s70 Bobcat Skidsteer parkbrake failure

Has anyone seen this before?

S70 bobcat skidsteer into workshop with park brake not working, had only done 140hours.
Was making any weird drive noises, just no park brake. Stripped it down and this is what we found. The park brake discs were just floating in the chaincase. The circlip groove that holds the discs to the splines had been smashed off, discs bent and badly damaged. Park brake wedge holder smashed up. When the chains were removed the dive shafts were bent they needed new drive motors. Very expensive, only thing I could put it down to was the operator putting the engine to full noise and slamming levers strait into drive. Unfortunately couldn't prove this, the brake system and interlocks had been working fine. Other theory is travelling at full speed and hit a bump and the seat interlock has kicked in. Just wondering if this has happened to anyone else before and did they find the exact cause??

hard to tell from the 2nd pic, but are the wedge guide blocks missing or loose?

theres only 1 person that really knows what happened, and what he was doing..

thats the guy sitting in the seat, it's hard to get the truth out of most "operators"

do bobcats "down under" still have the seat switch in the system?
they've been gone from the BICS system here for many years.

:drinkup

Fsmech. I'd put my money along the same cause as your observation, n chief is right as well. Most aren't going to man up n say what really happened here,,, Yet a picture does tell a tale as they say.
Had to be allot of deliberate force took placed to accomplish that type n depth of damage imho. N if machine has only 140hrs, I highly doubt parts failures are at fault. Yet the mysterious operator does know n playing it up for a warranty scam imho.
Although proving such may be difficult, but I am not there to consider what events took place either.

I could tell many a story of I Don't Know What Happen been spoke in my lifetime of such encounters? It's usually never anything they did naturally.
I'd atleast be up front with the equipment owner as to what the potential causes were placed to warrant such damage. Yet like you said, can't prove it 100% without ill feelings down the road. Looks like horseplay was the culprit, as I have had similar problems other hydrostatic driven units. An most were due to operator error in most cases. Yet the govt has deep pockets n we just fixed the problem,,,

If your machine has the power bobtach, I'd bet the operator was tooling along at full tilt, stuck a knee against a drive lever, and attempted to operate the power bobtach switch with his free hand, but instead hit the parking brake switch right next to it. Things come to a radical stop when that happens.

Yes it had a seat switch and the controls are just led lights, fuel gauge, and hourmeter, do the new s70s have something a bit flasher? Chief, not to sure I was thinking the wedge guide blocks were in picture 3 and they were badly bent out if shape. What interlock system do new bobcat have? If this was an accident were the seat bar bounced up, have bobcat looked at wAys to prevent this happening,

Thanks everyone

fsmech said:

Yes it had a seat switch and the controls are just led lights, fuel gauge, and hourmeter, do the new s70s have something a bit flasher? Chief, not to sure I was thinking the wedge guide blocks were in picture 3 and they were badly bent out if shape. What interlock system do new bobcat have? If this was an accident were the seat bar bounced up, have bobcat looked at wAys to prevent this happening,

Thanks everyone

Click to expand...

i'm not positive, but i dont think north american s-70's have a seat switch on them. it's been a couple months since i've seen one.
even if the operator raise up off the seat switch, the brake shouldnt lock immediately, there is a short delay (5 -15 seconds) that was built into the seat sensor. raising the seat bar while moving will lock the brake immediately.

i'd take a look at the ground connections, a loose/corroded ground will let the engine start and run, but if the bics system momentarily looses it's ground, it will shut itself off.
the brake coil incorperates 2 coils,
"pull" requires approx 20amps, and is poweed through the brake relay
"hold" requires less than 5 amps, and is controlled by the bics system.

about all you can do is fix the broken parts, and file a warranty claim


:drinkup