Gehl 4625 hydraulic strainer

[jlbart]

Drained hydraulic tank oil in order to service/clean the hydraulic oil strainer which is located inside the hydraulic oil tank. The strainer is suppose to thread onto the elbow leading the the hydraulic fluid supply line. The strainer was not screwed in place and was actually laying in the bottom of the tank Also, there is a plastic hose stuck in the elbow leading to the supply line. Is this plastic hose/tube supposed to be there?

 

[jlbart]

Here's a picture, taken of the inside of the tank. There's a little reflection from the camera flash. I question whether that hose should be there???? https://mail.google.com/mail/u/0/?ui=2&ik=83acbc56cf&view=att&th=163ecdfe171c4808&attid=0.1&disp=safe&zw

 

[jlbart]

Inside tank

 

[Tazza]

Inside tank

Is the plastic tube stuck in place or just stiting in there?
I don't see why it should be there. I assume this elbow is pointing upwards? If so, it could be a cause of the strainer to suck in air through the hose, that is not ideal.
I have heard of an oil reserve tank with a piece of hose stuck in it that lines up with the inlet to the pump, it fell off when filling the tank by a previous owner. This caused it to suck in air from the end of the tube.

 

[jlbart]

Is the plastic tube stuck in place or just stiting in there?
I don't see why it should be there. I assume this elbow is pointing upwards? If so, it could be a cause of the strainer to suck in air through the hose, that is not ideal.
I have heard of an oil reserve tank with a piece of hose stuck in it that lines up with the inlet to the pump, it fell off when filling the tank by a previous owner. This caused it to suck in air from the end of the tube.

Tonight I took the suction hose off and the orange plastic hose was stuck approximately 5" down the suction hose! Mind you the orange hose had to go through a 90 degree elbow. And...it was doubled in two. After seeing that I have no doubt as to whether it should have been there. It should not have been there. Previous owner not only left the strainer unsecured to the 90 deg elbow - which would have prevented the orange hose from entering the suction hose, but he also left it in the tank. Hose appears to be from a hand pump. My guess is the hose fell off the hand pump and dropped to bottom of tank. Additionally he was unable to get strainer to thread onto the 90 degree elbow, so he left strainer sit in bottom of tank. Eventually the orange hose was sucked into the suction hose. Suction hose is 1" ID. Tazza, the first picture was from inside the tank looking down. The picture in this post is outside the tank where the 90 degree elbow exits the tank. The orange hose was quite rigid; so I'm guessing it was restricting at least 50% if not 75% of the hydraulic fluid flow. This is why the skidsteer whined and why the lift arms worked but were jerky going up. Amazingly, the hydrostatic pump drive system worked fine. I'm not sure without looking at the manual where the hydrostatic pump get's it's fluid from.

 

[Tazza]

Tonight I took the suction hose off and the orange plastic hose was stuck approximately 5" down the suction hose! Mind you the orange hose had to go through a 90 degree elbow. And...it was doubled in two. After seeing that I have no doubt as to whether it should have been there. It should not have been there. Previous owner not only left the strainer unsecured to the 90 deg elbow - which would have prevented the orange hose from entering the suction hose, but he also left it in the tank. Hose appears to be from a hand pump. My guess is the hose fell off the hand pump and dropped to bottom of tank. Additionally he was unable to get strainer to thread onto the 90 degree elbow, so he left strainer sit in bottom of tank. Eventually the orange hose was sucked into the suction hose. Suction hose is 1" ID. Tazza, the first picture was from inside the tank looking down. The picture in this post is outside the tank where the 90 degree elbow exits the tank. The orange hose was quite rigid; so I'm guessing it was restricting at least 50% if not 75% of the hydraulic fluid flow. This is why the skidsteer whined and why the lift arms worked but were jerky going up. Amazingly, the hydrostatic pump drive system worked fine. I'm not sure without looking at the manual where the hydrostatic pump get's it's fluid from.

Scary that something dropped can be sucked in like that....
What's the bet that after you put it backtogether that it runs like a champ again?
With a restriction like that, i'm amazed it worked at all!

 

[jlbart]

Scary that something dropped can be sucked in like that....
What's the bet that after you put it backtogether that it runs like a champ again?
With a restriction like that, i'm amazed it worked at all!

