I have the radiator off, what else to replace? 300U

I have a 55 300 U and I had to take the radiator off to replace the fan belt. What else should I replace while I"m here? All the water pump parts, hoses?
I don"t have a radiator cap that fits, the neck doesn"t have any way to attach it? Is this the right one, how can I tell if it is correct, 3 versus 7 lb?
My tractor is making a wheezing noise from the water pump area and is overheating which is why I am thinking about replacing everything water pump related.
Finally I messed up the coupler that drives the hydraulic loader pump. It says moreflex 352 on it, the one I found on this site that looks like it only comes as a kit for a ford tractor. Does anyone know if it comes just as the coupler? PARTS FORD Moreflex Drive Kit - Morflex Series 352 coupler complete with 2 drive flanges(34in wkey), set screws, 4 bolts & lock nuts. Mounting is four 516in. holes spaced 2-14in apart. (Part No: L601-9) 57.47
THANKS!!


I haven"t had a chance to call but can I pick up the parts if I want or do they only ship? (I live in Washington and I think I am close to where they are located)
Thanks!


PARTS IH Radiator Cap - 7 LB, fits short filler neck. For Models- 300, (Part No: 393229R1)
PARTS IH Radiator Hose Kit - Radiator hose kit for tractors-300 Hoses-(1) 1-14 I.D. x 2-14L,(1)1-34 I.D. x 3-12L, (2) 1-12 I.D. x 2 (Part No: RHKH300) 9.60
PARTS IH Water Pump Bearing - Ball bearing for water pumps used on tractors- 300, 2 used per pump, replaces ST225. For 300, 350, 4, H, SUPER H, SUPER W4 (Part No: ST225B) 19.06
PARTS IH Water Pump Seal - For Models-300, 350, H, HV. (Part No: 51492DA) 19.31
PARTS IH Water Pump, Impeller - For Models- 300, 350, H, SUPER H.This is impeller Only, DOES NOT include shaft or thrust washer. (Part No: 9165DX) 20.00

Couple of things...

1. What exactly is "messed up" on the front PTO driveshaft? My similar setup seems to be a flat plate with bore, key, and setscrew to the shaft. Other end is a double-strand roller-chain coupler (essentially coupling 2 parallel sprockets together) to the pump input shaft. This is standard industrial power-transmission stuff typically which may be fixed by a machine shop or a visit to Applied Industrial, Motion Industries, (etc).

2. Waterpump work that I've done on a few of these tractors usually requires an arbor press and some custom pins/pushers to do properly if you don't have the right-sized sockets (usually they can work well inthis application).

3. If the 300 has the older "H" style block with the core-cover on the side of the waterjacket, I would definitely take that off, replace it and the gasket, surgically clean the gasket face and reapply with RTV. The ones I have taken off look Ugglee inside and definitely had restrictions.

4. Have you verified the pulley also turns the waterpump impeller? I had an "H" once which was missing these key pieces. Fan, fanbelt and hub all would turn like mad when running. But the cross-tie to the impeller shaft was lost/missing/discarded and so the impeller never moved. Very fast overheat nearly every time.

5. I think replacing the hoses is also an excellent idea. As is the coolant (sorta by default). The latest tractor I'm working on must have been run on straight water by some cheapo...incredible sludge and rust inside the water jacket.

Thanks for the suggestions. It only overheats when under load for a while, the belt was really loose so I tightened it and then it broke.
The coupler thingee is broken where the metal keeps the bushing in place. It is such a pain to get to that I figure I better replace it than have it break and ruin something else.