# 7090 belts



## 7090 (Aug 14, 2011)

I have a NH 7090 baler with about 15000 bales on the endless belts. The belts have been starting to slip on the drive roll, used to be just when it is empty and starting out for the day. Now it is starting to slip now when baling with any size bale in the chamber. Trying to bale corn stalks now. I have moved the back roller up one bolt hole to tighten up the belts a couple of years ago. I havent tried tighening up the springs but they are almost all the way tight anyway. Talked to three different dealers today two said the belts are stretched and worn out so just go ahead and replace them, supposedly about $400 apiece times 8 belts. Third dealer said to try rechargeing the tensioning cylinders. I noticed the tensioning cylinders dont retract all the way when the chamber is empty, about an inch or two of the ram is not fully retracted. Could this be the problem or is it time for new belts? Any ideas or thoughts?


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## rjmoses (Apr 4, 2010)

I'd try the tensioning cylinder first. (Lot cheaper that $3200 for belts plus labor). It's possible that you've lost the charge or that the cylinder is leaking internally.

What pressure do you run at? And does it hold steady as you;re baling a bale?

Hope this helps.

Ralph


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## Gearclash (Nov 25, 2010)

You said the belts slip at any size bale, that can hardly be a belt length problem, although that may exist also. How did the baler respond when you moved the tailgate roller up?

If you do need to replace your belts you can cut your endless belts and replace them with spliced belts. If the endless belts have a good surface yet it might be feasible to cut them out, resize them to 420", and continue to use them as spliced belts.


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## endrow (Dec 15, 2011)

I have a thought we had belts slip one baling stalks in just terrible conditions and our baler just gunked up inside terrible . Before anything start with entire area where belts run clean as a whistle . Under scrapers beside rolls build up on rolls . Lock door open take pressure off belts check the condition of bearings scrapers etc .


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## mike10 (May 29, 2011)

It is unlikely the belts are stretched out. If the belts were stretched out the tension cylinders would be collapsed fully. The amount of pressure in the bale tension system can cause issues but usually if there is too much pressure, so recharging the system is unlikely to help you if you have pressure being shown in the gauge. If you have not backed off on the pressure, that is the first thing to do. If you think more tension on the belts at core formation would help, then you can add an expeller roll which will take up some of the belt length.

The backside of the belts and the drive roll are probably worn to a slick finish. The grooves in the drive roll are probably worn down and will not bite into the belt. You can try to redo the grooves which is what NH recommended on the early NH balers that did not have the grooves.


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## 7090 (Aug 14, 2011)

Currently running about 1000 psi on the corn stocks, in grass hay and alfalfa run it abbout 1400, pressure stays constant as the bale is being made. When I moved the back roller up I didnt think it really made any difference in the tightness of the belts. Sure thought they would have been about fiddle tight but didnt see much difference. The belts sure seem slick on the inside the roller doesnt look to bad, still has some grooves in it. I havent measured the deflection in the belts but i would guess i have at least 3 inches maybe closer to 4 inches.


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## mike10 (May 29, 2011)

Open the endgate and close it, if there is still pressure showing on your gauge with the endgate closed the belts could be loose. You must open and close the gate at least one time before checking.


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## 7090 (Aug 14, 2011)

I installethe expellor roller a couple of years ago. The pressure always returns to zero after dumping a bale. I didnt get a chance to look at the drive roller today. Will do that tommorrow. How deep should the grooves be in the rubber and how wide and how close is the spacing. The belts are as slick as glass on the inside. What are the specs as far as deflection in the belt. I will measure that also tommorrow, like I said before on the back of the baler i can push them in easily 3 inches.


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## mike10 (May 29, 2011)

Some of the suggestions from NH are; Adjust pressure to a min of 1200. Some belts were manufactured using a release agent that causes the belts to be slick on the back side. The recommendation is wipe them down with mineral spirits. I would also wipe down the drive roll. Some people have flipped two of the belts over so the rough surface runs against the drive roll. In your baler that would be belts 2 and 7. Check the takeup arm so it is not binding in the pivots or against the sides of the baler.

I have never measured the grooves in the drive roll as far as depth. They are no deeper than 1/8". The belt deflection at the back of the baler can very between balers depending on how the takeup arm and tension cylinders move during the closing of the endgate. Three inches of deflection is not unusual. To be sure the tension cylinders are completely collapsed, loosen the fitting at the bottom of the right tension cylinder. Be careful, if there is pressure in the line you could get a bath. If there is no pressure than the cylinders are collapsed fully or at least as much the tension springs can provide. If there is pressure then the belts should tighten up more once the pressure is released. Do not drain an excessive amount of oil from the cylinders or you may not be able to reach maximum pressure if desired in the future.


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## 7090 (Aug 14, 2011)

Ok will check these things tommorrow. I may flip the two belts you suggested. I may even cut one or two belts and then lay them out and measure them to see what length they acctually are. Then splice and put back in. I will check for back pressure on the right cylinder. Could a set of belts wear out in just 15000 bales.


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## Gearclash (Nov 25, 2010)

I would look for something that is making the baler and or belts pull hard during bale formation. I am running a 780A with 15,000 plus bales on it and it still eats cornstalks just fine. I can't give a good answer on belt wear as I have been switching between two sets of spliced belts. One set has shrunk rather than stretched, and that is annoying. I wonder if a good measuring wheel could be used to verify the actual length of an endless belt?


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## mike10 (May 29, 2011)

I would not cut the belts. Belts seldom stretch and the endless belts, what I have found, are already @ 3 1/2" shorter than laced belts. You might also try baling early in the morning or later at night if the stalks are extremely dry.


