Page 1 of 8 12345 ... LastLast
Results 1 to 15 of 113

Thread: Repairing creeping Bobcat

  1. #1
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894

    Repairing creeping Bobcat

    Well, time for another Bobcat thread. (shut up turbo21835) Bah ha ha ha

    Ok, I'm seeing way too much of this on Bobcat machines lately, Bobcat has changed a component on the drive neutral centering device, they must be using some cheap steel or something. You don't typically see this on the older BC machines, I've got a 753 in the shop right now that looks like the original components and they don't have the wear the newer machine components have. What am I talking about? Let me get the centering plate off and you'll see it.

    Name:  T190 drive neutral plate 001.jpg
Views: 14937
Size:  110.6 KB

    Caution; before you make any repairs or adjustments to the drive centering device on a Bobcat, the first thing you must do is get the machine off the ground on 4 stands. Don't trust just tilting the bucket forward and lifting front wheels, it could drift down. It must be on stands or sturdy blocks.

    First, you have to remove the centering spring. Now, there's a little trick to this. You can remove it quite easily. But then putting it back on is a bit of a problem because you have to compress the spring to start the nut on the long center bolt, you only have two hands and no room for a helper in there.

    Here's a solution that works well for me. Thread a good quality zip tie under spring, at least two (three is even more durable) zips.

    Name:  T190 drive neutral plate 002.jpg
Views: 14416
Size:  161.7 KB

    Move one of the drive levers just slightly off center to compress spring just a little, then zip the ties.

    Name:  T190 drive neutral plate 003.jpg
Views: 14296
Size:  145.4 KB

    Now you can remove the center bolt/nut, and you have a handy caged spring that's ready for re-install.

    Name:  T190 drive neutral plate 004.jpg
Views: 14312
Size:  169.8 KB

    Name:  T190 drive neutral plate 007.jpg
Views: 14214
Size:  157.4 KB

    continued...
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  2. #2
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    Once the centering spring is removed, you just simply lift the centering plate off and you'll see the pintle arms that control the pump shafts. Now you can see the problem, the wear on those two centering spools bolted on the pintle arms. I'm seeing these worn spools more and more on newer model machines. We own an S185 that's just a little over a year old, about 800 hrs on it, and these spools have been replaced twice. Once this wear occurs, the pintle arm isn't being held in neutral position and will cause the machine to creep.

    Name:  T190 drive neutral plate 005.jpg
Views: 14187
Size:  147.4 KB

    The spools have a 3/8" hex key hole in the top of them, and are fastened to the pintle arms by a hex head bolt from underneath. And there's not enough room to get even a short socket under the pintle arm to grab head of bolt. Additionally, the bolt head is in a recess, can't even grip enough of the bolt head with the open end of a wrench. More brilliant Bobcat design.

    Name:  T190 drive neutral plate 008.jpg
Views: 14231
Size:  131.7 KB

    I have a 9/16" S-K wrench that has just enough protrusion on box end of wrench to grip just enough of the bolt head to pop spool loose with allen head socket on spool. All you have to do is break the spool loose, give it a half turn to clean metal, and lock it down. But I remove the spool and install a split ring lock washer on the bolt for a spacer, that makes getting a hold of the bolt head much easier. Here's one of thespools and bolt.

    Name:  T190 drive neutral plate 006.jpg
Views: 14057
Size:  143.1 KB

    Turn both spools on the two pintle arms around to fresh metal. And while your in there, be sure and check the bolt that locks pintle arm to pump shaft, that bolt needs to be tight.

    Name:  T190 drive neutral plate 011.jpg
Views: 14041
Size:  153.1 KB

    The steel bars bolted to the centering plate are going to be worn as well, simply remove the fastening bolts of the bars, flip the bars around, and bolt them back on. The bolt holes on right bar are round, the holes for the left bar are slotted. Lock down the bolts in the right bar, but leave the ones in the slotted holes for left bar loose to make adjustment.

    Name:  T190 drive neutral plate 012.jpg
Views: 14004
Size:  148.0 KB

    continued...
    Last edited by willie59; 08-28-2010 at 08:00 PM.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  3. #3
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    Here's the left pintle arm with the spools turned around. Notice the two 3/8" bolts that fasten the pintle arm to the pump control arm. The bolt that's in between the two spools goes through a round hole and screws into the pump control shaft. The bolt to the right of spools goes through a slotted hole and fastens to the end of pump control arm. This is how drive centering adjustment is done using the allen head screw on front of pintle arm. We'll go over that in a few minutes.

    Name:  T190 drive neutral plate 015.jpg
Views: 13991
Size:  139.0 KB

    Now we have spools and bars flipped around, simply fit the centering plate in place, and re-install that handily caged centering spring.

    Name:  T190 drive neutral plate 016.jpg
Views: 13944
Size:  169.3 KB

    The centering bar to the right is set because we locked the bolts down on it. Now we need to set the left centering bar. Make sure the left pintle arm is in centerline with right pintle arm as best you can as it will move fore and aft. Just slightly set bolts for left centering bar in slotted holes.

