The evolving tale of our Link Belt LS4300 CII - Travel motor issue and question

Yes, it's been about 2 years of solving just about every possible problem possible except the motor on our machine. It sat somewhat abandoned for over 11 years on the property next to our mining claim and seemed like a handy piece of equipment to add to our stable. We got it for almost nothing but have put in about two years and close to $20,000 to get it to where we could finally use it.

We rebuilt the main pump which kept taking out the pilot pump, we replaced the two travel motors with a used pair from Fraley Equipment, we had a new oil cooler made of aluminum from Active Radiator (a gorgeous work of art!), we replaced hoses, batteries, replaced wiring and modified the electrical system to run in bypass mode since the computer and wiring had been removed, and countless 5 gallon buckets of hydraulic fluid.

It still overheats as it reportedly did for the previous owner despite our having thoroughly flushed and steam cleaned the radiator and added a 24 volt dual 15" electric fan to push more air through the cooler and radiator. Active Radiator suggests we send it down to their southern CA facility to have it re-cored, and since we've exhausted every other possibility that's the route we're going to take.

The question I currently have concerns the left travel motor which lacks power in the reverse direction, and not that much more in the forward direction. Both used motors appeared to be working perfectly when we first replaced our old ones, but after some heavy operation initially I noticed the problem. HOWEVER... travel with the main pedal is straight and seemingly strong in both directions, even going up a grade using forward or reverse travel. The weak motor is noticed only when using the left pedal to steer.

The left travel motor is powered by pump #2 which also powers the bucket, Boom 1-speed, and Arm 2-speed which, other than the travel motor seem normal. Any suggestions on what to check for? I have our two old motors which I suspect went bad after the machine had run low on hydraulic oil and tore up the main pump bearings. I can either have one serviced, or maybe find a seal kit and do the work myself since the problem was likely seals and O-rings.

Thanks,



-Tom F.

I am going to bet on center joint seals are leaking. On my machine I had good power in reverse on the left track but almost no power in forward. I had some gouges in sealing surface. Welded them up, turned it down and polished it and threw in new seals and it's like brand new.

The way I checked it is took the case drain for the center joint and ran it into a bucket. Make sure to cap it off the port on the return piping. I then pinned the track and visually "gauged" the fluid coming out and in forward on the left track it was a full stream.

mutti_wilson said:

I am going to bet on center joint seals are leaking. On my machine I had good power in reverse on the left track but almost no power in forward. I had some gouges in sealing surface. Welded them up, turned it down and polished it and threw in new seals and it's like brand new.

The way I checked it is took the case drain for the center joint and ran it into a bucket. Make sure to cap it off the port on the return piping. I then pinned the track and visually "gauged" the fluid coming out and in forward on the left track it was a full stream.

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Thanks for the input! When we determined that our original travel motors were both bad we had observed a tremendous amount of case drain return coming from both motors. I've replaced the bearings and pilot pump on our pump, so maybe my next venture might be to tear into one of our old motors and see what trouble I can get into there. -Tom F.

How much are you traveling when the machine heats up? I have found over the years that often when a machine heats up it's the hydraulics causing the problem more so than a radiator problem. Since the hydraulic cooler sits right behind the radiator the heat from one transfers to the other. Any time a hydraulic system is leaking internally, either from worn components or from going over relief, it creates heat. So, if you have a bad travel motor, or center joint seals leaking or a problem in the control valve or pump, any of these could be causing your heating problem. Also make sure that the foam pieces are around the radiator and in good condition so all the fan air has to go through the radiator and not around it.

Like excavator said.

excavator said:

How much are you traveling when the machine heats up? I have found over the years that often when a machine heats up it's the hydraulics causing the problem more so than a radiator problem. Since the hydraulic cooler sits right behind the radiator the heat from one transfers to the other. Any time a hydraulic system is leaking internally, either from worn components or from going over relief, it creates heat. So, if you have a bad travel motor, or center joint seals leaking or a problem in the control valve or pump, any of these could be causing your heating problem. Also make sure that the foam pieces are around the radiator and in good condition so all the fan air has to go through the radiator and not around it.

