MF 40 digger slew motor

Andyt880

Member
Livestock Farmer
Location
Co. Down
Would anyone have a workshop manual/ parts book for an MF 40 that shows an exploded diagram of the slew motor?
Back hoe will slew but doesn’t stop when you let go of the leaver or digging on a slope, it just falls on round. Presumably it needs seals in the slew motor. Would like a diagram before opening it up.
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Any tips for checking that it’s not the spool? I know it will free wheel both left and right, doesn’t seem to matter which way you slew it.
Hi Andy,

Hope the attached parts diagrams are of help. There are two types of slew motor fitted to a MF 40, depending on its age / serial no. Both are shown in the attached pdf doc.

I'm afraid you'll have to read across from one page to the next to work out how many of each component there are or which bit is which number on the diagrams ........ The Parts Book wouldn't flatten enough to scan properly.

As to whether it's the Slew Motor or the Spool Valve, will it actually slew under power? If so, it isn't the slew motor seals ..... if they are gone you won't be able to slew the digger arm with any force at all. Instead it is likely to be a Spool Valve problem.

I seem to remember that the 'Slew' spool valve slice has special pressure / cross-line relief valves in it to prevent the valve block being damaged due to the digger arm continuing to slew under its own momentum. Chances are something there has gone wrong. To discount this, try swapping the slew motor pipes onto a different valve slice & see if you still have the problem ....... but treat it gently & don't use it like that in anger (without the special relief valve in-circuit). If your problem goes away, it's the valve not the motor.

If the problem remains then you'll need to dismantle the motor. You MAY be able to get seals either from P.V. Dobson or Kellands Plant Sales in Bridgewater .... or from somewhere closer to home.

Good Luck!

Andy
 

Attachments

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Andyt880

Member
Livestock Farmer
Location
Co. Down
Hi Andy,

Hope the attached parts diagrams are of help. There are two types of slew motor fitted to a MF 40, depending on its age / serial no. Both are shown in the attached pdf doc.

I'm afraid you'll have to read across from one page to the next to work out how many of each component there are or which bit is which number on the diagrams ........ The Parts Book wouldn't flatten enough to scan properly.

As to whether it's the Slew Motor or the Spool Valve, will it actually slew under power? If so, it isn't the slew motor seals ..... if they are gone you won't be able to slew the digger arm with any force at all. Instead it is likely to be a Spool Valve problem.

I seem to remember that the 'Slew' spool valve slice has special pressure / cross-line relief valves in it to prevent the valve block being damaged due to the digger arm continuing to slew under its own momentum. Chances are something there has gone wrong. To discount this, try swapping the slew motor pipes onto a different valve slice & see if you still have the problem ....... but treat it gently & don't use it like that in anger (without the special relief valve in-circuit). If your problem goes away, it's the valve not the motor.

If the problem remains then you'll need to dismantle the motor. You MAY be able to get seals either from P.V. Dobson or Kellands Plant Sales in Bridgewater .... or from somewhere closer to home.

Good Luck!

Andy
Thank you very much @Captain Sensible. That’s a great help. The digger actually belongs to my uncle and I just asked the question for him. I’ll pass that info on and tell him to check if the slew has any force behind it or not before he starts stripping it.
Thanks again for that
 

Andyt880

Member
Livestock Farmer
Location
Co. Down
@Captain Sensible would you have any idea how to get the wing off the shaft. Took out the studs with heads on them but those other studs seem to be threaded into the shaft too but there is no head on them
 

Attachments

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essexpete

Member
Location
Essex
Try find two nuts of the correct thread and wind them on the stud then lock them together and wind out. At least that is what I seem to remember doing about 40 years ago.
 
@Captain Sensible would you have any idea how to get the wing off the shaft. Took out the studs with heads on them but those other studs seem to be threaded into the shaft too but there is no head on them
Sorry Andy,

I never had to go that far on mine. My problem were knackered seals around the top & bottom of the shaft ..... The top seal normally goes first because (at least with a MF 50/50B series), the shaft sticks out of the top cover plate & dirt & grit work on down around it & wear the shaft & seal.

One piece of advice here ...... if the top or bottom seals have worn a groove in the shaft, clean it up really well (mechanically & chemically) and fill the groove with good-quality body filler. Then sand down level with fine sandpaper. Provides a new running surface for the seal & lasts a good few years (well, mine has!).
 

jf850

Member
Location
Co laois
Sorry Andy,

I never had to go that far on mine. My problem were knackered seals around the top & bottom of the shaft ..... The top seal normally goes first because (at least with a MF 50/50B series), the shaft sticks out of the top cover plate & dirt & grit work on down around it & wear the shaft & seal.

One piece of advice here ...... if the top or bottom seals have worn a groove in the shaft, clean it up really well (mechanically & chemically) and fill the groove with good-quality body filler. Then sand down level with fine sandpaper. Provides a new running surface for the seal & lasts a good few years (well, mine has!).

I'd agree on your comment on the shaft being worn where the seal seats , caused by dirt getting in and sitting there .

