Replace Glow Plugs B7500

Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
Hi Everyone,

Does anyone know the steps involved to replace the glow plugs on a Kubota B7500?

Any help would be appreciated.

Thanks in advance!
/Jerry
 

ve9aa

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Apr 11, 2021
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This is a trick question. . .
 

Russell King

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Lifetime Member

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Jun 17, 2012
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Austin, Texas
Disconnect battery ground cable

Remove the small nut that is holding the wire onto the glow plugs. The nut may be round with a slot and the wire will be a metal rod.

Use a deep thin wall socket to remove the glow plug.

There are no gasket or seal involved probably but verify that on a illustrated parts list.
 

Thatoneguy

Member

Equipment
Kubota b7200
May 20, 2022
67
12
8
Southern California
When i bought my b7200 the old owner said it was hard to get started and i assumed it was a faulty switch or a bad plug.... after tinkering with a test light, i pulled off the aluminum wires connecting the glow plugs together and cleaned the contact points with some fine grit sand paper. Works as it should now and fires much easier than it did before. Just a thought if thats the boat your in. Took me all of 10 minutes.
 

Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
Disconnect battery ground cable

Remove the small nut that is holding the wire onto the glow plugs. The nut may be round with a slot and the wire will be a metal rod.

Use a deep thin wall socket to remove the glow plug.

There are no gasket or seal involved probably but verify that on a illustrated parts list.
Hi Russell,

Thanks for the steps. So to clarify, I don't need to take the engine off to access the glow plugs on the B7500? I am getting mixed communication on this based on other websites I have read. My Messeck's parts manual isn't clear to me on this.

Any other direction you can share would very much be appreciated

Thank you!
/Jerry
 

Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
When i bought my b7200 the old owner said it was hard to get started and i assumed it was a faulty switch or a bad plug.... after tinkering with a test light, i pulled off the aluminum wires connecting the glow plugs together and cleaned the contact points with some fine grit sand paper. Works as it should now and fires much easier than it did before. Just a thought if thats the boat your in. Took me all of 10 minutes.
Thanks for sharing Thatoneguy! I'm hoping for the same outcome.
 

Mark_BX25D

Well-known member

Equipment
Bx25D
Jul 19, 2020
1,757
1,280
113
Virginia
Any other direction you can share would very much be appreciated
Mechanically, it's very similar to removing spark plugs in a gas engine. If you've done that job, you'll be in friendly territory right away.


I don't know if this applies to the B7200, but one glitch that can happen with SOME engines with SOME glow plugs is that the tips can swell, making them difficult to remove. That can get ugly. You'll know if they come unscrewed but won't come out. If you encounter that, you'll need advice from someone who has had that problem on your particular engine. Don't force it! If you break the tip off you'll be on a fishing expedition.
 
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ve9aa

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TG1860, BX2380 -backblade, bx2830 snowblower, fel, weight box,pallet forks,etc
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You shouldn't have to remove your engine to take out the glow plugs.

Think "skinny spark plugs" with bolt on wires (not boots) and that's all you really need to know.

Most of us should be able to do this job. If you cannot for some reason, please get someone qualified.

(re: my previous comment in this thread--I'm sorry), but I honestly thought your question was a joke. My apologies.
 

Henro

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May 24, 2019
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It might be wiser to evaluate the operation/condition of the glow plugs before changing them.

One thing that can be done is to measure and compare resistance of each glow plug. They should be about the same. Not sure but likely around 1 Ohm.

A better check to measure actual ampere flow through each glow plug. But you need an ammeter for this.

A basic first check is to verify you are getting voltage to the glow plugs to begin with. This can be done with a cheap, readily available voltmeter.

Just a couple thoughts…
 

Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
You shouldn't have to remove your engine to take out the glow plugs.

Think "skinny spark plugs" with bolt on wires (not boots) and that's all you really need to know.

Most of us should be able to do this job. If you cannot for some reason, please get someone qualified.

(re: my previous comment in this thread--I'm sorry), but I honestly thought your question was a joke. My apologies.
No offense taken. Just a new by here learning as I go!
 

Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
It might be wiser to evaluate the operation/condition of the glow plugs before changing them.

One thing that can be done is to measure and compare resistance of each glow plug. They should be about the same. Not sure but likely around 1 Ohm.

A better check to measure actual ampere flow through each glow plug. But you need an ammeter for this.

A basic first check is to verify you are getting voltage to the glow plugs to begin with. This can be done with a cheap, readily available voltmeter.

Just a couple thoughts…
Thank you for the thoughts. Replaced the glow plugs. No issues. Glow plug console light is now gone.

But, the Kubota still won’t turn over. Battery fully charged. I ohm checked the battery cables. And no issues there Won’t jump either.

I’m thinking replace fuel filter and maybe something with the fuel injectors?

Not sure how to tell if the starter itself is bad?

Thanks in advance for your thoughts.
Jerry
 

Thatoneguy

Member

Equipment
Kubota b7200
May 20, 2022
67
12
8
Southern California
Just for clarification, can you further describe the issue you are having, when you say the engine doesnt turn over do you mean it doesnt start but cranks or nothing happens at all...

If the issue is that it doesnt do anything, glow plugs would not be the problem. It possibly would be starter related. I would check wiring to make sure connections are not corroded, a rodent didnt chew through anything, check grounds, etc. If the tractor is stored out doors, humidity and other factors may play a vital role in electrical components. I have jumped a solenoid on an automotive starter to check its function on a car, im sure a tractor isnt much different. Most autopart stores can bench test a starter as well if you pull it out.

