Power Steering Fluid

[n2deep]

What kind of oil goes in my mack power steering. Someone put ATF or something in it, smells like Dexron to me.

[maxidyne237]

15w-40 diesel engine oil

[n2deep]

Seals in steering box swelled twice the size they are supposed to be. Wonder if the atf has worked on the pump too.

[HK Trucking]

May I suggest you read this entire thread:

http://www.bigmacktrucks.com/index.php?showtopic=8761

[Rob]

Seals in steering box swelled twice the size they are supposed to be. Wonder if the atf has worked on the pump too.

It sounds to me like someone down the line added some "snake oil" to get a seal to stop leaking and what you have is a byproduct of not fixing something correctly.

This late at night I cannot remember the chemical composition of the stuff that is added to oils to swell neoprene seals to get them to quit leaking. Brand name companies advertise these items for what I consider a miracle cure that seldom works long if at all.

The Ross Gear steering gears are well known for leaking around the pitman, (sector) shaft seal, and the input shaft seal. Both of these seals are relatively easy to change on the truck.

If your shaft seals have ballooned out it is probably because someone added much more of this stuff than recommended. Feel the sealing material, is is soft and supple and bend/conform easily? If it does, that is exactly what happened. Seals should be stiff and the annular garter spring should hold very noticable pressure against the shaft the sealing lips ride against.

I don't believe in the additives. If a seal is leaking, it needs replaced. That's just my opinion. If there is a groove worn into the sealing area, use a speedy sleeve to repair the area.

I'm sure you have a vane pump on that engine as there were very few gear pumps used on motive power applications. If the pump is not leaking I wouldn't worry about it unless it does not meet pressure/flow checks.

Rob

[greendog32]

It sounds to me like someone down the line added some "snake oil" to get a seal to stop leaking and what you have is a byproduct of not fixing something correctly.

This late at night I cannot remember the chemical composition of the stuff that is added to oils to swell neoprene seals to get them to quit leaking. Brand name companies advertise these items for what I consider a miracle cure that seldom works long if at all.

The Ross Gear steering gears are well known for leaking around the pitman, (sector) shaft seal, and the input shaft seal. Both of these seals are relatively easy to change on the truck.

If your shaft seals have ballooned out it is probably because someone added much more of this stuff than recommended. Feel the sealing material, is is soft and supple and bend/conform easily? If it does, that is exactly what happened. Seals should be stiff and the annular garter spring should hold very noticable pressure against the shaft the sealing lips ride against.

I don't believe in the additives. If a seal is leaking, it needs replaced. That's just my opinion. If there is a groove worn into the sealing area, use a speedy sleeve to repair the area.

I'm sure you have a vane pump on that engine as there were very few gear pumps used on motive power applications. If the pump is not leaking I wouldn't worry about it unless it does not meet pressure/flow checks.

Rob

yep they all used reg engine oil till a few years ago.all the new ones are using atf