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Noma/Murray won't turn right, skipping over gear

#1

M

mstar

Noma/Murray A4012-110(12 HP Briggs and Stratton 4 wheel steer is not turning right. It got harder to make sharp turns either left or right. One day I put more fixed and the wheel jumped the teeth so the steering wheel was upside down . I forced back but it was never the same.
Wheel but pointing perfect straight.

I can turn right slightly but then the wheel clicks past the steering gear.

Is there a process to Align and fix?

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#2

R

Rivets

If your steering gear is jumping over the sector gear, I would be checking this gears and the bushings. I'm will to bet one or all are bad.


#3

M

mstar

Thanks
What should I be looking for and how do you replace? That is, what makes sure it is in the proper place? I dont know much about it.


#4

R

Rivets

Look to see if the teeth on the gears are worn and if you have side to side play on the shaft. Trying to explain how to replace these parts is not something I can do on this forum. Every manufacturer does it a little different on set up. There are no service manuals for these units, so you will have to look at your parts diagram and the unit to see how to disassemble. I can tell you that you will have to more than likely remove the steering wheel and raise the steering shaft.


#5

M

mstar

Thanks,
I did included a parts diagram but it is not high on detail so I dont know what is involved in changing those parts so would like a general idea if they are pressed on or just pull off?


#6

R

Rivets

Sir, the parts diagram you included is a very good one, if you have the mechanical experience to do this job. You will look closely the sector gear is bolted to the frame with bushings. Steering gear is pinned to the steering shaft. Bearing is mounted at the end of the steering shaft. If you can't understand what I am saying, please do not attempt this repair.


#7

M

mstar

I have mechanic experience on autos. I am trying to learn what is involved as that diagram is detailed but not detailed resolution wise if you never saw the parts before.
Many parts can be hard to find on this model.

Just because you are familiar with the parts and it seems obvious to you, does not mean every who is not familiar can't handle the job. You don't start out knowing everything and sometimes you learn on the go. Pros sharing there knowledge helps the learning curve and helps avoid common mistakes.

Changing parts is one thing How it relates to the turn geometry is another and I was also asking about that.

I was having a hard time turning the wheel probably due to the inside of the tires rubbing. On the tractor when turning.
The caused me to turn hard and I guess I made it jump which put it out of alignment making it harder to turn.
I am not sure how the 4 wheel steering relates to putting it back together with new parts. I am sure it complicated things. I am sure the tires are rubbing for some other reason.
I had replaced the plastic bushings and there seems to be more wiggle that the tip over enough to rub. I had also picked up a used set of front tires that are listed as same size from a John Deere and I had a shop swap the wheels. The tire seemed to bulge out more than the original with same specs.

I probably should have looked into this sooner as now it is multiple issues.

BTW, that pin on the steering if fused in I will have to drill it out .
So before I started fighting things I am trying to figure out what is involved and the procedures to makes sure the problem is fixed properly.

Thanks


#8

M

mstar

I guess the attached image I found in my manual should have suggested first.
I am confused on the arrows pointing to mounting screws but the directions stating to loosen the lower bearing. re they saying to loosen those as well?
IMG_20170724_111006.jpg


#9

B

bertsmobile1

Well I had never worked on one of these either till mid last year and I did not have the luxury of an exploded parts listing.
If it is too small, scan it into your computer and print it out larger.
If it is still confusing draw over the lines with coloured pencils to make it clearer.
They were very expensive mowers, down here about the same price as a family sized 6 cylinder car so not a lot of them around.
A fairly simple operation but a lot of bits that could be giving you grief from worn out bush through to a bent tie rod or loose tie rod end.
We are here , you are there and you have the real thing in front of you.
There is a dozen or more bits that can be causing your steering problems and the biggest one is it is an obsolete mower so there is a very limited supply of spares.
I spent around 3 months working on that mower as I had to make all of the NLA bushes.

I do a lot of mowers so some time I get a bit fuzzy but from memory we took the rear body work off of that one to get better access.
And of course, don't forget to take lots & lots of photos.
Expect every pin to be rusted in solid, all of mine were and to add to that there were some dodgy welds including over the top of one of the roll pins.
A real PIA job, but the owner is a really nice bloke and under treatment for Hep C so was very ill at the time + had not worked for 3 years so had no money either.


#10

M

mstar

That is interesting. They were pretty low cost up here in NJ sold through AGWAY farm supply, and the mower repair place had an older guy who would keep telling me it was not made to last that long.

Seeing that allot has never been touched as far as maintenance, the steering has never been adjusted and maybe I will get lucky it just needs to be tightened,

But again, I ask, what is the process to put things right? I am assume both front and back wheels should turned straight. On one post for a different machine , someone was advising to make sure there was an even amount of teeth on each side of something.
What are the signs the bearing is worn? What should I be looking for? There is a play in that steering error and I was not sure what was normal. Advice like that is helpful. Thanks

bertsmobile1 said:
Well I had never worked on one of these either till mid last year and I did not have the luxury of an exploded parts listing.

They were very expensive mowers, down here about the same price as a family sized 6 cylinder car so not a lot of them around.
Click to expand...