    Name:  T190 drive neutral plate 017.jpg
Views: 13932
Size:  143.4 KB

    Tap the side of the bolt heads to move centering bar toward spools until it contacts spools. Give the bolt heads a bit more lock down.

    Name:  T190 drive neutral plate 018.jpg
Views: 13836
Size:  138.6 KB

    Grasp the machine right side drive lever that you use to drive the machine and move it gently fwd and rev, checking for any movement of the pintle arm. There should be no looseness of the pintle arm spools contacting the centering bars. If there is, loosen front bolt, move the drive operating lever slightly in reverse direction, and tap the front centering bar bolt with hammer to move it closer to the spool on pintle arm, lock bolt again. If you adjust too far, you will cause looseness of opposite centering bar on right side of centering plate, the side with holes that don't adjust. Once you get no looseness of either drive lever, firmly lock down bolts for centering bars and re-check that nothing moved during torquing bolts.

    Name:  T190 drive neutral plate 019.jpg
Views: 13820
Size:  167.9 KB

    continued...
    Last edited by willie59; 08-28-2010 at 08:03 PM.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  4. #4
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    Now, let the cab down, plant yourself in the seat, and start the machine. It may try and move one of the drives because final ajustment is yet to be done. You may have to hold one or both of the levers pushed or pulled slightly to neutral the pumps until you get the engine running and brake lock released. This is why you have to have machine on stands or blocks. Once you get it running and brake lock released, raise the cab back up. You'll more than likely have at least one side, or both sides, creeping a bit. To adjust and get drive neutral, slightly loosen bolt in pump shaft.

    Name:  T190 drive neutral plate 020.jpg
Views: 13888
Size:  160.1 KB

    Loosen bolt in pump control arm in slotted hole.

    Name:  T190 drive neutral plate 021.jpg
Views: 13729
Size:  141.7 KB

    Turn the adjusting screw CCW (screwing out) until that side creeps in reverse. Slightly tension the two bolts.

    Name:  T190 drive neutral plate 022.jpg
Views: 13735
Size:  153.7 KB

    Crank the adjusting screw CW (screwing in) with allen wrench until that drive finds neutral. Lock down bolts. Some movement may occur during lock down, you may have to tweak a bit more.

    Name:  T190 drive neutral plate 023.jpg
Views: 13680
Size:  139.4 KB

    If you adjust too far and get forward creep, you have to regroup and do it over again. Once you get neutral on both drives your good to go. On older machines that have aluminum pintle arms, the adjusting procedure is a bit different. I should be repairing the drive centering on the 753 with aluminum arms this coming week, hopefully will be able to follow up on those repairs at this thread.
    Last edited by willie59; 08-28-2010 at 07:57 PM.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  5. #5
    Junior Member
    Join Date
    Jul 2010
    Location
    manitoba
    Posts
    28
    looks like fun lol

  6. #6
    Senior Member frogfarmer's Avatar
    Join Date
    Aug 2010
    Location
    South East Missouri
    Posts
    234
    This is a simple adjustment operators should insist be done. There is no substitute for safety.

  7. #7
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    Now a little info about the older machines with aluminum pintle arms. Got in the cab of the 753 customer had dropped off and it was all over the place. I knew immediately that the clamping bolt for the right drive pintle arm had come loose. Well, here's the belly of the beast. Pretty much the same thing as on the T190, cage the centering spring with cable ties, remove centering spring, then lift neutral centering plate off. On this model, more difficult to get to the centering spring, had hoses and stuff in the way. Grrrrrr.

    Name:  Bobcat 753 drive neutral plate 001.jpg
Views: 14773
Size:  196.0 KB

    Centering plate removed, the pintle arm on the left is the one the clamping bolt that holds arm tight on pump shaft came loose allowing pintle arm to wallow all over and couldn't control pump shaft movement. These machines drive nutty when they come loose. Notice the difference in the spools on the aluminum arm models as opposed to the spools that wear on the T190 mentioned earlier. These spools actually look like a chromed steel.

    Name:  Bobcat 753 drive neutral plate 002.jpg
Views: 13881
Size:  191.1 KB

    Minimal wear on spools as well as centering bars.

    Name:  Bobcat 753 drive neutral plate 003.jpg
Views: 13476
Size:  164.5 KB

    Name:  Bobcat 753 drive neutral plate 004.jpg
Views: 13504
Size:  126.1 KB

    Two new pintle arms. One from being worn by loose clamping bolt, other had excessive wear where rubber torsion bushing goes. Install new torsion bushings, installed old but still good spools on new arms, rotated them around to fresh steel, and rotated centering bars on centering plate.

