New Holland LB75B Starter Issues

[808Mark]

Hi everyone,

I just joined hoping i could get some help on my backhoe! Thank you in advance for your time and help. I'll try to make this as concise as possible as it has been quite the journey.

I have a New Holland LB75B backhoe that's around 15 years old. I'm not sure of the exact age. My starter issues all started when the battery was constantly being drained to the point where I had to jump it even after one day. From this I determined the battery was no good and the starter was drawing too much energy from the battery. I got a new battery and had the starter rebuilt. I also installed a kill switch on the positive battery cable. (I am only running 1 battery, so i'm not sure if my current problems are a result of this. It came with two, but for whatever reason my father switched to one.)

After the starter was rebuilt, about 10-20 percent of the time the upon starting the starter wouldn't engage fully. It sounds like a power down noise from a sci fi movie. Before I did too much troubleshooting I replaced the relay. After this didn't fix the problem I went through the shop manual and started some troubleshooting.

Initially I tested the voltage draw through the grounding wire and the grounding through the starter flange. It was drawing too much voltage. The shop manual said it shouldn't draw over .2 V and it was drawing around 1V. I cleaned all the connections, tested continuity, tested resistance, and replace the battery clamp. This seemed to somewhat solve the problem as it's only drawing .3V now. Still the problem is persisting

I then did a voltage test of the starter relay and starter motor. All the values are normal except the bold values. If i'm remembering correctly, the bold values were supposed to read around 12 volts when starting. All of them showed a range and were considerably lower than 12 volts. (sorry the format of the table wasn't preserved, so i labeled the results and ignition switch position with letters.)

Starter Relay Voltage Test
Ignition Switch Position
Wire A Off (v) B Aux (V) C On (V) D Start (V)
1 White A 0 B 0 C 0 D 0-9-0
2 Black A 0 B 0 C 0 D 0
3 Red A12.6 B 12.6 C 12.6 D 12.6-6-12.6
4 White/Black A 0 B 0 C 0 D 0-8-0

Starter Motor Voltage Test
Ignition Switch Position
A Off (v) B Aux (V) C On (V) D Start (V)
Post 1(+battery cable) A 12.6 B 12.6 C 12.6 D 12.6-8-12.6
Post 2 (wire) A 0 B 0 C 0 D 0-6



I also did a voltage test of the positive battery cable. It was drawing around 1V when it is supposed to be drawing no more than .2V. I presumed that the lack of voltage during starting on the starter relay and the excess of voltage on the positive battery clamp when starting are related. I went through the positive cables cleaned all the connections, tested for continuity and resistance, and replaced the battery clamp.

After all this, the problem is still persisting. About 10-20% of the time, when I start the machine the starter doesn't engage fully and sounds like it's "powering down." I really don't know what the problem is at this point. Since the problem is intermittent, I suspect the wiring is bad. I can't believe the wiring from the battery to the starter is bad, but maybe I need to replace it? Sorry for the long winded post and thank you if you made it to the end!

 

[NH575E]

Make sure you have a good ground connection to the engine AND chassis. Follow the ground cable from the battery and see where it leads. My tractor had two ground cables and both were connected to the chassis for some stupid reason. I moved one to the engine block and solved my starting and battery problems.

 

[Delmer]

It's gonna take me a minute to read the book.

At first glance, I didn't see what kind of battery you put in it. One battery should be fine in Hawaii, a good battery is plenty around here 99% of the time. It has to be a good battery though. What CCA and how old?

I'm not saying this is the most likely, just the first question that has to be answered.

 

[Delmer]

12.6-8-12.6

I don't know what that means? Is that three separate starting attempts? These numbers don't mean much to me because I don't know what the wires are. The reading that matters is the voltage at the battery while cranking, post to post. And the voltage from the big terminal on the starter motor to the case of the starter while cranking. If you can also get those readings while it is in start but not working correctly, that's even better.

Battery "clamps" are not heavy enough for this application, use a crimp on or solder on terminal, or get new cables of the original size, or add another cable to the existing one once you have the resistance down to an acceptable level. I'd probably remove the kill switch from the starter cable too, at least for testing purposes.

What is this powering down noise? metal on metal? or like a turbo spooling down?

 

[808Mark]

NH575E: That's a good point. While I did check the ground connection from the starter to the chassis and battery, I didn't check the connection from the starter to the motor. I presume, since there isn't a wire going directly to the engine block, that the block is grounded through the starter and frame.

Delmer: I just got to work to check the battery and it's a Napa commercial with 950 CCA. I have a battery tester and it tested out good. The battery is about 3 months old. I should have clarified my numbers for the 12.6-8-12.6 The first and last readings are before starting and after the engine started. The middle reading was when the motor was cranking. I definitely will do the tests you recommended. Also I'm sorry my terminology is pretty rubbish. I am currently using a top post lead battery terminal with a 2/0 copper wire with electrical lugs crimped on.

The powering down noise is from the starter and doesn't seem to be metal on metal. I believe the noise is made when the starter doesn't get engaged and ends up spinning its way down kind of like the sound of a turbo. One time when i was testing the starter I actually felt the starter spinning when the engine didn't start.

 

[x-ray]

Might be wrong but that sounds dead like a bad/not engaging starting bendix..

 

[Tinkerer]

Time to remove the starter and take it to a professional rebuilder. If it is spinning and not engaged to the flywheel you have a problem with it. Unless there are some teeth missing on the ring gear.

 

[Hobbytime]

if you want a new starter, hit up ebay, I just got a new starter for a ford 555 1980s backhoe delivered for under $120.00, yeah its made in china, but then everything is( comes with a 1 year warranty) but its been in a few months and no issues...for the small investment of a new starter, you will eliminate a starter as an issue.. just because it was " rebuilt" doesnt mean it will work any better, depending on the rebuilder..I know 1 rebuilder around me that has a darn nice collection of spray paint and wire wheels..things look great after he " rebuilds" them...cant say they work too well though..lol