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We put a new aluminum oil cooler from Active Radiator in last month, replaced the upper and lower foam seals, flushed the cooling system, replaced the thermostat, checked fan belt and pulley, refilled with 50/50 antifreeze, and ran it without any issues. The overheating occurs when running full throttle for swing and boom/arm/bucket operation. The dual 15" fan assembly helps, and as long as we run at lower RPMs the heat stays below 200 degrees. The previous owner said that it always ran hot, so the only reasonable cause would be the radiator. The motor runs strong and smooth with nothing coming up the radiator cap.

As for the travel motor, we'll do a case drain bypass test and keep the fingers crossed.

Thanks for the input! -Tom F.

Fitting a new radiator, cooler etc maybe fixing the symptom and not the cause. Excavators advice is very sound IMHO and pressure testing everything is the best way of finding the cause, guessing is expensive.

Just to provide something else to think about, have you checked engine RPM when you put a full load on the machine? You might do a cycle time on the boom. Run the stick all the way out, open the bucket and set everything on the ground. Put the engine at high idle and then time how fast the boom goes from all the way down to top out using a stop watch of some kind. If it is faster than four seconds, you are pulling too much horsepower out of the engine which will cause your heat issue. If you can watch engine RPM, you shouldn't drop more that 150 RPM with the engine at full load which you should be able to see when running your boom up cycle time.

Tones said:

Fitting a new radiator, cooler etc maybe fixing the symptom and not the cause. Excavators advice is very sound IMHO and pressure testing everything is the best way of finding the cause, guessing is expensive.

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Thanks for the suggestions, always appreciated. There was no question of needing a new oil cooler as the old one was all-steel and had about 1/3 of the core tubes corroded out and sealed with some kind of sealant which still leaked. Both the old cooler and the radiator had about 1/3 or more of the core areas blocked with red dirt that had been long-soaked and baked from the leaking oil cooler. We fired up our big steam cleaner to try to blast the radiator core when we pulled the old oil cooler but I'm not certain we got everything out. And there's not telling what might lurk in the core tubes there either.

We used an infrared temp gun to measure temperatures of both cores. The oil cooler previously would get to over 225 degrees but since we put the new aluminum cooler in we run pretty consistently at around 170. We don't experience overheating until we run at full throttle. The oil cooler remains at around 170-180 but our temp gauge for the engine cooling goes over 240 and into tea pot mode. Reducing the RPMs for about 20 minutes eventually gets the temp down to 200 and even 190 using the auxiliary fan. Using the fan full time extends our running time before overheating by maybe 10 minutes or so. After all the testing and work we're pretty certain that re-coring the radiator will solve that problem which existed to a degree prior to our getting the machine.

John C offered up advice last year when we were trying to figure out why we had no travel on either motor despite having normal function on other hydraulics such as swing, boom, etc. Having noticed tremendous and obvious bypass from both travel motors led to our buying a used pair from Frayley Equipment which solved the problem. I'll do the case drain test when we go up again (we're VERY off-grid!). Meanwhile I have our two original travel motors here at my shop and am going to tear into one of them and if there is no obvious damage to hard parts, take a swing at installing new seals. I have the shop manual for the machine and there is extensive coverage of service on the motors. We also have the master parts manual with key sheets for our machine so getting part numbers should be easy too

I've bought parts from Hydraulex and Engineering Technology Services so they may be a source of advice and possibly parts as well.

Thanks again, -Tom F.

John C. said:

Just to provide something else to think about, have you checked engine RPM when you put a full load on the machine? You might do a cycle time on the boom. Run the stick all the way out, open the bucket and set everything on the ground. Put the engine at high idle and then time how fast the boom goes from all the way down to top out using a stop watch of some kind. If it is faster than four seconds, you are pulling too much horsepower out of the engine which will cause your heat issue. If you can watch engine RPM, you shouldn't drop more that 150 RPM with the engine at full load which you should be able to see when running your boom up cycle time.

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We did the track cycle time for each side per your advice last year when we were setting up the pump and each side clocked pretty much the same. The left travel motor seems to fail when under heavy load using the left travel pedal though using the main travel pedal forward and back seems normal. Again using your previous advice we'll do the case drain test for both travel motors. Since wet weather will hinder us for the next month or two I'm going to tear into one of the two original travel motors here at my shop and take a jab at servicing it. I managed pretty well when I replaced bearings on our main pump so am feeling confident enough to handle the motors, aided largely with the service manual.