Put it all back together tonight, new pump, new oil (just in case old oil overheated), new hydraulic oil filter. Runs great now. I'm realy happy I found the problem before it ruined something. in hindsight I may have not needed a new gear pump. However, I took old gear pump apart and brass bushings were quite worn. Gaskets all looked fine. Guy at local hydraulic shop said if bushings are worn the pump gears are working into the aluminum case and or causing a gap somewhere. That explans why the new pump seemed to make the issue worse - it was more starved for oil. Now that I have a good oil supply to the new pump things run smooth and fast. Does anyone know what temperature the hydraulic fluid should be? Air temp was 88 F degrees and hydraulic fluid after running 20-30 minutes was running 129 F degrees .

 

[flyerdan]

Put it all back together tonight, new pump, new oil (just in case old oil overheated), new hydraulic oil filter. Runs great now. I'm realy happy I found the problem before it ruined something. in hindsight I may have not needed a new gear pump. However, I took old gear pump apart and brass bushings were quite worn. Gaskets all looked fine. Guy at local hydraulic shop said if bushings are worn the pump gears are working into the aluminum case and or causing a gap somewhere. That explans why the new pump seemed to make the issue worse - it was more starved for oil. Now that I have a good oil supply to the new pump things run smooth and fast. Does anyone know what temperature the hydraulic fluid should be? Air temp was 88 F degrees and hydraulic fluid after running 20-30 minutes was running 129 F degrees .

129 F is just about hot bath temp.; water heaters run at 140 so that's nothing. According to this article temps under 180 are good.
If you have an overtemp light, just make sure it self tests ok at startup, and maybe give it another thermometer test after working it hard for an hour.
What you might want to do is change the filter soon if the pump was making metal, it will get any residual out of the system. I'd cut it open and check for aluminium and brass particulates, it shouldn't take long for it to catch everything, and the next filter change should come out metal free.

 

[jlbart]

129 F is just about hot bath temp.; water heaters run at 140 so that's nothing. According to this article temps under 180 are good.
If you have an overtemp light, just make sure it self tests ok at startup, and maybe give it another thermometer test after working it hard for an hour.
What you might want to do is change the filter soon if the pump was making metal, it will get any residual out of the system. I'd cut it open and check for aluminium and brass particulates, it shouldn't take long for it to catch everything, and the next filter change should come out metal free.

First let me say that every time I post I have to click the preview button and then go back to edit mode in order to get into the text box to type my response. Are any of you other guys running into this? Good point on changing the filter soon I've done it once I should have cut it open but I've already thrown it away. Also regarding the 180° temperature link that you sent that makes sense I've heard some guys say you can go all the way up to 200 - 210° going that high send risky. I am wondering what temperature causes your high temperature hydraulic light to come on?

 

[flyerdan]

First let me say that every time I post I have to click the preview button and then go back to edit mode in order to get into the text box to type my response. Are any of you other guys running into this? Good point on changing the filter soon I've done it once I should have cut it open but I've already thrown it away. Also regarding the 180° temperature link that you sent that makes sense I've heard some guys say you can go all the way up to 200 - 210° going that high send risky. I am wondering what temperature causes your high temperature hydraulic light to come on?

Yeah, the preview and return is just part of the process. As is having to code in everything like you were building a webpage in notepad, that's why I always open this cheat site to copy the code from as I don't slog it out in html all day to have it second nature.
The i80 degree number does seem to be a bit on the low side, as it's below most engine operating temps, and a quick image search of hydraulic temp gauges shows an upper range of 240-320 as common. Auto trans. run basically hydraulic fluid and they run in the mid 200's or higher.
As for finding the rating of the idiot light activator, if you can find a part number for it, the specs should be listed somewhere, worst case scenario would be to remove it and heat it in a pan of oil on the stove and measure the temp when the DMM says it closes.

 

[Tazza]

Yeah, the preview and return is just part of the process. As is having to code in everything like you were building a webpage in notepad, that's why I always open this cheat site to copy the code from as I don't slog it out in html all day to have it second nature.
The i80 degree number does seem to be a bit on the low side, as it's below most engine operating temps, and a quick image search of hydraulic temp gauges shows an upper range of 240-320 as common. Auto trans. run basically hydraulic fluid and they run in the mid 200's or higher.
As for finding the rating of the idiot light activator, if you can find a part number for it, the specs should be listed somewhere, worst case scenario would be to remove it and heat it in a pan of oil on the stove and measure the temp when the DMM says it closes.

Your hydraulic guy is right. Gear pumps do not wear in, they wear out. Any slack in the bearings will cause the gears to push out a little more and eat up the housing, You can replace the bearings, but that will mean the gears do not get close enough to the housing and you get less flow.
Vane pumps on the other hand, they can wear vanes or the housing a bit and still seal just fine, but they do not operate well at low RPM
Glad it's running well now.
I use internet explorer, so i don't need to hit preview, the site is quite fussy....