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New Member/ New (to me) 73 MGB / New issues in my life

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drcabe David R Cabe
Fort Worth, TX, USA   USA
I purchased a 1973 MGB last month on eBay. I felt comfortable enough with the seller and his thorough description and I'm happy with the purchase. I purchased on a Friday and I had it trailer-ed from Houston to Fort Worth in less than 24 hours after the auction was over. The car cranked right up, I gave it a quick once over and started driving in my neighborhood that evening to taking it a few miles from my home on Sunday and getting it on the freeway on Monday. Car drives straight, shifts great, sounds great and stays cool in this Texas heat and I couldn't be happier. The only known issues was the handbrake and wipe motor didn't work and the freshly painted car had a lot of overspray (all the chrome parts were powder coated black and while a purist might cringe it actually looks good).

So I have the car for two weeks doing what you do in an MGB, drive to the coffee shop, drive to the store and drive to the Sonic for a corn dog. The last night I drove it (foreshadowing) I took it on the back roads about 30 miles and just like every other drive it ran perfect. I sat in the garage with the car running while figuring out the switches and lights and turned it off for the evening. The next morning I went to start it up and it's dead...DEAD, no power, no radio, no headlights, no horn. I assumed I left the key on and planned to jump it later. I first attempted to jump it by coasting down my short but steep driveway but failed. I parked it in front of the house and tried to jump start it with my car and nothing. I had a couple of neighbors push it back in the garage so I could figure it out.

I've learned a lot in the forums and I've tried a bunch of things and my kinda smart mechanically inclined neighbor gave it a look and we are at a loss. Here's where I'm at:

1. The two six volt batteries are good (I think). The first day I tested they were at 5.75 and then a few days later they were 3.5 and today was 1.75. I hooked a battery tender to the battery on the drivers side because I assume charging one will charge both. Should these two six volt batteries read 12 if fully charged?

2. Everything I've read says all the power runs thru the starter and the majority of the time its cable related. The cable to the starter and the wires that attach to the solenoid look fine and there is no corrosion or goo or anything suspect.

3. When I was looking at the starter I tapped on it a few times with a hammer and about an ounce of water dripped out (never been near water).

4. My buddy who is smart checked the ignition and says that's not an issue.

5. I'm leaving on the tinder until I can figure out what to do next.

I am officially lost.

The bright side is I've picked this car apart so much that I love it more now than ever. The engine has been rebuilt, the transmission is new, new shocks and tires (205's waaay too big) and there is no rust. A little search found it won "best import" at a podunk car show in East Texas. The eBay buyer paid more at the Houston Mecum auction than I paid on eBay including shipping. The car is great but I kinda wished it started.

Here is a link to the car show's facebook page

Edited 1 time(s). Last edit at 2018-06-13 04:18 PM by drcabe.

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dohc281 Avatar
dohc281 Gold Member Ira Eckstein
Laurel Springs, NJ, USA   USA
I had a similar problem once with my ‘67 B and it turned out to be the starter solenoid. It would start if I pushed the solenoid button on the fender but nothing came on if I turned the key on.

If you hit your pony over the nose at the outset of your acquaintance, he may not love you, but he will take a deep interest in your movements ever afterwards.

Rudyard Kipling

mgdriver67 Avatar
mgdriver67 Silver Member Stephen Farrell
Pensacola, FL, USA   USA
1967 MG MGB MkI "Lulu"
2016 Volkswagen GTI
2017 Honda Ridgeline 4WD "Mom's Truck"
Consider a Conversion to a single 12 volt battery. 2 sets of cables and clamps are too much trouble waiting to happen. You can use the other battery box for storage using the plastic bins from Clark or other vendors.

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Eds green 74B Avatar
Eds green 74B Gold Member Edmund Schultz
Prior Lake, MN, USA   USA
The batteries are in series so charging one won’t charge both of them. You need to attach the negative side of the charger to the negative pole of the one battery that goes to Ground and the positive charger to the other batteries positive pole. That way you are effectively charging both batteries as though they were a single 12 volt battery. Once you get the batteries charges, see if the engine starts. If not let us know and we’ll see what you need to do.

You might want change out the two 6 volt batteries for a single 12 volt.

Welcome to the world of MGs and this forum.


JoeReed Avatar
JoeReed Gold Member Joe Reed
Cordova, TN, USA   USA
1978 MG MGB "Kermit"
For one thing, it sounds as of you have a wiring or component issue that is draining the batteries when the car is parked. If they are, in fact, good batteries they shouldn't drain that much that quickly.

You can take the batteries to your local AutoZone (and maybe other parts stores) and have them tested for free. They'll likely have to be charged before testing (also free). I'd do that as a first step to rule out a defective battery (or batteries).

Once you're sure you're dealing with good, fully charged batteries you can track down the source of the drain by pulling one fuse overnight, then check the battery voltage the next day or so. Once you determine which fuse you can remove to solve the problem, you'll know which circuit is the problem.

One common battery drain is the boot (trunk) lamp. If the switch is bad - or just not closing completely when the lid is shut - the light can remain on....and you won't know it since you can't see it - kinda like the light in your refrigerator. smiling smiley

V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
One 12v Group 26R is what you want.

MT-B Avatar
MT-B Matt T
City, NY, USA   USA
One good habit to get in to when diagnosing problems is to look at what happened immediately before the problem appeared and start there. It sounds like something about operating the lights and switches probably led to your dead batteries. The simplest possibility is that you left something like the parking lights on and since there is no auto shut off then you turn off the key, that could lead to a very dead battery pretty quickly. I would start by checking the voltage of your batteries and if it’s low try to recharge them with a real battery charger. Remember a battery tender won’t do anything for a severely discharged battery so you will need a real full power charger to get a charge back in them if they have been drained until they are totally dead.

