MF 220 digger slew actuator seals.

[essexpete]

Hi all
This is from someone on another forum. Their 220 digger has worn the seals out in the Dowty actuator for the slew service. They seem to be struggling for parts. Does anyone have an idea if some for the later and/or larger models might be compatible?
Thanks

 

[rob h]

Try dobsons

 

[essexpete]

I think they have already tried Dobsons. Thanks.

 

[jf850]

I have a 220 back actor on an MF 50 . It must be 15 years ago that it started leaking oil out of the top of the slew motor , where the outside "pot " turns .
I asked an MF expert , eg a man who had a similar machine for years .
He told me that what happens is ,
Dirt get down into that round groove , sits on top of the seal . It then wears the steel at that point , as well as wearing the seal to a certain degree.
The cure . There is a ring of Allen headed bolts holding the top ring on the pot . Open out all the studs , then , there are two threaded holes in the ring , but no threads for them to screw into in the bottom section . So , by screwing in these bolts , you are rising the top ring off .
The top ring is probably 2 1/2 to 3 inches thick. You will see the seal in a groove . Take it to an engineering place and they will machine a new groove in it , lower down , to take a new seal , that will.be sitting against a fresh undamaged bit of the inner shaft . Put a new seal in the old seal place as well . It will prevent dirt getting down again and damaging the new seal. From memory , the seal was a common seal , that the engineer had in stock himself .
Also , the slew pot should have a "Top hat " on it , which keeps the dirt out . I fitted a top hat when the new seal was put in and never had any trouble since .

 

[essexpete]

I have a 220 back actor on an MF 50 . It must be 15 years ago that it started leaking oil out of the top of the slew motor , where the outside "pot " turns .
I asked an MF expert , eg a man who had a similar machine for years .
He told me that what happens is ,
Dirt get down into that round groove , sits on top of the seal . It then wears the steel at that point , as well as wearing the seal to a certain degree.
The cure . There is a ring of Allen headed bolts holding the top ring on the pot . Open out all the studs , then , there are two threaded holes in the ring , but no threads for them to screw into in the bottom section . So , by screwing in these bolts , you are rising the top ring off .
The top ring is probably 2 1/2 to 3 inches thick. You will see the seal in a groove . Take it to an engineering place and they will machine a new groove in it , lower down , to take a new seal , that will.be sitting against a fresh undamaged bit of the inner shaft . Put a new seal in the old seal place as well . It will prevent dirt getting down again and damaging the new seal. From memory , the seal was a common seal , that the engineer had in stock himself .
Also , the slew pot should have a "Top hat " on it , which keeps the dirt out . I fitted a top hat when the new seal was put in and never had any trouble since .

Thanks I will get the guy to look in here. The problem is getting the seals for the paddles.

 

[jf850]

Thanks I will get the guy to look in here. The problem is getting the seals for the paddles.

I didn't delve into its innards. I know nothing about the major working parts. Mine was working perfectly , just leaking around the centre shaft .

 

[essexpete]

Basically a pot with ports and a post with paddles that are pushed inside the pot.