    Name:  Bobcat 753 drive neutral plate 005.jpg
Views: 14043
Size:  153.1 KB

    I should offer an installation note whenever perfoming repairs to Bobcat drive linkages. Whenever you remove the bolt that attaches drive link to pintle arm via the rubber torsion bushing, when you go to re-install the torsion bushing bolt you must have the pintle arm near the neutral position. Once the bolt is tight, moving the machine drive lever fwd and rev actually twists the rubber of the torsion bushing. Point is, if you had the machine drive lever and pintle arm all the way forward and installed the torsion bushing bolt and locked it down, then when you pulled back the drive lever, it would simply try to go back foward like a spring was pulling it. That's from twisting the rubber of torsion bushing. Always have pintle arms in line with each other when installing torsion bushing bolts.

    continued...
    Last edited by willie59; 09-02-2010 at 08:04 PM.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  8. #8
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    Now the main difference between the aluminum arms and two piece steel pintle arm, there's no centering adjusting screw like on the steel arms. The drive centering adjustments are done solely on the centering plate. Notice the holes on the centering plate that mount the centering bars. The holes on the left (for right side drive) are both slotted. The holes on the right (left drive) has one hole slotted and one plain round hole. That's where adjusting begins, the round hole is the pivot point and the slotted hole is the adjusting point for left side drive. Mount the centering bar to the plate with round hole bolt, then mount opposite end bolt in the mid point of slotted hole, lighty lock down bolts. Install opposite centering bar with two slotted holes, push bar away from other centering bar and lightly lock bolts.

    Name:  Bobcat 753 drive neutral plate 006.jpg
Views: 13532
Size:  134.3 KB

    Fit centering plate onto guide pins, re-install centering spring. Now we can start adjusting. Again, you must have machine on stands or sturdy blocks, wheels off ground. Start machine and release parking brake lock. Adjust left side drive first. If there's no creep of left drive wheels, lock down the bolts for that centering bar. If there is creep of left drive, put a little light torque on round hole pivot bolt.

    Name:  Bobcat 753 drive neutral plate 007.jpg
Views: 13885
Size:  176.7 KB

    Have a little tension on the slotted hole bolt. Move left side drive lever to reverse drive to seperate spool from the centering bar at that bolt, tap the side of the head of the slotted hole bolt in the direction needed to achieve neutral. Once neutral is achieved, start torquing the bolts, keep moving drive lever in fwd and rev while torquing and checking that neutral is good. Once you get neutral, lock bolts tight.

    Name:  Bobcat 753 drive neutral plate 008.jpg
Views: 13435
Size:  190.5 KB

    Now that you have the left side drive set and not creeping, it's time to adjust the right side drive. Since they are all the way left in there slots, there's going to be considerable movement of the machine drive lever. With the right machine drive lever holding the right wheels in neutral position, or close as you can, loosen the bolts in the centering bar and move it to the right in the slotted holes until centering bar is against the spools of pintle lever, lightly torque bolts. Adjust the two bolts to achieve drive neutral for right side drive, making sure the centering bar is contacting the spools, you can't have any slack between bar and spool contact or it will creep, but you have to make sure the adjustments on that side don't cause slack for the opposite side drive. Once you get right side drive neutral, lock bolts down tight. Move both drive levers in fwd and rev and make sure there is no drive creep.

    Name:  Bobcat 753 drive neutral plate 009.jpg
Views: 13248
Size:  169.6 KB
    Last edited by willie59; 09-02-2010 at 08:07 PM.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  9. #9
    Member
    Join Date
    Jul 2010
    Location
    Alabama
    Posts
    34
    Excellent tutorial. Thanks ATCO!

  10. #10
    Junior Member
    Join Date
    Sep 2010
    Location
    85929
    Posts
    5

    creeping bobcat

    Very well detailed reply with pictures-I like it.

  11. #11
    Junior Member
    Join Date
    Oct 2009
    Location
    norther california
    Posts
    4

    ziptie!

    thanks so much for that trick.

  12. #12
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    I'm kinda hoping this info will help some machine owner do his own repairs instead of unloading the wallet to pay the big shop to do them.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  13. #13
    Junior Member
    Join Date
    Sep 2010
    Location
    oklahoma
    Posts
    15
    this is my third reply. Yeh! and i hope that when i finally get to ask a question this guy is around to give me an answer.

  14. #14
    Super Moderator willie59's Avatar
    Join Date
    Dec 2008
    Location
    Knoxville TN
    Posts
    9,894
    Quote Originally Posted by jean View Post
    this is my third reply. Yeh! and i hope that when i finally get to ask a question this guy is around to give me an answer.
    OMG...I hope I am too! LoL

    Welcome to the forum jean.
    A good mechanic isn't expensive, he's priceless!

    http://www.bluediamondattachments.com/

    Read Forum Rules Here

    Please don't respond to spammers...makes our job tougher mopping up their mess

  15. #15
    Probationary Member
    Join Date
    Oct 2010
    Location
    oregon
    Posts
    1

    863 creep adjustment

    Is the adjustment procedure basicly the same on the 773 and 863's. I have a 863 1999 vintage.

    thanks

Page 1 of 8 12345 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •