delco shock absorber oil substitute

[dancorti]

What are folks using for oil in the Delco shocks. I am replacing the links and want to top off the reservoirs on a 55 Special. My friends at NAPA had a hearty chuckle when I asked for Delco shock absorber oil.

[old-tank]

Dan

Use any hydraulic jack oil. No need to buy the expensive specialty stuff. I still have an old can of Permatex jack oil that says to use in shocks also. I have used this to top off and for complete refill after a rebuild and it works well.

Willie

[RocketDude]

I just got a call from the company that rebuild my front shocks, telling me they are ready to pick up. So, I asked him what he reccomends to top off your shocks.

He said the best oil for them, is to go to a motorcycle shop and buy fork oil. It is between 5w and 10w, and is the closest thing you can get, to the original oil.

In case you have any other questions, or discover yours need work, here ya go....

http://www.classicautoshocks.com/

[NTX5467]

In the 1980s, when Peugeot was still being imported into this country and had normal dealers (usually tagged onto an existing, established dealership), an alignment associate noted than the owner of one of those older cars went to the dealership to price new struts and also to inquire about oil replacement. The price of their original-equipment "strut oil" was "like gold", so they went to Randy to see what his ideas were (he was well versed in imports and such, plus having grown up in the alignment business). He went down to the motorcycle shop and bought a few quarts of fork oil (I think he ended up with the 10W after finding that the 5W was too thin). Car rode like new, customer was happy, repair bill was LESS too.

Many car enthusiasts tend to forget that motorcycle forks have a specific oil in them, can usually be "overhauled" to change the valving for particular terrain (especially motorcross bikes!!), and most cycle shops stock it. Just like when synthetic brake fluid came out, a friend bought a couple of bottles at the bike shop for less than one bottle was selling for at the chain auto supply.

In the case of the shock absorber oil, it might well have the same viscosity as other hydraulic lube oils, but like in power steering fluid (vs ATF, where ATF and PSF are NOT the same), it's the additive package that sets things apart. Personally, I'd trust the fork oil more as it's closer to what was in the shocks to start with (I suspect), plus it should have some anti-foam additives (to help prevent "shock fade" on rough roads) and there probably are some synthetic versions for consistent damping in all temperatures.

Just some thoughts,

NTX5467

[old-tank]

Willis

I tried the fork oil about 8 years ago and the car rode like a truck and broke one of the shock links on the end. I used the 'standard' oil instead of the 'racing' that was also available at the Harley store. It was much more expensive than jack oil and more viscous. Maybe if a rebuilder changed the valving to match fork oil, it might work. As far as foaming, if the unit is at the normal fill level with no leaks there will be no air to contribute to foam production. Maybe other lever shocks will like fork oil, but 55 Buick Century rear shocks do not like it.

Willie

[NTX5467]

Could it be possible that the autocross bike shops might have additional viscosities to choose from? Tuning those shocks/forks is, from what a friend told me about his autocross bike "ride" tuning, akin to NASCAR shock absorber tuning--lots of internal variables and the different viscosities of oil would go with that too.

I don't mean for this to get into a "USA vs. rice rocket" sort of thing either! Only looking at alternative sources for shock oil that is readily available at decent prices.

Oil foaming would be minimized with a "full" cylinder, but air bubbles can be generated by the rapid motion of the shock absorber piston (with dedicated and spring-loaded drilled orifices in it) through the oil chamber--even with a full and sealed chamber. The additional pressure on the oil chamber from a pressurised gas "bladder" or "chamber" is there to decrease oil bubbling/foaming, for greater control of wheel/body motion.

I'm glad that what you've found, Willie, works for you.

Enjoy!

NTX5467