MF 34A Loader Hydraulic Filter Assembly Question?

[PM Baker]

I have a MF 30B with a 34A Loader. The attached picture is of the 10 micron hydraulic filter assembly for the 34A loader.

The manual says for one to disassemble the part numbered 5 (called a By-Pass Indicator Assembly), from the #2 (Filter Head Assembly). I can't get the part out from inside of the #2 (Filter Head Assembly). It also shows a seal #6 for the #5 part. Can anyone tell me how this seal is mounted. I don't see any seal, and I assume that it is tucked inside the filter head assembly, in that groove shown in #5. Is anyone familiar with this filter assembly?

 

[PM Baker]

This 10 micron filter is the important one, since the other filter in the hydraulic system is just 40 microns.
That piece marked #5 is supposed to be some kind of a by-pass valve in case the filter gets clogged. Looking at it, I can't see how it would work. It makes no sense. The part however, looks to be crucial to hold the filter in place, for without it, the filter can wobble open at the top.

The #5 is stuck, and I'm not going to play with it unless, someone tells me otherwise, for the only way to remove it , looks to be to break it (it's plastic). The part is still available from MF ($18.50).

I removed both filters and they are MF OEM's from 1988, that means the last filter change may have been 30 years ago. Amazing!

 

[PM Baker]

This is a representative sample of a similar part number P160351 (Donaldson has no picure online of P160353)

I found that the part #5 of my first post, the by-pass indicator assembly (which is Massey Ferguson part 1096245M91), is made by Donaldson, and is their part number P160353.

I'm now trying to find out exactly how that part works from Donaldson, to see if it should be removed or not.

 

[J_J]

Maybe a replacement filter housing would be better. Look at these.

http://www.surpluscenter.com/sort.asp?keyword=HTF1&catname=hydraulic&PAGELEN=20&PageNo=2

hyd filter from Northern Tool + Equipment

An example of how bypass assembly works .

http://www.tpub.com/content/engine/14105/css/14105_147.htm

 

[PM Baker]

re: Is there a window in the upper filter "head" where you could see a change in color if the plastic part moved due to pressure from a plugged filter?

I received drawings and explanations from Donaldson Filter (they appear to be the OEM supplier for this part). The filter head indeed has a "a window in the upper filter head where you could see a change in color if the plastic part moved". However, my unit has no window, the port is capped off. The service manual says nothing about the "window", or how to know if the filter is in bypass. It appears (?) that MF didn't use that "window" feature, but does use the bypass plastic piece. Although it is hard to believe that pressure on the filter can compress the spring on my unit. I ordered the By-pass indicator assembly 1096245M91 from MF to compare with the one I have in place now.

Here's description from Donaldson:

Dirty oil comes in the inlet port and is directed to the top of the filter assembly by a internal baffle tube. The oil goes down and thru the element from the inside out. As the element becomes dirty the oil pressure on the inside of the element increases until the spring force is overcome then the entire element starts to shift down along with the bypass valve assembly compressing the spring even more and eventually creating a gap between the bypass valve and the baffle assembly. The dirty oil will now go thru the gap created between the baffle and bypass valve and flow out the outlet port. When this happens the filter is in bypass and no fluid is being filtered.[/QUOTE]

 

[PM Baker]

Donaldson definitely is the OE manufacturer of the entire filtering assembly. Their name is right on the head. The filter head indeed has "a window in the upper filter head where you could see a change in color if the plastic part moved". However, my unit has no windows, MF didn't use that "window" feature, but does use the bypass indicator plastic piece.

I ordered the original By-pass indicator assembly 1096245M91 from MF to compare with the one I have in place now. It is the same. The old one was stuck and so, it is likely that the filter (It was 23 years old! Savages!) if it went into bypass, would just pop out from the bypass indicator, instead of the indicator sliding down with the filter (the indicator snaps into the filter).



Here's description from Donaldson:

Dirty oil comes in the inlet port and is directed to the top of the filter assembly by a internal baffle tube. The oil goes down and thru the element from the inside out. As the element becomes dirty the oil pressure on the inside of the element increases until the spring force is overcome then the entire element starts to shift down along with the bypass valve assembly compressing the spring even more and eventually creating a gap between the bypass valve and the baffle assembly. The dirty oil will now go thru the gap created between the baffle and bypass valve and flow out the outlet port. When this happens the filter is in bypass and no fluid is being filtered.