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8000 series Hydraulic Pump Repair

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13K views 33 replies 10 participants last post by  Gravely16G  
I
#1 ·
Wanted to share some info on my most recent repair to my 8179G.

Symptoms: Hydraulic pump filter changed, Dexron ATF used to fill filter, lift worked fine but progressively got worse. Fluid kept "disappearing" with no apparent leaks at any fittings, pump, etc.

However, transaxle kept "weeping" -- it was always seemingly coated with a nice mix of gunk: fluid that apparently kept getting pushed out the seals and the grass/dirt/junk from mowing over summer.

I found this very helpful thread elsewhere:
http://gravelytractors.proboards.com/index.cgi?board=howto&action=display&thread=72

The thread above was great because it was then I realized the Dexron was being forced under high pressure into the transaxle because of a leaking rotary shaft seal. That gentleman posted pics of the pump (looked exactly the same as mine) and SKF seal number (SKF 4985) which I found at a local outlet of Motion Industries (I'm sure there are others, but if you Google, they seem to have locations all over and it was a $4.33 part).

I'm sharing this because of the problems I had in getting everything to work. I called up the Ariens/Gravely toll-free customer service line:
1.888.927.4367

I don't remember the sequence of numbers to push, but I was able to get to the Gravely guys -- there are 2 guys there that were development engineers that are quite helpful: Al or Lee.

Unfortunately, those guys weren't available when I called after having installed the new seal and bolted everything up to the tractor. I started the engine and tried the lift -- nothing, no sound whatsoever!!! Here's where I wish I would have gotten some good advice -- the guy I ended up talking to was pretty unhelpful -- Dan -- who said that I didn't need to do anything except bolt up, start the engine and use the lift, stop the engine, take off the filter and then refill. Problem was, nothing was being pulled from the filter into the lines.

Dan said the unit was sucking air -- everything must not be tight. I checked, rechecked and still didn't work.

I decided to take matters into my own hands. I disconnected the line going into the top of the filter and slowly poured Dexron into the line (with the filter off) until it ran back out the other line. I put the filter back on, made sure everything was tight -- and wonder of all wonders, everything worked! Maybe a new pump works without priming, but after 23 years, mine needed some help. So, if anyone runs into the same situation, hopefully this will save a few hours of your time.
 
I
#3 ·
Hi John (Mickeymotormount),
Thanks for the welcome! I have really enjoyed reading through the threads on this forum -- really seems like a great group, very helpful. I've got a few (more) things now to check on my tractor as a result that will help keep it running (and running well).

Just in case anyone here doesn't have one -- Farm & Fleet has got a good price on one of the better Milwaukee 4 1/2" angle grinders (#6148-31 -- it's the 10amp version, comes with a nice carrying bag). I just picked one up, on sale til 11/30 (was $79.99 every other place I checked was $99.99). Along with the work on my hydraulic pump, I just had my 48" blower's bucket re-welded) and in getting it ready for winter, decided I needed to do a little prep and repaint. That was a nice find.

Finally, I also used a can of spray Slip Plate (it's a graphite based "paint" that does dry dark grey -- and also comes in a can like paint) to "line" my chute, impeller, etc. I was able to pick this up at Grainger's (I picked it up at one of their locations but they ship too). You can buy this stuff direct from Slip Plate but only in mass quantities (a case of 12, they ship for free). I decided I wanted to try a can, it was less than $9 at Grainger's and from what I can tell, this will really help keep the snow and ice from sticking as it has in the past.
 
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#5 ·
Hi 8122tom,

Since this is the 1st time I'm going to use it, can't say for sure -- however, based upon what I've found elsewhere in several other forums, seems like it would be really helpful. If you go to www.slipplate.com you can get lots of info on how the product is avail. From what I can tell after spraying it on the blower/chute, I am guessing it's going to be one heck of a lot better than just having the painted surface -- it is slippery as heck! You might be better using the liquid version and paint it on with a brush since it's a flat surface.
 
#9 ·
Hi IL,

I read your post with interest since the hydraulic lift on my 818T is VERY slow. You mention a hydraulic filter? I was not aware of any filter or screen in the hydraulic system. Is there something in there which is not on the parts list?

Thanks.

Jack
 
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#10 ·
jackhdn,
If you go to www.oldgravelys.net, you can find an illustrated parts list from Sept 1977 for the 800 series tractor. I could not find any service info but it appears that the 818 has a hydraulic tank (not a filter) and on the top of it is a plug/dipstick -- since I'm not real familiar, I can't say for sure, but I would assume you take the plug/dipstick out and you can check the level of fluid in the tank.