#11

B

bertsmobile1

The pins 51 & 45 will both be roll pins and you will not be able to drill them out they have to be punched or pressed.
I use cheap pin punches m machined down to the size of the hole in the middle and the outer diameter then a G clamp to press them out.
Your skipping is because the gear on the shaft shown in the last image is not meshing properly with the fan gear part # 47 and usually it is because the bearing at the bottom of the shaft has worn allowing the gear to move just enough so that the teeth skip.
When you have it off generally there is a hole that had nothing in it.
That is the index hole and it will align with another hole when the gear is directly ahead.
This is a good mower as all of the drag linkages have adjustable tie rod ends so you set the fan gear to strait, set the steering wheel to strait, engage them then adjust the drag links to give you the correct toe in and the rear wheels to be strait ahead.
If the tie rod ends are really loose they might need replacing but luckily they are standard engineering parts available from engineering supply shops & most farm shops.

Grab the fan gear, if you can move it back & forth then it's pivot hole is flogged out oval or the pivot pin # 49 is worn oval & it will need to be repaired.

The steering gears are awkward to get at so no one ever lubes them thus they wear.
The one I did was branded Husqvarna so had a different bady and a stronger front end but the rest was the same .


#12

M

mstar

This is helpful for diagnosis. Why would it turn left, center and only a slight turn to the right? If it was worn wouldn't both directions skip?


#13

B

bertsmobile1

Strait physics.
because there is a single rod connecting the fan gear to the wheels, the fan gear pushes it to turn one way and pulls it to turn the other way
So one direction the gears get forced together and the other direction they get pulled apart


#14

M

mstar

Update
So for the most part it was that an adjustment was needed as the teeth were barley meshing. I loosened the two nuts from underneath on the lower bearing and pushed it tight to the fan gears as instructed..
I do have up and down play if I push on the bottom of the shaft. How much play is too much. It lifts the plastic upper bearing (42 on diagram) out of the frame hole and the corrosion seems to hold it up there.

I tried to make all wheels and steering wheel straight but something is still off. At first the back wheels to the right still would not turn even when the front wheels were turned all the way.
IT would turn to the right and theback wheel turned a little.For some reason I kept going in circles a few times in one direction then the other and then the real wheels started to turn on both sides.
It does steer much easier but there still is tension that I am not sure is normal, since it not power steering or if there is still an issue.

What happens is that small movements the wheel has easy in either direction But if going to make a sharp turn more effort is needed but something strange is happening. If I turn right tight it works but if I go to turn a hard left, it takes a little extra strength to get it to fully turn. Then after if has gone that hard left, it seems to stay easier to turn into that hard left but if I now switch to a hard right, there is a point the front wheels are turned but takes an extra push of strength to get something to switch over to get that back wheel to fully turn.


I wonder how the back wheels could have not turned and then just started turning even though I did not touch the back end. If something is loosening up, then I wonder if there is a way to get them moving smoother.

The steering wheel has a little left to right play. I did see the fan gear is moving when this is happening but not enough to make the wheels do much.
I would like to know how much up and down play that bearing normally has?
I am betting it is still out of alignment.

Someone mentioned the tire rods. I had wondered about how one tells if they are overly worn, They are wobbly in that I can wiggle the rod and there is play.


#15

M

mstar

This is a vid of the steering before I adjusted the bearing tighter to the fan gear. The up an down play is still the same and I don't know what is normal. It is no longer skipping out over the fan gear.
https://youtu.be/Yi_K71TnR14


#16

B

bertsmobile1

mstar said:
Update
So for the most part it was that an adjustment was needed as the teeth were barley meshing. I loosened the two nuts from underneath on the lower bearing and pushed it tight to the fan gears as instructed..
I do have up and down play if I push on the bottom of the shaft. How much play is too much. It lifts the plastic upper bearing (42 on diagram) out of the frame hole and the corrosion seems to hold it up there.

I tried to make all wheels and steering wheel straight but something is still off. At first the back wheels to the right still would not turn even when the front wheels were turned all the way.
IT would turn to the right and theback wheel turned a little.For some reason I kept going in circles a few times in one direction then the other and then the real wheels started to turn on both sides.
It does steer much easier but there still is tension that I am not sure is normal, since it not power steering or if there is still an issue.

What happens is that small movements the wheel has easy in either direction But if going to make a sharp turn more effort is needed but something strange is happening. If I turn right tight it works but if I go to turn a hard left, it takes a little extra strength to get it to fully turn. Then after if has gone that hard left, it seems to stay easier to turn into that hard left but if I now switch to a hard right, there is a point the front wheels are turned but takes an extra push of strength to get something to switch over to get that back wheel to fully turn.


I wonder how the back wheels could have not turned and then just started turning even though I did not touch the back end. If something is loosening up, then I wonder if there is a way to get them moving smoother.

The steering wheel has a little left to right play. I did see the fan gear is moving when this is happening but not enough to make the wheels do much.
I would like to know how much up and down play that bearing normally has?
I am betting it is still out of alignment.

Someone mentioned the tire rods. I had wondered about how one tells if they are overly worn, They are wobbly in that I can wiggle the rod and there is play.
Click to expand...

Before you shifted the steering gear did you centralise the fan gear by turning the front wheels strait ?
Remember it has skipped a few teeth so will be in the wrong position.


#17

M

mstar

Yes,
I counted teeth on each side and it seemed to be the same


#18

M

mstar

Does this up an down play normal?
https://youtu.be/Yi_K71TnR14


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