Bosch Rexroth Hydrostatic Trans

[cherokee101]

The beat goes on.

Discouraged and I have not even turned a wrench.

Spoke to a guy yesterday who seems to know what he is talking about and he just about has me convinced that the pump or motor or both are shot.

Fluid heats up, performance drops = drop in viscosity = high pump or motor leakage = drop in pump or motor performance.

It is getting long in the tooth with 6000 hours, not by me, and a lot of apparent neglect, also not by me.

What should a rebuild on an
A4VG40DA1D4 32R-PZC02F015S Bosch RexRoth Pump
and an
A6VM80DA 60W0290-PZBO 20B Bosch Rexroth Motor cost?

I just want to brace myself somehow and start saving my lunch money.

 

[tctractors]

The End.

This World is full of doom and gloom sorts, at 6,000 hrs your shovel should just be about run in and going well, Rexroth make great pumps that are simple and robust, easy to work on as I have often stripped them on site in all weathers, get your spanners out and have a go ????
tctractors.

 

[cherokee101]

Yes, nothing ventured nothing gained.

Spanners in hand.

 

[cherokee101]

An update the the continuing saga. The problem has been largely fixed.

For the help of others as uneducated on this subject as I:

Inspection of the pressure relief valves showed one to be pitted / eroded, this has been replaced.

Finally laying hands on a Rexroth service manual (excerpt only) concerning said pop-off valves we find that the external jamb nut and socket head screw on the forward and reverse side of the pump are for the TOW MODE BYPASS only. Turning these in six turns will open the pop-off valves allowing for limited towing while bypassing the pump. They are NOT for adjustment of the relief pressure, as both the previous owner and I had assumed. Upon further inspection one was found to be turned in 1.5 turns and the offending valve (the eroded one) was turned in 3 turns! Backing both screws out all the way resulted in an unbelievable increase in performance ...duh.

Adjustment of the pressure relief cartridge valves is accomplished by backing out a socket head lock screw within the spring assembly and turning a small bolt. All this adjustment is internal and must be accomplished with the valve on the bench. For this particular machine / pump the pressure adjustment is approximately 620 psi per turn of the adjusting screw.

 

[tctractors]

Valve .

Yes thats the correct valve, swap them over and the fault should transfer, dont forget to vent the hydraulic tank before you start with spanners.

tctractors

 

[Dieseldoctor]

Could you please post the Rexroth excerpt you found?

Doc

 

[cherokee101]

I'd be happy to but it is 2.4mb and this site only allows 100kb and won't let me upload it.

Want to mail me an address and I'll send it to you?

 

[cherokee101]

WTH are you doing in Nigeria? I've been there and done that and am a little leery of anyone claiming to hail from there.

 

[Dieseldoctor]

Yes-0
I'm out here in the jungle looking after the maintenance, repair,and training for a large construction project. 3 years now......a 10 year project, glad to be here away from the finincal crisis in the USA. Africa never had an economy so not much different here.

My email is pardo4@juno.com would appreciate the info you have.

Doc