MF35 Utility - Power Steering seal

[twosocks90]

My MF35 Utility (gas engine) leaks power steering fluid. I suspect it's going into the crankcase. I have googled for a replacement seal but am not sure if the MF35 utility uses the same power steering pump as the regular MF35. Can anyone point me in the right direction?

Is it a difficult repair?

Pics of the pump are attached.

 

[shaeff]

Hey Bob, nice to see ya posting. I had the exact same issue on mine. Judging by your pump, I'm guessing it's a later model 35 Utility. So what happened with mine is the seal on the snout of the pump where the drive gear is leaked, and as you guessed, the fluid went into the crank case. In my specific situation, the pump shaft was worn, so even a new seal leaked. Here's what I did to fix:

Buy new seal, carefully sand it down until I took enough off to press the seal in further than it originally was. Doing this allowed me to get it to ride in a different spot on the shaft, thus fixing the leak. I'll grab you a part number, give me a few.

 

[shaeff]

So you're looking for #20, PN 834089M1.

Not a difficult job, but as usual when working inside ANY hydraulic system, keep it super clean and dust free. Now is also a good time to replace the filter if it hasn't been done yet.

 

[twosocks90]

Hi Shaeff,

Thanks for the replies and it's good to hear from you again

I have never replaced the filter and will order one of those, plus the gasket that mounts the pump to the tractor. Anything else you can think of?

I'm hoping to time this seal replacement at a time when no snow is in the forecast... hopefully it goes well!

 

[shaeff]

You bet!

Filter is cheap enough insurance, keep in mind there's an o-ring in the bottom of the reservoir that may also tear when you take the pump apart. It's inexpensive, in fact if you PM me your address I can ship one to you free. I bought a pack of them when I did mine. I'll make sure I still have them if you're interested.

I don't think I even replaced the pump-to-tractor gasket, or if I did I probably cut my own. I don't recall buying that one. I hear ya on the timing, these things always pop up at the worst times! I got lucky, no longer use my tractor for plowing. Now have a company truck with a plow. Not as fun, but certainly warmer!

I'll keep tabs on this thread in case you have any other questions. The pump is pretty straight forward, just be careful of the copper sealing gaskets between the sections of pump body. Keep them super clean and make sure it goes back together the same way. I used a little bit of hylomar/gasket sealant on those mating surfaces to ensure no leaks.

 

[twosocks90]

Ha, I just checked my filter and found out there isn't one! So I guess this is a good time to "replace it"!

What kind of oil do you run in the power steering system?

 

[shaeff]

Ha, I just checked my filter and found out there isn't one! So I guess this is a good time to "replace it"!

What kind of oil do you run in the power steering system?

Not surprising. I use the same oil that's in my loader hydraulics and in the transmission/axle- Traveller's Premium UTF. Works fine, keeps the number of oils required onhand to a minimum.

 

[twosocks90]

I finally got the pump disassembled. Getting the gear off the shaft was a minor pain until I found the right puller - I think it was a tie rod end puller. Then it popped right off.

I found the gear was wearing into the pump housing where the seal is. Apparently this is because the retaining rings that hold the internal gear in position on the shaft are wore and don't hold it in place any more. This means the shaft moves around too much. I'm going to order those snap rings and maybe a couple more seals/o-rings while I'm at it.

I also found a small piece of bright colored plastic debris stuck in one of the oil passages Not sure how long it's been there but it's definitely not original equipment!

 

[shaeff]

Bah, it's always something! At least you've identified the issue. Hopefully it'll be a quick repair. That piece of plastic lodged in the pump sounds interesting!

You should be receiving that o-ring any day now, I'd guess. I've got some pictures of the pump breakdown if you need.

 

[twosocks90]

I received the O-ring - thanks!

I found pictures of the pump on Welcome to AGCO Parts Books which is quite an amazing resource. The diagrams there are extremely helpful.

I'm pretty sure the o-ring is part #27 on the diagram but I can't figure out what's holding the reservoir on the pump. I took the bolt out that's in the bottom of the reservoir but that did nothing. Do you know what's holding them together?