Splines gone on hydraulic pump shaft

Fatjay · May 12, 2016

Found the issue with no hydraulic flow. My splines are gone on the pump shaft. I was thinking of taking the dremmel with a cutting wheel and cutting a key slot, then using a ¼x¼x1" key, drilling the outer collar and tapping it, and putting a bolt in on the opposite side of the key.

If anyone has a better idea, i'd love to hear it. I'm not to confident in that one as it is.

BarnyardEngineering · May 12, 2016

Your idea will get you going temporarily, but it is not a permanent fix.

Because everything's worn, the bolt idea may push the coupler out of alignment worse than it has been, which will result in a very wobbly pump.

Only permanent fix I see there is a new pump and coupler collar, unless you know a machinist that works cheap and can build up and machine that pump shaft back to a 1-3/8" 6-spline.

It must have been running loose and/or misaligned for a long long time.

wilson ind · May 12, 2016

I would drill through the shaft and collar. Use a bolt through it all. Its old and worn . What have you got to loose? respline
the shaft with build up would cost more than a new pump. What does the pump power?

Eric in IL · May 12, 2016

Do you have any good hydraulic shops locally ? If so, get a quote on a rebuild or check new prices online.

I'm afraid at this point any fix to that shaft is going to result as a short lived "Band Aid".

Steve@Advance · May 12, 2016

Time for a new shaft AND coupling. Only other option would be find a used shaft or pump, either way replace the coupling also.

Determined · May 12, 2016

Probably not much to loose by trying at this point.
I would try wrapping some shim stock around the shaft, them when you tap the coupler on to the pump it will give you the best chance of it being centered and snug fitting.
Drill it and put a tight fitting bolt through it with a nylock nut on the end.
You can probably see a ridge indicating how far on the coupler needs to be on to the pump shaft.

DLMKA · May 12, 2016

(quoted from post at 09:49:50 05/12/16) It must have been running loose and/or misaligned for a long long time.

never underestimate the power of fretting corrosion which is what appears to have happened here. I worked on a project a few years ago on Cat 3176B military gensets where the fuel transfer pump would have the splines wore off in a couple hundred engine hours. They were in storage in NC and the humidity in storage got in those splines and started corrosion and there was nothing that could be done to stop it short of removing the FTP and cleaning and applying a new assembly lube before putting it in service.

old · May 12, 2016

Common problem. I have probably 3 or 4 of those laying around that I have replaced in the past 30 plus years. Best way to fix it is buy new shaft and hub. Your way may work for a little while but since the spline shaft are has some flex your way will not and could cost you the pump or other parts which would cost more

Fatjay · May 12, 2016

Pump powers front end loader and back hoe on my '52 oliver 77. Everything is worn, sadly. However prior to this, it was running great. Engine and rest of tractor still in good shape.

There is a hydraulic shop in the area, they're a bit on the expensive side, but do good work. The PTO shaft that the coupler attaches to is just a keyed shaft with a bolt, that's what gave me the idea, but it's properly machined.

Still have quite a few stumps to pull out, one of which is 3' across, so no rest yet for it.

rrlund · May 12, 2016

I think you'll find that shaft is so hard you'd have trouble even putting a mark on it with a Dremmel. Even trying to drill it,you'd better have a pretty good bit in a drill press.

Traditional Farmer · May 12, 2016

Go the Surplus Center website and match up a new pump,they're not that expensive.

430WLPG · May 12, 2016

One way to fix it is to grind a good flat
side on the shaft and then fill a flat side
in the coupler with a welder and match them
together the best you can

David G · May 12, 2016

Those shafts are usually pretty hard.

Determined · May 12, 2016

If the shaft is as hard as you suggest then what is that coupler that did not wear out made of?

Alan K · May 12, 2016

Ive got my dads Super 77 like that, minus the backhoe.

Splines gone on hydraulic pump shaft

Fatjay

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BarnyardEngineering

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wilson ind

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Eric in IL

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Steve@Advance

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Determined

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DLMKA

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old

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Fatjay

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rrlund

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Traditional Farmer

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430WLPG

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David G

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Determined

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Alan K

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