There should be a "Top Hat " on top , which will keep out the dirt . It wasntnon my 50 , but have one on it now .

I was told to take off the top ringnof the slew motor , where the seal is fitted. Get another groove machined lower down , put a new seal there , leaving the old seal fitted still . It will catch the dirt , and the new seal will be working against a fresh surface.
 

Simon_F3

Member
Mixed Farmer
Hi Andy,

Hope the attached parts diagrams are of help. There are two types of slew motor fitted to a MF 40, depending on its age / serial no. Both are shown in the attached pdf doc.

I'm afraid you'll have to read across from one page to the next to work out how many of each component there are or which bit is which number on the diagrams ........ The Parts Book wouldn't flatten enough to scan properly.

As to whether it's the Slew Motor or the Spool Valve, will it actually slew under power? If so, it isn't the slew motor seals ..... if they are gone you won't be able to slew the digger arm with any force at all. Instead it is likely to be a Spool Valve problem.

I seem to remember that the 'Slew' spool valve slice has special pressure / cross-line relief valves in it to prevent the valve block being damaged due to the digger arm continuing to slew under its own momentum. Chances are something there has gone wrong. To discount this, try swapping the slew motor pipes onto a different valve slice & see if you still have the problem ....... but treat it gently & don't use it like that in anger (without the special relief valve in-circuit). If your problem goes away, it's the valve not the motor.

If the problem remains then you'll need to dismantle the motor. You MAY be able to get seals either from P.V. Dobson or Kellands Plant Sales in Bridgewater .... or from somewhere closer to home.

Good Luck!

Andy
Sorry to post into an older thread, but I have a similar sort of issue on a MF40 digger I have just bought - the bearing at the base of the backhoe kingpost has fallen out, and I am trying to work out if I just need to get a bearing or if there are other bits (retaining nut, for example) that are also missing! At the risk of being really presumptuous, would you be willing to share the diagram of the kingpost from the parts book please? I am about to order a copy for myself but I'm a bit unsure regarding the exact model and year of my digger so just waiting for confirmation from Agrimanuals.
I assume it'll be a case of removing the boom and then taking off the kingpost, as it looks like the bearing goes in from the top of the lower mounting, but I'd like to get a better idea of the likely scale of pain in the backside before starting the job :LOL:
Many thanks, Simon
 

rob h

Member
Location
east yorkshire
I did our 50hx years ago.put the boom out flat supported on blocks .then just un bolted the bottom bracket to remove the bearing.wasnt a big job and no need to remove the boom and motor
 
Sorry to post into an older thread, but I have a similar sort of issue on a MF40 digger I have just bought - the bearing at the base of the backhoe kingpost has fallen out, and I am trying to work out if I just need to get a bearing or if there are other bits (retaining nut, for example) that are also missing! At the risk of being really presumptuous, would you be willing to share the diagram of the kingpost from the parts book please? I am about to order a copy for myself but I'm a bit unsure regarding the exact model and year of my digger so just waiting for confirmation from Agrimanuals.
I assume it'll be a case of removing the boom and then taking off the kingpost, as it looks like the bearing goes in from the top of the lower mounting, but I'd like to get a better idea of the likely scale of pain in the backside before starting the job :LOL:
Many thanks, Simon
Hi Simon,
haven't time to dig out the diagram at present, but will try to do so over the next 24 hours. Unsure exactly how it's all configured, BUT if it's anything like the MF50 series (50, 50B, 50D, etc) the bottom kingpost bearing is a specialist ball-bearing whose outer race has a curved / convex outer surface. This fits into a concave-shaped recess in the (cast / forged) bearing support housing, which then bolts to the main (kingpost) support casting. The bottom end of the kingpost goes through the bearing (from top to bottom) & is secured by a couple of locking nuts. Sounds complex but it isn't too bad ..... but as the top end of the kingpost passes through an upper bearing & then attaches to the Slew Motor, you do have to be very careful that you don't accidentally get the kingpost out of line when replacing the lower bearing, and thereby damage /bend the insides of the Slew Motor.

This is how I did the job. Ideally fit a wide (ditching) bucket to the digger & extend the arm right out behind the machine & lower it down. Support the dipper arm, make sure it can't topple over side-to-side, & remove it from the kingpost unit. There should be enough spare length in the hyd hoses so that you can drive forward enough to detach the dipper arm & give you enough room to work. You now need to support the kingpost, keeping it square & in-line, so it doesn't drop down or move side-to-side while you replace the bottom bearing. This is best done using lifting equipment because you need to work freely underneath the kingpost. You can then replace the bearing, refit the bearing housing & refit the dipper arm. If you want you can remove the Slew Motor from the Kingpost before doing all this, but it isn't strictly necessary .... it's only splined into the Kingpost & retained by a couple of bolts ...... That way you can also check out the Kingpost top bearing, but it's the lower one which takes both horizontal & vertical loading & so usually fails first.

