JD 500B Industrial backhoe loader Hydro Pump question.

[mikehenya]

I just purchased my first backhoe, late 60's 500B Industrial. I am going through and replacing several worn hoses and though I may get a seal kit for both the front and mid mount pumps. I have the parts manual and have located kits.

Question is, is there any trick to removing and replacing the pumps? I have ran across some references to "Pump Timing" and shaft matching, etc....I know nothing about either, does that apply to the late 60's models?
Thanks!

 

[Tx Jim]

Are you referring to hyd or fuel pumps? Is frt hyd pump leaking? There's no timing involved with R&R of hyd pumps.

 

[mikehenya]

Just the hydraulic pumps. They are leaking a little, but I think one of them may not be working.

 

[Tx Jim]

Closed center hyd such as your tractor require diagnostics utilizing gauges and determining flow or lack of flow. Uilizing a flow meter to determine amt of flow is the best method. Many frt hyd pumps have been replaced only to determine that pump replaced wasn't at fault. I'm curious how you're determining trans pump is leaking seeing as it's hidden inside trans case?

 

[mikehenya]

The seller said the middle pump hasn't worked for a couple of years. I may have misunderstood, but isn't the Mid mount pump the secondary unit hanging externally under the transmission? I thought I might freshen up the seals in both pumps and clean the transmission control valves and replace all the filters over the winter. Then once it warmed up I could start doing some troubleshooting. I figured freshening some things up wouldn't be a bad place to start.

 

[Tx Jim]

To renew any seals in trans pump one needs to split the tractor or remove top cover depending on type of trans. What type trans (PS or CS) trans does your tractor have??

 

[Zebrafive]

TxJim. JD parts shows a mid mount hydraulic pump that is not the trans pump. I think you two are talking about two different pumps

 

[Tx Jim]

Zebrafive
What heading are you finding that schematic or could you post a part number listed on the page? My industrial knowledge is very limited but I don't find this page listed under hyd pump in index in PC 1128. 500B and Ag tractor 3020 are similar models

 

[Zebrafive]

Zebrafive
What heading are you finding that schematic or could you post a part number listed on the page? My industrial knowledge is very limited but I don't find this page listed under hyd pump in index in PC 1128. 500B and Ag tractor 3020 are similar models

The pump looks like a front mounted pump. The drawing I posted is the mount/drive for the pump.

PC 1128 > Sectional Index > 75 Mid-mounted hydraulic pump, drive, filter. and hoses > 2 Mid-mounted hydraulic pump drive

P/N key 8 is R34315 Pinion

 

[mikehenya]

I am referring to the external Mid Mount pump as ZebraFive is showing in the diagram.