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IH Backhoe, just have a few questions

Joined
May 1, 2014
Messages
7
Location
The Farm
I picked up an international 3400A backhoe that had been sitting for several years and have been working on getting it up and running for use around the farm. I Got the engine running nicely and it seems to drive around no problem, but neither the loader nor the backhoe respond to input. Even though the loader and backhoe don't work, there is still flow through the low pressure lines which makes me think something is stuck open. I know I still need to change the hydraulic oil, but I was hoping I could at least get the systems to respond before I dump $150 in fresh oil in it. With my luck, I'd put new oil in it only to find out the next day that I've got to pull the pump or something and loose most of what I put in. Anyways, Ive got a few questions that I'm hoping someone might be able to help me with:

1) The previous owner must have lost the transmission dipstick, as it had been replaced with a cap over the dipstick tube. Does anyone happen to have a IH3400A dipstick that they could measure for me so I can make a replacement?

2) Of all the pressure relief valves on it that I've checked, none of them have looked too out of the ordinary, with the exception of one in the backhoe valve block that had some crud built up on it. Despite the "crud" they've all appeared to be closed, at least when not under any pressure. Does anyone have any tips for what I should be looking for in these pressure relief valves? I had to pull the whole valve block to access the pressure relief valves, and I would really like to not re-install it until I know it's fixed or I've ruled it out as the issue.

3) Any other ideas for what could be causing this issue? I've been trying to chase down this hydraulic issue for several days now, and it seems all I accomplish is taking the whole thing further apart.


I've got the chassis manual for this machine which includes the hydraulics and backhoe/loader, but I haven't found it very helpful so far.

Sorry for the lengthy post, I appreciate your help.
 

Delmer

Senior Member
Joined
Jan 3, 2013
Messages
8,891
Location
WI
I agree, get it figured out and running, and THEN change the fluid.

What do you mean by "there is still flow through the low pressure lines"? I'm not familiar with IH, I'm just assuming this is a simple gear pump setup, or is there a charge pump?

Have you verified that the pump shaft is turning when the control is activated? not uncommon for splines or couplers to wear out and slip under load. Do you get any noise from the pump? a plugged up suction screen can cause no function. Either of these will usually make noise at the pump.
 
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