Hydraulic Fluid Canister Removal, Inspection and Cleanup

[Koal]

On our ‘98 American Dream We currently have our the old (likely original) PS Pump removed and awaiting replacement. In addition the hydraulics manifold / valve assembly has also recently been removed, inspected, cleaned up and reassembled including all new O-rings . With the hydraulic lines empty of fluids it made for the perfect opportunity for us to remove, inspect and cleanup the big hydraulics fluid canister found and mounted at the rear of the engine bay compartment. This post documents that removal, cleanup and reassembly and reinstallation of this canister.

The entire canister was extremely dirty, coated with dirt, grease, grime and it had wet marks on the exterior sides giving us concern that it may be leaking. The canister has a steel top, held in place with a two piece metal strap/bracket, and there is a round port on the top with a screw in dip-stick for checking the fluid level. The main body of the canister is held in place by a large steel mount bracket bolted to a vertical steel beam.

We have learned that the canister acts as a holding, cooling and filtering reservoir for the hydraulic fluid. It also provides an area for the fluid to expand as it heats up and contract as it cools. At the bottom of the canister are three hydraulic hoses. The larger hose is the hydraulic fluid outlet to the power steering pump inlet port. Below are pictures of the canister components before during and after cleanup. Our canister contained a single hydraulic fluid filter. We understand that others have instead up to three smaller filters stacked on top of each other.

[Koal]

Removing the decades of accumulated grease, grime and dirt from the canister and related parts was accomplished using a large 5 gallon pail, mineral spirits, scrubbing and scraping tools and elbow grease . We were pleasantly surprised to find that the top and main canister were made of stainless steel. The two piece strap that secures the canister top to the canister bottom as well as the main bracket that secures the entire canister to the steel frame are made of regular steel. These parts had started to bleed rust that had coated the exterior of the canister. After cleaning the interior and exterior of the canister parts and then carefully inspecting the canister we were pleased to find that the integrity of the canister itself was solid with no leaks or cracks detected.

Below are pictures of the mostly cleaned up parts , but prior to applying any paint . Also shown is the rubber gasket that forms the seal between the canister bottom and the canister top. Also note the stamped markings on the exterior of the canister indicating that it is a Nelson canister and it also identifies the filter and gasket numbers for replacement.

[Koal]

During the removal of the canister hoses we had inadvertently damaged the threads on the middle hose fitting, so as part of our cleanup we removed it and replaced it with a new equivalent fitting using white pipe compound containing Teflon .

We also painted all canister and related parts with a high gloss black rust paint. We also purchased a new replacement equivalent filter from WIX

We have reinstalled the painted canister back into the engine bay and reattached the three hoses to their respective fittings which are helpfully all different sizes.


We will include that picture of it installed in a future post as well as confirm the WIX hydraulic filter part number used and compatible with the OEM Nelson filter originally used in this canister.

[Ray,IN]

Great work! Your detailed progress W/pictures can be invaluable when i decide to do that to mine.
My problem is, Winnebago welded an angle iron above it that prevents removing the top. My entire tank has to somehow come out from the bottom.


I'll be monitoring your thread and progress. Thank you for taking the time to document this project and sharing it with us.

[bluebirdBMC]

Excellent work. I didn't have the time to pull my '97 vintage cannister out and refinish it properly like you did so I only cleaned out the insides with paper towels (nasty grey coating on the wall surfaces), replaced the filter, and refinished the lid and locking ring. As my rig is about to hit 27 years old, I think its time I seriously considering replacing those critical hose lines. I already own a portable hydraulic hose crimper kit. This would be one hell of a project...

[Koal]

Thanks for the positive feedback Ray,IN and bluebirdBMC. Much appreciated.

Ray our canister mounting bracket that is bolted to a vertical frame member has a strap that wraps around and secures the lower part of the canister in place … that strap is held in place by two bolts … if you loosen those strap bolts the whole canister should loosen and you might be able to lower the canister with its attached hoses left in place sufficiently to remove the top of the your canister . The big main canister strap and one of the two bolts I’m referring to can be seen in the previous posting by bluebirdBMC.

One of things that was suggested to me that I found very helpful… if you need to remove and replace any of the fittings that directly attach to the canister, heating the metal fitting on the canister with a small propane torch for a minute or two makes a huge difference in getting the old fitting removed.

Below is an Amazon link to the canister filter we used that is compatible to the Nelson 87610 OEM filter.

It’s a WIX 57317

https://www.amazon.com/WIX-Filters-5...ps%2C93&sr=8-1

[411jeff]

I'm about to work on mine. I'll drain the tank first but when you disconnected the hoses did you loose much fluid from the hoses? Is there any concern of air getting into the lines and causing problems? Or will it self purge any air?
Thanks

[bluebirdBMC]

Are those 37-degree JIC fittings? Maybe you can buy some cheap hydraulic hose connector caps on eBay. I actually own a set of caps that I haven't used yet. I wouldn't mind pulling my tank too as it's nasty and needs a cleaning and fresh paint.

There is an active thread on the irv2 Spartan Chassis section that journalizes a refurbishment of the same tank. The fittings appear to be JIC style. It probably would be a great time to do maintenance on your hydraulic fan too if it has a bad seal, etc. and you could also try to flush the lines too.

[Koal]

For our coach, I siphoned the fluid from the tank as there is no drain cog. I disconnected each hose and immediately zip tied the lines high enough so there would be no spillage. We didn’t lose more than maybe half a cup.
In our case our pump was shot, so all hydraulics were drained. As most of these pumps are vane style pumps, it’s critical that if the pump drained it must be “primed” to prevent air lock which would cause the internal workings of the pump to possibly start cavitating and chew itself up.
We aren’t there yet, but when we install new pump, our intent is to disconnect the large fitting on the bottom of the canister, loosen or remove the output fitting on the new pump, and pour the hydraulic oil directly into the big fitting until you see fluid coming out of the loosened pump fitting. This procedure was recommended by the experts at “Strictly Hydraulics “ in Dartmouth Nova Scotia.
We’re not quite there yet, but we will keep you posted as to how this works for us.