Radiator Cap

[DennislB]

Bought a 39 "B" that was missing a radiator cap. Bought one at Car quest. Too small. Took the cap off of my 42 "B" and it is too small to! Did the early B"s use a different cap?
 

[mdtractormechanic]

The early B radiators were atomspheric (non-pressurized) systems. It uses the same cap as does the gas tank.
 

[Bobby 9891]

What year did they go to pressurized systems ?
 

[old]

I can not tell you what year they pressurized them but can say there is a good chance they never did since the WC, WD and at least some WD45 did not have that system on them
 

[bg/mo]

was shortly after that ,a farmall a or a b cap should fit. as far as pressurized all wd"s and 45"s are.
 

[old]

Guess my WD45 has the wrong radiator on it then since it has the non pressurized one. And my W Speed Patrol is also the non pressurized one
 

[chalmersbob(Pa)]

I know that my 47 B and 48 C are presurized. Also my 50 WD and 51 CA are presurized. So I'm going to say after the war they wer mostly predurized. Bob
 

[chalmersbob(Pa)]

According to my parts book, prior to serial # B61222 they were atmospheric type and after same serial # they were pressure type. 61222 would be 1942. Bob
 

[bg/mo]

your saying neither one has a waterpump?
 

[old]

Bot have water pumps but just because it is or is not pressurized has nothing to do with a water pump. You can have a water pump on either type of radiator and it works the same. So why do you believe a system has to be pressurized because it has a water pump???? Lot of old tractors have water pump but the cooling system is non-pressurized
 

[bg/mo]

because on farmall"s non pressurized means no water pump, thats why it is called thermo syphon.I have never seen a wd with out a pressure system, you must have a very very early one, unless someone has done some parst swaping.
 

[bg/mo]

and correction the allis B with non pressure system do have water pumps, got confused there for a bit.
 

[old]

Ya one never knows what may or may not have been done to one of these old tractors. But as I said water pump and pressurized do not fall hand in hand some do some do not but yes my BA Farmall has no water pump and my B JD has no water pump
 

[mdtractormechanic]

Dennis,
Just use the gas tank cap and you'll be fine. Steiner's Tractor Parts for one has the cap for about 20 bucks. Just look on-line.
Joe
 

[MisterT]