Dead Jeep - any ideas very welcome

[UKTJ]

16 hours ago, Caroline12 said:

Does the starter turn the engine at all now ? 
check with a insulated handle screwdriver as Phil said above. Jump power from main +12v to solenoid connection, to see if it fires in and turns the engine.

 

 

It gives you a jump the first few times I did it, now I know what happens and I’m used to it. But my big screwdriver has burns/melted metal on it from testing the solenoid on starters. 

Do NOT use copper cable to do this test, the copper melts and then welds itself to the starter posts. Use a single piece solid steel metal bar with a good insulated handle to do this test. 
 

sometimes, they just fail for no reason, mud and water do destroy them quicker

Just to doubke check, you are both saying make a direct connection from the terminal on the starter motor connected to the battery and the other terminal that is wired to the starter, so bypassing the solenoid.  I am not good with electrics, so want to be sure.

[UKTJ]

@digger and @Caroline12, sorry if I am being dumb.  I have checked out my screwdriver collection and I don't have an insulated one.  Have looked into buying one on a few websites, but all the VDE insulated ones are insulated down the whole shaft, soo don't think that would make a connection.  What am I missing?

[Caroline12]

Work big work screwdriver with solenoid starting burn marks on the metal. 
the handle has to be an insulated material from the main metal shaft. A wooden handle works too.

[Caroline12]

Hi Terry, 

 

if your not sure then don’t do it that way with a starter motor.
this video clip shows a safer way to do it, which would probably be better for you and help you understand what’s happening.

hope that helps. 

[UKTJ]

Deleted, duplicate

Edited June 10, 2023 by UKTJ

[UKTJ]

1 hour ago, Caroline12 said:

Hi Terry, 

 

if your not sure then don’t do it that way with a starter motor.
this video clip shows a safer way to do it, which would probably be better for you and help you understand what’s happening.

hope that helps. 

My initial thought was taking the starter off to test was a pain, but as I can test miltiple things I think this is what I will do.

 

I did put charger on battery, not sure how long to charge as was required ro go on a shopping trip, but was on 3 of 4 blips when first connected.

[UKTJ]

OK @Caroline12, @digger and @V I have tried the first two tests in the video posted above and get nothing at all.  I am pretty sure I am making a connection as when I touch the small pin I see a small spark.  Is this telling me the starter moter is just plain dead?

 

Edit: just tried again to check for user error, on one try got a brief moment of action, but could not replicate.  Guessing I must be making a connection as solenoid is warm to the touch after my tests.

Edited June 10, 2023 by UKTJ

[Caroline12]

Sounds like the starter is dead. 
recommend, get a new one and get the old one refurbished. 

[UKTJ]

3 hours ago, Caroline12 said:

Sounds like the starter is dead. 
recommend, get a new one and get the old one refurbished. 

Thanks for that.  I have found a local place that does starter motor refurb.  Not sure how economic it will prove as they say online their minimum chatge is £45 plus parts plus VAT, so minimjm £54 even if no parts.  But they give free estimates, so no harm getting one.

[V]

£92.39 from Rockauto.com FedEx delivery and VAT paid.

[V]

That's a new part, not remanufactured.

[UKTJ]

9 hours ago, V said:

£92.39 from Rockauto.com FedEx delivery and VAT paid.

Exactly my thoughts re the economics of refurbishment, it doesn't take much of a charge for replacement parts and refurbishment ends up more than a new replacement.

 

I have had a TYC starter motor in my basket for a few days now.  But of course that is the one I bought and fitted in February which has died - albeit after a swim in Wales.  Interestingly I only noticed when testing it yesterday that the one delivered in February has a manufactured date of 2016, so its been on a shelf somewhere for some time.

 

These events do give rise to a few thoughts.

1. Is there any way to protect a starter motor when crossing water?  On a TJ it is the lowest slung of the vulnerable components.

2. Should a starter motor be removed for drying / preventative maintenance after offroading?

[V]

3 hours ago, UKTJ said:

1. Is there any way to protect a starter motor when crossing water?  On a TJ it is the lowest slung of the vulnerable components.

Flowing river water isn't usually a problem, it's liquid slurry that hardens inside when dry.

 

3 hours ago, UKTJ said:

2. Should a starter motor be removed for drying / preventative maintenance after offroading?

I guess if you have a functioning spare starter motor, preventative maintenance would be swapping them over then disassembling the removed one for a clean, inspection and refurb as required.

 

 

[V]

I haven't repaired a starter motor in ten years or so. The last time I bought parts for one of my Jeep motors it was getting harder to find the repair parts. Omix-Ada still sell a few and Lighthouse in Diss will likely have them.

 

From memory there is a flat copper spring plate in the solenoid which was quite difficult to find. I guess it's the entire solenoid to replace now. I am looking for the link to the parts site I bought from, I haven't found it yet but I found this website that sells repair parts https://www.autoelectrics.net/starter_motor_diagnostics.html

 

This company sells repair parts too:

https://www.startermotor-alternator-store.co.uk/jeep-cherokee--12kw-starter-motor--25-40-ac-t103-3375-p.asp

 

[UKTJ]

Good news all around.  RockAuto / FeDex got my parcel here 4 days ahead of schedule.  I've fitted the new starter and the Jeep starts fine.  Now I get to open up the starter I have taken off to see if I can get it working again.

 

I do still need to think about the vulnerability of that starter though, it had only been on the Jeep four months and one series dunking killed it.

[Cameron]

Great news...tis the day to get TJs moving again!!!

