[pdruff]

I have a 648 i purchased a long time ago, when I got it the engine was in pieces in a box with it (still have it may eventually put it back in) I repowered it with a Kohler 18 hp I had. Yes it has the backhoe/loader and those have lots of power (loader will pick up the rear end of my crown vic) problem I have it when I drive it it does not have much "drive power" I have checked all the linkages all are good.
when cold it drives slightly better (more power) than when warm. does not have much power in high range, low will move it but slows to a crawl when going uphill. it does appear that the drive motor on transmission is different color than rest of tractor.
any ideas on what to check?
Thanks.
Paul

 

[xfolkboat]

Has it ever worked well in your possession?

By "no power", is the tractor slowing down while the engine revs stay up, or are the revs dropping as well?

If the engine revs are staying up..
First and easiest, the oil in the hydraulics has to be proper motor oil, 30 wt or 15W40 or some such. If you use "hydraulic" oil, it will be too thin.

We would need a little more information to go much further.

Aaron

 

[Hydriv]

Paul,
Welcome to the group.


The most common problem with these tractors is that owners do not read the Operator's Manual. Instead, they THINK that they know what they are doing and put "hydraulic oil" in the hydraulic system. Bad mistake.

The very first thing you need to do in order to properly diagnose the true problem, is to change out ALL of the oil in your tractor and that's no simple task with a LBH model. Please go to the FAQ's section of the site and find the documents pertaining to draining the hydraulic system along with the one about the correct oil.

I cannot stress how important the correct oil is. Think of the oil being the equivalent of the drive shaft in a vehicle. All that engine power is useless unless it can be effectively transmitted to the rear axle. That's what the oil does and in order to do it efficiently, you have to use motor oil.

So....I suggest that you purchase a 5 gallon pail of the correct oil and set about the messy task of removing all the oil. Once you have done that and then test driven your LBH, you will know whether it was just the wrong oil or there is something else going wrong. If it turns out that the oil change does not cure the problem, then return here to this thread and we'll discuss the next step to isolate the problem.

 

[99flhr]

I have a 648 I have checked all the linkages all are good.

The infamous banana plate is not all "wollered out" ?

 

[pdruff]

I am impressed with the speed of responses. I use the shell rotella oil that is recommended. the engine does not bog down when driving (it will bog down when using the hoe or loader. I have the read the manuals. my guess is that the pressure bypass in the drive circuit valve is stuck/defective. I just realized the other day that the drive motor may be the problem. Mostly looking for suggestions. Suppose to get to mid 50's tomorrow and going to cut a bunch of firewood to sell to the campers this summer tomorrow. going to use to loader to lift move the wood...

 

[Hydriv]

Please allow me to expand.

I don't know how new this machine is to you or what you have done to it since purchase. Therefore, my replies are based upon YOU not knowing what the previous owner has done with respect to maintenance.

The hydraulic cylinders in a LBH hold a tremendous amount of oil. If a past owner has failed to use the correct oil, then doing a simple oil change will only remove the oil that is in the reservoir. That is not good enough if someone put the wrong oil into this machine in the past.

Now, if you reply and tell me that you removed EACH and EVERY hydraulic cylinder on the tractor and emptied them of oil 100 percent along with the hydraulic reservoir, then that would indicate to me the correct oil is in the tractor. Anything LESS, just won't cut it and we are all spinning our wheels when it comes to figuring out what's really wrong.

You are complaining about a lack of travel movement that worsens as the machine warms up. Those things point to the oil as the possible culprit. The second likely culprit is the one that was mentioned already by Randy (99flhr) which is the infamous "banana plate". This is often overlooked because the wear on these plates doesn't look to be all that much. However, you have to understand that the oil being fed to the drive motor is controlled by a "spool" that moves less than an inch. Even a small amount of play in the linkage that controls that spool will greatly affect how much it travels or in this instance... does not travel.