Hope this helps
 

Simon_F3

Member
Mixed Farmer
Wow - that is a huge help!! Thank you so much for the prompt reply and the description. It sounds like I was generally on the right track which is reassuring!
Annoyingly on the 40 model there is a single casting that holds top and bottom bearings - the 50B has a bolt-on lower bearing housing. I wonder if that was a strategic change to make this task a bit easier...
I'll probably take the slew motor off as a matter of course, and if all else fails I have a friend with a machine shop so we can make various bushes, nuts, etc. Sure it can be fixed one way or another.
Anyway, thanks again for the reply - I'll let you know how I get on.
Cheers, Simon
 

jf850

Member
Location
Co laois
Hi Simon,
haven't time to dig out the diagram at present, but will try to do so over the next 24 hours. Unsure exactly how it's all configured, BUT if it's anything like the MF50 series (50, 50B, 50D, etc) the bottom kingpost bearing is a specialist ball-bearing whose outer race has a curved / convex outer surface. This fits into a concave-shaped recess in the (cast / forged) bearing support housing, which then bolts to the main (kingpost) support casting. The bottom end of the kingpost goes through the bearing (from top to bottom) & is secured by a couple of locking nuts. Sounds complex but it isn't too bad ..... but as the top end of the kingpost passes through an upper bearing & then attaches to the Slew Motor, you do have to be very careful that you don't accidentally get the kingpost out of line when replacing the lower bearing, and thereby damage /bend the insides of the Slew Motor.

This is how I did the job. Ideally fit a wide (ditching) bucket to the digger & extend the arm right out behind the machine & lower it down. Support the dipper arm, make sure it can't topple over side-to-side, & remove it from the kingpost unit. There should be enough spare length in the hyd hoses so that you can drive forward enough to detach the dipper arm & give you enough room to work. You now need to support the kingpost, keeping it square & in-line, so it doesn't drop down or move side-to-side while you replace the bottom bearing. This is best done using lifting equipment because you need to work freely underneath the kingpost. You can then replace the bearing, refit the bearing housing & refit the dipper arm. If you want you can remove the Slew Motor from the Kingpost before doing all this, but it isn't strictly necessary .... it's only splined into the Kingpost & retained by a couple of bolts ...... That way you can also check out the Kingpost top bearing, but it's the lower one which takes both horizontal & vertical loading & so usually fails first.

Hope this helps

A well written description.

It's quite some time ago , 10 plus years ago , that I bought one of those bottom.bearings ,for my 50 . Special bearing as you say . €258 from memory .
 

pycoed

Member
Wow - that is a huge help!! Thank you so much for the prompt reply and the description. It sounds like I was generally on the right track which is reassuring!
Annoyingly on the 40 model there is a single casting that holds top and bottom bearings - the 50B has a bolt-on lower bearing housing. I wonder if that was a strategic change to make this task a bit easier...
I'll probably take the slew motor off as a matter of course, and if all else fails I have a friend with a machine shop so we can make various bushes, nuts, etc. Sure it can be fixed one way or another.
Anyway, thanks again for the reply - I'll let you know how I get on.
Cheers, Simon
I'm pretty sure "Watch Wes Work" on Youtube did this job on one of these - worth a look? (His channel is great anyway)
 

Simon_F3

Member
Mixed Farmer
I'm pretty sure "Watch Wes Work" on Youtube did this job on one of these - worth a look? (His channel is great anyway)
Just had a look for this - thanks for the tip! On closer inspection this morning it looks like on the MF 40 it's the top bracket that unbolts, so to get to the bottom bearing the kingpost needs to be lifted out (or at least raised up enough to get to the lower bearing housing). I'll watch the video later to get an idea of the size of the task - doesn't seem nearly as daunting as it did the other day now!!

A well written description.

It's quite some time ago , 10 plus years ago , that I bought one of those bottom.bearings ,for my 50 . Special bearing as you say . €258 from memory .
jf850 - wow! I'll make sure I'm sitting down when looking for the part! I was genuinely wondering if I might be better off turning a bronze bush, maybe with a couple of grease channels, rather than replacing the bearing. I guess it will depend on whether I can find the right part, and whether it costs more than the digger did...:ROFLMAO:
 

Simon_F3

Member
Mixed Farmer
@Captain Sensible could you tell me the reference for the parts book you have for the MF40 please? I just received my MF40 parts book from Agrimanuals and was very saddened to find although it has the digger pictured on the cover, it only contains parts lists for the tractor skid! I'm now trying to find the right reference to get the loader and backhoe parts lists as I think these will be handy to have over the next few decades!
Many thanks, Simon
 

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HSENI names new farm safety champions

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Written by William Kellett from Agriland

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The Health and Safety Executive for Northern Ireland (HSENI) alongside the Farm Safety Partnership (FSP), has named new farm safety champions and commended the outstanding work on farm safety that has been carried out in the farming community in the last 20 years.

Two of these champions are Malcom Downey, retired principal inspector for the Agri/Food team in HSENI and Harry Sinclair, current chair of the Farm Safety Partnership and former president of the Ulster Farmers’ Union (UFU).

Improving farm safety is the key aim of HSENI’s and the FSP’s work and...
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