# HS928 Frequency of checking hydro fluid and precautions



## hank (Nov 25, 2013)

Sorry if this has been addressed before or is otherwise off-track. But ... the Honda blower manual says check hydro fluid before every use. There's a rubber diaphragm covering the fluid that needs to be physically lifted out to view fluid and it's tacky on its surface with the fluid itself. In holding a flashlight with one hand trying to view the markings inside the cup, and holding the rubber diaphragm in the other hand, I bumped it against the top of the blower. While the chances this contaminated the fluid are low, it raises the question of whether one might do more harm than good by such frequent fluid inspections and also the question of why the diaphragm is needed in the first place, as it increases the risk of picking up sand or other grime if bumped against a surface. 

While the marks are hard to see, I suspect that on a cold day any fluid showing in the bottom of the cup probably represents an adequate level. Wondering too if any users have simply removed that black rubber diaphragm - which appears unnecessary and which may actually contribute to the issue it's supposed to solve - contamination of the fluid?


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## Shryp (Jan 1, 2011)

I thought that little container was see though.


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## hank (Nov 25, 2013)

Yep. Appears that was their intent. There are markings on outside. But the fluid is pretty clear, with maybe a trace of yellow color. Can't read it even rocking the blower & shining a light on the outside. It did appear just a hair low and I added a little. But still can't read level from the outside.


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## Shryp (Jan 1, 2011)

Hopefully with some use the fluid will dirty up and you will be able to see it.


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## hank (Nov 25, 2013)

Ya - any additional color would help. 
Brighter LED on the way. Might be better than what I have now.


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## [email protected] (Nov 21, 2011)

HST fluid expands and contracts with temperature, so there are two limit marks (UPPER and LOWER) on the reservoir. At ambient temps below -4°F, the level may drop below the LOWER mark. After the unit has warmed up, the level should rise to a visible point.










Over time, the reservoir may become discolored, making a visual inspection more difficult. A new reservoir should help (Honda part number 56850-767-000, list price $23.20) and it includes a new diaphragm and cap. 

The good new is, generally speaking, if the HST ain't broke, don't fix it. Honda would like you to check the level each time, for sure, but if you aren't having any problems (operation, leaks, etc.) it is probably okay. HST fluid is designed to last the life of the transmission, and does not usually need to be topped off or changed unless there are problems.


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