Thank you Bill.

Robert5,
That's great.  I see the "L" on the head of the left side bolts, but I am not sure what the bolt manufacturer is trying
to say with all the letters on the right side bolts.  It could be hardness, date of manufacture, size, length, # of threads
per inch or other things.  But, I'm happy you conquered this.  Now, on to the next adventure.

OK.....completely solved!

They were right hand thread on the right side.
I found that 19mm was very slightly tighter than 3/4" .
And a fresh new 19mm socket 1/2" drive and a 4 ft. Breaker bar accomplished the stubborn last 2 bolts .

Now I can bring tire to get fixed tomorrow.

Thank you to all who joined the conversation.

So, the left side bolts clearly have an "L" marked on them.
And the right side do not.
Are ALL left threaded bolts marked with an "L"  or are some made left handed without
being marked with the "L" ?
This is important because a previous owner may have replaced the drums with left side drums.

Thanks all.

2 Pics.....
First one is left side.
2nd one is right side. [attachment id=0 msg=19350]

Bill

  Thank you for answering.
I will examine mine closer tomorrow.
  If I can't make sense of it .....I will post pics of both sides tomorrow and perhaps you can tell from the photos.

Thanks.

Robert5,

See attached photo of the wheels on my car.

Robert5,

Your '51 Plymouth should have LUG BOLTS, not STUDS and NUTS.  The BOLTS should have an "L" stamped on the end (head of BOLT)
for those BOLTS used on the left (driver's) side of your car.  And, the BOLTS on the right (passenger) side of the car should have an "R"
stamped on the head of them.  If someone has changed it to STUDS and NUTS, there should be enough threads (one or two) to be able
to determine if the STUDS and NUTS have left or right hand threads.

Tod....thanks for the story.
So my car could have either right thread or left thread on the right side depending if a previous owner swapped out the drums with left threaded ones......
Oh boy! How am I going to figure this out without doing some damage?
I hope someone here can offer some way of getting the answer without me incurring damage.

Quote from: Robert5 on April 14, 2019, 12:03:47 PM
OK....next dumb question.
I know my car is supposed to be left hand thread on left side of car and right hand thread on the right side of car.
I have 1 wheel I need to remove on the right (passenger) side.
The lug nuts on that side have this on them....envision a 6 slice pie. And it reads  0/1/8/N/B/A reading it from left to right in a circular motion. Anyone know if that means something?
Previous owner initially said both sides of car were left hand thread?????  Could something have been changed to make that possible? Or is he just mistaken and it's left on left side and right on right side?
I have tried breaking them going either way without success. I am using a large breaker bar but being kinda gentle because I do not want to break either the lug nut or the stud.
Any advice is greatly appreciated.

Not sure I can help a lot, but I do have a story. :)

I acquired a 63 Dodge D200 back in the 1970s and knew from previous experience that one side should have left hand threads. What I hadn't paid attention to was that some previous owner had swapped the drums from one side to another. About busted a gut trying to get the wheels off until I notice the "L" on the studs was on the side opposite that I expected.

Moral of story: Previous owner may have swapped drums side to side. Or some previous owner may have needed new drums and could only find left hand thread ones so put them in all positions.

On the cars with studs there is usually a "L" on the left hand threaded ones. But I don't know if that is true of the cars with lug bolts (my '33 Plymouth is from a year when they used right hand threads on all wheels, which also caused me to nearly bust a gut until I figured that out as I expected left hand threads on the left side).

OK....next dumb question.
I know my car is supposed to be left hand thread on left side of car and right hand thread on the right side of car.
I have 1 wheel I need to remove on the right (passenger) side.
The lug nuts on that side have this on them....envision a 6 slice pie. And it reads  0/1/8/N/B/A reading it from left to right in a circular motion. Anyone know if that means something?
Previous owner initially said both sides of car were left hand thread?????  Could something have been changed to make that possible? Or is he just mistaken and it's left on left side and right on right side?
I have tried breaking them going either way without success. I am using a large breaker bar but being kinda gentle because I do not want to break either the lug nut or the stud.
Any advice is greatly appreciated.

Go Fleiter.....

Many thanks.
Part #
1346 849

Is indeed a 4 lb. Radiator Cap for my '51 Cambridge.

I think that solves that mystery.

Go Fleiter

  Thanks..I will give that a try.

Tod
Thank you for your kind words.

Hello Robert,
  my Parts book says " 7-12-1    cap, Pressure   1346 849" for P22 and P23 radiators.
I couldn´t find any information on the pressure in the Service manual too.
Maybe Andy Bernbaum´s Chris Paquin with the above can tell You the rating of the original?
https://www.oldmoparts.com/
Greetings from Düsseldorf!
Go

Finding all that paperwork would make it an outstanding day in my book. Congratulations!

