertise. But on to the "parking brake". I'm assuming your 7753 works the way most earlier machines work (pre 2000 or so?). The foot pedal brake only actuates a switch at the base of the foot pedal, which in turn releases power to a springloaded solenoid. That solenoid is below your rear end when you're sitting in the seat, you need to flip the cab up to see it. If there is no power to that solenoid, its spring will insert the solenoid moving core into a toothed wheel which is attached to the drive mechanism, effective stopping the wheels from turning. It's really not a shoe/drum "brake", just a brute force piece of metal inserted into a "cog". Your basic control system (BICS or computer control) will also remove power from the switch as needed (lap bar up, etc). There's no way the machine will move at all if the solenoid core is not powered up and retracted from the toothed wheel, so that's really not your problem. As a side note, I never use the foot pedal. On my 751, the switch went bad. Unsure to this day of how it is actually wired in, but I had to flip the cab, unbolt the solenoid coil, retract the core, and hold it retracted with a hose clamp to get the machine to move. So chasing the foot pedal deal (assuming your 7753 works that way) won't help you solve your problem. Best I can do.
---Bobbie Gyou're exactly right on the foot brake. you're either stopped or you're not. i keep going over and over (in my head) what was done and what is different now vs before the repair. the only thing i can thus far think of is that i gave it a good power washing down in the drive area. i had to get under it with a screw driver and clean out all the drain holes while it was still up on jack stands.Well, the bogging down is beyond my experience and expertise. But on to the "parking brake". I'm assuming your 7753 works the way most earlier machines work (pre 2000 or so?). The foot pedal brake only actuates a switch at the base of the foot pedal, which in turn releases power to a springloaded solenoid. That solenoid is below your rear end when you're sitting in the seat, you need to flip the cab up to see it. If there is no power to that solenoid, its spring will insert the solenoid moving core into a toothed wheel which is attached to the drive mechanism, effective stopping the wheels from turning. It's really not a shoe/drum "brake", just a brute force piece of metal inserted into a "cog". Your basic control system (BICS or computer control) will also remove power from the switch as needed (lap bar up, etc). There's no way the machine will move at all if the solenoid core is not powered up and retracted from the toothed wheel, so that's really not your problem. As a side note, I never use the foot pedal. On my 751, the switch went bad. Unsure to this day of how it is actually wired in, but I had to flip the cab, unbolt the solenoid coil, retract the core, and hold it retracted with a hose clamp to get the machine to move. So chasing the foot pedal deal (assuming your 7753 works that way) won't help you solve your problem. Best I can do.
also, i find, when i go into a pile of dirt/gravel/etc and as it begins to stall, the hand controls/levers shutter and shack. i let off trying to push forward and it (shutter) stops. it lifts and dump a load just fine.
very possibly found the problem. the big drive belt was extremely loose. tightened per the service manual and it's not bogging down. would not have thought a loose belt would have resulted in that type of issue. fixing a few other items now and then back together totally. i'll give a final report later.
Hopefully it's just the belt, they do need to be tight.