Good Morning Team: Am working to resurrect an old Melroe M-500 loader. The bucket tilt valve body is seized in its bore. It looks like battery acid over the years slopped out of the battery and dripped down on the rear of the housing were the rubber seal resides. The Melroe Service manual has no information on its disassembly and repair. I do have a good original Melroe parts manual that shows it breakdown, but unfortunately there is no reference of the original supplier of that valve to Melroe. I was thinking that the valve bodies were made by Cessna along with the hydraulic pump, but not sure - there are no markings on the Valve body housing to provide a reference, perhaps Gresen - not sure at this point. My hope is to secure a specific reference of the series of valve and its manufacturer along with a service manual for the valve body itself. Hopefully, I can service this unit in place without disassembly of all the spaghetti of lines running along the bottom of the structural cross member were the valve body is located. Any insights or help with this is greatly appreciated! ~ Orangeman
OK - so yesterday after calling our local Melroe-Bobcat-Doosan Dealer and talking with the parts personnel - even though I have the part number for the valve and the pieces that the valve is comprised of nothing comes up. They were able to advise that the valve body number was correct and original to the machine. Unfortunately, there is no support for much of their 60's machines with the exception of the floating steering clutch plates, chain, and wheel and rims. That said, a call to Gwinner North Dakota was placed to talk with customer service, the company has no reference or engineering librarian for any of the old machines that were responsible for launching their success. What was learned that since the days of Melroe - Clark- Melroe - Ingersoll Rand- Melroe - then Doosan that the employees chasing parts have a "Conversion List" that will get you from an old part number (i.e. 1960's) to a currernt part number that is "if available". Couple that with newbie experience personnel and you have the recipe for nothing much available. On the good, Gwinner was able to provide a brief listing of Melroe - Bobcat parts yards that the company is aware of. I guess us old geezers working on old equipment are faced with obsolescence and/our modification to keep these units running. There must be an engineering document that list the OEM suppliers of parts for Melroe - Bobcat machine - surely Melroe Bobcat didn't manufacture all of their own hydraulic parts! Well still searching - any guidance or pearls of wisdom on this are most welcome. ~ Orangeman
I would bet this is a valve that was built and used on several things you just need to find the right person to help you out. I also bet you will have to remove that valve. I see non running bobcat of this kind for sell alot you may have to buy one for parts. If you could get a good picture or use some info you have found maybe some one like Surplus City could help you.
Morning Old Doug: As much as I wish to see this "Old Melroe Donkey" run again and move a little topsoil, am absolutely sure that your right on the removal of the valve, and yes its design is tied to the loader lift valve through a 3/4" close nipple, so yes both valves and plumbing to those valves will need to be disassembled in order for the tilt valve to come out as a unit. Was thinking that there might be a few Melroe folks still with us that worked in Melroe Design Engineering and now part of the retirement club/pensioners community -lol. In close, appreciate the reference of Surplus City - I'll be certain to check with them. Respectfully, ~ Orangeman
From the one picture on the web I could find of the tilt valve, it looks to be a Gresen SP series valve most likely with a fixed relief. Should be pretty easy to reseal. If it is too bad to fix you may want to replace with a mono block type valve from surplus center.
After some more research, I believe a new alternative to your valve would be a Prince RD2500 series valve. I believe they are basically a clone of the old Gresen mono block valves with some modern updates available. If your inlet and outlet ports are 3/4” pipe thread, this may be the one. RD-2575-T4-ESA1.
Morning Acecadet: Thanks for all your excellent efforts and importantly the great information! I have worked with Prince Engineering controls before to source a replacement sectional valve for an old Dynahoe Model A backhoe equipped with a HUSCO valve body. Prince's Engineering staff was extremely helpful. The inlet and outlet ports appear to by 3/4" - unfortunately I have not been able to progress with removal of the valve yet as the unit is outside and snow has been frequent here. Will post details here as a follow up as work progresses on this. Hopefully, by doing so this thread will help others with perhaps a similar or related problem. Again, thank-you for all of your insights and efforts on this - much appreciated! ~ Orangeman
Just a little update since some warm weather has come our way. I recently resumed work on the old Melroe - Acecadet nailed it on the Valve body. After removing some dirt and dried out topsoil from the top of the valve, it clearly shows the following embossed into the housing: Gresen 2701 LMN After a few searches it comes up as a Gresen SP mono block valve. In order to access the valve body there is a total of seven hydraulic lines that need to be removed in order to service this unit, (i.e. there is a bank of two complete valve bodies that are tied together with a 3/4 SAE close nipple so in order to work on this both valve bodies have to come out as an assembly then remove the SP-1 mono block from the 3/4 SAE close nipple. While I am in there I think it would be prudent to replace the 3/4" close nipple. Is there a secret to the removal of the snap ring at the end of the valve body? There is a rubber cap that cover ups the end of the valve body, then the inside snap ring that holds what appears to be a steel (dished) type endplate I have seen some cut the end of the valve body to remove the snap ring - would prefer not to modify the unit just to service it. It might be feasible to salvage this unit if I can remove the snap ring and nudge the valve in its bore. Any guidance or insights on this would be greatly appreciated. Thank-you! ~ Orangeman
Give that metal disc a good hit with a brass drift or even a small piece of wood. Then you can get the snap ring out. When you get the seals be sure to slide the spool in the seals very carefully from the back to the front. I have cut more than one seal trying to put those damn things back together. The seals I used were from Deere, part number T10638
Acecadet - thanks for the sage advice. Will try that - now that our snow is melting - things are turning to mud. Appreciate the parts number - fortunately I have the manuals for the old Melroe and they also list a part number but I am sure there is a conversion to the new Melroe Bobcat - Doosan listing.
Lubricate, tap, tap, tap with the machinist hammer and brass drift very gently. Did I see it move, yes I did see it move, more lubricant, (kroil) very light tap, tap, tap - more movement of the valve! Will it go for and aft, then return to center - yes! It's great when these things work out. Next up moving on to magneto service. End bearings that center the armature shaft are worn allowing radial and lateral end play. Fortunately the bearings are available so service should be pretty easy. In close, certainly appreciate all the good guidance and advice here. Respectfully, ~ Orangeman