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Hobart D300 mixer transmission grease level
I have been getting contradictory answers from Hobart how much grease should be in the transmission box. One guy told me that it should be enough to cover all gears in the box, another told me that it should just cover the middle of the worm gear on the motor shaft. Any ideas?
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11 Replies
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Worm gear planetary mixers have been around for almost a hundred years. Your D300 will probably be 20 or more years old. The top gear case does not get grease, but gear oil. The lower gear case is usually grease due to leakage with a worn seal. As long as the worm gear is wet, that is ideal situation. As it turns it throws oil over the other gears that are higher. To high and the auxiliary shaft stands to leak. And if over the worm, a lack of splash lubrication. To low and the worm gear will wear excessively. Most damage to them is from lack of maintenance. The oil absorbs moisture and then the case gets condensation. This intern makes rust that gets into the ball bearings and act as wheel chocks. Bearing failure. Or it binds the gear shift collars. So having clean fresh oil is more important than having a precise level.
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Thanks for your reply, fixbear. It helped a lot.
In no way I question certain details of your reply since you know about D300 mixers much more than I do, but I would like to respectfully ask you to clarify them for me:
The staff that Hobart sells for lubricating transmission in D300 part# 00-103881-0044 is called lubricating grease and not oil although it’s probably just semantics as far as lubricating is concerned.
Regarding leakage from the auxiliary shaft: there is a seal on the attachment shaft. If it’s worn out, can it also cause the leakage?
Is there a certain time period when oil/grease should be replaced regardless of how it looks, e.g., every 4 years, every 5 years, etc.?
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It was very common for the aux drive to wear and leak. It is the last item to get lube and also the highest point of the gear case so it’s where condensation inside is the worst. What happens is a foreign particle gets into the bearing race and makes the race spin in the housing or on the shaft. This creates wear and makes it loose. Lip seals will only work if to spec. I used to use a syringe and hypodermic needle to lube them. Often when you have a dry seal, you will hear a very faint squeal.
As for a change interval, it depends on environmental conditions and usage. The worst is varying temps and high humidity. If the bakery has multiple rooms so that the ovens are away from the mixing area and heated/cooled to a constant temp you can easily do 2 years.. Recommended annually. Most machines of this size see very little use and never get hot. Unlike say a 120, 180 machine. The nice thing about the D300 was that it could use smaller bowls.
As for the lubricant, years ago we used a SAE 50 hypoid gear oil. Then they went to a 80-90 gear oil. But with food specs changing over the years and constant complaints about leaks, Often you’ll find a #1 food grade grease in them. They still weep. Most often from overfilling the planetary. The lower case is unvented, so as it heats up it makes pressure. Older mixers didn’t have the drip guard like todays do.
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Thanks again.
From your reply above, “Lip seals will only work if to spec.” Could you clarify it for me?
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The bore ID is a press fit. The shaft ID has to be smooth, level and not concentric. If off center, it creates a gap or loose seal on one side and a tight high friction on the other. Also, if the bearings are loose, the shaft will wobble with load variations. All these conditions increase the possibility of leakage. Different seals are make for different tolerances and lubricants, liquids, grease. Most common seals are neoprene material. but there are ones that use leather, Silicone, Viton and even poly’s. (used in high pressure applications).
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Does changing this shaft seal require special tools and/or specific know-how or the old seal can be relatively easily removed and replaced with the new one?
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Planetary sea, aux, or main gearbox?
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Attachment hub. Hobart part# 00-070090 attachment hub seal
Hobart D-300 Instruction Manual (Page 20 of 24) | ManualsLib part#23
manualslib.com
Hobart D-300 Instruction Manual (Page 20 of 24) | ManualsLib
Hobart D-300 Instruction Manual (Page 20 of 24) | ManualsLib
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Alright, I believe you want to do the aux. Problem with that on is that it is only a single needle bearing with shims for the gear clearance behind it. So, previous experience tells me that the housing and shaft will have wear and need to replace the housing and shaft. Before removing the housing, use feeler gauges to check how much thrust clearance is on the shaft. You will need that to shim for reassembly. You will also need to make a driver for the new seal. If you have a socket that is slightly smaller than the OD, it will work.
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I should caution you that Hobart purged parts support for a lot of older machines. When ITW took them over they decimated Hobart.
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The leakage isn’t so bad. It’s more like light seepage. At this point, it’s just a nuisance for the operator who has to occasionally wipe the attachment hub and the attachments. Since Hobart 00-103881-00044 lubricating grease the last time was changed in the transmission case 6 years ago, it’s probably broken down and much less viscous than it originally was. Will changing the grease alleviate the seepage problem?
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