Sundstrand In-Line Hydro Purchase

[bc.gold 3,403]

Not exactly earth shattering news, purchased a sundstrand with the disclaimer from the seller that the unit was once locked up and that he managed to free it up with a large wrench. Then the hydro was shelved until, well it arrived in the mail this morning.

 

I've disassembled the unit, the major problem was a broken shear pin on the charge pump and this was what kept the pump from turning over. The broken pieces were some how binding.

 

Second issue is that the transaxle had admitted water into the system this is evident from the oil residue left inside the hydro along with a bit of rust. The point I'm trying to make is that we should change the hydraulic oil or at lease do a crackle test to see if any moisture is present.

 

A single drop of oil from the dip stick is enough for the crackle test.

 

When the input shaft is spun by hand the bearing emits a noise indicating a bearing replacement is required, I use the numbers from the OEM bearings and order bearings from a bearing supply in Brandon who are able to cross reference the numbers. I'm sure that you'll have a supplier that specialises in bearings nearby.

 

I have a source in Winnipeg for the gasket set.

 

When the seller told me the hydro was at one time locked I was expecting much worse, I'm pleased with my purchase and looking forward to getting my ( other ) Allis 720 mobile.

 

 

 

Edited October 12, 2018 by bcgold

[oliver2-44 9,873]

Kep us posted with pictures as you replace the bearings and all.

[bc.gold 3,403]

13 minutes ago, oliver2-44 said:

Kep us posted with pictures as you replace the bearings and all.

 

Will do, for starters the seal on the left is SKF 7443 used for input shaft, the pair to the right used on trunnion shaft these were removed from the box's that I no longer have the numbers for.

 

Any decent shop will take measurements from your old seals just be sure to inform them they're for hydraulic use.

 

[bc.gold 3,403]

Rather than have post that runs on I'm going to comment on each of the parts needing attention.

 

In the box list below I think the large bearing for the pinon still has to be ordered, I did not open the box's so as not to get the bearings mixed with old parts.

 

[bc.gold 3,403]

The charge pump on the small gear you can see the slots for the drive pin that broke, with the pin broke your 3 point will not lift tractor will not move or only slightly if the broken pin has wedged, There is a pressure port to test to see if the charge pump is operational.

 

Ths pump on inspection looks good, no wear on the faces or on the case, if there were I suspect you would have to replace both gears and the front cover and may have to resurface the face of the hydro case.

 

The gears are case hardened so I don't think surface grinding them is an option.

[bc.gold 3,403]

This is the pump assembly it looks identical to the motor assembly do not mix them up, they both have a spring in the center to keep the piston slippers preloaded against the valve plate.

 

Also there's two valve plates that look identical, the one shown below is from the pump.

 

This valve plate has some damage and needs lapped, hopefully I can get that score lapped out and stay within OEM specs.

 

 

 

 

 

 

Edited October 12, 2018 by bcgold

[bc.gold 3,403]

In this center section two needle type bearings are used and each bearing protrude from the face just enough to secure the valve plate in position also take note of the pin this is used to key they valve plate into its proper position.

 

In the bottom image the valve plate is hanging from the bearing protrusion.

 

Top image at the 6 o'clock position the dowel pin, just below that two o-rings. 

 

 

[bc.gold 3,403]

On the collar of the pinon housing there are some numbers stamped into the housing, in the repair manual is a chart that tells you by that number how many shims are required for the pinon gear.

 

If you order your replacement bearing for the output shaft from a bearing supplier this bearing will have dust shields as shipped from the factory you'll have to remove them.

 

The bearing as used by Simplicity allows hydraulic oil to flow freely through that bearing back into the transmission case, helps to keep the bearing cool and free from debris any junk is captured in the filter. I did not notice if a magnet was installed inside the transmission anywhere. 

 

 

 

Edited October 12, 2018 by bcgold

[bc.gold 3,403]

The swash plate used for motion control has to be positioned  when looking down at it dead flat, one side uses two short roll pins with a longer one at the other end.

 

When the case was cast they allowed for a pocket to accept the longer roll pin during removal. When reassembling make sure to install the short and long pins on the same place they came out of. Or the nextr guy to work on the hydro is going to have some very unkind words for ya, Your ears will be burning.

 

As for installing a bearing that in my opinion is fairly straight forward.

