IH 1420 combine--hydro pump ctrl valve seal frustration!

zooeyhall · Jul 12, 2020

I'm posting this here, rather than in the combine section, in the hopes that some experienced IH mechanic can advise me.

I'm trying to replace a leaking seal on the control valve assembly for the hydrostatic pump. It's the little o-ring and plastic ring that seals around the control valve shaft.

The problem is that I can't figure out how to remove the shaft (item 4 in the parts schematic) in order to replace the seals. I'm assuming this has to come out to do this.

To remove the shaft, I need to drive a roll pin out from the linkage connecting collar (see arrow in picture). But I can't get a proper angle with a punch to get the friggin' roll pin all the way out! Only partially, but not enough to slide the shaft out (see picture).

Would really appreciate any advice from someone who has done this job before. Thanks!!

ben brown · Jul 12, 2020

your on the right track i done several on jd 6500 sprayes but none on ih combine i wonder if you can get a pair lock pliers on the end of the roil pin then pry it out

used red MN · Jul 12, 2020

If you view this on Modern switch over to Classic, I posted a couple replies there and they didnt transfer to Modern. I am a little miffed right now I was airing some feelings about the two views here and it ate my post. All the better was probably saying more than I should.

used red MN · Jul 12, 2020

(quoted from post at 05:17:27 07/13/20) If you view this on Modern switch over to Classic, I posted a couple replies there and they didnt transfer to Modern. I am a little miffed right now I was airing some feelings about the two views here and it ate my post. All the better was probably saying more than I should.

After a second look the linked diagram I posted is not it either. The other brand system is similar to what you show and not very detailed. I am thinking disassembly of the plunger looking part may be the key. AgTalk may be your best bet, a lot of guys on there know their stuff, and the views a way more than this site.

used red MN · Jul 12, 2020

(quoted from post at 06:44:43 07/13/20)

(quoted from post at 05:17:27 07/13/20) If you view this on Modern switch over to Classic, I posted a couple replies there and they didnt transfer to Modern. I am a little miffed right now I was airing some feelings about the two views here and it ate my post. All the better was probably saying more than I should.

Click to expand...

After a second look the linked diagram I posted is not it either. The other brand system is similar to what you show and not very detailed. I am thinking disassembly of the plunger looking part may be the key. AgTalk may be your best bet, a lot of guys on there know their stuff, and the views a way more than this site.

Now coming back to give this another look, by reading your description of the problem with the roll pin and Rogers reply that probably worked. Not thinking it through real well the first time I thought he was suggesting to saw off the actual through shaft.

zooeyhall · Jul 13, 2020

Update on this:

I got the roll pin out far enough get the shaft out. The problem is that it's impossible to get a straight punch in to get the pin far enough out, due to the angle (it hits the
edge of the casting). So I bent a nail enough to clear the casting, and get the roll pin out.

The next problem: the o-ring fits on a groove in the shaft, and the white plastic ring (teflon) goes over the o-ring. And it does the actual sealing.

The problem is that you have to stretch the teflon ring to get it onto the shaft. When inserting it back into the casting, it keeps catching on the edge of the bore. Usually
tearing the ring.

The bore has a beveled edge intended to guide the ring in. The problem is that a teflon ring doesn't "snap back" like a rubber o-ring, after being stretched.

I'm getting another couple of these rings from IH, and trying it again. Going to be very careful not to stretch it absolutely more than necessary. Also going to try feeding
the ring into the bore, with a small screwdriver. Will let everyone know how it works.

wore out · Jul 13, 2020

"a teflon ring doesn't "snap back" like a rubber o-ring, after being stretched"

Automotive automatic transmissions use many teflon seal rings and there's the same issue you are having when overhauling them.

The trick is to use a "resizing tool" (specific to the application) that is a close fit over the "shaft" and has a long, gentle taper.

You lube the teflon ring, then gently slide the "resizing tool" over it, and set it aside for a while and allow it to hold the ring reshaped to a smaller size, then remove the tool and install the part.

There MAY be a service tool available for your parts, with a lathe it would be easy to make one.

used red MN · Jul 13, 2020

Cut a strip of milk jug or the like that just wraps around the shaft. Place it inside a hose clamp so the gap is opposite where it draws down, tighten it down around the ring once you get it in the groove and let it set a while. Once you get the tightening process going running it under hot water will soften the plastic ring.

littlefarmer · Aug 2, 2020

Thanks for the advice. I cut a thin strip from an aluminum pop can. Wrapped it around the seal, and then put a 3/8 spring clamp over it (one of those pinch clamps like are used for fuel lines on cars.) Left it overnight. It compressed the teflon ring enough that I was able to insert the shaft no problem.

IH 1420 combine--hydro pump ctrl valve seal frustration!

zooeyhall

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ben brown

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used red MN

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used red MN

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used red MN

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zooeyhall

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wore out

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used red MN

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littlefarmer

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