Hydraulic problems

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Waldershrek

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I have Allis Chalmers 170 with a Allis front end loader. Not sure if it's the 170 or 500 loader. It's in great shape but a few years ago I noticed the bucket hydraulics didn't have the power they once did. Well it kept getting worse and then started making this god awful screetching noise when trying to lift the bucket (even with nothing in it). Figured the pump was shot so dad had a local guy who does mechanic side jobs put a new pump in it and fix an oil leak.

I am running the tractor the other day for the first time since it was "fixed" this spring and the damn hydraulics are still doing this. Now I figure one of a few things is happening.

1. Either the guy didn't replace the pump and lied
2. He did replace the pump but didn't bleed the system or something
3. The problem was never the pump to begin with


Any hydraulic experts on here? I'd like to try bleeding the system but I don't know how.
 
What about filters? I had an International that did that and it turned out to be the filter in the case being clogged and the pressure relief valve screaming for mercy. Don;t know about Allis' but I always check filters first now.
 
What about filters? I had an International that did that and it turned out to be the filter in the case being clogged and the pressure relief valve screaming for mercy. Don;t know about Allis' but I always check filters first now. :nod:

Did your mechanic change the filters when he changed the pump?
 
Where is the noise coming from, pump area or from the pivot points on the bucket? If everything else works ok you may have a pin siezed up.
 
sounds like you are the one that said the pump was bad not the mechanic. if he replaced it it's because you told him too so if its doing the same thing its your fault.

make sure it has enough hydr fluid in it. Have you ever changed the filters and or cleaned the screen. If it has air in it, then more than likely you would just be getting "jerky" operation as your raise and lower the loader
 
Thanks for all the replies! It could be the filter but sadly I don't know where it is on the old girl. I just ordered a shop manual for it so hopefully I won't be in the dark much longer. I am assuming that the mechanic would have changed it and/or checked the screen but you know what happens when we assume.

I don't believe he was ever told the pump was bad, I think dad just explained what the problem was and let him do what he thought would fix it. Again, I'm not entirely sure as I wasn't involved personally. I'll try and take a video of what it is doing.
 
For future reference, you or your dad should have said "fix these screeching hydraulics" instead of "replace the pump".
All the references to filters are correct. I cannot imagine a mechanic would replace the pump and NOT the filters and the fluid. I would change the filters AND the fluid. There are gauges that measure PSI (pressure) at a remote. Find one.
 
I'm not sure what dad told him, I'm assuming he told him replace the pump since that's what he did and the problem is still occurring. However I would think that he would have tested the hydraulics after replacing the pump and noticed that they still weren't right but who knows.

I assume I can get a relief valve any where that sells hydraulic stuff and it's not tractor specific? Tractor data says the hydraulic pressure should be 2000 psi. Does this test gauge just plug right into the hydraulic hook ups on the back of the tractor?
 
Could it be that you actually have 2 pumps? One for the tractor 3 pt and another for the loader? Look under the radiator. If there is one mounted to the front of the engine then it is for the loader. Pumps like this usually have a seperate canister type filter. Other tractors also have 2 seperate pumps inside the transmision (Massey). One for 3 pt the other for auxillary. Both have screens inside the trans. Does the 3 pt. make the same noise when in use? Does the 3 pt. still have power? If so it is not the 3 pt. pump.
Like someone else suggested, First isolate the noise. They also said it could be a siezed pin. A siezed pin will rob power and squeel.
 
Three point power is ok although when you lift the arms it doesn't stop automatically when it's all the way up like it should. The lever kinda sticks open and you have to click it off manually.
 
Waldershrek":2pntmxvj said:
I'm not sure what dad told him, I'm assuming he told him replace the pump since that's what he did and the problem is still occurring. However I would think that he would have tested the hydraulics after replacing the pump and noticed that they still weren't right but who knows.

I assume I can get a relief valve any where that sells hydraulic stuff and it's not tractor specific? Tractor data says the hydraulic pressure should be 2000 psi. Does this test gauge just plug right into the hydraulic hook ups on the back of the tractor?

Yes, gauges plug in to remote hydraulics on the tractor.
 
Well I got my service manual from SSB tractor in the mail the other day. Honestly it's less than helpful in most ways since there isn't a lot of pictures and the ones it has are of such bad quality you can't really tell what it is. It does ave some good parts diagrams though.

The more I read on this problem the more it sounds like the relief valve. This book tells me how to disassemble and such but it doesn't tell me where it is so that will be my next quest.
 
IMO those manuals are usually a joke. Check eBay for the FSM or factory service manual. It's the same manual that the dealers have or had. You will pay 50-100 bucks each. They are well worth it when you consider that's less then an hour of shop labor at a repair shop.
Randy
 
A hydraulic hose can age and deteriorate to the point that the inside can separate and clog the hose. Then when pressure is applied the flow path is blocked which in turn can cause a relief valve to open resulting in a squeal.
 
agmantoo":3eaxfp1l said:
A hydraulic hose can age and deteriorate to the point that the inside can separate and clog the hose. Then when pressure is applied the flow path is blocked which in turn can cause a relief valve to open resulting in a squeal.
That is a good point, he needs to isolate where the noise is coming from. More than likely that will point the him in the direction of the problem.
 

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