1931 shock absorber

[Per Mysen]

How much oil in shock absorbe on deoto 31

I opend them . They was emty.

[Taylormade]

You should fill them to the top, working the lever as you do to get the air out.  Most folks use motorcycle fork oil or oil for hydraulic jack cylinders.

[Narve N]

Bruk grease, så blir dei meir effektive..

 

(Translation from Norwegian: I recommend filling up with grease)

[Spinneyhill]

Surely the dynamic viscosity of the oil is important? Grease would be quite a bit higher than hydraulic jack oil? What oil was originally recommended for these shock absorbers?

 

I have seen reference to hydraulic oil being about ISO 32, equivalent to SAE 10W, fairly low viscosity. The kinematic viscosity is about 5.1-5.7 cSt at 100 ^oC. Fork oil comes in a range of viscosity and is pricey? The base oil for NLGI 2 grease seems to range from about 110 to about 200 cSt at 40 ^oC (11 to 17 cSt at 100 ^oC).

 

Depending on the Specific Gravity of the hydraulic oil and grease, the damping might by two to three times as much with grease. (The kinematic viscosity and the dynamic viscosity are related by the Specific Gravity of the oil or grease. )

[jpage]

Grease would not work as the oil must pass through the valves or the shock would not operate.

[Narve N]

Got this as a tip from a seasoned (born 1927) hotrodder. Works OK on my 1929 Chrysler and leaks a lot less than the heavyweight oil I first put in.

[robert b]

It might work on small bumps but hit a big one and see the arm snap off, had a bloke do this here , filled it with grease and he found out the hard way when both back arms snapped of , I tell you it cost a him a lot of money for me to supply replacements . complete  units .

Edited January 30, 2018 by robert b (see edit history)

[Vintageben]

I guess not everyone has potholes like ours in Northern NSW Australia I keep telling people I need to turn the lights on to see my way out them?

[retiredmechanic74]

5 hours ago, Vintageben said:

I guess not everyone has potholes like ours in Northern NSW Australia I keep telling people I need to turn the lights on to see my way out them?

I guess you have never seen the potholes in Michigan. You have to be very careful going through them because......children might be swimming in them.

[keiser31]

45 minutes ago, retiredmechanic74 said:

I guess you have never seen the potholes in Michigan. You have to be very careful going through them because......children might be swimming in them.

Yep...I'm a 20 year witness to the "potholes" in Michigan. The reason they are called, "chuckholes" there is because you could fit a guy named Chuck in each hole. My wife from Oregon was VERY impressed with the size of them.

Edited February 1, 2018 by keiser31 (see edit history)

[Vintageben]

Ha ha so that must be where our council got their road management skills from?. Actually a few years back I was driving a small car  and stopped in the middle of one of the holes waded out and took a photo and then sent it to the council, funny enough they were out the next day to fix the problem. This is why I love the earlier cars they do seem to have more clearance but it still hurts sometimes taking them out

[robert b]

Ben you taken the day on that on , good work mate , still laughing