Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

QT16 Jerks In Forward Only


  • Please log in to reply
11 replies to this topic

#1 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 21, 2016 - 07:47 PM

Sundstrand Hydro. New oil and filter in the unit.  Unit is full, free wheeling valve is closed.  Going forward on a little pull it starts to jerk.  Level and down grade it works fine.  Can go in reverse full speed and it stays smooth as can be.  Only in forward on a pull.  I suspect a linkage problem some place but could not see any thing out of place or excess wear.  Any suggestions as to where to start looking for the problem?


  • MyBolens1053 said thank you

#2 EricFromPa ONLINE  

EricFromPa

    Tractorholic

  • Senior Member
  • Contributor
  • Member No: 2135
  • 2,287 Thanks
  • 2,326 posts
  • Location: Bedford County Pa.

Posted September 21, 2016 - 08:37 PM

Did you inspect the hubs? Might have sheered a key or split a hub.Could of sheered the key in the driveshaft coupler to.Doesn't take as much power to go in reverse and your other tire gets the power in reverse because of the Differential gears.

 

I would check for sheered keys 1st.Easy to do on the hubs.If the axle moves and the hub doesn't then the key is sheared.Will still move till it's gona slip as soon as it tries to put any real power down.


Edited by EricFromPa, September 21, 2016 - 08:38 PM.

  • Alc, boyscout862, MyBolens1053 and 1 other said thanks

#3 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 22, 2016 - 07:58 AM

Thanks Eric.  Never gave a thought to a sheered key, at the hub or the drive shaft.   Remove the fenders pan, chain it to a big post and put some power to it and see where it gives at.  There is always a reason one of these old tractors get parked.  Some are good reasons - and others are not so good.


  • Alc and MyBolens1053 have said thanks

#4 ClassicBolens ONLINE  

ClassicBolens
  • Senior Member
  • Member No: 48806
  • 946 Thanks
  • 375 posts
  • Location: IN

Posted September 22, 2016 - 12:38 PM

Check to make sure the frame rails have not cracked or broken, allowing the transaxle assembly to tilt forward. This was not too prevalent on the QS16 and QT16 tractors, but was a known issue on the QT17 tractors. Check all the linkages for any slop. Check the pedal for slop. May just have some worn bushings or linkage.
  • Bolens 1000, MyBolens1053 and chieffan have said thanks

#5 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 23, 2016 - 11:37 AM

Check to make sure the frame rails have not cracked or broken, allowing the transaxle assembly to tilt forward. This was not too prevalent on the QS16 and QT16 tractors, but was a known issue on the QT17 tractors. Check all the linkages for any slop. Check the pedal for slop. May just have some worn bushings or linkage.

I checked the frame early on and everything looked good.  All the linkage seems tight also.  Some was to tight and seized up but got that all free again.  Pedal is tight, takes very little movement to change speed or go from neutral to reverse or the other way.

 

From the parts breakdown I have it looks like one key must hold the brake disc and the hub to the axle.  At least it only shows the one key, 5/16 X 1-1/8".  The keys at both ends of the drive shaft were good when I replaced the engine about 2 running hours ago.  Pretty much brings it down to the hub keys :thumbs:  or internal problems  :mad2:   :(   :wallbanging:


Edited by chieffan, September 23, 2016 - 11:44 AM.

  • MyBolens1053 said thank you

#6 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 26, 2016 - 07:24 PM

Got the QT in the shop and removed the fender pan.  Cannot see any way of getting at the key on the rear axle without removing the hub and all.  I really don't think it is a key as it all feel tight as can be when up on the jack.  Jerking the wheel forward and back don't show any looseness anywhere.  Afraid it is going to end up being another hydro problem.


  • MyBolens1053 said thank you

#7 Hydrohusky OFFLINE  

Hydrohusky
  • Member
  • Member No: 48182
  • 36 Thanks
  • 36 posts
  • Location: Fox Point, WI

Posted September 27, 2016 - 01:41 PM

Upfront, I don't have any QT experience.  On tube frames there are 2 compression springs where the peddle control arm connects to the transmission control arm.  Rather than this connection being a hard/rigid connection, the springs provide play which when setup correctly smooth the transition from stop, forward, reverse etc.

 

Is it possible these springs are missing, have failed or are torque down incorrectly?


  • MyBolens1053 and chieffan have said thanks

#8 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 27, 2016 - 02:23 PM

I went back and looked at the parts diagram some more.  It show two extension springs in the linkage plates at the hydro.  I did not see them when I was looking the linkage over but will have to go back and look again now that I know where they are.  It does act like a spring type failure as it is a fairly rapid jerking, like a spring is not holding something in position and letting it move back and forth.  Make any sense?


  • MyBolens1053 said thank you

#9 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 27, 2016 - 05:03 PM

Checked the hubs and the springs.  Everything is fine and intact.  There is some end play in the rear axles though. Found nothing in the manuals that addresses this so guess it is normal.  Hubs and axles were solid to each other.  Drive shaft is not slipping either.  Running out of options.  Down to the hydro I guess.


  • MyBolens1053 said thank you

#10 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 28, 2016 - 07:46 AM

Not sure what the function of the "extension springs" is.  They appear to be original and rusty looking but still attached on both ends and do stretch some with forward pedal travel.  Wonder if those springs are week and allow the linkage to flutter some causing the jerking motion?  If that was the case, shouldn't it do it in reverse as well as level going?


  • MyBolens1053 said thank you

#11 Hydrohusky OFFLINE  

Hydrohusky
  • Member
  • Member No: 48182
  • 36 Thanks
  • 36 posts
  • Location: Fox Point, WI

Posted September 28, 2016 - 12:44 PM

I took a look a parts manual for a QT16 and determined the transmission linkage is very different from a Tube Frame.  So my sugestion doesn't appear to apply to your tractor.  I apologize.

 

The extension springs you mention are used on many hydrostatic packages, including tube frames.  The springs connect to the hydrostatic package neurtalizing arms.  These arms ensure the foot peddle is return to neutral if your foot comes off the pedal. It's a safety feature.

 

As others have suggested you potentially may have some binding in the linkage.  Other than that, I'm not sure how the package itself would cause the lunging unless the speed control arm or input shaft are somehow damaged.  If this were the case though the package would likely be leaking oil.

 

Last thought is the ring and pinion gears in the final drive are damaged or worn.


  • MyBolens1053 and chieffan have said thanks

#12 chieffan ONLINE  

chieffan
  • Senior Member
  • Contributor
  • Member No: 62695
  • 6,134 Thanks
  • 4,486 posts
  • Location: SW Iowa

Posted September 30, 2016 - 07:32 AM

I took a look a parts manual for a QT16 and determined the transmission linkage is very different from a Tube Frame.  So my sugestion doesn't appear to apply to your tractor.  I apologize.

 

The extension springs you mention are used on many hydrostatic packages, including tube frames.  The springs connect to the hydrostatic package neurtalizing arms.  These arms ensure the foot peddle is return to neutral if your foot comes off the pedal. It's a safety feature.

 

As others have suggested you potentially may have some binding in the linkage.  Other than that, I'm not sure how the package itself would cause the lunging unless the speed control arm or input shaft are somehow damaged.  If this were the case though the package would likely be leaking oil.

 

Last thought is the ring and pinion gears in the final drive are damaged or worn.

Parked the tractor back in the shed for the winter.  Think this is will be a spring project, which will involve checking out the gears in the rear end.  Seems like excess end play at the axles, moves about 3/16" in and out.  Don't think it should be that much but don't know for sure.  Tractor can keep the cub with a bad pump company this winter.






Top