300 u hydraulic pump rebuild.

[Paul 300 U]

I'm finally about to rebuild the
hydraulic pump on my 300 utility. The
pump is quiet and I have no issues
lifting my front plow, rear mower or
power steering. The pump however leaks
like a sieve from where the tach cable
screws in .(see picture) and it's costing
me a fortune in hytran!! I don't have
much mechanical experience but have been
doing ok done with the help of these
forums so don't be bashful with your
suggestions.
Two questions up front:

1. Have any of you folks ever used one of
these kits and how'd it work out.

2. The instructions say that when
reassembling be sure to set the #1 piston
at top dead center of the compression
stroke as described in the operators
manual (which i do have). How do i do
this? And, Do I need to do anything
before I disassemble to make sure I get
the timing correct when i reassemble?
Thanks for the help!

 

[used red MN]

Follow number one spark plug wire ..plug closest to the fan.. back to the distributor cap. On the metal distributor housing make a mark with a Sharpie or tape and a pen at the centerline of the terminal that number one plug wire is attached. If set as factory it is usually near the 1 oclock position when viewing from the rear. Remove the distributor cap and turn the engine until the rotor terminal points nearly to your mark. Now look in the manual and find how to set the ignition timing. It hopefully describes which mark on the front pulley to line up with the pointer for TDC. Line those up and you are there.

Edit: I was not clear that this should be done before removing the distributor.

This post was edited by used red MN on 08/06/2021 at 10:44 am.

 

[Charlie M]

In my opinion lining up #1 to TDC with the distributor attached is easier than without it because you can see the rotor to know where you are. Its not likely the distributor can be removed and not have it move in the process so you need to be on TDC when reinstalling it. The piston can still be put to TDC without the distributor but you have to see into the cylinder.

 

[Janicholson]

Tips on the seal replacement. While you have it apart, replace both end seals. The front seal into the timing cover is also pretty easy to fix. The primary issue will be making sure the pump shaft is not grooved where the seal now rubs. The wear should be very minor and almost undetectable with your fingernail. If deep enough to see/feel, there are two solutions. the first is to purchase a speedy Sleeve to cover the shaft where the groove is located, it is a very thin steel cylinder that restores the surface. The Kit seal will flex enough. Put chassis grease on the seal lip when assembling the seal. The second possible solution is to put one or possibly 2 thinner seals into the housing (OD ID the same, thickness thinner) this allows the lip of the seals to be on different locations on the shaft. Again put grease on them, and between them when assembling the pump. Seals can be removed using multiple sheet metal screws into the seal steel flange to allow prying them out. If you do not take the main body of the pump apart, you will be better off. (opinion) (don't go deep with the screws). Use locktite on the gear nut to assure it does not come off. They can, and it is a disaster. Follow the locktite directions for cleaning, and primer. Jim

 

[Janicholson]

Oh yeah. Make sure the pump gear goes back into the same tooth timing on the cam gear when installing the pump, or the timing of the distributor will be way off. Jim

 

[the tractor vet]

Ah yup the seals can get old hard and leak , they can groove the shaft like Jim has said , yep sometime you can luck out with replacing the seals and the use of a speedy sleeve , BUT here is the kicker the shqafts of the pump gears ride in bushing on sone that can be replaced and on some the shaft ride on the pump housing and when the housing gets woren and has excess play no new seal will solved the problem as in short order they will start leaking and you are back to square one .And you will have to get a new pump .

 

[D Slater]

If you don't think any hydraulic oil is getting in crankcase oil? Little simpler to replace rear seal without removing pump and see if it holds. If pump is worn enough so outlet or part of outlet pressure gets to seal it won't hold. Just turn engine so distributor rotor points straight up. remove the two attaching places at pump. Then make sure the drive shaft doesn't fall out of the distributor drive. Notched drive in back of pump has a screw in center to remove, then it comes off shaft and has a little key in shaft. Watch not to lose it. You can get to seal then. Long as you don't let shaft slide out of distributor put it back in the notch with rotor to top and you will be in the same time it was when removed. Don't turn engine after distributor is out.

 

[Paul 300 U]

Thank you. Would have been nice not to remove the whole pump. Unfortunately hytran is mixing with oil so it looks like i will be removing the pump.

 

[Paul 300 U]

Thanks for the reply. I read something about that a while back but didn't quite get the point. You're explanation makes sense. Anyway of knowing what my situation is? Will it be obvious when I look at the pump housing? Thanks.

 

[Paul 300 U]

Thank you for the info. Hopefully my kit is complete and contains both seals, i believe it does. From other responses i hope the worst case is a slightly grooved shaft that i can repair with a speedy sleeve. I was not familiar with that problem, solution and product so the the advice is appreciated.

 

[Paul 300 U]

Thank you. Between this and the manual it looks like i should be on a good track to getting this started correctly. Much appreciated.

 

[Paul 300 U]

Thank you. Having not done this before I will need to learn as I go along to understand how seeing the rotor allows me to line up #1 to top dead center. I'm sure i will be posting again as I progress. As you suggested, I will start by keeping the distributor in attached to align to TDC.
Thanks!