94 763 Hydraulic pump seal

[turbomoparboy]

I have a small hydraulic leak. It is on the belt side of the pump. When I replaced the belt it was oily under the belt cover. It is not that bad and I can live with it if I need to but I was wondering if there is a replaceable pump seal and if so how difficult it is to replace. It is possible it may be comming from somewhere else but every where else I can see is dry. Thanks! Justin

 

[7LBSSMALLIE]

when you say hyd pump seal , do you mean gear pump.i think not i belive you mean the hydrostatic input shaft seal which locateted under belt cover (the front pulley) and yes get done now . not doing it will result in input shaft brg failure which will grenade into hyd sys resulting what could be called murder,of entire hyd sys, yea it sucks. package needs to come out, in order to acces. 25 dollar seal two days labor, while packege is vout replace fuel pick up ,sender, and check pump mount thourghough clean,etc it being a 763 (the best bobcat ever made) its worth getting it squared away, these units were bullet proof (providing maint done) if it starts and runs and overall good condition. its worth putting some time and labor into. 2 grand would a hard hit for me, that being said the parts are in inexspenisve just labor intenisve., if you got game you can do this. but not a job for the shade tree

 

[mrdeere1959]

when you say hyd pump seal , do you mean gear pump.i think not i belive you mean the hydrostatic input shaft seal which locateted under belt cover (the front pulley) and yes get done now . not doing it will result in input shaft brg failure which will grenade into hyd sys resulting what could be called murder,of entire hyd sys, yea it sucks. package needs to come out, in order to acces. 25 dollar seal two days labor, while packege is vout replace fuel pick up ,sender, and check pump mount thourghough clean,etc it being a 763 (the best bobcat ever made) its worth getting it squared away, these units were bullet proof (providing maint done) if it starts and runs and overall good condition. its worth putting some time and labor into. 2 grand would a hard hit for me, that being said the parts are in inexspenisve just labor intenisve., if you got game you can do this. but not a job for the shade tree

are you sure its hyd. oil and not engine oil? rear main seal is an easy fix right in machine

 

[turbomoparboy]

when you say hyd pump seal , do you mean gear pump.i think not i belive you mean the hydrostatic input shaft seal which locateted under belt cover (the front pulley) and yes get done now . not doing it will result in input shaft brg failure which will grenade into hyd sys resulting what could be called murder,of entire hyd sys, yea it sucks. package needs to come out, in order to acces. 25 dollar seal two days labor, while packege is vout replace fuel pick up ,sender, and check pump mount thourghough clean,etc it being a 763 (the best bobcat ever made) its worth getting it squared away, these units were bullet proof (providing maint done) if it starts and runs and overall good condition. its worth putting some time and labor into. 2 grand would a hard hit for me, that being said the parts are in inexspenisve just labor intenisve., if you got game you can do this. but not a job for the shade tree

I never knew until now that they were 2 seperate units. I was referring to the hydrostatic pump. It is definately hydraulic fluid. I was looking at it better last evening and I am going to degrease it and look for the leak. If it was leaking from the input shaft I would think it would be splashing around when the pump is turning and the pulley does not seem that wet. It looks like it is much wetter from the fuel tank and lower so it may be leaking somewhere else and running down the tank. As for the fuel pickup. I replaced it a few months ago because it colappsed. I was able to change it without removing the engine. I am assuming on the hydraulic dipstick, it is 1 gallon from the full to low mark and it is in the middle so I lost about 2 quarts in 11 hours. I will keep you guys posted as to where the leak is. Thanks again for the help! Justin

 

[HarryN]

I never knew until now that they were 2 seperate units. I was referring to the hydrostatic pump. It is definately hydraulic fluid. I was looking at it better last evening and I am going to degrease it and look for the leak. If it was leaking from the input shaft I would think it would be splashing around when the pump is turning and the pulley does not seem that wet. It looks like it is much wetter from the fuel tank and lower so it may be leaking somewhere else and running down the tank. As for the fuel pickup. I replaced it a few months ago because it colappsed. I was able to change it without removing the engine. I am assuming on the hydraulic dipstick, it is 1 gallon from the full to low mark and it is in the middle so I lost about 2 quarts in 11 hours. I will keep you guys posted as to where the leak is. Thanks again for the help! Justin

Try to take some pictures along the way....we love pictures!

 

[turbomoparboy]

Try to take some pictures along the way....we love pictures!

