Bought a painted up TL150 from an auction. Got it very cheap but it was an as-is "take a chance" events Started machine up, pulled lap bar down and no hydraulics worked. raise throttle to 75% and then the boom started to work. Pulled back on joystick to back off trailer and it went very slow and wouldnt turn as it reversed. Barely made it off the trailer. Noticed pulling forward it would not turn right. When on ground machine would pretty much just go straight and not turn right. When I tried to turn left the machine went into reverse What the hell is going on.
Check pilot pressure/ pilot hose routing
So machine never moves below 75% throttle? Hours? How does hydraulic oil look?
Try letting your machine warm up for about 15-20 min at 1/4 idle and then test it. I have a TL130 that the left track won't back up well until the machine is well warmed up. Also clean the lap bar sensor.
I think I know what your issue is. There is a weak point in the TL-150 / Mustang MTL25. The HST Pump "servo control cylinder" design is terrible. Hard operation (ie...employees who know only two speeds...100% and off) causes the piston to rock, and there is only one seal ring. It starts to rock, and then wears grooves / deep spots in the control cylinder liner. With small control inputs, the pump will not pump. Instead of pilot pressure moving the cylinder, it leaks by. So you push more on the control...still nothing. You push more, then finally the control piston gets past the worn area, and it goes like crazy. It makes the unit impossible to drive. These are Sauer Danfoss HST Pumps, Series 42 with NFPH Control. You want the Axial Piston Closed Circuit Pumps Series 42 Service Manual and the Sauer Danfoss Series 42 Manual. Go to page 37 of 51 of the general Manual. See how there is just an O-ring? That is the problem. The Piston is hard...but the liner is soft. There should have been brass seal rings...not just an O-Ring. The eccentric loads will cause it to fail if you hammer it like an idiot. Solution? Not easy. #1..you have to pull the main pumps. That means everything. Not easy. Also, you need to plug EVERY line and port when you pull, with proper British hydraulic plug fittings. This keeps debris from contaminating your hyd system. As soon as you pull a line...you plug both sides. It cost me over $300 just to buy all the fittings to block off the lines as I disconnected them. Then I took the pump to a local, reputable Hyd repair shop. They said the main housings needed to be replaced because it was all one casting, and the control cylinder liners were shot. No big deal..just $4500 x 2! So I asked them why we could not bore and re-sleeve? They said "we are not a machine shop". "If you want to do that...you can re-machine, and bring it back to us when it is done". "Your risk if it does not work". So I did. I made a drawing (I happen to be a Mech Engineer that works in mfg and machine design)...took it to a local machine shop. They line bored it out, and we pressed in a new ductile iron sleeve (hard steel was way too much @$) to my specs. I let them determine the press fit based on their experience, but the ID and end interface was my specs. It cost me about $1300. I did the final re-honing (I also used to race MX and karts...and have precision honing equipment) because I did not trust the machine shop to hold it to +/- .0002" as I wanted. After I re-honed to fit....I took it back to the repair shop. They rebuilt it, tested it, and told me the unit was 100% as good as new. They were actually pretty impressed with the control cylinder repair as it saved $8000+. The core Sauer Danfoss pump is GREAT...solid as a rock. You can not kill it. But the servo control cylinder is a crap design. It will last about 2500 hours till it stops working due to the control cylinder. I bet there are hundreds of those units sitting around scrapped due to bad control cylinders...and the core pump is perfect. Mine was. If I had a machine shop, I would make a new piston, and add a dual brass ring design and ditch the weak single o-ring so the piston was better stabilized. But as it stands...my unit has 3000 hours. By the time the control cylinder goes again...the rest of the machine will probably be done. Good luck. Great machine except for that flaw...and a few electrical gremlins.
Had my share run ins with Series 42, and I don’t like the servo piston design either! Another thing that it has only one centering spring on one side and sometimes when pilot pressure gets weak it will only drive one way, there’s difference in piston effective area on spring side it’s lower because of the spring rod. But the problem you described is not that common and probably was caused by poor oil quality or pilot pressure issues. Nice repair BTW!!! Usually those pumps get killed by “unsanitary” repair practices well before they have a chance to develop servo piston issues! Not a lot of people understand peculiarity of closed loop systems, and important of “ surgical room” cleanliness when, let’s say - replacing the hoses, or if drive motor went bad - first thing you do is to pressure wash the hell out of machine before you start taking any fittings off of it! Or when changing the charge filter take the whole housing off, because it is impossible to replace it in place without contamination! And like you said - plug, plug and plug again everything the moment you took fitting off!!!
Interesting to hear your perspective. It was a BIG project to fix it, and I was a complete newb to hydraulics, so it was a learning experience. Since you sound knowledgeable on Taks (and I apologize in advance to the OP for thread hijacking....!) but I have a bucket that droops when loaded. I was guessing that the best bet would be to change the whole Bucket Section Assembly in the control valve?
