pump replacement?

notme · Wednesday at 7:39 PM

hello... i have an old case 1816 uniloader the aux hydraulic pump has a bent shaft... still works but has quite a shake to it. need to find a replacement and not having much luck.

its a borg warner pump
# on the case is S125OAK 55R
under that # is 05098
can anyone give me an idea where i might find replacement parts (shaft) or a replacement pump? its belt driven so a replacement would have to be capable of that. can anyone explain what the stamped in #s might say about this pump?

oldnslo · Wednesday at 8:11 PM

Bosch Rexroth purchased Borg Warner gear pumps many many years ago and the info that I have does not exactly match the model code that you have. Attached is old data sheet that you can use for displacement and dimensional reference. The unknown appears to be the shaft.

S = External gear pump
12 = displacement range (size)
50 = 0.58 cubic inch/rev (9.5 cc)
A = SAE ORB side ports
K = SAE A-A 2 bolt mtg flange
5 = unknown shaft
5 = design series
R = clockwise rotation

notme · 2025-11-27T20:57:21-0500

oldnslo said:
Bosch Rexroth purchased Borg Warner gear pumps many many years ago and the info that I have does not exactly match the model code that you have. Attached is old data sheet that you can use for displacement and dimensional reference. The unknown appears to be the shaft.

S = External gear pump
12 = displacement range (size)
50 = 0.58 cubic inch/rev (9.5 cc)
A = SAE ORB side ports
K = SAE A-A 2 bolt mtg flange
5 = unknown shaft
5 = design series
R = clockwise rotation

thanks alot... now i can check surplus center or maybe amazon for a cheap replacement.
so the unknown shaft what does that mean? its a 1/2 shaft? which really doesnt matter as i can match a pulley to any shaft?

oldnslo · 2025-11-27T21:06:48-0500

By unknown shaft I meant it didn’t show as an option in the data sheet

Might have some different bearing option for the side load from belt drive

SiteEngineer · 2025-11-27T21:44:14-0500

A bent shaft will only get worse, so good call trying to replace it. Those Borg Warner pumps are hard to find new now. I’d check with salvage yards or a hydraulic shop that can cross-match the numbers to a modern pump.