I degreased the maching and let it run for a while. I found several leaks at a few fittings which appeard to stop after either tightening or loosening and then then retighten. The large line going from the tank to the pump was oily as well and I tightened the hose clamps. I am getting oil around the front of the pump ( belt side) of the hydrostat pump so I am pretty sure its the front seal. I topped off the fluid today and it took 2 quarts so I lost about 2 quarts in 15 hours with all of the leaks but I would say the majority is from the pump seal. I know this may be a lot of then again I doubt I would ever put more than 30 hours on it a year so it does not get used much. It was mentoined earlier that if I dont change it it will take out the pump bearing. Can someone explain why if I keep the oil topped off? I am not saying it will not just curious. I am also asking because I am going for hand surgery Friday so it will not be getting pulled this year but I may need to put a few more hours on it this year. Next question is, is it possible to remove the pump without pulling the engine? I have never pulled an engine on a skidloader before. I have done many car engines. Thanks! Justin

 

[Tazza]

I degreased the maching and let it run for a while. I found several leaks at a few fittings which appeard to stop after either tightening or loosening and then then retighten. The large line going from the tank to the pump was oily as well and I tightened the hose clamps. I am getting oil around the front of the pump ( belt side) of the hydrostat pump so I am pretty sure its the front seal. I topped off the fluid today and it took 2 quarts so I lost about 2 quarts in 15 hours with all of the leaks but I would say the majority is from the pump seal. I know this may be a lot of then again I doubt I would ever put more than 30 hours on it a year so it does not get used much. It was mentoined earlier that if I dont change it it will take out the pump bearing. Can someone explain why if I keep the oil topped off? I am not saying it will not just curious. I am also asking because I am going for hand surgery Friday so it will not be getting pulled this year but I may need to put a few more hours on it this year. Next question is, is it possible to remove the pump without pulling the engine? I have never pulled an engine on a skidloader before. I have done many car engines. Thanks! Justin

I think the reason that the bearing *may* fail is due to dirt getting in past the seal, you would be really unlucky for that to happen though.
Personally, if you can live with the leak, keep an eye on it and do it when you are able to do it.
The way it's done is by pullin gthe engine and pump as one unit, honestly it's much easier than you may think. Remove the hoses to the drive motors, case drain hose, high pressure hose from the pump and the suction line. You then remove the wiring to the engine, inlet and exhaust lines, coolant lines, throttle linkage and the blower belt.
You then remove the 4 mounting bolts, two at the back, two under the cab. Lift and slide the entire engine/pump out as one.
The pulley has a taper and key. They can be really tight to get loose. Tighten it up with a puller and tap the thread to shock it free. Remove the retaining clip and remove the washer, drill a small hole in the seal and pull it out with a self tapping screw and pliers. Replace the seal and re-install the engine/pump.
That is a very basic guide, i probably missed some things, but as you have done car engines before, i'm sure you can work it out.
You can actually make a lifting jig to balance the pump/engine. It should be in the servica manual the sizes and angles, they work very well.
Good luck with the surgery and the pump work.

 

[turbomoparboy]

I think the reason that the bearing *may* fail is due to dirt getting in past the seal, you would be really unlucky for that to happen though.
Personally, if you can live with the leak, keep an eye on it and do it when you are able to do it.
The way it's done is by pullin gthe engine and pump as one unit, honestly it's much easier than you may think. Remove the hoses to the drive motors, case drain hose, high pressure hose from the pump and the suction line. You then remove the wiring to the engine, inlet and exhaust lines, coolant lines, throttle linkage and the blower belt.
You then remove the 4 mounting bolts, two at the back, two under the cab. Lift and slide the entire engine/pump out as one.
The pulley has a taper and key. They can be really tight to get loose. Tighten it up with a puller and tap the thread to shock it free. Remove the retaining clip and remove the washer, drill a small hole in the seal and pull it out with a self tapping screw and pliers. Replace the seal and re-install the engine/pump.
That is a very basic guide, i probably missed some things, but as you have done car engines before, i'm sure you can work it out.
You can actually make a lifting jig to balance the pump/engine. It should be in the servica manual the sizes and angles, they work very well.
Good luck with the surgery and the pump work.

Thanks! Does this require a special puller or just a standard 3 jaw or 3 bolt puller? Are there any other seals or things I should plan on replacing while it is apart that are hard or impossible to change without pulling the assembly? I already did the fuel pickup. Justin

 

[Tazza]

Thanks! Does this require a special puller or just a standard 3 jaw or 3 bolt puller? Are there any other seals or things I should plan on replacing while it is apart that are hard or impossible to change without pulling the assembly? I already did the fuel pickup. Justin

A 3 jaw puller should do the job just fine. I can't remember if it has holes in it to pull on too, you'll find that out when it's all out anyway.
That is really the only seal that should need replacing while it's out. Check the seals on the steering linkages on the pump too. If it's wet, they may need doing, easier while it's out of the machine, but totally doable in the machine too.