The spool has a center or neutral position and reverse is on one side of center and forward is on the other. If your pedal will not push and then pull the spool 100 percent, then the ground speed will suffer dramatically. What we are trying to do here is to tackle your problem by eliminating the cheapest and easiest known problems, one at a time. We don't want you to leap to the wrong conclusion. You seem to have the drive motor in your sights. Do you realize that a new drive motor may cost you $1000.00 to replace?

Drive motors have been known to fail but failures are super rare compared to the things we are talking about. Now, it could be this. Someone else thought that the drive motor was at fault and then bought a used motor from a 400 series tractor. After installing it, there was no difference in performance and so they just sold the problem by selling the tractor.

So, please.... work with us by providing full disclosure and together, we will get your tractor working like it did when it was new.

 

[pdruff]

I purchased the tractor in 1999? like I said the engine was in a box. from what the owner said he purchased it from the original owner (original owner used the unit to dig graves, He saw the unit out a couple years ago when driving by stopped in, said that he sold it after employee ran it low on engine oil and damaged the engine, after looking it over he offered to buy it) 2nd owner said engine was weak, started a rebuild and there it sat in the shed for years, he is the one that stressed to me about the shell rotella oil. I had a buddy fab up a adaptor for the engine/ oil pump.
I needed a new septic system when I got it and used the hoe for that
when I got it running I drained and replaced the oil (I just went and looked it was shell rotella 15w-40) the oil had been drained when the person took the original motor out. as I recall I added around 3 1/2 to 4+ gallons out of a 5 gallon bucket
the banana plate was checked and does pull the valve completely (I put the unit up with a car lift and had the pedal operated as I watched)

I never did ask the original owner about the drive issue, 2nd owner never mentioned a problem with it.

I could flush the entire oil system. I'll dig out my books that came with the unit to look at my notes from the last time I pondered this drive issue. I may have some of the 648 manuals that you need on this site (I'll have to see what I have)

 

[pdruff]

also the difference between travel when cold to travel when hot in not that great, just that it is less when hot. I will get the unit out tomorrow and snap pictures or video to help diagnose.

thanks again
paul

 

[Hydriv]

In my opinion, this is the descending list of cuprits

- wrong oil in system

- too much play in linkage that controls travel spool

- weak hydraulic pump

- improper relief valve setting in the travel circuit

- drive motor


You will have to decide whether or not you wish to spend the time and money to do a thorough change out of the hydraulic oil. If the tractor was mine, I would do this, if only to have a base line for my service records. I would want to know beyond a shadow of a doubt that the machine was operating with fresh, clean oil of the correct grade. If I had no intention to run this machine in sub zero temps, then I would choose 20W50. Shell does not offer that grade but many others do. It's covered in the FAQ about correct oil.

I would also install an hour meter to keep track of the time on the tractor and record that in my service log. I'm not trying to be a wise-ass here but i don't know how one would determine the brand of oil, the grade of the oil or the cleanliness of the oil by simply looking at it. Those are the things that are determined in a lab by skilled technicians using some pretty sophisticated equipment.

So... let's say that you resolve the oil issue one way or the other and you are correct about the linkage being tight enough to give full movement. The next step calls for pressure tests to be made and you will have to spend the money to buy the gauge, hose and fittings. You need a 5000 PSI gauge that is glycerin filled plus a hose with 3000 PSI working pressure minimum plus the fittings to hook it up to the test port in the bottom of the travel/lift valve that the lines from the motor are attached to.

The test port is also the drain port and is the hex hole pipe plug.

If you go into our new Hydraulics section in the TECH Service Manuals, you will discover a whole host of manuals that apply to your tractor. If there is anything you don't understand after consulting those manuals, by all means post again and we will help you further with the diagnosis.

I am currently scanning the first three parts manuals for the loader tractor and backhoe models but I am looking for the fourth book. I'm also looking for the Operator's Manual as well. Any help you can provide in that regard will be very much appreciated.

 

[Bart]

Based upon the discussion so far I would suggest checking the relief valve setting in the travel control valve as potentially the easiest and quickest fix. If the pressure is good then the motor becomes suspect.