Hello, I have looked to the Internet for help with a problem I have encountered. I own a small 13ton crane/boom truck that was hand built from the ground up. I have ran this crane all my life and worked with construction and steel welding/framing. It's fully operational except for hydraulic boom and out riggers. The crane has 2 engines one in the front, 379 V-8 Chev. and one in the back, 350 V-8 Chev. The back engine runs all the crane operations. This leads to my problem, the hydraulic pump (Haldex model) is connected to the transaxle and the pump started screeching extremely loud while I was doing a job and had to quit the job. I have replaced the pump with a new one of the same model and it does the same thing, screeching. I put in new hydraulic fluid, put in an all steel feeding tube from the fluid holding tank to the pump(replacing a standard hydraulic hose) and it still screeches. I have done all and called everyone I could think of to help fix this problem so I could resume my business. I need help. If anyone can help me out this would be greatly appreciated so much. Thank you
Any chance it has a screen or filter inside the tank going to the pump inlet.
No it doesn't have a screen or filter in the tank.
Then your problem is most likely downstream from the pump, where does the pressure flow from there?
Are you sure the screeching is coming from the hydraulic pump and not the valve?
It goes to the control system. The handles that controls the winch, boom, turntable, turntable lock.
I know it's no the valve. The control system is in the cab.
Do the controls work properly and at the same speed as before the screaming started. If things are moving slower it is possible you have a hose or line between the pump and the control collapsed and folded over internally resulting in low flow and high pressure. It could be the pump bypass screaming. If the control went bad so it does not flow thru properly when not feeding a circuit it could still make the pump bypass with the noise coming from there.
So it is possible a hose is bad or the controls might be a problem. I'm leaning toward a hose problem at this point. Maybe?
Screechin most likely means air or cavitation in hydraulic fluid. See if 1) there is a hole in intake line and the pump is above the reservoir 2) There is an intake filter 3) Intake line is obstructed 4) oil in reservoir is foamy
Haldex may have an internal relief, could be a blockage somewhere.
A few pictures of the pump, pump drive and "transaxle", control valves and hoses would go a long way. Is there a bearing locked up in the transaxle? That could screech something aweful.
I don't think its a bearing in the transaxle. I'll to get some pictures up of the pump and the setup.
Pump Fluid Reservoir Tank and steel pipe that feeds to pump. Exit hose from pump. Hose runs under turntable and leads to Control Valves. System Controls Hose that feeds back to the Reservoir Tank. Hoses that lead to winch, cylinders, turntable, and turntable lock. Transaxle
Does it screech all the time, or only when you operate it? Does it screech the same for a light load as it does for a stalled cylinder? Do the cylinders operate the same, or slower, or not at all? It doesn't look like there's any bearings in that transaxle/bellhousing, and is that a brand new U joint? How about the flywheel end of that driveshaft? any chance that's slipping.
Ujoint looks new....certain the pump is turning and u joint connection not slipping or the like? I had a similar issue with my crane when purchased.......in-tank hydraulic filter was completely loaded.
I was always told to never use galvanized pipe in a hydraulic system. I was told that something in the hydraulic oil will react with the zinc in galvanizing. I see all the bright stuff on the suction side there have have to wonder. Lots of noise many times comes from a leaking main relief. I have seen it on a broken control valve also.
When I put the new steel piping in, I cracked it up and the pump was screeching but not as loudly as the system warmed up. I started to winch the cable up and down and the screeching became louder. When winching down it screeches a lot more than up. I let it idle down and the screeching was quieter when using the turntable and boom with out the winch. I cranked today and the pump screeches very loudly now and more so with using the winch than other mechanisms. I also can't understand why the hydraulic fluid is foaming lightly in the tank. I know this is a lot but any and all help is appreciated.
Should maybe get some gauges hooked in and see what's going on. Have you made sure that all the spools are centered? Screeching like you are describing sounds like a stall maybe?
The foam in the tank makes it sound like a suction side leak and air being pulled into the hydraulic pump. My thought would be to get rid of all the water pipe on the suction side and put in a hose.
You think it could be drawing air even though the tank is higher than the pump? He hasn't said and I have no idea of the gallons per minute, maybe there's too much restriction with the multiple fittings?
Yes, too many joints and liquid should be used on intake lines not tape
It shouldn't be drawing in air. The pump got quieter when I installed an all metal piping for the intake at idle, as opposed to the hydraulic hose where the screeching was louder at idle. I really think it could be a hose somewhere but I'm just not sure exactly.
It looks like you have a good length of delivery hose coming from the pump? If you disconnect it and put the end into the hydraulic tank and let the pump just circulate the oil, that would tell you if the problem was in the pump or the rest of the machine. You say that there's no filter or anything in the tank. Have you actually looked inside to check? It very much sounds like the problem could be a blocked suction screen.
Is that the only pump that is getting oil from that hydraulic tank? We had loader that had hyd fan and the fan pump seal was leaking and allowing air into the system and making screeching noise! Why would the oil be foamy if it wasn't getting air into the system somewhere? does a bypass internally whether it be a relief or hose blockage create foamy oil?
I might have to try this. I could narrow down things much quicker. And yes I've drained the tank and put new fluid in. There isn't any filter or screen.
Yes, its the only tank that has hydraulic fluid and its the only place the pump pulls fluid from.
Possibly the pipe union is not completely sealing. Pipe threads and teflon may hold but get another union, new/separate and examine how its sealing surfaces mate. Some used to have a brass/copper inlay soft enough to seal. Cheap chinese production may be your trouble. First shot is to lay a couple of 36 inch Stillsons on that union and seat it good, just saying.
Ok I took the delivery hose and just ran it straight to the tank and it seemed like it made a difference but still not sure. I took more pictures and a video. In the video all I was doing was booming up and down. Tank Engine Video https://vid.me/pnjk
Yeah Tylerb , just caught the video you posted . If a hydro pump is making noise like that it's generally from air in the oil . Got plenty of oil in the tank ? Tank at least 3/4 full ? Small block Chevy sounds good .
Is this the same hyd tank you have always had? Is there any baffles in the tank? The way the return line is piped aiming at the general direction of the outlet/suction it could easily introduce air into the oil as it will still be turbulent by the suction outlet. I would keep the tank very close to being plump full.
Yes it's the same tank and the same amount of oil. I just don't understand what's causing this.
One u-joint and no slip is not good on a pump. Did you tear the old pump down to see what was wrong with it?