 

Installing the seals make sure all the grit and rust is removed and a little bit of grease to lube the shaft helps

 

I'll have to ask admin or one pf  the mods for access to the joke section before commenting further.

[bc.gold 3,403]

Final polish on valve plates and shaft surfaces, crocus cloth comes in sheet and rolls. WHen working on flat pieces I use a heavy sheet of glass for backing and work the piece in a figure eight motion turning the part every so often.

 

Fine grain crocus cloth in an endless belt in a hand held electric unit is used to polish crankshaft journals, the video below shows an alternative for the do it yourselfer.

 

Last video, hand lapping.

 

 

 

Edited October 12, 2018 by bcgold

[bc.gold 3,403]

Gauge Blocks for entertainment.

 

 

[Machineguy 877]

Good DIY tech here! Thanks for sharing! 

[bc.gold 3,403]

Springs 2,6 and 10 weaken over the years and should be replaced.

 

You could boost the implement pressure by adding shims number 4, do so at your own risk IMO better to replace the spring with a genuine Sundstrand part to improve performance.

 

Edited October 12, 2018 by bcgold

[bc.gold 3,403]

Wear limits and torque specifications 

 

 

[bc.gold 3,403]

Using the pressure gauge.

 

[bc.gold 3,403]

On 10/11/2018 at 11:35 PM, bcgold said:

On the collar of the pinon housing there are some numbers stamped into the housing, in the repair manual is a chart that tells you by that number how many shims are required for the pinon gear.

 

If you order your replacement bearing for the output shaft from a bearing supplier this bearing will have dust shields as shipped from the factory you'll have to remove them.

 

The bearing as used by Simplicity allows hydraulic oil to flow freely through that bearing back into the transmission case, helps to keep the bearing cool and free from debris any junk is captured in the filter. I did not notice if a magnet was installed inside the transmission anywhere. 

 

 

 

 

Chart numbers listed on the left would be found on the tag attached to the hydrostatic collar numbers stamped into the case are at the top of the scale.

 

The shims go between the bearing and the backside of the pinion gear, the shims make corrections for gear backlash. Installing a different hydro from the original may require that you install the hydro then measure the tooth pattern and backlash. May require several tries before you get it right.

 

Edited October 14, 2018 by bcgold

[bc.gold 3,403]

Lots of grit.

 

If the thrust washer looks as bad as this one you can flip it over for a fresh side.

 

This is the motor end, the fixed swash plate comes in various degrees of angle, steeper the grade more piston travel = speed. Less angle would give your tractor more pulling or pushing power but less top end for speed.

 

Edited October 14, 2018 by bcgold

[bc.gold 3,403]

Clamping the input shaft to remove pinion gear, replace bearing part number NACHI 6304, don't forget to remove the dust seals.

 

Housing is in the oven warming up, bearing and input shaft in the freezer, the bore in the housing is machined for a shrink fit.

 

 

 

Edited October 14, 2018 by bcgold

[bc.gold 3,403]

For assembly find something that will hold and support the hydro in an upright position.

 

[bc.gold 3,403]

Hydro is completed and ready to install.

 

Edited October 15, 2018 by bcgold

[bc.gold 3,403]

The small pucks labeled as number ( 4 ) are used to make adjustments, Implement ports.

 

[bc.gold 3,403]

Before the introduction of the SAE ( Society of Automotive Engineering ) parts were hand made in other words if you needed a water pump it had to be specially fitted to your particular engine.

 

The SAE set standards, you could now buy a water pump off the shelf or pick one off a donor knowing that it would be a straight over swap.

 

Exchanging one hydro for another without making the proper shim correction you could end up with an improper backlash with the pinion drive gear being to tight of loose. Ending up with premature wear.

 

Using the numbers stamped into the transaxle and hydro the chart below tells me that I'll need an 0.045" shim or a combination of shims.

 

 

 

 

Edited October 16, 2018 by bcgold

[Machineguy 877]

@bcgold

 

Thanks for all all the tips and procedures! Great stuff! 

[bc.gold 3,403]

If your replacing the pinion drive gear measure the thickness of the old one, my replacement was 0.006 thinner than the original and required shims to make corrections for backlash.

 

Also make sure your pinion bearing is properly seated.

Edited October 19, 2018 by bcgold