Help with swapping hydraulic hoses to check weak track

[JimSage]

Greetings folks. I hope to get some advice whether what I'm going to do is a good/bad idea :

I have a pretty old mini excavator (IHI is4gx) and the left track is hardly moving now (in fact, it just jerks a little & stops when I try forward or reverse). I'm trying to figure out what is wrong, and I had someone suggested swapping the hydraulic hoses around for left & right tracks to see if the problem is with the KYB valve block OR possibly the LEFT final drive itself. Meaning, if after the swap the left track regains power & the right track loses power, then it means the valve block is bad (?).

So, I wanted to get some advice on 2 things :
(1) Is that a good way to test why the left track is so weak?
(2) If I do go ahead, do I swap both the top & bottom hoses on the valve block for each of the LEFT & RIGHT controls (ie. total of 4 hoses) ? I've marked the LEFT track hose as BLUE & the RIGHT track hose as RED. I'm told the hose just right below each of the marked forms a pair of the inlet & exit hose for each track.

Any suggestions/advice would be greatly appreciated! Thanks in advance.

 

[Peter 315]

Sounds good to me... You check the final drive for oil ? Does the track turn with no weight on it could the front idler be seized and binding up ?

 

[JimSage]

Sounds good to me... You check the final drive for oil ? Does the track turn with no weight on it could the front idler be seized and binding up ?

Thanks for quick response, Peter. I lifted up the left track in the air & it will move but very very slowly. The left front idler seemed free.

So, am I correct to say that if I do swap, then I will have to swap the 4 hoses? 2 for each track? I'm told the 2 hoses for each track is aligned vertically on the valve block ... just wanted to confirm if it is correct. Or can I just swap only the RED & BLUE hoses? (ie. just this 2 hose instead of 4 hose). Thanks!

 

[ptsg]

Thanks for quick response, Peter. I lifted up the left track in the air & it will move but very very slowly. The left front idler seemed free.

So, am I correct to say that if I do swap, then I will have to swap the 4 hoses? 2 for each track? I'm told they're aligned vertically on the valve block ... just wanted to confirm if it is correct. Thanks!

Yes, you need to switch the hoses by the pair. One pair for each motor. And yes, they are aligned vertically.

Also, if you take the covers off around the track motor, you may see 3 lines. One of those lines is the case drain. One good test that can also be done is to take the case drain out of the motor and just put a bucket or pan underneath. Rotate the track and if you get a lot of oil is coming out, the motor may need to be rebuilt. It's normal for the case drain to put out a small stream of oil but a lot is not normal.

By the way, it's the first time I see a mini excavator with a 5 speed manual transmission. Must cruise really fast down the road. :laughing:

 

[JimSage]

Yes, you need to switch the hoses by the pair. One pair for each motor. And yes, they are aligned vertically.

Also, if you take the covers off around the track motor, you may see 3 lines. One of those lines is the case drain. One good test that can also be done is to take the case drain out of the motor and just put a bucket or pan underneath. Rotate the track and if you get a lot of oil is coming out, the motor may need to be rebuilt. It's normal for the case drain to put out a small stream of oil but a lot is not normal.

By the way, it's the first time I see a mini excavator with a 5 speed manual transmission. Must cruise really fast down the road. :laughing:

Thanks, PTSG. I'm going to try that case drain test you suggested to see what's going on. Oh, lost the original knob & the 5-speed knob was just conveniently lying around ... lol

 

[/pine]

If it's believed to be a fluid/pressure issue...would a pressure gauge test not be easier ?

 

[CoyPatton]

I agree that you need to swap 4 hoses. Your forward and reverse directions are controlled by changing the flow direction of fluid, just like on a cylinder piston. If you only swap 2 hoses, you could have a collapsed hose and leave it in place and misdiagnose the issue completely.
A pressure test on the 2 lines would in my opinion be the better route to go for diagnosis. Run the test on both ends of the hose to check for an issue with the hose itself.

 

[racerboy832]

Is your machine a 40gx or 4 gx?

