Very Slow loader..... Help JD420 Backhoe

[Reaney in NH]

I purchased with this problem, I will do my best to explain.

early 80s JD410 Backhoe..... Backhoe, Reverser, Steering etc all work fine.
Front loader is VERY slow.

I am told this happened after a clutch install....


I am a retired Master tech for Autos... limited experience with Hydraulics. Im sure I can fix it... once I find a place to start.

Thank you

 

[Tx Jim]

410 hyd system is closed center with a trans pump(low pressure) that lubricates the trans plus supplies oil to frt pump that creates the high pressure. Sometimes on clutch R&R the hyd lines(parts key 16 & 20) have been inserted in the incorrect holes when tractor is slide back together. Normally when this happens no hyd's operate. How long since hyd filter was changed and sump screen(parts key 15) checked? I would also suggest to check stand-by pressure which should be at least I'm guessing 2350 psi but my knowledge of JD ind tractors is limited as I was formerly employed by an "ag only" dealership. There's also a pressure control valve(photo 3) down by hyd filter but it is designed to give priority hyd pressure to steering except it has fitting(parts key 16) that ag tractors don't have that I know not it's purpose.

 

[Reaney in NH]

410 hyd system is closed center with a trans pump(low pressure) that lubricates the trans plus supplies oil to frt pump that creates the high pressure. Sometimes on clutch R&R the hyd lines(parts key 16 & 20) have been inserted in the incorrect holes when tractor is slide back together. Normally when this happens no hyd's operate. How long since hyd filter was changed and sump screen(parts key 15) checked? I would also suggest to check stand-by pressure which should be at least I'm guessing 2350 psi but my knowledge of JD ind tractors is limited as I was formerly employed by an "ag only" dealership. There's also a pressure control valve(photo 3) down by hyd filter but it is designed to give priority hyd pressure to steering except it has fitting(parts key 16) that ag tractors don't have that I know not it's purpose.

Thank you.... Very helpful.

 

[Tx Jim]

You're welcome

 

[Reaney in NH]

Update..... I like to post results incase someone else runs into the same problem....

Its fixed.... I removed the Prioity valve and took it apart very carefully.... #6 in the above diagram was lodge in the tube sideways. The prev person did not get it in straight... it was actually stuck. I had to knock it pretty hard to get out. the edges were rough. I filed down the rough edges... reassembled correctly... and it works great.

Your advice was spot on.

Now to fix the blown up rear diff.... That the guy told me was a Planetary gear.... $1100 in parts alone... UGGGG

 

[Tx Jim]

Thanks for the update. I never witnessed many pressure control valve problems when I worked at dealership. Have you considered acquiring a differential from a salvage yard?

 

[Reaney in NH]

Thanks for the update. I never witnessed many pressure control valve problems when I worked at dealership. Have you considered acquiring a differential from a salvage yard?

I'm pretty sure this was self inflicted by the idiot I bought this from. Good thing I got it Cheap. LOL

Im just starting the search for the Diff.... Can you or anybody rec-amend a salvage yard that will ship?

 

[Tx Jim]

IMHO buying a JD tractor with closed center hyd's that has hyd PROBLEMS is not a wise decision. Maybe you'll be LUCKY.

 

[Reaney in NH]

IMHO buying a JD tractor with closed center hyd's that has hyd PROBLEMS is not a wise decision. Maybe you'll be LUCKY.

If you dont have something positive to contribute why bother?
It cost me nothing but time to fix the Hydro problem... I now have a useable Backhoe and front loader.... That will drive and dig.... and I get less then $1600 invested.... So tell me Mr Smartass... how is that a bad investment?
Even if I have to buy a NEW Diff for $1000.00... Im still into a great running hard working machine for cheap money and some time.

 

[Tx Jim]

Reaney in NH
I wasn't trying to belittle your purchase as on this purchase you did well and please accept my apology for offending you.

My point is unknown non-working closed center hyd systems can turn into a NIGHTMARE. If the system had been previously water contaminated this can cause premature failure of brake/clutch linings then the wear from metal on metal causes metal filings(fines) to contaminate entire hyd system causing every hyd valve & pumps to require cleaning/repair or sometimes replacement. This can take a lot of labor & $$$$$$. But congratulations on you current purchase I think you lucked out.
Jim