Hydraulic Filters

[Edward Buker]

I have convinced myself to use Allison/Castrol Transynd in my hydraulic system and will be changing that fluid soon. Given I am going to Transynd, the next fluid change will be a far into the future. Given that, I was looking at the hydraulic filters that are available that would best serve this purpose. What I have installed now is a Napa 5151 which is actually a Wix 51551. The rating on that filter as stated by Wix is 10 micron nominal, Beta 2 at 20 microns which indicates that it pulls 50% of 20 micron particles per pass. No bypass valve.

There is a Cat cross  PN 077-3492 (high efficiency) to a Baldwin BT839-10 which crosses to the Wix 51551. The Cat filter spec just says 11-27microns which in Cat terms would mean a 10 micron nominal with a 27 micron absolute which would be a better filter then the Wix filtration wise. The Cat filter has a 25psi bypass valve while the Wix and Baldwin do not have a bypass valve.

So the questions are, has anyone used the Cat 077-3492 for a hydraulic filter in their coach and what are the pluses and minus of having or not having a built in bypass valve at 25psi? In general I like the robust construction of a Cat filters and the better performing filter media but I have no real idea what is right regarding a bypass valve in our application or if anyone has already been using one of these Cat filters.

There is also a cat standard filter PN 119-4740 for this application which is rated at 28 to 40 microns, while it fits, it would not be a PN I would consider using. I bring this up for information in case someone already has one in their coach. There is also an Ultra High Efficiency Cat version rated at 2 microns but I would be afraid that would plug up so that is out.

Any thoughts or experience?

Later Ed

[Gerald Farris]

Ed,
I am using the Napa filter on my coach. However, the by-pass valve in the Cat filter may be beneficial, and it may reduce the risk of high pressure in the return circuit assuming that the filter is in the return circuit instead of the pump suction circuit. I have seen hydraulic cooler failures caused by excess pressure in the return circuit during start-up in freezing weather in the Monaco era Beaver that uses AW 46 hydraulic fluid. 

Gerald

[Joel Weiss]

Ed:

I'm planning on replacing the hydraulic filter and fluid on my MH next spring.   Do you know what the filters were for that application in SMC-era Beavers?  My understanding is that the system is currently filled with ATF.  Do you know the fluid volume, that is, how much will a replacement by Transynd cost?

Joel

[Edward Buker]

Thanks Gerald, I will do a little more checking with Cat regarding that filter and post if there is anything preventing its use in our application. Thanks for clarifying that the relief valve may be advantageous and not a negative.

Joel, my Marquis is a 2002 that says Roadmaster on the back frame but for all intensive purposes it is an SMC era chassis. My hydraulic tank is in the back passenger side compartment. It measures 21 inches wide, 7.5 inches high to the sight glass, and 7.5 inches deep. My calculations were 1102.5 Cu In which was 4.77 gallons + the filter, so 5 gallons would be about right. Gerald thought about 5 gallons did it.

I have a local truck supply shop and they have Transynd priced at $35.84 a gallon. My local Freightliner shop was getting $40 and change. So with the filter if you had the means to do it yourself, about $200. You can weigh the pricing you get with labor and markups against that cost.

Later Ed

[LaMonte Monnell]

I am still trying to figure out where my hydraulic filter is located. I have a 2001 Contessa . I do see a huge type filter in the rear right side that must be 8'' in diameter that looks like it may screw on..is this it?

Is this just used for the power steering of this coach?

 My plastic hyd fluid tank is in the last bin on the passenger side of coach. It says Dextron III on it.

[Edward Buker]

LaMonte,

The Dexron 3 sounds right but I am not sure what unit you are looking at. The 8 inch diameter seems large for a hydraulic filter and the size maybe more like a receiver drier cartridge. You should check the tank and filter housing and see if the plumbing goes between the  two. Your Beaver manual should identify a hydraulic filter number if you have one and if you look up that number it should have the dimensions to help sort this out.

You may want to post a photo to see if what you are looking at can be identified. On my hydraulic system the filter is by the tank in the rear compartment and looks much like an old GM Chevy V8 PH8A spin on type that holds a quart if that rings a bell with you....you could be a Ford or Mopar man in that era.

Later Ed

[Michael Rump]

Hi Ed,

Was wondering if you changed your hydraulic fluid over to transynd?  And, if so, what filter did you decide on?

Additionally, did you notice any performance changes in the system, I.E. operating temperatures, etc.?

Thanks!