Hydraulic pump shaft coupling

[markiz41]

Hey all, sorry if this is off-topic, but I need some quality input. Got a front mounted pump on my IH that has a 7/8 13 spline input shaft. The pump is driven by an adapter shaft that bolts directly on the crank pulley. On the pump end, there is a splined coupling that wears out after 2 solid hours of work. I cut the adapter shaft in the middle and installed a flex coupling to correct for the misalignment, but the splines on the pump shaft are already somewhat damaged and because of the play in the connection and the pump shaft being a lot harder than the coupling material, the internal splines get shaved off regularly. What can I do about this, short of tossing the pump? Can I just pin or bolt the coupling to the pump shaft to eliminate any play between the splines and let it be taken up by the flex coupling like it's supposed to? Appreciate any advice.

 

[IH2444]

I think you have some shaft to pump misalignment and until that is corrected you will have problems no matter what you do. My IH has a front mounted pump and no problems. Other option is to get a Barnes bolt in replacement pump which has a round keyed shaft and put a lovejoy type coupler in there.
That is what I plan on ding when my pump wears out.
Darned origional Cessna things are IH only and expensive! the barnes replacement was only about 250 last time I checked. Hoses and bolt pattern is the same, shaft is different.

 

[JDemaris]

The 7/8 x 13 spline is a standard spline used by IH, Ford, Deere,Case, etc. You can buy surplus pumps new - aftermarket, along with new shafts and couplers. You do NOT have to buy from IH.

Pump, mount, couplers, and shafts are all generic.

 

[markiz41]

there's definitely some misalignment, but like I said, I got a flex lovejoy type coupling in the drive. The slop in the pump/coupling connection is what kills it, I think. Could I just drill through the the coupling and the pump shaft and put a 1/4 grade 8 bolt in there so it doesn't wobble around anymore? Or will something snap? We are talking 105 foot pounds of torque max...

 

[IH2444]

Hmm glad to hear that. guess I need to change my IH parts dealer.

Where can I find such pumps and shafts ?

 

[JDemaris]

One place that sells the pumps is the Surplus-Center. Those pumps usually have a standard SAE mount. Also listed by size, pump-shaft type, etc.

http://www.surpluscenter.com/sort.asp?UID=2006120707493820&catname=hydraulic&keyword=HPSR

Baums, and many other places sell the splined couplers, shafts, etc. Smaller pumps have 3/4" splined shafts, and larger 20 GPM and up pumps often have 7/8".

Some of the parts were also very cheap when bought over the counter from Ford/New Holland - much cheaper than Deere, IH, or Case. But, I haven't checked in a year or so.

 

[Joe (Wa)]

Like most of us, you expect the coupling to compensate for other than very minor misalignment. Not going to happen.

Go to the link and look at some of the alignment tolerances for different style coupling under "technical resoures".

Joe
lovejoy

 

[markiz41]

Crazy.. Thanks, Joe. This design sucks. Got a gear driven secondary pump on the same tractor - never gave me a minute of trouble.