Like almost anything related to working on heavy equipment, the hardest part besides learning is buying the additional tools and special equipment needed for the job... and PAYING for it!

Thanks as always John... Be well. -Tom F.

I asked the guy who rents heavy equipment at the place next door to my shop about how to get heavy mud out of my equipment. His advice was to not get into it in the first place. That hadn't occurred to me last Thanksgiving!...

iowahill said:

We did the track cycle time for each side per your advice last year when we were setting up the pump and each side clocked pretty much the same. The left travel motor seems to fail when under heavy load using the left travel pedal though using the main travel pedal forward and back seems normal. Again using your previous advice we'll do the case drain test for both travel motors. Since wet weather will hinder us for the next month or two I'm going to tear into one of the two original travel motors here at my shop and take a jab at servicing it. I managed pretty well when I replaced bearings on our main pump so am feeling confident enough to handle the motors, aided largely with the service manual.

Like almost anything related to working on heavy equipment, the hardest part besides learning is buying the additional tools and special equipment needed for the job... and PAYING for it!

Thanks as always John... Be well. -Tom F.

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Just to add to my post my machine tracked straight when using both pedals. The issue only reared it's head when the left tracked was used on it's own. I did check the case drain on my travel motors first, but the one that showed me what was going on was the case drain for the center joint. It was bypassing fluid before ever getting to the motors.

mutti_wilson said:

I am going to bet on center joint seals are leaking. On my machine I had good power in reverse on the left track but almost no power in forward. I had some gouges in sealing surface. Welded them up, turned it down and polished it and threw in new seals and it's like brand new.

The way I checked it is took the case drain for the center joint and ran it into a bucket. Make sure to cap it off the port on the return piping. I then pinned the track and visually "gauged" the fluid coming out and in forward on the left track it was a full stream.

Click to expand...

That's the "meat and potatoes answer" I was seeking! Did you do the rebuild yourself and if so where did you get the replacement seals. O-rings, etc.? I'm going to try my hand at tearing into one of our old travel motors and see if all hard parts are serviceable, then re-seal. Thanks again, -Tom F.

Yet another Fall adventure... Halloween - 2021 carwash!

mutti_wilson said:

Just to add to my post my machine tracked straight when using both pedals. The issue only reared it's head when the left tracked was used on it's own. I did check the case drain on my travel motors first, but the one that showed me what was going on was the case drain for the center joint. It was bypassing fluid before ever getting to the motors.

Click to expand...

Having gone back and re-read your post, are you referring to the rotating joint? That had been re-sealed back in 2011. I was under the impression you were talking about the travel motor itself. You'v now given me another thing to look at. Thanks again, -Tom F.

iowahill said:

Having gone back and re-read your post, are you referring to the rotating joint? That had been re-sealed back in 2011. I was under the impression you were talking about the travel motor itself. You'v now given me another thing to look at. Thanks again, -Tom F.

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My travel motors were in good shape. It was just the rotating joint on mine. Check the case drain on all of them and I think you'll find your issue.

mutti_wilson said:

My travel motors were in good shape. It was just the rotating joint on mine. Check the case drain on all of them and I think you'll find your issue.

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Will do, though I don't look forward to having to pull the rotating joint. Did yours come out from the bottom or the top? -Tom F.

When my Hitachi was having trouble traveling it turned out to be the rotary manifold also known as center joint. The joint was leaking so bad there was oil all over the turntable. You may or may not have an external leak, depends on which seals failed in joint.
Nick

iowahill said:

Will do, though I don't look forward to having to pull the rotating joint. Did yours come out from the bottom or the top? -Tom F.

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Mine drops out the bottom. It's not an enjoyable job and I'm sure with the extra size of you machine it'll even be more fun.

mutti_wilson said:

Mine drops out the bottom. It's not an enjoyable job and I'm sure with the extra size of you machine it'll even be more fun.

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Many thanks. Before we were informed that our rotating joint had been re-sealed only 6 years earlier my partner and I were about to try pulling it and didn't know. Coming out the top seemed impossible, and out the bottom only a little less so! -Tom F.