Need help ...not a crawler but excavator

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Lisaed
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Need help ...not a crawler but excavator

Post by Lisaed » Sun Apr 08, 2018 6:43 pm

1990 590D excavator ....had pumps rebuilt as thought this was problem but my left track travels slow ...if using bucket while traveling it works great but once I stop track wants to also ...all pressure test are great. Been going through my 3 books and no matter what I do nothing seems to work ...at a loss

pondhogvt
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Re: Need help ...not a crawler but excavator

Post by pondhogvt » Sun Apr 08, 2018 8:19 pm

this is one of those things that upsets me about dealer ignorance or is it just dishonest... they don't seem to tell their customers until after they buy new main pumps for ungodly money... you described it perfectly.. it is your swivel joint needs an o-ring seal kit.. some mechanics call it a rotary manifold.. it is right beside your rotary gearbox, swing gear,,,, this is the manifold that all oils go thru from the upper to the lower track frame..

this is what allows your upper to go around in circles but stop at any position and oil goes to the correct port of which ever function you activate..
heat and time wear the o-ring seals and some other seals in there so oil starts going the easiest place it can, not necessarily where you want it to...
they wear slowly over time and you don't notice it until finally it is so bad and slow and you have no track power that you assume it is the main pumps,, and it can be the main pumps but if the rotary manifold has never been resealed that is the place to start.. they should be done every 4 to 5000hrs,,, factory seal kits run around $4 to 600.. for your size machine.. and a factory mechanic can do it in the machine in 3 to 4hrs.. we did the cat last fall,, cat mechanic was done in 4hrs,, this guy is really good I must point out and not his first rotary manifold by any means.. but with the cat dealer they charge travel time and mileage up here,, so it was $1500 by Cat total parts and labor and travel etc.. way cheaper then main pumps...

the clue is if your tracks are slow and while you are still traveling run the boom or stick function to bottom it out and the track speed picks up when you do this,, that's the manifold.. best of luck ... Mark.
350 loader,350c dozer winch and arch,450c winch and arch,450e winch and arch,D37p komatsu lgp dozer,D85 Komatsu dozer,D8k Caterpillar.

Lisaed
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Re: Need help ...not a crawler but excavator

Post by Lisaed » Mon Apr 09, 2018 6:05 am

The rotary manifold has been rebuilt. I am thinking it is something to do in the main control bank that switches from one pump to the other , just don't know what .....Lisa

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CatD8RII
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Re: Need help ...not a crawler but excavator

Post by CatD8RII » Wed Apr 11, 2018 8:47 am

Is the track slow in both directions?
Most excavators use whats called a "straight travel" (not sure what Deere calls it). What normally happens is that pump #1 will do one track and pump #2 will do the other, when you travel and use 1 function it unevenly loads the pumps, because then you have each pump providing oil to a track and one of the pumps has to do the bucket or stick etc. The valve senses a combined (travel and implement) operation and shifts to make 1 pump do both tracks, while the other runs the implements. If this valve has issues, it can partially block off 1 track. Ill see if i can dig up a schematic from one of my buddies tonight and confirm and get a machine location, usually they are in the main control valve.

Lisaed
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Re: Need help ...not a crawler but excavator

Post by Lisaed » Thu Apr 12, 2018 6:32 am

That would greatly help if you could get me a schematic ...would greatly appreciated

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