Have you confirmed the engine or transmission isnt siezed in anyway?
 

Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
Just for clarification, can you further describe the issue you are having, when you say the engine doesnt turn over do you mean it doesnt start but cranks or nothing happens at all...

If the issue is that it doesnt do anything, glow plugs would not be the problem. It possibly would be starter related. I would check wiring to make sure connections are not corroded, a rodent didnt chew through anything, check grounds, etc. If the tractor is stored out doors, humidity and other factors may play a vital role in electrical components. I have jumped a solenoid on an automotive starter to check its function on a car, im sure a tractor isnt much different. Most autopart stores can bench test a starter as well if you pull it out.

Have you confirmed the engine or transmission isnt siezed in anyway?
Sorry. Engine cranks, but won’t fire/start. Which what I am reading, rules out the seloniod and the starter, correct? I checked and it’s getting fuel from the tank to the pump. Battery is fully charged and I just replaced the battery cables and ground down the chassis to get a better connection for the black cable. And as I shared earlier, I replaced the glow plugs because I had a glow plug console light on at all times.

So she cranks but just won’t start.

My battery tool tells me the battery is 100% charged and showiing 12.7 volts while off and when trying to start her.

How can I determine if the engine/transmission is ceased?

Any other thoughts?
 

Henro

Well-known member

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B2910, BX2200, KX41-2V mini Ex., Beer fridge
May 24, 2019
5,784
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North of Pittsburgh PA
It likely could be an issue with the fuel cutoff device that is part of your tractor. Generally the engine is shut down by cutting off the fuel supply. Sometimes manually, but often on newer tractors electrically.

IF you have a electrical fuel cutoff setup, you could have a failed fuel cutoff solenoid or a power supply issue feeding that solenoid. That is where I would look at this point.

Perhaps someone who knows your specific tractor can offer some detailed help…
 
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Cyrus73

New member

Equipment
B7500
Aug 7, 2022
9
0
1
Sidney,OH
It likely could be an issue with the fuel cutoff device that is part of your tractor. Generally the engine is shut down by cutting off the fuel supply. Sometimes manually, but often on newer tractors electrically.

IF you have a electrical fuel cutoff setup, you could have a failed fuel cutoff solenoid or a power supply issue feeding that solenoid. That is where I would look at this point.

Perhaps someone who knows your specific tractor can offer some detailed help…
I just tested the fuel pump and no fuel is coming out if it when I turn my key to light up the glow plugs. Is this correct or shou;d the fuel pump be passing fuel to the fuel injectors when I turn the key to light up the glow plugs?
 

Thatoneguy

Member

Equipment
Kubota b7200
May 20, 2022
67
12
8
Southern California
Oh okay, that clarifies things a little better. If the engine is cranking chances are its fine to just keep things simple.

What is the background on this tractor? Did you just purchase it, was it a family heirloom thats been sitting for a long time until you started to get it going? What did the previous owner say about it? The reason ask, is starting from the most basic things first and working your way up to the more conplex problems. If its been sitting, you may have bad diesel in it causing it to not fire up. Are you pre-heating the glow plugs properly before trying to start it. My 7200 requires i turn the key the opposite direction for about 30 seconds or so before cranking it over. Im not sure if your machine is similar or not. Is the air filter extremely dirty, fuel filter plugged up? When you crank the engine do you get any puffs of smoke coming out of the exhaust? If you do is it white smoke or black? Also is this an HST or gear model? If its an hst i read it may have to be shifted into the neutral position to start.

The fuel cutoff switch was another recommendation to ensure it fires. Engines need 3 things: fuel, air, and spark or in our case heat and compression. If the fuel system has been opened up at anypoint. Diesel engine run at high pressure, if any air has been introduced into the system it would need to be properly bled to get the air out.

If the fuel pump is mechanical, turning the key on shouldnt pressureize the system, cranking the engine would
 

fried1765

Well-known member

Equipment
Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
Nov 14, 2019
7,843
5,066
113
Eastham, Ma
Oh okay, that clarifies things a little better. If the engine is cranking chances are its fine to just keep things simple.

What is the background on this tractor? Did you just purchase it, was it a family heirloom thats been sitting for a long time until you started to get it going? What did the previous owner say about it? The reason ask, is starting from the most basic things first and working your way up to the more conplex problems. If its been sitting, you may have bad diesel in it causing it to not fire up. Are you pre-heating the glow plugs properly before trying to start it. My 7200 requires i turn the key the opposite direction for about 30 seconds or so before cranking it over. Im not sure if your machine is similar or not. Is the air filter extremely dirty, fuel filter plugged up? When you crank the engine do you get any puffs of smoke coming out of the exhaust? If you do is it white smoke or black? Also is this an HST or gear model? If its an hst i read it may have to be shifted into the neutral position to start.

The fuel cutoff switch was another recommendation to ensure it fires. Engines need 3 things: fuel, air, and spark or in our case heat and compression. If the fuel system has been opened up at anypoint. Diesel engine run at high pressure, if any air has been introduced into the system it would need to be properly bled to get the air out.

If the fuel pump is mechanical, turning the key on shouldnt pressureize the system, cranking the engine would
"bad diesel in it" ????
A 20 year old B7500 will likely burn any diesel that is in it, especially during these Summer temperatures.
Older diesels are very tolerant of poor fuel quality (unless water).