Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix!

   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix! #1  

Ed in Maine

New member
Joined
Oct 4, 2013
Messages
20
Location
Minot
Tractor
Cub Cadet 7205
Single owner of this 7205 since new in 2000, 550hrs now, no issues aside from glow plugs but that is another story with tons of threads.

I mowed with a 5' finish for about 4hrs then parked tractor, next day it was surging bad and eventually would not move after 5min of running. Then it was like the selector was still in neutral, no sounds or anything from hydro when in gear.

Dealer was VERY helpful over the phone and I mentioned I used a napa gold hyrdostatic filter they crossed me to. After scolding me some, I left with an oem filter (black one that goes right under seat). Still nothing. They said I am pulling air in from somewhere and air bound. I went through all fittings going to the charge pump of the hydro (side of hydro drive, then following line up to cooler and back) and was surprised that I could easily get a 1/4 turn on each.

Like magic, the tractor surged forward some finally! I kept rocking it back and forth but there was obviously still air in the system. I parked it nose down on a steep hill and lost all hydro, so I parked it nose up and worked it back and forth some. She came out of it perfectly and hyrdo is running smooth, quiet, and stronger than ever.

I think the after market filter had too much pressure drop on the return and actually created the air leak. Just sharing my experience and recommending you buy the right oem filter! MA-19632558 is PN for my 7205, and likely same for the Mahindra 2015.

Throughout the whole deal, I was looking closely at the EX3200.... hard to get rid of this nice little tractor but the EX3200 looks rugged.
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix!
  • Thread Starter
#2  
Well, I thought I was onto something but it is taking in air again. I was hoping that tightening the bajo fittings fixed it but now I am going to try replacing the washer/seals on the suction side of the charge pump. I hope the charge pump is not bad, it was running real strong just yesterday before the air got back in.

Open to any and all suggestions, but I think I am getting close!
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix! #3  
My B2400 is in need of a new charge pump. The tractors hydro tranny works fine while cold till the fluid warms up. Then it whines and surges. Some times it wont work at all when the fluid is hot. Also sometimes when going down hill it will break away and roll. No back pressure in the hydro, classic bad charge pump symptoms.

I bought this tractor with a bad hydro. I did rebuild it, but left the charge pump alone. I also had to replace the hydraulic pump.
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix!
  • Thread Starter
#4  
Same signs here, it will roll down hill and get away from you a bit and then kick back in. I just took out the hex plug in the middle just to see if there was any pressure and there was only a few bubbles.

Anyone have a service manual that they can scan a few pages in on how to remove the charge pump? Tractor needs to come apart, just not sure if there are any settings or tensions when putting it back together?
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix! #5  
There are several Cub Cadet 7205 service manuals on CD on Ebay.
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix! #7  
I'm not sure if this is the same manual as what OldMachinist linked to or not, but it is a shop manual that covers the following Cub Cadet Models. It's broken down into the different sections also in case you're on a slow internet connection.

Shop Manual

7192
7193
7194
7195

7200
7205
7232
7233
7234
7235
7260
7265
7272
7273
7274
7275

7300
7305
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix!
  • Thread Starter
#8  
OldMachinist hit the nail on the head, this is the exact manual I need! Thanks a ton.

I am going to tear into this thing and see what I can make of it. But now that I know what each of the valves in the hyrdo do, I am going to inspect each of them. I also have some of the rubber coated washer on order that go on each side of the 16mm banjo bolts. One had a slight score on it from the line being torqued when tightening hyrdostatic filter. Still can't rule out an air leak.

Fired tractor up again just for heck of it. Surged forward a few ft then stopped, would not go forward or backward again after that.
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix! #9  
Sounds to me like the charge pump is not getting any fluid. Like it just fed what ever fluid was sitting inside of it out to the hydro and then quit because no more fluid is being pumped to the charge pump.
Or whatever drives the charge pump isnt being driven anymore for whatever reason.

Hydros can be a big headache, sometimes I wish i just had a simple clutch and gears.
 
   / Cub cadet 7205 Hydrostatic drive surging - sharing my problem AND fix!
  • Thread Starter
#10  
Yes, that is exactly how it sounds. It is taking in air or a high pressure valve is stuck open?
 
 
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