Repairing creeping Bobcat

[myron60]

Hey y'all,
I reset neutral, the bucket works, replaced the belt that connect to the pintle pump. I have been told that if the tensioner pulley on the pintle pump doesn't keep the right tension that will affect fwd and rev. My other options are to replace that spring and if that doesn't work replace the tensioner pulley on the main drive belt.
Every thing worked fine until I tried to fix neutral, now when I try to go fwd or rev, I get a growling type grinding that sound like something is not quite fully engaged.
I am at my wits end.
Thanks for all help.

 

[dukeyjoe]

Thanks Willie,
Just replaced all torsion bushings front and back, flipped the bars and rotated the cams on my 773 F-series using this tutorial.

And thanks to some help from crewchief888, I, also, replaced the bics solenoid and stem, cause the one that was on it was rusted to the stem. This solved the lift/tilt problem. Tracked the brake solenoid pull side, white wire and realized it was hooked into the glow plug relay and vise versa. When I switched the plug ins to the correct relay, the machine quit blowing fuses, WAHOO!!! I'll be changing the relay for the glow plugs and all will be well!

 

[willie59]

Good news to hear dukeyjoe. :drinkup

 

[Randy88]

Excellent job of explaining this on bobcat, how about other brands like say new hollands, my 565 creeps, just haven't had time to look at it and figure out what's going on.

 

[willie59]

I haven't worked on a NH Randy88, not a strong presence around these parts. Sorry I can't help with that one.

 

[ValleyFirewood]

On my S250 it doesn't creep but I can hear hydro fluid flowing. Kinda of a pssshh noise. If I push the levers forward about 1/4" or so it stops. Another 1/4" or so and it starts again.

I'm guessing its barely in reverse. Is this worth messing with even? It's a 2003 or 2004 with about 3200hrs.

 

[willie59]

As long as it's not creeping I wouldn't worry about it yet. Once you raise the seat bar to exit the machine it engages the parking brake. If it does begin creeping it will load the drive hydraulics against the parking brake, you'll want to adjust neutral at that point.

 

[NH Murph]

I am a newby This tred is amazing. I have red the intire tred and have learned a great deal. Alittle knoledge is dangerious. I have a 743 BobCat Cerial #5019M30583 that creaps, after reading and studing this tred, I figured I could fix the 743 myself no swet looks easy. I am 71 years old have all the time in the world to do it. Placed BC on Jack stands. Raised OP Cage. Wow Murphys Law this is nothing like Willie95 Photos. Ahwell a little different it is on the side instead of on the top. (wrong) Well here goes I remove the conecting arms that go on to the steering linkage. I remove the spring (did use zip ties) :notworthy How do I remove the steering lingage bracket bar, it slides back and forth this is the plate the pintle is bolted to. What holds it to the Hydrolic Pump

 

[willie59]

Sorry about that NH Murph. Yes, the 743 is very different, they have Vickers drive pumps with the centering plate mounted on the side of the pumps. I see you've already found help from crewchief at a different thread, you're in good hands with him.

Welcome to HEF. :drinkup

 

[dsinclair88]

Will this also fix a problem with the forward controls returning to neutral? Centering works fine in reverse drive but forward the skidsteer keeps driving forwards for 10-15 feet before it slowly returns to neutral

 

[willie59]

Sorry about the delay in reply dsinclair88, I've been on vacation. Since it seems the drive neutral is good, I'd disconnect the shock dampeners from the drive link bars and see what it does.

 

[Hawk-57]

Love your replies and advice. Just got an 873 Bobcat, hard tire that creeps. The difference in this one is there are hydraulic hoses that connect to a "T" on top of the centering plate. Managed to get it turned but not off. Is it necessary to open the hydraulic system and remove the hoses in order to repair the pintle arms, bushings and such? Also I read about the zip ties and it occurred to me that you can remove the nut on the spring and after it comes off just take it your vise and then add the zip ties. No need to try and fish them through while it is on the machine. Also at the end of the coupling arms where the control handles are there are bushing connecting the rotating shaft that couples the handles to the flat plates. Mine are worn out. Can they be replaced on the machine or must the whole assembly be removed first?
Thanks

 

[willie59]

Welcome to HEF Hawk-57. :drinkup

Yeah, it's been some time now, but I've worked on one of those that have the big T pipe going right up through the middle of the centering plate. Seems I recall that if all you need to do is work on the pintle arms, you can lift the centering plate up and move it around on the pipe enough to do the work, a bit of a pain to do though with the plate in your way, but can be done.

