Finally I now have my 640, now what?

russ207 · Apr 5, 2014

As a 14 year old teenager in Kansas, I helped my dad overhaul tractors at Buck Astle's Ford dealership in Newton, KS. I remember the new model 600 setting in the showroom floor. Now, 58 years later, I finally procured a model 640. It does not look like that new one on the showroom floor. The tractor runs fine but it has several issues that will require fixing. I was pretty good at tearing down the old "n" model tractors back then, however many, many moons have set since then so I am going to need lots of help.
My issues are:
1. the previous owner had a clutch put in it. The lift worked fine before the installation but does not work now. I checked to make sure the pump (piston) was primed and it appears it is.
2. there is a knock or pop coming from the transmission in 2nd gear, no noises from 1st, 3rd, 4th or reverse. Maybe a broken tooth?
3. the steering works fine in a right turn but is very, very stiff turning to the left - the tractor has no power steering assist.

I have the manual and will follow it as I address the above issues. I would very much appreciate any thoughts you fellows might have that might help hasten my efforts to return my 640 to a proud iron horse.

Thanks, Russ Crawford

Soundguy · Apr 5, 2014

the thump is very likly going to be a tooth or teeth missing. pitty they put a clutch in a machine that may have a trans needing work..

east to pull the top cover on a 4spd however and take a gander.

stiff steering to one side is indicative of either way too much sector backlash adjustment done on one side or , more likely.. bad thrust bearings... fortuately.. that manual box is very easy to rebuidl with new seals and bushings and upper and lower thrust bearings, cups, and a new top bushing.. if it holds oil.. oil it .. otherwise.. 00 ep grease. sometimes the bearing diameters on the sector shafts wear where seals will weep on gear oil.. all depends on what it saw for maintenance..

if the pump IS primed.. and no lift. you may have a stuck unloader valve. not common.. but certaintly not rare either..

as a jump start. i reccomend al 437 plugs.. though champ H12 ( 512 ) work.. gap at .025 just like the points. avoid cheap tisco points. get echlin or other premium points sets.

crankcase holds about 5.5qts.. if it uses a spin filter.. grab a fl1a motorcraft.. otherwise the cartridge is a ch6pl fram.. or napa 1004, other half a quart can go in the oil bath air filter cup after celaning media and cup.

trnas fill by gear shift, check plug on right side above running board near right heel., drain under trans.

hyds fill under left front of seat.. dipstick on left side near pto lever, drain underneath..

diffy fill under back right rear of seat, check plug back left of pto shaft... drain underneath.

PS.. check thrust paly on pto shaft. new assy is only about 135$...

utf fluid meeting m2c134 spec is fine for hyds, trans and diffy sumps. I like a 15w40 C/S rated oil for the crankcase ( here in florida ).. should be ok for GA too.

don't forget the thermostat hiding under the top rad hose connection.

russ207 · Apr 7, 2014

Murph, thanks for the welcome and navigation advice - even though it suggested us Ford folks might somehow be mentally inferior.
SounDguy - thank you for the input. I had been watching the forum for a bit and I hoped you would jump on my inquiry.

I will post my progress as I move ahead.

I just picked up a boom pole this morning and will go look at a box blade later this week. Which means I better get the lift working. I think I will leave the tranny problem until this coming winter when I plan to do an extensive renovation. Meanwhile I hope to be moving dirt by this weekend.

Again, thanks for the warm welcome and sound advice.
Russ

russ207 · Apr 7, 2014

One other question - is there a favored source for parts?

Soundguy · Apr 8, 2014

russ207 said:
One other question - is there a favored source for parts?

depends ont he parts needed.

what ya needin?

russ207 · Apr 9, 2014

Hi souNdguy

It is more looking like I will need near everything other than an overhaul manual 'cause I already bought one.
Seriously, I did some more checking yesterday.
I found out it has a 12 volt battery set up as negative ground. It still has original looking starter and generator. I tried changing the cables around to positive ground but it didn't work - I went back to negative ground and the tractor started fine. However I am certain the battery is not getting any charge to it. So, I will have to get a 6v battery and set it up for positive ground. If I remember correctly I will have to polarize the charging system by shorting across the reverse current relay on the voltage regulator.
I drove the tractor around and can hear a "knock" in 3rd and 4th gears also. I might be looking at a tranny overhaul sooner rather than later.
You are correct a out the PTO play. I don't plan on doing anything that requires PTO for now so I may wait on a new shaft assy.
The steering is not as bad as my son said but it will still need rebuilding - later.
I took the plug out of the hyd pump and cranked the engine. I saw a few air bubbles but it finally was fluid only. I put the plug back in but still no lift. I spoke with the person who had the tractor and he said the fellow who installed the clutch said he may have improperly installed the O rings on the hyd manifold. I cant't imagine that doing anything other than causing a fluid leak - there are no viable leaks.

Regarding the parts purchases - my early purchases will be a proofmeter and drive cable, 6 volt battery, carb rebuild kit and some nuts and bolts. I have a friend who works for NAPA and I get very good prices from him so my first choice will be NAPA (battery, tune up parts, etc.)

Again, thanks for the sound advice, Russ

Soundguy · Apr 10, 2014

incorrect orings on the hy manifold can prevent the pump from priming by sucking air.

Make sure the prev owner did not install a 12v genny. they look almost the same except will have cooling slots at the back. but those can be covered with clip in covers.

not sure why it would not work positive ground UNLESS it has an ei unit. and if it does.. I think you got lucky that it did not try.

genny systems will run positive or negative ground assuming it has a mechanical vreg... starter don't care. it should have turned over positve ground just fine.

when you say reverse current relay, I assume you are talking about the cutout.

That's actually not the preferred way to polarize a B circuit system. ( It is the correct way for an A circuit system like the 8n used ).

To polarize the B circuit, jump from bat hot to field on the genny, wiht vreg field wire disconnected.

russ207 · Apr 10, 2014

Thanks souNdguy,

Going back some 50 years as I recall, after putting new brushes in a generator you would mount the generator, hook up the wires and then short across the"reverse current relay" and field terminals on the regulator to "motor the generator prior to installing the fan belt. This was to set the polarity on the generator. But, I will do it the way you recommend after I get a 6v battery and make sure the generator is 6v.
I just ordered a proofmeter, cable, brake lock and gasket kit for the pump and hyd lift cover kit and a new ammeter. I ordered the stuff from yesterdaystractor.com which is the place I got my overhaul manual. Before I tear into the lift I want to put the proper O rings on the hyd manifold in hopes that will cure the lift problem. Since removing the manifold was the only thing the clutch guy did, I am hoping that will fix the problem.
Again, thank you for all of your help - I reckon I will need to drive to FL and take you out for a cup of coffee to compensate you for your time and talent.

Russ

Oldtractorfixer · Apr 10, 2014

don't assume a bad battery. most 6 volt systems are positive ground, most 12 volt systems are negative ground. buy a cheap voltmeter and see what it is charging at, if at all. if it has been converted to 12 volt it likely will not start on 6. the coil will have been converted to 12 volts or a resistor installed. do proper diagnostics don't throw parts at it. in the long run running it on 12 volts will be more trouble free.