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## 7090 (Aug 14, 2011)

No stalks are not to dry, actually was snowing some when baling Tuesday. I am going to check all the rollers for ones that are hard turning. This problem has gotten much worse with the cold weather. I am sure everything turns harder with the cold. Also do u think the belts shrink a little or expand a liitle as the temperature drops.


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## Gearclash (Nov 25, 2010)

If you are operating in temperatures cold enough to snow then your take up arm is going to return slower than what the door can close. That means the belts will be loose until the take up arm "catches up". The colder the weather, the slower the take up arm. New Holland has a kit to eliminate this, I have not tried it. This nuisance seems to show up when temps are in the 30's or so, and by the mid 20's I can be waiting an extra 10-15 seconds for the take up arm to tension the belts and get them turning.

Also, snow can make things very slippery. The first year I round baled stalks I baled some with a little snow in them. Went OK until the sun was down, then the stalks got so slippery that the start of the core wanted to churn too much and would make belts flip.

I have not seen operational problems with New Holland balers baling super dry stalks. It seems no matter what the dryer the better.


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## mike10 (May 29, 2011)

Gearclash makes an excellent point about the cold weather kit and seeing that you are from ND you probably could use it. The part number is 84498446 and is about 260.00.


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## 7090 (Aug 14, 2011)

What does the kit do? This baler will slip the belts when u first take it out of the shed in the summer time but then once they start turning they are good for all day. Then this fall when the weather got cooler it was a liitle tougher to get them going but eventually it was good for all day. Now this "" winter"" is when I started having trouble getting them started but it would keep stopping all day. Starting out empty was a problem then it would sometimes slip as the bale was forming and sometimes just as it was about to put the net wrap on the belts would stop. Talk about frustrating. I did open that cap on the end of the tension cylinder and all that came out was oil, no air and the cylinders didnt retract any. I didnt get to check any of the other things. Too dam cold today to work on the baler 0 degrees this morning and made it to 16 this afternoon.


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## mike10 (May 29, 2011)

In cold weather the oil can not pass fast enough from one side of the cylinders into the other side when the endgate is closed. The kit has a hose, check valve, and tee that are installed on the left cylinder so oil can pass back into the opposite side of the left cylinder without have to go through the tension valve on the right cylinder. This kit will not help once the bale has enough mass to raise the pressure in the gauge. For those situations you might try increasing the pressure as NH recommends in those cases so more tension is applied to the belts on the drive roll.


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## Gearclash (Nov 25, 2010)

Seems impossible but it sure sounds like your infeed discs went missing. I have baled in cold conditions, in stalks that were not dry enough (more turning friction) at 500 gauge psi and never had belts slip. Is it possible that the back side of the belts is getting wet?


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## 7090 (Aug 14, 2011)

Infeed disks are in good shape. Yes the belts were geeting wet on the inside as I baled but this doesnt explain why the belts wont turn when the baler is in the shed. Usually happens just when u take it out first thing. The last few times when starting out i would raise the tailgate a little to get the belts turning, open and close a few times and eventually start turning.


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## Gearclash (Nov 25, 2010)

I agree belts will slip for different reasons if the bale chamber is empty vs. full. I wonder if applying a light lubricant like WD-40 to the main pivots of the take up arm and to the points that the tension springs and cylinders pull on the take up arm would help the springs reset the arm a little better. When the bale chamber is empty, the only thing putting tension on the belts is the springs. The cylinders put a lot more tension on the take up arm than the springs do, but only when they begin to extend.


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## mike10 (May 29, 2011)

It is not unusual for the belts not to turn after the baler has set awhile even overnight. The belts take a set to the rolls that the drive roll needs to overcome to get the belts moving. If you could take your belts out and lay them flat on the floor you would see humps where the rolls were in contact with the belt. The cold weather is probably making it worse.

The only roll that might be causing you additional drag would be the follower roll, the roll directly above the dimpled rolls. Material likes to wedge between the roll and the scraper causing it to be hard to turn. To eliminate the wedging problem, remove the scraper and grind a sharp edge on it and adjust it to the roll. You will need to lengthen the mounting bolt slots in the scraper. Probably will not help a lot but it may let the belts start when empty.

The wet conditions on the drive side of the belts is not helping either especially if they are trying to ice over.

It may just be a case the drive side of the belts are wore smooth to where the drive roll can not generate enough friction to turn them in this cold weather.


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## 7090 (Aug 14, 2011)

Yes I should check under and around that roller. I have always wanted to grind an edge on the scrapers. I dont know why they dont come from the factory with a 45 degree edge to them. Still havent had an oppurtunity to tear in to the baler, hasnt been above 15 degrees for almost a week now.


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## mike10 (May 29, 2011)

If you are going to sharpen the scraper, I would also suggest you go one step farther. The scraper does not go the full width of the sledge frame, though it covers the entire roller. The open area between the scraper the sledge frame will hairpin material, also causing drag. I use a wire welder and extend the length of the scraper too fill this gap which is only about 1/4" on each side. A 1/4" bead about 1/2" long is all it takes and then grind the edge on the entire scraper.

When you installed your expeller roll, did you remove or modify the angle under the tailgate nose roll scraper? If the angle is still in there, remove it and just use the scraper. Depending on what model year you have, you could have an angle and scraper, just the angle, or just the scraper. You only want the scraper. If you did not modify the angle or remove it on installation of the expeller roll the belts will be pinched causing excessive drag.


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## 7090 (Aug 14, 2011)

Yes I did remove the angle. I also thought that scraper should have been made a little longer. Thought about adding to it but never did. Mike you are very knowlegeable and helpful with these New Holland balers.


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