[V]

My two guesses are:

1. Dried mud passing under a brush pushed it up into it's holder where the brush jammed and was no longer in contact with the commutator.
2. Mud or corrosion fouling the solenoid contacts. Not easy to examine on a sealed solenoid, some older designs were fixed with screws and sealed with an O-ring.

[V]

 

 

[V]

I would have used JB-Weld or Araldite Epoxy to secure and reseal the cap for it's second life. No need to drill and tap just keep it squarely clamped while the glue sets.

 

[UKTJ]

17 hours ago, V said:

My two guesses are:

1. Dried mud passing under a brush pushed it up into it's holder where the brush jammed and was no longer in contact with the commutator.
2. Mud or corrosion fouling the solenoid contacts. Not easy to examine on a sealed solenoid, some older designs were fixed with screws and sealed with an O-ring.

And I believe we have a winner!

looks like number 1 to me, except it is more than mud by the looks of it.  Looks like water was sitting in the starter motor and has completely corroded 2 of the brushes in the housing.

 

Not sure this is salvageable.  Unless somebody has some good ideas or I can buy a replacement ring assembly thingy (not looked yet).

 

What it says to me is that after any time spent in water it will likely be worth pulling the starter motor and disassembling to look to ensure there is no trapped water.

[UKTJ]

Looks like that part can be bought, trouble is working which one is the right one as can't find an exact match.  Also, based on testing done not sure the solenoid hasn't gone in some was as well.

[V]

The brushes are usually made from a carbon material like the graphite in pencils. There are two that look like they have been pushed back into their holders and are now jammed. Try pushing them from the bottom of the jolder to see if they will push out. It may be worth trying this in a bowl of warm water with some detergent. If they free up and stay movable on their springs they should be OK to reuse when dry. They don't need lubrication.

[V]

It is sometimes hard to find the actual part numbers for aftermarket brush plates as they are often just listed by the starter motor numbers that they fit. The shops use their own SKU and not the manufacturers which isn't much use for cross referencing.

The Mopar parts are in two pieces, the harness with two brushes and the plate with two brushes. These numbers are from 1993. The 2001 parts list doesn't show them, the starter motor became a 'non-repairable' stock item somewhere in between.

• Mopar 83503670 Two brushes with cable
• Mopar 83503671 Two brushes in holder

The aftermarket parts usually come as one kit but ALWAYS worth checking before purchase.

If you condemn the brushes that you have removed, the shiny ones connected to the lead are worth saving in case you get a plate only kit at some point in the future.

The key number for starter motor part searches is Mitsubishi M1T74281 - This is the base model number for the family of starter motors used on the Jeep 4.0L . It is also used on may Japanese vehicles and Saab and Vauxhall according to a cross reference I found today. As long as it has a 10 tooth gear, it will be fine. The kW can vary a little between models but I can't say I have ever detected any differences in use. I have swapped all ages of starter motors between my 1993 and 2001, repairing those that I could and returning them to my shelf stock.
 

[UKTJ]

8 hours ago, V said:

The brushes are usually made from a carbon material like the graphite in pencils. There are two that look like they have been pushed back into their holders and are now jammed. Try pushing them from the bottom of the jolder to see if they will push out. It may be worth trying this in a bowl of warm water with some detergent. If they free up and stay movable on their springs they should be OK to reuse when dry. They don't need lubrication.

The two corroded brushes are the ones attached to the holder, so I would likely need to buy the holder and brush unit.  They are very stuck.  I have already given it a go to push them and all that happened was that I started to break the carbon brush with the flat head screwdriver I was using to push.

 

A replacement unit is cheap enough that I will order one and see if that does any good.  Not sure it will fully resolve it as I think there may also be an issue with the solenoid, but worth a try.

 

I also pulled the original starter motor out that I replaced with the one that has just gone bad.  I tried to open that up as well, but one of the two screws would not budge, got to the point where I could feel I was twisting the head off, so stopped and will give a bit of penetrating oils a go.

[V]

Tap the head of the bolt with a hammer a few times like you would hit a nail on it's head. This can help fracture corrosion between the threads.

 

If the short screws securing the brush holder to the end cap are about to snap, it won't matter if you are replacing the brush holder. I reckon replacement screws will be metric if you can get the broken part out.

 

Test the solenoid on the original starter, if it is better than the solenoid on the one you have just removed, swap them over. You will then have a working spare starter motor.

 

If you have a solenoid that you are likely to scrap, you may enjoy taking it apart to see if you can save it. See the 'Repair the unrepairable' video above. I think it will be better to use epoxy to secure the cap on reassembly.

 

Remove rust from the solenoid core and the inner surfaces of the casing and lightly oil the surface of the core, don't use grease as it will harden. Wipe off the oil with a paper towel so that only a thin film is left which should help slow further rusting. The next bit is a bit tricky seeing that you've just used oil as a corrosion inhibitor. The surface to be bonded to the plastic terminal cap must be free of oil for the epoxy to stick. Spray some brake cleaner on to the bonding surfaces of the casing and the cap. Wipe around them with a paper towel to remove any trace of oil. With some fine emery paper or wet-and-dry, abrade the bonding surfaces to enable the epoxy to adhere to them. Mix up some 24hr epoxy and glue the cap to the casing. Ensure the conductor is through the cap for soldering later. It may be easier to brighten the surfaces for soldering before glueing the cap on. Clamp the solenoid securely and leave for 24hrs to set. Use some flux on the conductor before soldering or a good flux core solder. If there are any gaps in the epoxy joint these can be filled with fresh epoxy and left to set.