In reply to # 3755121 by drcabe ......just like every other drive it ran perfect. I sat in the garage with the car running while figuring out the switches and lights and turned it off for the evening. The next morning I went to start it up and it's dead...DEAD, no power, no radio, no headlights, no horn.

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DanN1DLH Avatar
DanN1DLH Dan DiMartino
McDonough, GA, USA   USA
1976 MG MGB
1980 MG MGB
Hi David,

I can't stress enough the wisdom in ditching those 6v batteries and old cables. Within that setup there are now double the amount of potential (no pun intended) stress points caused by either corrosion, loose wires, arcing, broken strands of wires and more.

Consider the fact that the basic design is antique and may have worked fine when new(er) but at this point my educated guess is that you're sitting on a mess of variables which, even if not the cause of the problem, will become obstacles in rooting out and solving the issue.

Side note: I used to drive a 74B way back when and it was only a year old. I was constantly cleaning those connections to the pair of 6's in order to get full voltage out of them. Once, while dropping a friend off at LaGuardia I found that my car wouldn't start when I returned. I then discovered that one of the cable's insulation had worn through, to result in intermittent shorts to ground. Untimely breakdown for sure.

FWIW, you need to see about 12.5 - 12.6 volts from the pair while the car is just sitting (not running) and at least 13 volts while the engine is running, preferable closer to 14. Once you have a new 12 volt arrangement installed, with a charged battery, I have a feeling things will either fire up again or become much easier to figure out.

Sorry to repeat what you've been told already but this would be my first step. It will have to be done at some point soon anyway. BTW, new 6 volt batteries are very pricey for what they bring to the table!

Have fun with this thing,


drcabe David R Cabe
Fort Worth, TX, USA   USA
I like the idea of having one 12v vs two 6v batteries so that was my first task. Read a thread on swapping batteries, seemed simple enough, pulled both batteries, found a 26R 12v at Auto Zone, slid into passenger side compartment, positive cable to the starter and new negative cable to the frame...nothing.

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78 B PaceCar Avatar
78 B PaceCar George Funderburke
Kennesaw, GA, USA   USA
Hello David,
When you said nothing, does that mean no power to anything? The brown circuits should be hot with the key off. I would expect the headlights to come on and the emergency flashers to work. The bottom fuse with brown circuit power fused to purple wire circuits should also work with the switch off assuming the fuse is not blown. That would include the horns, the trunk light, and the interior light.

My guess, you need to check the positive battery cable to the starter and make sure something hasn't come lose. You will also notice the brown wires connected to the same terminal, one to the alternator and the other to the brown circuits including the bottom fuse. You also want to check that the ground for the negative side of the battery is grounded to the car and the engine is grounded to the chassis.

If you have 12 volts on the battery, you must have a break in the cable to the starter or a cable lose from the starter to get no power to anything.

Good luck.

drcabe David R Cabe
Fort Worth, TX, USA   USA
Ok, someone needs to protect me from myself. Got underneath, followed the black cable from the starter to the battery and figured out the car is wired negative earth. I used jumper cables to get the interior lights to come on and will need to do move the ground cable and get a larger clamp for the positive terminal but at least I can go to bed knowing I'm moving in the right direction. I truly thank everyone for their far.

GWHITE75 Avatar
GWHITE75 Gold Member Gary White
Sugar Land, TX, USA   USA
1973 MG MGB "OldBlue#2"
1975 Chevrolet Corvette Stingray "Old Red"
2006 Chevrolet Corvette "OldBlue"
Hey David, lots of good information so far and I’d like to second the 2x6 to 1x12v conversion. Also, water from the starter should be of concern, so need to figure that out. The 73 I bought last July off of eBay came with a v6, 12v battery and a battery cable disconnect switch, some members install due to battery drain issues. That being said, mine has no drain, but if it did, I would suggest using the old tried and true battery charger to track down battery leaks by simply disconnecting both + & - cables from the battery/ies, then connect the charger to the negative cable going to the body and positive cable that goes to the starter, to see if there is any amperage draw showing on the battery meter, then you can start to pull fuses to see which circuit has the drain. I’d suggest using the wiring diagram for your car from: to help track possible wiring issues, if any. It seems like your batteries are discharged, maybe due to a drain or age, because you said you hooked up your charger and got results, so the auto cabling is in tact. Remember to turn off all switches and ignition switch as if you were parking it for the night. You should see no amperage draw from the charger.

albeegreen1 Avatar
albeegreen1 Gold Member bob tresch
bordentown, NJ, USA   USA
Dave, I suspect your ignition switch. Also your starter is a great place for leakage to ground. Clean up the solenoid connections and check voltage to the ignition switch. You woke up the Lucas in your car, go get em'.

"Be yourself, because everybody else is already taken". - Oscar Wilde.

"If wishes were horses, beggars would ride" - Phineas Quimby.

chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
If you have the lead head battery cable ends, don't throw them away! They are N/A and sought after by restorers.

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drcabe David R Cabe
Fort Worth, TX, USA   USA
I successfully moved the ground cable over and purchased a terminal shim vs replacing the cable to the starter. Car turned over strong but would not start and the strong smell of gas made me think (hope) it was flooded. Over the next several hours I tried to start it a few times but it will only crank. So...the starter is obviously good, I checked the wiring and connections to the coil, solenoid, distributor and fuses and all appear to be A-OK. What am I missing, what is my progression on figuring what the issue is?

I am very happy with the battery swap and so very thankful for the suggestions and direction this group has provided.

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