A Different Kinda Clutch Fluid Question...

BigSky

A good friend was telling me that with his Hudson, the clutch would slip with Dextron II & the club store’s clutch fluid but NOT slip with Maas’s clutch fluid.  

So my question is thus, with an older clutch that’s seeing some slippage is there anything others have found to be helpful in stopping slippage & ultimately getting a little more life out of their clutches?  

Old Fogey UK

It should be Dexron 3 not 2.

BigSky

Everything I’ve read & have been told was that if one was to use ATF then it was Dex 2 but that’s not available so by default it becomes Dex 3.  

However, let’s not loose focus on the point of my thread, which is to find out if one readily available formulation is going to provide improved grip with a clutch that slips some.  As I said, very good friend found this to be the case by actual use, so I’d love to hear if others have similar experiences.

bob ward

Is your clutch properly adjusted? The clutch should take up with the pedal part way up, not right at the top.

BigSky

That is a very good question & I’ve been trying to figure that one out.  I’ve been told that the only adjustment I can do is the pedal arm to firewall.  Below is from my 37’s manual.  Which was more like 1” the other day but I adjusted it to the recommended 1.5” distance.  The only thing which may play a role is the rubber donut spacer I could find locally was only 1/8” thick, but at least the spring now has something to push against.  

Geoff

If the clutch is slipping and the free-play is correct then it is worn out. 

BigSky

Someone’s gotta have had some experience with different clutch fluids & effect on slipping or not.... 

Geoff

No matter what type of fluid, once it has been displaced from between the disc, flywheel and pressure plate there should be no slippage.   If the fluid is too thick you may have trouble with hydraulicing, making engaging gears  a bit of a crunch.  If it too thin, it will shudder as you engage the clutch. If it is too full it will indeed slip a lot more when engaging, but once the fluid has been fully squashed out  from the surface  it should not slip.  If it is slipping I suggest draining a bit out and seeing what happens.

bob ward

Is it correct that Hudson clutches have stronger springs than equivalent dry clutches?

Geoff

Yes, that is why when converted to dry clutch they are so ferocious. Plus steel flywheel warps and wears much more.  the only successful conversion is when the entire flywheel, clutch and pressure plate is  changed to a dry unit.  But then the wet clutch works perfectly, so why bother?

Old Fogey UK

Apparently, you can use 50/50 kerosene and engine oil as clutch fluid but as Dexron lll works fine for me, I'm not inclined to try it but you could give it a go.
3/4 inch free movement on the pedal as Geoff and others recommended to me works fine on my car. I was having problems gear shifting with 1 1/2 inch play, especially when the clutch was hot.
The advice from the ROC is 3/4 inch free movement on the pedal.

BigSky

Geoff, No disrespect but I can’t quite agree with your statement.  In theory when the fluid is squeezed out and it’s cork to steel it shouldn’t matter what fluid is being used but I’m sure it’s not that simple.  

Cork faces have voids which hold fluid plus I imagine there are variations in the steel that cork pushes against which can also hold fluid. Thus if one type of fluid is more slippery or has a higher shear strength than another then I imagine slippage could occur.  Additionally I’m sure different fluids have different effects on the cork swelling which can certainly have an effect on a clutch slipping or not.  

My friend who has actually used the club store fluid couldn’t get up his driveway without a lot of clutch slippage.  After trying Maas’s fluid he had no more slippage & no more issue.  He’s a quite skilled mechanic so I’m confident in his experiences & correct use of clutch fluid levels, etc.  

I’ve also read some old threads on the forum which sighted different ingredients if used cause a bit more swelling of the corks to occur which could help on a worn clutch.  Such as 8-parts 20 weight non detergent oil to 2-parts Kerosene, which is said to give a more positive grab than ATF.  I’ve also seen neatsfoot oil & ATF 50/50 mixture, which it’s said that the neatsfoot oil helped the swelling of the cork & a more positive grab. 

This is why I wanted to explore what others have experienced with different clutch fluids as a simple fluid change could mean the difference between Someone needing a new clutch or not.

lostmind

Neatsfoot oil was used in Hudsonite.

Glowplug

The purpose of the neatsfoot oil; when used in Hudsonite was an attempt to keep the leather seals used in the throw out bearing soft.  The petroleum based components of the clutch-fluid attacks those leather pieces. But, as I learned last year storing Hudson clutch throw out bearings in neatsfoot oil was a mistake.  Over time it hardens the leather and causes the bearing to seize. Corks are not conditioned by neatsfoot oil, once corks have been conditioned through use they must be physically reconditioned to create the opportunity for fluid absorption which creates their expansion.

BigSky

So your telling me neatsfoot oil has absolutely no effect on the cork and “only” had an effect on leather?  I’d love to see your scientific study on that one....

I have to say it’s surprising how much “nay saying” is going on here....  

I only brought this up because I found it interesting that a friend’s personal experiences of using different clutch fluids, one caused slippage & the other did not.  

Geoff

Not scientific, but I have left a cork disc soaking in  kerosene/oil mix for a month and the corks did not swell up.  Therefore when compressed in between the flywheel and pressure plate it is a physical impossibility for the  corks to absorb anything.    I am now  withdrawing from this discussion. 

LHudson

I run the mixture that was recomended by either Walt or Josh, I don't remember which one came up with it. It is one third 10w30,one third Marvels MO, one third Dextron. I have had very good results running it.