Ok, it's me again, shaft seal on main pump on JD300b

The shaft seal on the main pump started leaking yesterday and we were making progress too darnet, I have never messed with something this in depth, so if it's not a job for a not so experienced person in the hydraulic field, it's going to the shop, I've gotten the pump off and you can see where a small section the seal has gone at the shaft, any suggestions would be appreciated.

Patrick

By the way yawls help has been very helpful and the different post are very helpful I just hope people learn from my questions as I ask them.

The seal you can see is more or less a dust seal. The seal that holds oil pressure is a "quad ring" an inch and a half deeper in the pump.

MAY be just a worn ring, typically the shaft is grooved, as well.

Also, if the shaft endplay is excessive it"s tough on the seal ring.



A thorough OH of the pump is pretty detailed and, at the very least, you need to peruse a good shop manual before deciding if it is something you feel comfortable doing yourself.

I agree a JD tech manual is required. I think a person with good mechanical skills can R&R shaft to renew quad ring & dust seal. If hyd's are functioning properly there's no real need to R&R inlet/outlet valves except for peace of mind. Remember to identify pistons so they can be returned to original piston bores.

I've good mechanical skills the hydraulic end like this is something I've never tackled though with the exception of the hydrostatic drive on mowers, I also have a tech manual (TM-1087) and parts manual (PC1428) and the tech manual does mention what you said Tx about making sure you put the pistons back in the same bore they come out of, how important is the bench fixture D-01006AA mentioned in the book, from what I can see from the book this is not much more than something to help in supporting the pump and I can build something to do that and mount it in a vise on my bench.

If the pump is already out - it's not that big of job to pull it apart and put in a new quad-seal and teflon backup washer. Before you take it apart - put a dial indicator on the shaft and pry it back and forth. Make sure it has around .002" end-play down to zero. If it's too loose - now is the time to order the correct shims. If it measures let's say - .008" then you can just order a .006" shim and be fine. You add shims to make the bearings tighter. Once you are done measuring - just take out all the piston-caps, springs and pistons. If the springs show wear on the sides - get new ones. Standard procedure it to mark each cap with a stamp, from #1 to #8. Put each cap aside with the piston that came out of it. Deere says to do it. Personally, I don't think it makes a d*amn bit of difference. New pistons are all the same, i.e. not custom matched to bore. When you pull out a used piston -even if put back in the same hole it's likely you'll have rotated it and it won't be in the same place anyway. I've rebuilt many pumps without worrying about it and they worked out fine. But -can't hurt to "follow the rules." Once the pistons are out - take out the four 1/2" bolts from the end-cap housing. Remove it with that part facing up when you do it Then pluck out all the loose valves from the pump face (8 of them). Then yank out the shaft. Turn the pump over and take out the snap ring that holds in the dust shield. Then pry out the seal. Then take out the shaft. Not too far below that dust seal is the groove where the quad-ring and teflon backup washer goes. Pick out any remnants and put in the new washer and seal. Make sure the shaft does not have a deep groove worn into it where that quad-rind rides. Now just put it all back together with new seals (Deere has a complete seal kit). One main updated for "virgin" pumps. Originally the big piston caps just had o-rings. When putting in new o-rings - there are teflon sheafs that go over the o-rings to help them from getting cut when you tighten the caps. Start to finish it's a half-hour job for someone with experience. Even it takes you a few hours the first time - it's not a big deal. I strongly suggest you take out the stroke control valve and inspect. If ANY wear get a new valve and seat. It is a major wear item.

An update, I've got the pump off apart, shaft is in good condition no signs of wear end play is .015 a local repair shop that I found today about 10 miles out of town helped check the end play at no charge he also said once I got the parts in (on order) to bring it back and he'll help me set the end play, as I was taking the pump off I noticed what looked a bolt broke off at the pulley that the pump drive is attached to I checked the book this evening (forgot to check it out before I ordered the parts) remembered it this evening when I was washing the caked up dirt off the front. I feel like this probably caused a lot of the problems along with age of the pump. With the info jdemaris sent (Thank you very much) and the tech manual I have it so far has been a relatively easy job a little slow because I went step by step reading ahead to make sure I wasn't going to miss anything, if all goes well I should have it back up and going tomorrow afternoon.

Thanks everyone
Patrick

The end play on the pump was what I would say is excessive .015 allowance according to book is .001-.005 recommendation is .002 shims should be in today I've found a person yesterday at a shop that I've seen as I passed by it but never new what it was sets back behind a trailer sales place that's going to help me set the end play once I get the parts this person has been very helpful I will be doing some advertising for him. If things go well should be back to digging tomorrow.