Hydraulic clutch fluid

[Professor Fate]

Today I was replacing the clutch master cylinder on my '66 D200, and as long as I was doing that I figured on replacing the slave, too. Then a buddy, who is a heavy equipment mechanic, stops by and says that as long as I'm into the system this far I should consider filling the system with a light hydraulic oil instead of the normal brake fluid. Reasons being: it's not subjected to possible overheating like brake systems are, and it doesn't tend to absorb moisture like brake fluid... Well, I'm pretty set in my ways, already had brake fluid for it, and figured that is what the system was designed for and the factory specifies; so that's what I used. But it got me thinking- does his suggestion actually have some merit? What other positives and or negatives would there be to following his suggestion?

 

[S'cuder]

It has merit.
Both are lubes with anti-wear and anti-rust additives.
Hydraulic oil is less expensive than brake fluid. Finding it in a container smaller than a gallon may not be easy, though.
Hydraulic oil isn't as nasty if leaked.
Brake fluid would probably be easier to find in the field, but almost any engine or transmission oil could be used to add to hydraulic oil. On the other hand, I wouldn't want to add any other substance to brake fluid. If I did, I'd want to flush it at the earliest opportunity.
If I were you, I'd use the brake fluid because I already have it.

 

[RustyRatRod]

Use brake fluid. That's what it's designed for.

 

[Professor Fate]

Use brake fluid. That's what it's designed for.

Oh, I did, like I said. But when I was done, and popped open a beer and began pondering... Well, you know how it goes.

 

[Murray]

Then again I knew a fella that filled his auto trans with hydraulic oil.

 

[67Dart273]

Just be happy you don't own an original Korn-national -Inter-binder Shout. They use British master/ slave/ natural rubber components, and required special "British Girling" fluid. "Back in the day" I sold auto parts, and we sold a fair number of replacement kits or components after someone with original parts mistakenly used U.S. brake fluid in 'em.

 

[Professor Fate]

Just be happy you don't own an original Korn-national -Inter-binder Shout. They use British master/ slave/ natural rubber components, and required special "British Girling" fluid. "Back in the day" I sold auto parts, and we sold a fair number of replacement kits or components after someone with original parts mistakenly used U.S. brake fluid in 'em.

View attachment 1715550737

At least you didn't need Whitworth tools to work on them- still got a box of those buried in a corner of the garage from my BSA/Triumph days...

 

[67Dart273]

At least you didn't need Whitworth tools to work on them- still got a box of those buried in a corner of the garage from my BSA/Triumph days...

LOLOL Every once in awhile I remember the term "Whitworth." I never owned such a vehicle, but in my Navy days at NAS Miramar, there were a couple of guys working on Brit stuff at the hobby shop.