Suction Side Hydraulic Filter

[dieselscout80]

I bought a new hydraulic pump for my IH 424 tractor. IH did not put a filter on the 424 rather just a metal mesh strainer. I want to protect my new pump with a filter, but Surplus Center suction filters are either 9 gal per minute or 25 gal per minute my tractor pump is 10 gal per minute.

The 9 gal ones have .75" fittings where the 25 gal ones have 1.25".

Should I get the 25 gal or 9 gal?

 

[PILOON]

Since there was no filter to start with surly the 9GPM is better than none and it fits, besides the mesh will take care of any big stuff.
Also .75 fittings is probably a closer match for your system.
Worst case, change filter at say, every 500 hrs.

 

[MHarryE]

IH has only a suction strainer for a reason. Suction filter restriction with cold oil can harm a pump. Also if only a suction filter is used, it cannot have the same filtration capability as a pressure filter. Recommended design guideline is to have a pressure filter downstream that will clean the circuit to a finer level.

My Kubota CUT is an example of a tractor with a suction filter; however, the filtration level of that suction filter is not capable of meeting the requirements if the hydrostatic transmission. Therefore an additional filter is required after the hydro charge pump and before any of the rest of the hydro circuit.

Wanting a suction filter for your tractor, I suggest the larger one. I believe your tractor has a gear pump so it is pumping at max flow for the design speed at all times. You really want as little restriction as possible at all times.

 

[mrmikey]

Keep the strainer and go with a return filter, cavitation caused by a suction filter will take out a pump. A pressure filter is nice but expensive....Mike

 

[J_J]

Suction filters are necessary on hydrostatic transmission. Usually around 10 micron or smaller and changed often

 

[dieselscout80]

Suction filters are necessary on hydrostatic transmission. Usually around 10 micron or smaller and changed often

JJ, what I'm understanding from your statement is to not to add another filter is that correct?

 

[dieselscout80]

These are the filters I am looking at.

3/4" NPT 9 GPM FA1112-25 SUCTION FILTER W/GAUGE 9 GPM at 25 microns

1-1/4" NPT 25 GPM ZINGA SUCTION FILTER 25 GPM at 25 microns

1-1/4" NPT 25 GPM 141 MICRON ZINGA SUCTION FILTER 25 GPM at 141 microns


Current filter/Strainer
3044368R93

 

[J_J]

IH has only a suction strainer for a reason. Suction filter restriction with cold oil can harm a pump. Also if only a suction filter is used, it cannot have the same filtration capability as a pressure filter. Recommended design guideline is to have a pressure filter downstream that will clean the circuit to a finer level.

My Kubota CUT is an example of a tractor with a suction filter; however, the filtration level of that suction filter is not capable of meeting the requirements if the hydrostatic transmission. Therefore an additional filter is required after the hydro charge pump and before any of the rest of the hydro circuit.

Wanting a suction filter for your tractor, I suggest the larger one. I believe your tractor has a gear pump so it is pumping at max flow for the design speed at all times. You really want as little restriction as possible at all times.

I tend to disagree about the suction filter. It is there for a reason and that is to keep the hydro clean as possible.

I also disagree about the suction filter to filter as good as a pressure filter if they are both 10 micron.

My closed center hyd hydro system uses a 10 micron filter and has been using one since about the mid 90's. Of course I change them often.

It doesn't make any difference about the size of filter as long as it is equal to or larger. Tractors with gear transmissions, use return filter.

 

[J_J]

JJ, what I'm understanding from your statement is to not to add another filter is that correct?

You can add all the filters you want.

Some hyd system choose to add large micron filter directly in the tank.

Other hyd systems only use a suction filter especially for hydrostatic transmission,

Other hyd system only use a return filter thinking that the fluid in the tank is now filtered.

 

[dieselscout80]

I decided to order the 25 gal per minute / 25 micron filter.

https://www.surpluscenter.com/Brands/Zinga/1-1-4-NPT-25-GPM-ZINGA-SUCTION-FILTER-9-4544.axd

 

[muddstopper]

My personal preference is to use both a suction and return filter. Take the lid off a empty 5gal bucket of hydraulic oil and look in the bottom. You will see all kinds of little nasties stuck to the side of the bucket and the bottom. Just because you open up a new can of oil and pour it into the tank, dont take it for granted that that new oil is clean. Without a suction filter, all that nasty stuff goes thru the hydraulic pump, then the valves before it is filtered. I am like JJ, use a suction filter at least as small micron size as the return filter. Also make sure you have a mesh screen in the fill port of your tank to catch anything that might accidentally enter into the tank when the cap is removed. Dirt, sticks, trash, etc. If someone is having a problem with their pump cavitating because of a suction filter, they either have a dirty filter, or one that is of insufficient capacity to carry the flow of oil required.

 

[dieselscout80]

The return on my IH 424 is inside the cast iron reservoir where the three point valve is, so I don't think a return filter is a option.

 

[dieselscout80]

Well I installed the new pump and filter and now my 3 point works great. The install was a bit of a pain to get everything lined up.

JJ, thanks for convincing me to add the filter. I appreciate you knowledge and assistance.

 

[doxford jim]

Suction filters are necessary on hydrostatic transmission. Usually around 10 micron or smaller and changed often

Hi JJ,

I live in a cooler part of the country and even a 10 micron filter can be slow in our summer. I usually run a 30 micron and it does clean up the oil.
During the winter (our temperatures can get down to -35C or colder) the hydraulic oil gets too thick for a fine filter to be used. I tend to use a wire mesh type suction screen (around 140 micron) as originally supplied with the tractor as this allows better operating during cold weather.
I also change out the hydraulic oil fairly regularly so that probably helps too - only around 12 litres per fill IIRC.

 

[doxford jim]

Ooooops - I didn't notice the hydrostatic transmission comment. Don't take any notice of the above post as it isn't that relevant.
Thanks