Your 873, does it have the hyd tank up high behind the seat, or is it in the belly of the machine?

 

[Axel]

Time for an update to this thread. One common problem with Bobcat drive pumps is leaking seals on the pump control shafts. It's an easy fix, doesn't require drive pump removal or major disassembly. If you happen to be in there doing repairs to the pintle arms or drive centering and you see leakage of the pump shaft seals, you should consider replacing the seals while you have things apart. This one is on a T200 track machine.

Once you have the drive centering plate and pintle arm removed, simply remove the 4 bolts that mount the centering plate guide bracket.


View attachment 76323


Remove the guide bracket, you'll then be looking at the seal plate.


View attachment 76321


Lift the seal plate off of the pump.


View attachment 76324


There's the lip seal you need to replace.


View attachment 76320


There's also a ring seal that seals the shaft seal plate and pump housing. Some models use an o-ring seal, others use a square cut lathe ring seal, you're Bobcat dealer may ask which one your machine uses, so you might want to get a peek and see which one you have before you order/pickup your parts.


View attachment 76322


One thing to keep in mind, there's going to be some oil leaking out when you remove the seal plate. On this one I wasn't terribly concerned because it has already made an oily mess in the area. But for one that's just seeping oil, and you don't want to make a big mess, keep the hose from your suck bucket evacuating the oil from the area while you have the plate off and are replacing the seal in the seal plate.

Also, be sure and polish the pump control shaft with fine emory cloth to remove rust or roughness of shaft before re-installing the seal plate. Use your suck bucket to remove the rusty oil caused by cleaning the shaft.

does the fluid leak continuously while the seal plate is out? Will I need to work quickly?

 

[willie59]

It depends on the machine model Axel. Older models that have the hyd tank mounted high behind the operators seat will leak more, later models that have the hyd tank mounted in the belly of the machine will be less, but it's all workable. And the leakage/flow can be beneficial to a degree. When you take these components apart you expose them to dirt/debris. This leakage actually helps flush that debris and prevent it from entering the hyd system. It's all good. But do prepare, have everything ready to do the repair in an expedited manner to keep oil loss (mess) to a minimum.

 

[Axel]

Thanks,
Yeah mine has the tank mounted high.
What would you recommend as the BEST oil to replace the bobcat brand stuff?
My bobcat is an 863F. what do you think about Mobil DTE 10 Excel 46 or Napa aw32?
Are they both antifoaming? for now I just plan to fill up but would like to do a total fluid change soon since I'm guessing it's a cocktail in there.

 

[willie59]

I'm not familiar with the Mobil DTE 10 oil, don't know the specs, but the AW46 or AW32 should work just fine. I've been using AW46 oil for years with no issues.

 

[Axel]

spoke with someone at NAPA.
He informed me that the Bobcat oil is actually a fancier version of regular AW46 (with antifoaming and other features)

He then told me that they have an equivalent to the bobcat stuff, PREMIUM HEAVY DUTY TRACTOR & TRANSMISSION FLUID which sells as NAPA part #85405 $49.99 for 5 gallons
they also have a cheaper one that's $2 less

After replacing the seals on the pump control shafts will I need to recalibrate anything?

 

[willie59]

After replacing the seals on the pump control shafts will I need to recalibrate anything?

If it's a standard control machine the only thing you might have to adjust would be a slight creep as things typically don't go back together exactly as they came apart. I'm guessing a 763F has aluminum pintle arms, a littly more tricky to adjust than the two piece steel pintle arms.

 

[Axel]

it's an 863F
it does have aluminum linkage with ball joints, not sure if the pintle arms are aluminum I'll have to check