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piston slapper
03-05-2012, 09:45 AM
I've got a hydrogear bdp10A pump on a Dixie Chopper that is weak under load.
I disassembled and inspected the parts, and found a warped valve plate.
Not a very common failure. The pump has no vibration or noise and all other parts look OK.
My question is : Did something cause this plate to warp? Factory defect?
Did the aluminun head warp, allowing the plate to shift off flat?
Cylinder block springs are good and piston are free and snug.
All bearings are good, no signs of wear to the sides of bearing seats or shaft.

Anyone else seen this.........

Restrorob
03-05-2012, 12:34 PM
I would say defect/mis-assembled, Put a straight edge on the head before re-assembly..... :waving:

MowerMedic77
03-05-2012, 06:38 PM
I almost never work on them but first thought is possible bad dampner allowing the rotor/piston block to slap back and forth against the plate?
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piston slapper
03-05-2012, 07:11 PM
These dixie choppers are in full race trim...no dampners...no safeties...etc....
There is something not fitting squarely. Its hard to think that its a defect, as
The pump already has a few years of service. I guess I really need to take a good look at the locator pins that hold the plate in place.
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ricky86
03-06-2012, 01:52 AM
Iv'e never seen a valve plate in a 10cc pump. They are in 12cc and up. (I thought)
They can and do lift off the end cap when they get beat. Hi pressure oil coming from the cylinder block and hi pressure returning from the wheel motor can bend them. As fixer said, they need dampeners. They are getting away from the plates in newer production.

piston slapper
03-06-2012, 07:23 AM
I was really hoping that someone that was familiar with the Bdp10A pumps would offer some insight to the problem.
The tension of the piston springs should never allow the valve plate to budge.
Some Dixie Choppers were made without dampner springs. The larger bypass hoses and high pressure hoses dampen the initial engagement of the pumps.
The spring setup on the pumps is more of a deadband adjustment than a dampner.
The newer pumps were designed without a serviceable valve plate so that they would wear out and be replaced intead of repaired.
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BigFish
03-06-2012, 10:08 AM
I would take a close look at the check valves, ya might want to install shock valve kits. Peruse the Hydro-Gear site for details.

piston slapper
03-07-2012, 01:45 PM
Just got the pump re installed...
Plenty of power in reverse.... still soft in forward.....bypassing somewhere.
Installed new valve plate.....check valves looked real good...seating areas had light grey circles similar to valve seats in heads.

Could the wheel motor have directional problems?
When I put the mower against a tree to check the power, the wheel almost stops and about a second later the wheel starts digging in.
Only happens in forward position....reverse is solid...

piston slapper
03-07-2012, 02:04 PM
Guess I"ll bring my flow gauge to work tomorrow....only way to know for sure...
Thanx for the help.....

Floridalandcare
03-07-2012, 05:01 PM
I have a 2009 dixie that does the same thing . The left side is real week on a slope and barely noticeable on a straight run , reverse is normal . It started about a year after I bought it from cutter power brand new . Wonder if it was some kind of defect . The pumps on mine are both connected to a (tarnsaxle ? ) I think .Keep us informed

T-Trim
03-07-2012, 10:10 PM
You didn't lose any check balls in the end cap. I never saw a warp plate before just ones installed backward. Also, may have you installed the end cap 180 for orginal?

piston slapper
03-08-2012, 08:23 AM
You didn't lose any check balls in the end cap. I never saw a warp plate before just ones installed backward. Also, may have you installed the end cap 180 for orginal?

This aint my first hydro pump.....
Everything is marked for position and location as it is disassembled.
Should know something after I finish my coffee this morning and do a flow test.
(all us shade tree mechanics have these tools)

piston slapper
03-08-2012, 09:28 AM
Its a bad wheel motor.
Did a flow test.....10gpm at 500psi.......8.5 gpm at 1100psi....in the forward position
10gpm at 500psi.......8gpm at 1100psi.....in the reverse position
actually weaker in the stronger (reverse) porting direction....pump burns the tires in reverse.
I realize Chopper says a droop of more than 1gpm is a bad pump....but...I'm not selling pumps.

