JD350 hydraulic pump squeel

DaveP · Post by **DaveP** » Sun Oct 24, 2010 8:06 pm

Nice to have found this forum. From looking around on it, it is a wealth of information.

From a post on this site, I believe my crawler is a 1966 based on the serial number. As some others have mentioned, the dealer didn't have much information on this machine.

I have a screeching noise coming from the, I believe, hydro pump. The noise is very light when the valve is not actuated. But when the valve is actuated to move the blade in any direction, the screeching is very loud. Originally I thought the noise was from the valve assembly, but I think its being amplified to it. It gets loader as the rpm is increased. There is also some vibration as the blade moves. Is the hydraulic pump starting to fail?

I have a manual that shows how to disassemble the pump. I beleive the pump is a Cessna model, but haven't taken it off yet. Has anyone rebuilt these pumps or can they be rebuilt? I've seen replacements on the web for $425. Are there cheaper pumps, assuming it is the pump?

Thanks in advance.

KenP · Post by **KenP** » Mon Oct 25, 2010 4:34 am

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Tigerhaze · Post by **Tigerhaze** » Mon Oct 25, 2010 12:29 pm

This should be a useful thread for you:

http://www.jdcrawlers.com/messageboard/ ... ght=cessna

DaveP · Post by **DaveP** » Mon Oct 25, 2010 6:25 pm

Thanks for the replies.

As stated, the first thing to do is check/change the filter element and clean the mesh filter. Thank you for bringing this up, I'm having brain farts in my old age.

I've removed the six bolts on the filter cap on top of the reservoir tank, but it will not lift out easily and I don't want to force it without knowing what will happen. Looking down the fill neck I see the threaded hole that the filter element would be bolted to, based on the manual diagram, but there is no bolt in this hole. So either the filter spun loose and dropped inside or was removed in the past. Could somehow the filter be hanging up on the cap and not allowing it to come off? I've tried prying a little with a screw driver but it will not lift more than an 8th of an inch. It seems to be catching on the bypass side of the cap. The cap will not even twist or rotate. Do I get a bigger monkey wrench and go for it? Or is there something I'm not seeing?

Again, thanks.

DaveP · Post by **DaveP** » Mon Oct 25, 2010 8:09 pm

Update. I did manage to get the filter cap off. It would have been nice if the manual had said it was pushed onto a pipe with an O ring. I was smart enough to pry evenly on both sides and lift the cap off without damaging anything. And the filter element was laying in the bottom of the reservoir. The oil seems pretty clean, but I'll go ahead and drain it, remove the mesh filter and clean and put new oil in.

The manual call for John Deere type 303 Special-Purpose oil or equivalent. I was given AW 46 hydraulic oil with the machine. Is this the right stuff?

Will post if the screech goes away.

cdunn · Post by **cdunn** » Tue Oct 26, 2010 6:21 pm

My 350 dozer is making the same noise you describe. It's a little hard to determine just where the noise is coming from, but its somewhere in the hydrolic system. My dozer does not have a filter inside the reservoir, all reference in my manual that refers to this filter is associated with a loader. Do the dozers not have it or do I have an odd ball.

DaveP · Post by **DaveP** » Tue Oct 26, 2010 8:23 pm

cdunn, my machine is a dozer and has both the filters described in my manual which is a loader manual also. The wire mesh filter is in a housing as shown in the picture in the manual and is located forward in the reservoir where it gets narrower. You won't be able to see it unless you drain the oil. You should be able to see the T handle up against a pin on the top of the reservoir.

The wire mesh filter was clogged with a gooey sludge and was most likely almost totally stopped up. The oil itself didn't appear that dirty, but this filter may never had been removed and cleaned. I have it soaking now and hopefully can get it cleaned up.

cdunn · Post by **cdunn** » Wed Oct 27, 2010 3:45 pm

Thanks DaveP, Possibly I missed it, I'll check again. Sometimes I'm having so much fun with it, I don't pay real close attention to things like filters, and trees behind me and such. I have a number of trees that I wanted to save with the bark skinned after backing into them.

BSims66173 · Post by **BSims66173** » Thu Oct 28, 2010 11:20 am

One thing to check is the coupling splines. If they are worn and allowing the coupling to slip it can cause alot of noise. I had to replace mine, but my hyd would not work at all. When I tried to lift the blade, it would just be a loud screeching noise.

DaveP · Post by **DaveP** » Thu Oct 28, 2010 5:03 pm

Wow, what a difference clean filters make. The hydraulics are so quiet now I have to watch the blade to make sure it's moving

.

Thanks KenP for pointing the filters out and to check them first. That's the first thing I think of when trying to diagnose a fuel problem. And thanks to the rest of you for your info. I'm glad it didn't turn out to be the pump or splines.

KenP · Post by **KenP** » Thu Oct 28, 2010 5:32 pm

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gerald · Post by **gerald** » Sun Oct 31, 2010 9:01 am

My hyd holds good but the system is shuddering all the time it could have air or the atf some on put in it who know what other oil, any way I pulled the filter cover it was tight on the vent , reached inside the tank is clean . I ordered hyd filter , fuel filter an trans filter from O .Rielly 303 jd oil. Il get back to it this week end good luck. Thank Gerald

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JD350 hydraulic pump squeel

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