Foaming fluid

[Deereguy5343]

Hi,
I hope my message finds everyone happy and healthy!
I have a 95 John Deere 310D backhoe (T0310DDG814698). I was having reverser issues so I pulled it and had a local company do a rebuilt. I reinstalled it and ever since the reverser foams the hydraulic fluid and when I turn the machine off it pushes air out the fill tube (hissing sound for a few seconds). Things I have done; 1. changed hydraulic fluid, 2. inspected the screen. 3. kicked and screamed at it!
Is there a breather or something that could introduce air in the system? I am getting an introduction of air somewhere that seems as though the pump is pumping along with the old and causing the foaming and air from the fill tube. At least that my thoughts.
Any help to know where to look now would be much appreciated! You guys/gals have been an tremendous help in trying to refurbish this older machine. Thank you in advance for offering your years of expertise.

 

[funwithfuel]

I would start by checking the feed to whatever function you just disturbed. Foam can only be caused by introducing air at the suction side. Does your tank have a pressure cap or a pressure relief valve? Something to maintain positive pressure in the tank, essentially forcing oil into the pump. Is your oil level sufficient so that the pump doesn't starve for oil while running? Just a few things to think about .

 

[Deereguy5343]

if this helps here is a picture.
the label that says "left side goes to the intercooler, 2nd row and left side from the drivers seat.
the label that says "intercooler" goes to the right side 2nd. row.

 

[Deereguy5343]

Thanks for the reply Funwithfuel. I'm not 100% sure but i think the reverser is a closed system that does not connect to my main hydro tank. If i am understanding it correctly, the system is a loop from reverser to intercooler and return. If someone has a different manual with more detail than myself please chime in and correct me. But I agree air is being introduced somewhere on the suction side. I will check on what you mentioned though for sure

 

[funwithfuel]

Maybe MG2361 can add some insight. I am not a deere guy let alone combos. I just know a wee bit 'bout hydraulics. Good luck in your search

 

[Deereguy5343]

Awesome, I tried to reach out to him directly, but guess I don't have enough post to have the privilege of direct messaging.

 

[HarleyHappy]

One thing I don’t see, is any evidence of pipe dope or Teflon tape on those NPT fittings.
Has this problem been consistent since you had the reverser rebuilt?
Did you happen to change fluids?

 

[Deereguy5343]

Yes the problem has been consistent since rebuild. And I do not have either on threads, should i?

 

[Deereguy5343]

Oh and yes I changed fluid with hyguard

 

[mg2361]

See if you can get a good picture of the dipstick tube and the hoses that are connected to it and post it.

 

[Deereguy5343]

Ok, so an update. I find out that when the reverser is overfilled it seems to work better and not foam as bad.

 

[mg2361]

Unfortunately, I cannot see what I need to in the pictures. Maybe a picture from below at the lower end of the dipstick.

What was your original issue that it needed to be rebuilt?

You did not have the oil aeration issue prior to the repair? If not, it makes me wonder what the rebuilder did?

When you checked the screen, was the O-ring installed on it?

I am sending you some information. Look it over and let me know if your unit is plumbed like the pictures/instructions show.

 

[Deereguy5343]

Thanks Mg2361, I will take a look at the machine this morning and get back with you!

 

[Buck Wilder]

Thanks for the reply Funwithfuel. I'm not 100% sure but i think the reverser is a closed system that does not connect to my main hydro tank. If i am understanding it correctly, the system is a loop from reverser to intercooler and return. If someone has a different manual with more detail than myself please chime in and correct me. But I agree air is being introduced somewhere on the suction side. I will check on what you mentioned though for sure

I have a 1995 310d and I've had it foam up . Turned out the pickup was starving while running the machine hard on a side hill in 95* weather. Good luck

 

[Welder Dave]

Ok, so an update. I find out that when the reverser is overfilled it seems to work better and not foam as bad.

Something looks wonky with the spring in the lower left of the last pic.

 

[mg2361]

Something looks wonky with the spring in the lower left of the last pic.

That is the foot throttle return spring.

 

[Welder Dave]

It looks twisted funny with what looks like metal findings around it.

 

[mg2361]

That spring has had its issues. I don't know a dealer anywhere who doesn't stock that one.

 

[Welder Dave]

That was supposed to say filings. Damn auto correct.

 

[Tyler d4c]

In the filler tube the return for the parking brake valve goes in when you turn it off it dumps in there theres a ball beqring that has to be in there or it blows out the dipstick