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jdemaris
02-11-2004 06:06:39
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Re: 4020 Roosa pump, seal kit, advice? in reply to Adam, 02-10-2004 19:15:35
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Just going to add my two cents. In my opinion, some of your replies were astute, and some a little wacky. I did the pump rebuilding for two Deere dealers for a long time. Although it was certainly better to do such work on the bench, in the shop, I've done many on the tailgate of a pickup truck in the middle of the woods - with no compressed air, parts cleaning tank, etc. Usually, things went just fine. At the outset, I recommend mixing some engine oil with diesel fuel an putting the mix in a hand-held oiler. When assembling any pump parts, make sure they're well lubed - i.e. don't assemble anything dry. You probably will need one special tool to get the DB or JDB pump apart. The pivot-stud for the cam-ring takes a special fluted wrench. In regard to your immediate problem, i.e. the plastic governor weight-retainer ring. You have the option of installing the new one that comes with the kit, or . . . separately purchasing the updated weight retainer assembly that is much better and will NOT come apart again. The updated version is similar to what's used in the DB2 pumps and costs around $50. If you choose to use the old-style ring, it won't last any longer than the original - which is not necessarily bad - but not great. The repair kit comes a new delivery valve stop. You SHOULD remove the rotor from the head, then remove the allen-headed screw, and then the old delivery valve stop, spring, and delivery valve itself. 9 out of 10 times all is fine, but sometimes the spring shows wear. If all looks fine, put it back together with the NEW stop, and torque the nut to proper inch-pound specs. The kit also comes with an improved steel pressure regulator plug that needs to be installed at a certain depth. This is an updated part and replaces the original which was rubber and tended to blow out. Considering the age of your tractor, it may of already been updated a long time ago. Three more important areas to check are - visable wear on the metering valve,visable wear in the bronze bushing where the shaft seals ride, and the vane fuel pump blades and liner. All these parts can be purchased separately and are reasonably priced. On the subject of fuel delivery. This can be checked with a micrometer when the pump is apart. If, however, the tractor started and ran well before, it's probably best to leave well enough alone. One more comment. I understand the principle of "leaving well enough alone" when it comes to certain aspects of tractor mechanics. With the injection pump though, there are other wear items other than the plastic ring that failed. If you're going to go through the trouble of removing and disassembling the pump, you might as well attempt to be thorough. Otherwise it's a crap-shoot. One note on the cost of having pumps rebuilt. Many pump rebuilders charge a set price for exchange rebuilt pumps. Many times a pump can be rebuilt for $100 in parts and one to two hours of labor. There are other times though, that major parts are trashed. If the head and rotor need replacement, a pump is hardly worth fixing. I used to buy head and rotor assemblys for $700 back in the 80s, and that's when a brand new complete pump could be bought for $850. So, my point is that many rebuilders offset the potential loss from "unrepairable" pumps by charging a flat rate for all of them.
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