Since I don't know the service recommendations (without the service manual, hard to tell) but I know on mine, Gravely recommends changing the filter/fluid every 2 years. I do know, though, that the hydraulic pump is the same as what I have and the link I posted with the pics above. You might have a combination of old fluid, low fluid and a leaking rotary seal causing slow movement.

Right now, even at idle, my hydraulic system works perfect and I have cured the leak into the transaxle. It's worth looking into now if you, like me, use your tractor for winter service and need it to lift a blower or blade.

Good luck!
 
#11 ·
Thanks for that. I do have the parts and service manuals and neither mention a filter. I have changed the fluid and it did not make any difference. If there is no filter or screen in the system, I am thinking either the pump is too worn or that seal is bad. I will take it off next chance I get...and yes I will be using it to blow snow this winter.

Jack
 
#14 ·
Always at WOT Ron. It will pick the deck up well enough but I have to wait 30 seconds or so to lift the rear tiller. Maybe that is just the way it is. First small piece of equipment I have ever run with hydraulics and I probably cannot expect it to operate like a full size machine.

I was thinking about your front lift you would like to add hydraulics to. Have you thought about a power steering pump? I used on to run a snowplow once and it worked well.

Jack
 
#15 ·
30 seconds to lift a rear tiller at wot! I would say there is an issue. I run a tiller on the back of an 8199KT and it will lift up in 4 or 5 seconds at half throttle. If you lift it up and shut down the engine, how long will it stay up?

I never though about a power steering pump. That's a pretty good idea.....
 
#16 ·
It will stay up for a long time. I have never left it up when parking the machine but I would say there is very little bleed down through the valve or cylinder.

The PS pump works and they can be had for free/cheap. Only real problem is lack of tank capacity...and getting some fittings to work with it. As I remember, the hoses attached to it were an odd size and the hydraulic shop had a tough time crimping a standard fitting on.

Jack
 
I
#18 ·
From what I was told -- the pumps are no longer available through Gravely, nor do they even show the various parts for the pump. When I called Gravely (Ariens direct), Lee said that he was one of the engineers that tested stuff on that line and knew exactly what I was talking about. He could not give me any kind of help, though, re the part number which was why I posted that earlier link with images. I suspect if you were to take the pump to a place that specializes in hydraulics repair, they could help. I have seen the pumps for sale on ebay (used) going for $100+ and have seen a few new ones for over $400. From my perspective, much quicker/easier to simply buy the SKF seal, pull the pump, replace the seal, make sure all fittings are tight and that the tank is filled to the proper level (and I would suggest priming by trying to slowly pour fluid into the line to make sure you can get it pumping). I'd say it would take me well less than an hour now that I know what needs to be done. Far easier to try that than to mess around w/checking the pressure. Of course, that's JMO, YMMV.
 
L
#21 ·
Does anyone have pics of replacing the pump seal?
 
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#22 ·
Not pics of replacing it actually. Because of the suggestions on this thread i thought that was my probleem. I had the pump off, have photos of the seal. visible on the pump side that mounts to the transmission. I also successfully sourced and bought the actual seal which i still have.

Ron C's postings convinced me to try other things before replacing the seal and those things worked. You are talking of the mechanical version correct? As opposed to the electrical ones used on later models?
 
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L
#23 ·
Thanks Al I found your 20G thread that had the pics I was looking for. Jason
 
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#24 ·
Dad I replaced the pump seal on the 8123 tonight. The old one was blown out pretty bad. In fact it came out of the pump with a pair of pliers, no force needed. Applied gasket sealant and closed her back up and we'll find out in a few days if it works again.
 
#25 ·
Which seal did you replace Brad?
 
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#28 ·
Yes. That's the one.

The gravely has been sitting in a friends garage and he's been starting it for me now and then one day he alerted me it wouldn't lift up and there's was no fluid on the ground. I just refilled it and figured it was maybe low from before.
I picked it up a week ago and took it to dads for him to use and it wouldn't lift for him.
Jason and I discussed the issue and the seal was likely the culprit.

The old one was barely in there. As you can see in yours it's flush with the pump housing. Mine plucked out with a small pair of pliers! The new one we just took a 5/8 socket and a ball pen hammer and gently tapped the new one in.

If I was trying to get the old one out I'd just take a couple small wood screws and drill the old seal.

Some of the trans fluid dripped onto the concrete and you could easily see the "red" in it. In fact, looking back I can remember changing the trans fluid when I bought the tractor and it had a red tinge to it. I described it as maybe the improper oil. Now I know different!
 
#29 ·
Thanks for the details Brad. I didn't have to mess with mine but want to know about it for the future. I have 2 pumps like that one. In your case mystery solved - same issue as the OP of this thread.
 
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#31 ·
Those pics are way better than mine.
 
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