# How to Repack Lift Arm Ram on Fisher MM1 SEHP straight blade



## alohazabel (Dec 9, 2013)

Can someone give me a quick step by step tutorial on repacking the lift arm on my fisher MM1 SEHP straight blade?

My plow has been leaking slightly from the packing nut since I've owned it, but it seems to be getting a little worse lately. I also noticed the plow is making a new noise the last few days every time I drop it down. Its still functioning OK, but I thought I should try to fix the leak and hopefully get rid of that noise.

It looks pretty easy, but I just want to make sure I'm not missing anything, get all the parts I need to do it right, etc.

Thanks


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## alohazabel (Dec 9, 2013)

*packing nut size*

also wondering ...what size is the packing nut on the sehp lift arm?


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## dieselss (Jan 3, 2008)

There's seals on the ram, and one wiper seal inside the nut.


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## alohazabel (Dec 9, 2013)

can I get to everything by unhooking the triangle, loosening the packing nut and pulling the ram?


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## dieselss (Jan 3, 2008)

Rams gotta come out. How's the ram? Rusty and pitted means replacement


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## alohazabel (Dec 9, 2013)

some slight pitting, no visible rust... hoping to get about three more years out of the plow, should I replace it?

how do I get the ram out?


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## dieselss (Jan 3, 2008)

If it was mine yes I would.


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## SnoFarmer (Oct 15, 2004)

Have you tried tightening it a little and topping off the hydro fluid

Unless its gushing out I'd try this first


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## alohazabel (Dec 9, 2013)

yes. The only wrench I have on hand that would fit it is a big old pipe wrench. I tried to tighten it, but I couldn't budge it with the wrench I have.

Its not gushing, and the plow is still functional. 

I just wanted to get it taken care of before I have a problem during a snow storm.

But if repacking it is a huge hassle, I guess I could just keep using it as is for a while


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## dieselss (Jan 3, 2008)

Actually, removing the nut is about the hardest part


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## alohazabel (Dec 9, 2013)

Diesel- Tell me if this sounds about right....

Pull the pin that attaches triangle to lift arm

Loosen and Remove the packing nut

then pull the ram up and out of the tube, 

replace the seals and packing, slide it back in 

retighten the packing nut 

and reattach to the triangle

????????


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## alohazabel (Dec 9, 2013)

and I can replace the ram if needed at the same time


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## dieselss (Jan 3, 2008)

That's about right....how ever I'll.add

Remove Allen plug on the side of the lift ram housing. That'll drain the fluid in the ram housing.
Lift up ram with triangle attached still.
Then loosen the nut.
Then take off triangle, but before you do, bungee cord the pump "back" or it'll fall forward.
Take nut all the way off. 
Pull up on the ram.


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## dieselss (Jan 3, 2008)

Pull the seals off.
Replace the seals.....I like to use lubriplate on the seals to get them "wet" 
Install seals.
Push all the way down to the lock ring of the piston.
Install....May have to use a hammer and a punch to get the seals all the way down in the bore.
Replace wiper seal in the nut......May have to wire wheel the nut as they rust.....If you really wanna be anal you can order a nut just to be safe.
Tighten nut....hand tight
Raise ram. Install triangle....Then tighten nut....Tighten to nut contacts the packing then 1/4 more.


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## dieselss (Jan 3, 2008)

Since the lift ram is gunna be out, I always flushed the bore out. You wouldn't believe how much crap was in the bottom. Just fyi..


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## alohazabel (Dec 9, 2013)

Diesel- thanks alot for the detailed step by step. It seems alot clearer to me now.

I'm going to have to wait until monday to get the seals and then I'll attempt it. 

If I get stuck I'll be back begging for more advice.

Thanks again


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## dieselss (Jan 3, 2008)

No bother....


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## alohazabel (Dec 9, 2013)

*stuck packing nut*

Diesel- You weren't kidding about loosening the packingnut being the hardest part of this job.

I've been giving it doses of PB blaster, working on it with a big pipe wrench, a crescent wrench, a cheater bar, and I can't get it to budge.

I tried a little heat, but not much yet. I wasn't sure if I should heat the nut or the tube.

Any advice or tips on how to break it free with out twisting the top off of the packing nut?

Its not reverse threaded or anything like that is it?


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## dieselss (Jan 3, 2008)

No it's not reverse threads. Heat just below the nut where it threads into the housing. Be careful tho the housing is aluminum, so light heat and keep the torch moving.


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## alohazabel (Dec 9, 2013)

*mission accomplished*

Didn't go exactly as planned, but its done...

The packing nut was really seized in there, and I ended up breaking the top off of the packing nut, so I had to cut the ram off with a sawzall, then I unscrewed the "tube" from the housing, and I was able to get to the threads from the packing nut out by cutting three vertical lines in them with the sawzall and then tapping out the chunks with a chisel with out hurting the threads in the tube

Went and bought a new ram, packing nut, packing, etc.

cleaned everything out, put it all back together, filled it with fluid, and it works good.

new seals, no more leaks.

thanks again for the help


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## dieselss (Jan 3, 2008)

How'd the top come off?


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## alohazabel (Dec 9, 2013)

I had a big crescent wrench and about a 5 ft pipe on it, and as I was heating it and banging on it and getting more and more frustrated, I finally pushed a little too hard, and a couple sides of the nut just kind of crumbled off....

then we knocked another side off trying to turn it out with a hammer and chisel

I didn't realize that the "barrel" that the ram moves up and down in was threaded into the pump housing. It looked like it was welded right on there, but when I was messing with the packing nut, it started loosening.

If I hadn't been able to remove the whole barrel, it would have been really hard getting at those threads with a sawzall


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## dieselss (Jan 3, 2008)

Ok. Well good to hear it's not leaking


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