Yesterday was a good day ( even though there is still snow surrounding my Cambridge).
Was able to confirm that my cables are intended for six volt use.
And I charged the battery for 5 hours. That was sufficient to spin the starter nicely. The motor started and idled beautifully. There was a miss when I first got the car and now that miss is gone.
I attribute that to the replacing of the Champion (never been a fan of Champion plugs) spark plugs with AC/Delco plugs.
Also paperwork was found inside the car that revealed the original owner's name and address. It was a female who lived in Carlisle, PA. The dealership was Arnold Plymouth/Desoto, also in Carlisle, PA. And she took delivery of the car on Feb. 27, 1951.
It was a good day.

Thank you CHS.
I believe the '51s left the factory with 4 lb. Radiator caps.
If anyone can confirm or deny that 100% it would be appreciated.

you were asking about a radiator cap. I have a 55 Plymouth 6 cyl flathead. The radiator cap is 7 lbs pressure. It is also stated in my service manual.

From research I've done, seems 6V cables are generally twice as thick as 12v cables.
As soon as our weather gets back to spring like weather, I'll be back at it. I'll determine if my cables are 6V thickness or not. And I'll figure out if I need a new battery or not.

I put 00 cables on my 35 and it starts much easier.  The 00 are almost as thick as my thumb.

Thank you Plymouthcranbrook and napmaster.
What is the circumference of a correct 6V battery cable? I'm not sure if my cables are correct?

Welcome.. Make sure you have 6 volt cables not `12 volt cables as the 12 volt  ones are not thick enough to carry the amperage of the 6 volt system. Be aware also that sometimes when driving slow or at idle the generator will not produce enough voltage to charge the battery correctly especially if using headlights for example

That is a beautiful car.  Hope you enjoy it.  I hope you continue to take advantage of this forum.  I can't tell you how much I have learned just lurking here.  I have spent hours search past posts and studying before I do anything on my car.

Thank you delaware for the welcome!
Tod--yes, it does come out to about that 6.37 volts mentioned earlier.
And mine is reading between 5.98 to 6.02
All the cells do indeed have water.
Can't exactly check too much else when car does not spin fast enough to start.
But I did verify ground cable was good and there is continuity in the battery cables and the wiring  to the starter and the resistor is good.
I'm thinking probably battery is shot. It was replaced by previous owner in 2017. By he only drove the car about 300 miles since then. I don't think he ever used a battery tender or similar.
I have a 6V battery charger coming late Tuesday. I may run out of patience before then.....if I do I can get a battery for $97. locally with the exchange of old one.
We had a little snow overnight and rain for today so today looks like an off day.
To be continued next week......

There's been a running argument forever about the pro's and con's of 6 vs 12 volt systems. Tod's advice is good; often there are little things like corroded connections or an out of adjustment voltage regulator.
Beautiful car. Hope you have fun with it. Welcome to the club.

Quote from: Robert5 on April 05, 2019, 04:42:16 PM
Is it true that a "good" 6 volt battery should read (with car off )6.37 volts and if your battery reads 6.00 volts as mine does .....its 80% dead and in need of replacing?

Look up the equivalent for a 12v lead acid car battery and divide the numbers in half.

6.0v is pretty well discharged. But before throwing money at a new battery I'd check the charging system to make sure it has the correct voltage and verify that all cells of the battery have water and that the state of charge as measured by a hydrometer is the same across all cells.

Is it true that a "good" 6 volt battery should read (with car off )6.37 volts and if your battery reads 6.00 volts as mine does .....its 80% dead and in need of replacing?

Thank you Tod!

The 1946-54 Plymouth Factory Service manual notes that they started using a pressurized cooling system in 1950. But I don't see specifications in that book for what the radiator cap should be rated for. I imagine it was a rather low pressure compared to current cars but won't hazard a guess about what it should be.

Does a 4 lb. Radiator cap sound right?

Good looking car. If it runs as good as it looks you've got a real find!

Thank you Tod.
Not sure how to attach a pic....but I'll try.
Pic. from seller.....our weather here in NH not real suitable for old cars.
We had a little snow this a.m.

Welcome to the forum.

I don't know much about that era car, and it sounds like you're pretty familiar having had a similar one earlier. But if there are any bits of information I can help with, I'll try.

Do you have pictures of your new car?

Just saying hello.
Bought a 1951 Cambridge sedan. Got it yesterday.
My first vintage car in 14 years.
Throughout the 80s,90s, and early 2000s I had about 25 collector cars....usually 3 at a time.
Then things changed.....divorce, relocation, etc.
My very first was a 1951 Cranbrook Belvedere.
So, now after 14 years without a vintage car, it only seems right that I bought another '51 Plymouth. Retired now.....so this it. Not likely to buy any others.
I'm sure I'll have some questions so I thought an introduction would be good.