JD 420

tzbmcp · Post by **tzbmcp** » Sat Jun 18, 2011 3:40 pm

New to site. Looked at a 420 today, hadnt been run in 3 years, cleaned birdpoop off and it started right up. drove fine, but overheated. very little coolant in radiator. Oil was clean. fan belt a little loose. Price seems about right but dont want to get into something way over my head. Owned by same guy for 30 years, has rebuilt undercarriage, engine, transmission, but theres probably been a few hours on it since those were done. Any advice would be greatly appreciated. thanks.

Willyr · Post by **Willyr** » Sat Jun 18, 2011 6:51 pm

What kind of money? Take a close look at how the tracks contact the idlers. A previous post mentioned that tracks have been rebuilt with Case chains and they dont align.

tzbmcp · Post by **tzbmcp** » Sun Jun 19, 2011 6:26 am

Thanks. What would I be looking for with those tracks? Most worried about the overheating issue. Will return today to top up radiator and run it again. If it overheats, worried this would be indicative of much bigger problem. Where else could I look, any chance there would be an easy non scary explanation other than low coolant?

H-D · Post by **H-D** » Sun Jun 19, 2011 4:37 pm

No sense getting too bent before draining the oil a bit to check for coolant being present, or the milkshake look of mixed oil & coolant. A failed/failing water pump seal could cause your diminished coolant/overheating condition. Blown head gaskets often leave a milky 'clouding' on the sparkplugs that can be discerned (helps to narrow the area of intense scrutiny).

Post by **Lavoy** » Sun Jun 19, 2011 5:39 pm

If the undercarraige has truly been rebuilt, on the whole, I wouldn't care if the crawler did not even have a radiator. $600-$700 give or take will replace the entire cooling system with new components. When it comes to undercarraige, $600 doesn't even get you started. Put anti-freeze in it and run it again and see what happens. If it still heats, you have a problem, but nothing insurmountable.
Lavoy

dr1zsk1 · Post by **dr1zsk1** » Sun Jun 19, 2011 8:00 pm

Lavoy's point is right. I would check on the undercarriage. Work it to see how cluthes hold up. A good 420 is wolrth what you arewillin.g to pay. The past few ebay ones got no bites aside from the couple of redone ones but they did not met reserve.

tzbmcp · Post by **tzbmcp** » Mon Jun 20, 2011 6:57 am

thanks. filling it up this morning. how long do i have to run it to assess clutches? last time i ran it for about 30 minutes or so - forward, reverse and lots of hard turning left and right, spinning around, all of which it did without a problem. only other issue is the blade slowly lowers on its own and i see a small bit of hydraulic fluid leaking out of the piston.

dr1zsk1 · Post by **dr1zsk1** » Mon Jun 20, 2011 9:08 am

I can guarentee that after you get the machine home you will have plenty of new surprizes.

As long as it appears to steer and work you are going to have as much info as you can as a buyer.

As Lavoy said -- make sure you know that gaskets and seals for one side of the finals will run you $230, steerings discs about the same, a brake about the same. Tracks, rollers and so on are extremely pricey.

The cylinders are generally available they will cost ya, I see one on eBay right now for $300.

As they say -- Caveat emptor (If I'm spelling that right). Otherwise they say something else ...

Good luck .. someone one here has a signature that says there is no such thing as a cheap crawler.

BOAT meand Bail Out Another Thousand

CRAWLER might mean "cant really assess what little expenses reappear"

Mike

tzbmcp · Post by **tzbmcp** » Mon Jun 20, 2011 6:18 pm

thanks again. couldnt make it out there today - got stuck at work so had a friend go for me. he filled up radiator which was almost totally dry and ran it for about 30 minutes, no apparent overheating but temp gauge is broke - last time we had steam coming out radiator cap. off work tomorrow, will check oil level to see if its increased after adding all that coolant and run 'er again myself. told that blade wont push dozer off ground - evidently hydraulic fluid is basically empty as well. what weight fluid/oil is used for the hydraulics?

Swawpy · Post by **Swawpy** » Mon Jun 20, 2011 10:02 pm

You mentioned the fan belt was loose...tighten the belt when you add coolant or you really can't expect the water pump to do its job anyway. I wouldnt worry too much about any external leak and water pumps are cheap to rebuild if needed. If it runs, steers, and brakes and with a good undercarriage you are ahead of the game.

Any tractor or auto parts hyd fluid will be fine, no need for the spendy hygard or similar fluids just for hydraulics.

tzbmcp · Post by **tzbmcp** » Tue Jun 21, 2011 5:34 am

belt is only a hair loose but looks like its maxed out on adjustment. will be heading back this am to take some pics. this thing has a winch on back. is conversion to 3pt hitch either by original or aftermarket parts a big job, or near impossible? thanks.

Pat · Post by **Pat** » Tue Jun 21, 2011 6:32 am

Can be converted to 3 pt. with correct rockshaft and associated adjusters and arms. McGrew has one on e-bay for $3500 without the top link!! Winch would have to go.

tzbmcp · Post by **tzbmcp** » Tue Jun 21, 2011 10:38 am

heres link to some pics from this morning. owner put winch on himself. does this make conversion to 3pt really difficult? any thoughts on the undercarriage or anything else would be greatly appreciated! Thanks

http://s1086.photobucket.com/albums/j456/tzbmcp/

dr1zsk1 · Post by **dr1zsk1** » Tue Jun 21, 2011 11:08 am

It looks like a 50+ year old crawler, only an addict could love. Which is good.

Should those front idler bolts be that far back with that much torque on those springs?

Willyr · Post by **Willyr** » Tue Jun 21, 2011 11:22 am

The adjuster is broken

What you want to look at is to sit on the ground and look at the underside of the tracks. You want to see what pin wear there is. Anybody can tell you that it has had new pins and bushings. But what do they really look like?

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JD 420

JD 420

if you can take picts of the tracks

Its a 50+ year old machine

Nice snow tracks ..

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