 

[JimSage]

If it's believed to be a fluid/pressure issue...would a pressure gauge test not be easier ?

hi Pine, unfortunately I don't have pressure gauges & attachments handy at the moment ... it will be on shopping list Our little hobby farm is way out in the boonies with limited tools available ...

 

[JimSage]

I agree that you need to swap 4 hoses. Your forward and reverse directions are controlled by changing the flow direction of fluid, just like on a cylinder piston. If you only swap 2 hoses, you could have a collapsed hose and leave it in place and misdiagnose the issue completely.
A pressure test on the 2 lines would in my opinion be the better route to go for diagnosis. Run the test on both ends of the hose to check for an issue with the hose itself.

Thanks CoyPatton, useful info for me! I have some basic mechanical knowledge but not as much in hydraulics

 

[JimSage]

Is your machine a 40gx or 4 gx?

hi Racerboy, it's just a tiny little IHI is4gx that weighs in at 400kg Powered with a small Robin 27 diesel engine. I sometimes load it on the back of our Isuzu 4x4, it fits!

 

[Peter 315]

You get the HYD lines swapped yet ?

 

[/pine]

Delivered to your door...

https://www.ebay.com/sch/i.html?_fr...e.TRS0&_nkw=hydraulic+pressure+guage&_sacat=0

 

[JimSage]

Ok, did final drive oil change (it was dark but I don't see bits of metal etc). Raised non-loaded left track still moves really slow & I can stop final drive from turning using my bare hands.

Open up the back of final drive to see 3 very rusted hose & components. I can't tell which is the drain hose, but just guessing by the looks is it the top hose? And what does this hose actually do???

 

[JimSage]

You get the HYD lines swapped yet ?

Trying to do that now. Access is pretty difficult!!! Think I need some better tools in the box

 

[JimSage]

Delivered to your door...

https://www.ebay.com/sch/i.html?_fr...e.TRS0&_nkw=hydraulic+pressure+guage&_sacat=0

Thanks!

 

[JimSage]

Update: Ok, I tried swapping hoses & found out it is not as easy. The lengths are all different and some just won't reach the hydraulic ports I wanted. Looks like I either need some extra custom length hoses, or perhaps I'll wait to buy a set of hydraulic testing equipment to check pressures.

Question : Does the ability to move the left track forward & backwards fairly smoothly when lifted up without load (albeit moving rather slowly & can be slowed down with bare hands) means that the left final drive is most likely in OK condition? What are the chances that the left final drive is in good condition & problem is elsewhere? It would good to know ... any educated guesses from those of you with more experience & knowledge?

Not sure what I'll do next now until I get more tools, test equipment, spare hoses ... etc.

Ideas anyone? Thanks again for being part of such a great community!

 

[racerboy832]

If its the same setup as my old IHI. You can test the hydraulic pressure at the valve body. The three lines at the drive are forward-reverse and Case drain. If you pull the case drain off and try to move the machine back and forth only a small amount of fluid should come out. If a lot comes out then the valve plate is worn and its bypassing.

If its a two section main pump one part may be weak

If you want to play the hose swapping game. Do it at the center swivel. The hoses at the wheel side are usually pretty crunchy.

 

[racerboy832]

My hoses from the wheel motors to the center swivel are rubber. I can swap the hoses around at the swivel cause they are all next to each other.

 

[JimSage]

If its the same setup as my old IHI. You can test the hydraulic pressure at the valve body. The three lines at the drive are forward-reverse and Case drain. If you pull the case drain off and try to move the machine back and forth only a small amount of fluid should come out. If a lot comes out then the valve plate is worn and its bypassing.

If its a two section main pump one part may be weak

If you want to play the hose swapping game. Do it at the center swivel. The hoses at the wheel side are usually pretty crunchy.

Thanks racerboy, really appreciate the tips. "Crunchy" is the perfect description!

(1) Can we tell if a pump is two section just by looking at it? Mine seems to be connected somehow & have 2 part numbers on it. (found a photo here : Inventories in Stock by Oemsurplus911.com)

(2) For the 3 hoses, can I safely assume the top hose (which is thickest) is the case drain hose?

Have a great weekend!