First thing you do is check your suction strainer, and the whole suction piping! Because you got single suction for both functions and drive system! Then start checking pressures! Pilot circuit runs everything on that machine! There is a strainer in your supply fitting in your joystick - check for restriction, if it’s hard black ( carbonized ) deposit - check for water in the hydraulic fluid! It is also your charge circuit for your drives, if your drive goes one way but not the other - your pilot pressure is very low ( I described why in previous post )! Don’t want to give too much information right away too not to overwhelm you. Let’s take one step at the time. Last machine that didn’t turn had that happen to it, but it doesn’t mean that yours the same! But look at travel motors and see if one on the left was replaced.
To not to guess - I usually pressurize MCV and cylinders separately with hand pump and gauge, to see which side is leaking! Didn’t mess too much with functions side of the machines, but I’m sure there’s port reliefs and other stuff that might have bad O-rings or something like that, but for what i have seen the cylinders start leaking before anything in controls going bad.
No leaks anywhere. Without physical leaks, the cylinders can not droop due to volumetric mismatch. I will see what the dealer parts dept says... Thanks.
Well! Whatever you say! What do I know?! I’m not an Engineer!!!
Engineers are over rated. I know from personal experience. Thanks again for your expertise.
While the more input, the better, before chasing the travel issues, let's start with something more simple. No hydraulic function works correctly, so, as mentioned above, the pilot pressure is suspect. And, without sufficient pilot pressure, nothing works right. I'm saying stay away from the travel issues because even the loader arms respond poorly, which points to, if the pilot pressure is good, a problem with the gear pump. There are 4 pumps...front to back, pilot, loader, travel 1 & travel 2. The front 2 are gear pumps and, if you dont have gauges to test them, they can be easily dissected and inspected. Myself, I'd find gauges first. And, all four pumps need sufficient oil supply. The loader hydraulics are filtered with a horizontal filter under the passenger side of the cab. That cartridge has been known to suck shut on my 3 TL150 machines. I believe a 1-1/16 or 1-1/8 wrench fits the hex at the rear. It won't affect travel, but it sure will affect loader operation. Regardless, it absolutely should be changed, and the old one inspected.
Back to the OPs issue, I agree that double checking Pilot Pressure is key. In fact, you should check ALL the key pressures. You need a set of proper pressure gauges, lines and fittings. Generally you need a low pressure gage, a high pressure gage, lines, and some adapters to suit the various connections. Something like this to start.... https://www.amazon.com/Hydraulic-Pressure-Test-Kit-Excavators/dp/B01IF4J6TI I pieced mine together at a local hydraulics shop, and it was about 3x as much $..... Get the Tak TL150 Service Manual (798 Pages). Page II-16 describes all the key pressures and readings. Pages II-17-21 describe all the key pressure checks, and where you should take them.
Like I suggested before: when it comes to charge filter - remove the hoses and take the whole thing out! Save yourself aggravation and contamination. Also remember about strainer in joystick supply line!
Thanks so much guys... i'm still having the same issue but have not checked into it. Selling machine for $13800 without a bucket for any takers.
What auction did you buy it at? Send it back to auction. Lol
All So I removed the charge filter and saw no metal. Machine operated the same with filter removed. Here are the current symptoms: Loader function and drive function don’t work until 70 percent throttle now. Still drives funny but it does track straight front and back but extremely slow. When loader functions work machine will easily lift machine up.
Did you check the strainer like mentioned earlier? It seems you have a restricted pilot flow. Or perhaps weak pilot pump.
Where is strainer
Strainer is in the hydraulic fluid tank. The suction pipe comes from tank all the way to the front to double gear pump, which has single mutual inlet for both pumps. One of the two gear pumps is your charge/pilot circuit pump, the other is your functions pump. And your problem consistent with restriction in that area.
This is what happened.
Last pretty looking, painted up piece of equipment from auction I worked on - turned out to be real “pickle”! Every hose was disintegrating, and I guess that manlift worked at some kind of a concrete plant or something, because it was looking really pretty, and they even bought original decals from Grove! But on the bottom everything was covered in big globs of concrete ( I think cement mixed with hydraulic oil), so to get to the hoses I had to first chisel out the chunks of that concrete, and probably because it was mixed on oil it was really crumbly! It was impossible to replace the hose without contaminating the system! So I had to diss assemble and clean all the manifolds and flow divider, clean them and re install. Center swivel and platform rotate leaked a rivers as soon as you touched controls, and one of the boom hoses had 1/4” hole in it!
To OP: if your strainer and suction turns out unobstructed, next step is to get a needle valve and the gauge, and pressure test both gear pumps. That’s if you don’t want to remove and inspect them. The functions and charge/pilot circuits are separate systems, but low pilot pressure could be too weak to move the spools.
PeterG have you ever found out what the problem could be? My Gehl CTL80 does the EXACT same thing and I’ve been trying to get a lead on what is wrong.
McCall, I’m wondering if that filter sucking closed could be causing the whine that this tl150 has. Or a more likely suspect? I traced it to the gear pump with stethoscope. Is that filter inspected and serviced from underside of the machine? Thanks