Rtv 1100 hst repair

[vicegrip]

Hi guys. So I got an older 1100 that's got 6800 hours and it's gotten slow. Can't keep speed going uphill. Engine doesn't seem to stress at all. Machine will slow down to 5 mph going up some inclines.its had this problem for a couple of years now and I decided to tear into it. The piston that destrokes the piston pump was at an awkward angle when I opened the pump case...the thread was stripped. The copper backing plates also look a little scarred the pistons In the pump and motors look OK. Here are pics what do you think of the backing plates? Also no O ring on the destroke piston.im hoping to fix the thread in the block just replace the piston and the copper backing plates?

 

[oldnslo]

Can you feel the scratches with your fingernail? If yes You can lap or polish those brass port plates. Just make sure you get ALL the lapping compound off of them before assembling the units.

Also make sure what you use for a lapping base is smooth like a piece of plate glass.

Not sure if there is supposed to be an O-ring on the stroking piston

 

[vicegrip]

ok we will polish the plates and go from there.In the last pic you can see the last motor grouping on the shaft.Im ASSUMING the groupings are ok based off of the other ones. I can not seem to remove it is it just part of the input shaft?

 

[oldnslo]

I can’t tell from the picture how the motor rotating group is assembled. Based on the ASSUMPTION nothing has moved out of place I would not try forcing that apart so agree fix the threads on stroking piston and polish the brass port plates. Clean everything super clean and reassemble making sure to oil ALL of the rotating wear surfaces.

 

[vicegrip]

I can’t tell from the picture how the motor rotating group is assembled. Based on the ASSUMPTION nothing has moved out of place I would not try forcing that apart so agree fix the threads on stroking piston and polish the brass port plates. Clean everything super clean and reassemble making sure to oil ALL of the rotating wear surfaces.

so i polished of the brass plates and fixed threads on the stroking piston and it it now goes 24 25 mph. it will lug the engine right down under load!

 

[oldnslo]

Thanks for posting the problem and fix. Glad it is resolved

 

[Dryland Farmer]

Could you possibly post more pictures of where on the machine the part is that you fixed? Did you have to pull the transmission out to get to it? I have a 2012 with 3000 hours and I suspect it has a similar problem.