Case 580d hydraulic pump questions

[ScottAR]

My 580d has developed an oil leak at the input shaft seal... The seal is plenty cheap enough and replacement seems simple enough. I seem to remember reading a post about the replacing the pump coupling and/or the input shaft during this job?
What are the indicators for replacement of these parts?

The machine is on a job at the moment but I will bring it home before winter and get into it further then. Just looking at possible problems and solutions before I start.

 

[willie59]

The coupling and shafts are a spline connection. Of course, the spline shaft on the front crankshaft and the spline shaft of the pump are hardened steel, not so with the coupling. For this reason, typically, the female splines of the coupling wear out first (from age/hrs worked) and the splines of the crank nose shaft and pump shaft will remain solid. Enough time and neglect will wear the splines of the crank nose shaft and pump shaft will wear as well. Once you pull it apart you will easily be able to tell what is worn beyond tolerance and know what needs to be replaced.

 

[mikebramel]

I wouldn't waste the time. 95% of the time the shaft is grooved and the bushings are worn out inside of the pump

 

[willie59]

...and the bushings are worn out inside of the pump

True. The pressure load inside the pump typically pushes the shafts to a certain spot on the shaft bushings. Over time, the bushings begin to wear. This bushing wear allows the shaft to "offset from center". This "offset" will open a gap on an aged/hardened shaft seal and cause leakage. As pump shaft bushing wear even more, pump shafts offset even more, which leads to the gears of the pump to chew into the pump housing. The pump is pretty much done at that point.

 

[bobbyblades]

if so is there play or a way to check if its only a seal issue / pulling my 580k pump this year too/ same leak issue

 

[lantraxco]

Just wiggle the shaft... more than a few thousandths and she needs rebuilt if that's even possible, or replaced.

 

[ScottAR]

Well the leak got bad enough that I didn't want to chance driving it home. The pump came out easy enough. The pump shaft feels plenty tight (no play besides rotation) in the housing but has a distinct wear pattern where the coupling slides on.

My gut tells me to replace all parts but I've been known to go overboard. At least it was a nice day out.

 

[willie59]

Scotty, if the pump shaft seal is easy to replace, go ahead and replace it and give it a go. Even if it leaks again in short order (indicating other pump problem) you're not out a lot of coin. A 580D is an aged machine, every seal on that thing has to be leaning to the hardened (from heat) stage. Likewise, with your machine and it's limited use (it's not like a contractor machine being used daily), it's very possible the pump and its bushings are still in good shape and it's just the seal is hard as a brick bat.

 

[ScottAR]

Seal is out and and new one ordered. (A23903 for anyone watching) We'll see.

 

[ScottAR]

Seal is installed and machine is reassembled. And still leaking... Much less than before... a drip every minute or so... Good enough to get it home at least... I was rewarded for this effort by blowing a loader hose during testing. Such is life with machines.

Likely get a new pump and coupling in the next couple months. This is a personal machine so it doesn't go to work everyday.

 

[bobbyblades]

A freind told me to buff the shaft fine steel wool or sandpaper ,cleanand swab vasaline on shaft before slip on seal. ..good idea? Or dip seal in hydro. During install

 

[lantraxco]

Vaseline is good, if the seal is the kind with a tiny spring on the back side of the lip, pack some vaseline or whatever grease you use around that spring, keeps it from popping off as you drive the seal into place.

 

[ScottAR]

Good tips... Small update. My dad who is retired picked up the seal for me Friday went ahead and reinstalled it against my advice without a driver so we're gonna try again. This seal is not real beefy in cross section so it may be warped. If any of you wonder where my stubborness came from I can introduce you.

 

[lantraxco]

LOL, I think I have the same dad out here in Oregon! :tong

Speaking of dads, on thin stamped seals (I hate thin metal seals) I was learnt to slightly chamfer the edge of the seal that starts into the bore on a grinder or belt sander if you have one, just enough to remove the paint on the corner really. The newer stamped seals are usually not exactly round and don't like to start square. That and a bit of #2 permatex just a very thin coating to work as lubricant and sealant, can really help take the frustration out of installing them.

 

[willie59]

That and a bit of #2 permatex just a very thin coating to work as lubricant and sealant, can really help take the frustration out of installing them.

It's been said that great minds think alike, just not comfortable having my mind being considered in such a comparison.

 

[lantraxco]

:drinkup

 

[ScottAR]

We got chance to mess with again finally. Since the learning process was over it went pretty fast. I found a short piece of pvc pipe about the right size for a driver. No leaks as of yet. We ran it for a couple hours cleaning up an area we want to mow.

The tutorial steps are:

Take the front bumper/skidplate thing off.

Break loose the pressure lines. Ds and down are two lines. Es and up only have one I think. Do not remove till your ready to remove pump as fluid will run out.

Undo the pump mounting bolts.

Loosen the hose clamps on the return hose and gently wiggle the hose with some channelocks so it will come loose without drama.

Get your plug ready for the drain line. We used a big wooden dowel from the shop that measured 1 1/4". If you leave the fill plug for the hydro tank closed it doesn't come out real fast.

Pull the pump out and plug the line.

Change seal. and reverse the process... Return line. bolts. Pressure lines. bumper/skid plate. Hope this helps another sometime.

 

[willie59]

Loosen the hose clamps on the return hose and gently wiggle the hose with some channelocks so it will come loose without drama.

After all these years of working on this stuff, I'm still trying to work our that "without drama" part.

A little trick, whenever you pop loose a suction or return line to tank, apply a little vacuum from a shop vac to the fill port of tank, then fluid loss from the line that's opened will by minimal.