Thanx again for all the help......
Slapper

djagusch
03-08-2012, 09:57 AM
Its a bad wheel motor.
Did a flow test.....10gpm at 500psi.......8.5 gpm at 1100psi....in the forward position
10gpm at 500psi.......8gpm at 1100psi.....in the reverse position
actually weaker in the stronger (reverse) porting direction....pump burns the tires in reverse.
I realize Chopper says a droop of more than 1gpm is a bad pump....but...I'm not selling pumps.

Thanx again for all the help......
Slapper

So are the wheel motors rebuldable or do you just replace?

piston slapper
03-08-2012, 10:15 AM
So are the wheel motors rebuldable or do you just replace?

Anything more than seals is cost prohibitive....they are really proud of those parts.
Its almost always clearance issues on weak wheelmotors.
A few thousanths here or there make all the difference.

pugs
03-08-2012, 12:26 PM
Its a bad wheel motor.
Did a flow test.....10gpm at 500psi.......8.5 gpm at 1100psi....in the forward position
10gpm at 500psi.......8gpm at 1100psi.....in the reverse position
actually weaker in the stronger (reverse) porting direction....pump burns the tires in reverse.
I realize Chopper says a droop of more than 1gpm is a bad pump....but...I'm not selling pumps.

Thanx again for all the help......
Slapper

What were the numbers before the pump was disassembled? Did you do the motor tests with the flow meter or is that not possible on Dixies with their extra plumbing?

piston slapper
03-08-2012, 12:59 PM
Never checked the pump before disassembly...I was pretty confident that the problem would show itself. After a thorough inspection, I replaced the warped valve plate.
I didnt expect perfect #'s on the flowtest because I didnt replace the cylinder block assy.

I just took the high pressure hoses off the wheelmotor and connected the gauges.
Probably should have connected an old hose to seal the fittings on the wheelmotor, but , I just put a pan under it...didnt leak much.

piston slapper
03-08-2012, 01:29 PM
What were the numbers before the pump was disassembled? Did you do the motor tests with the flow meter or is that not possible on Dixies with their extra plumbing?

Here you go Pugs......
I always do better with pictures myself..

ricky86
03-09-2012, 08:50 AM
Its a bad wheel motor.
Did a flow test.....10gpm at 500psi.......8.5 gpm at 1100psi....in the forward position
10gpm at 500psi.......8gpm at 1100psi.....in the reverse position
actually weaker in the stronger (reverse) porting direction....pump burns the tires in reverse.
I realize Chopper says a droop of more than 1gpm is a bad pump....but...I'm not selling pumps.

Thanx again for all the help......
Slapper

Now, you have the gpm droop reading, which is at reject. So, your going to replace the wheel motor because you don't believe the manufacturer suggestions, because they are trying to sell parts?

pugs
03-09-2012, 09:16 AM
Here you go Pugs......
I always do better with pictures myself..

For the motor test you hook the gauge up in line with the motor and pump and do some things. I dont remember off the top of my head as I dont do it very often. It may not be a viable test on Dixies because they have that 3rd line on the motors that I am not familiar with.

Also like ricky86 said the numbers are telling you the pump is still bad. Thats not Dixie's test, its Hydro Gears test specs.

First thing we do is test the pump. If the test shows bad, put a new pump on and done.

piston slapper
03-09-2012, 10:12 AM
For the motor test you hook the gauge up in line with the motor and pump and do some things. I dont remember off the top of my head as I dont do it very often. It may not be a viable test on Dixies because they have that 3rd line on the motors that I am not familiar with.

Also like ricky86 said the numbers are telling you the pump is still bad. Thats not Dixie's test, its Hydro Gears test specs.

First thing we do is test the pump. If the test shows bad, put a new pump on and done.

You guys are right.....I'm starting to miss the dealership days....Fix it right and forget it...
Working in the "Land of No Parts" is challenging at times, pushing the limits of your technical abilities, and sometimes it can be fun...but ....somedays I understand how Moses felt when told to "Make Bricks With No Straw"...

BTW...disassebled the wheel motor....rotor and pistons were pock marked really bad.