Shock Absorber oil?

[rvwp]

Hi all, what is the best modern shock absorber oil to use to replace the probably 44 year oil thats in the Dampers on my 65 Moggie 1000, and where can yo buy it? Thanks Rich

[Cam]

Jack oil for trolley & bottle jacks is pretty close (available from most motor factors). In fact it's what you get if buying damper oil (shocker oil) from the Minor suppliers.

Do NOT be tempted to use engine oil though, it's the wrong viscosity and is not recommended.

[bmcecosse]

Engine oil works very well! Used it for years - never had any probs - you KNEW that was coming Cam! The 750MC have been using different viscosity engine oils in their dampers for at least 60 years - to vary the damping as required. SAE30 or 40 (that's NOT 10W40) is good. Motorcycle shop - or Tesco do the SAE30 in the lawnmower section. the important thing is to get ALL the stinking/thin old oil out - it's long-chain molecules have been ripped apart about 20 years ago - it's now likely thinner than paraffin!

[Cam]

you KNEW that was coming Cam!

Certainly did!

the important thing is to get ALL the stinking/thin old oil out - it's long-chain molecules have been ripped apart about 20 years ago - it's now likely thinner than paraffin!

Could not agree more.

However, using too thick an oil will take the damper & mounting loads outside of the design specification which may result in failure / shearing of certain parts, especially if they are old and tired.

I put this very question to a chap who used to work at Morris Motors back in the forties/fifties. He used to work in the experimental department and worked on the damper specifications and he told me the above.

[droptheengineout]

Hi,
I'm just trying to get my newly restored lowlight registered, and the inspector has informed me that the shocks aren't strong enough. At first we were talking about replacing them completely (hasn't been on the road since 1984!) but then he advised I replace the current oil with differential oil, and then he went one step further and said I should replace it with "stop smoke" which is a hugely viscous oil (he said to heat the bottle up in boiling water to make it thin enough to pour properly). What are your thoughts on this?

cheers

[Trickydicky]

SAE50 oil would be my limit, I say this because you may not know the condition of the dampers,for the reasons Cam points out above.
Currently my dampers are filled with SAE40 oil and perform well.
It may be best to experiment with different grades of oil starting from SAE30 to find the level of damping you are happy with.

From your comment about the Inspector I take it you are not in the UK? The roads here are poor to say the least and EP90 might be a bit too heavy.

[bmcecosse]

As above - the important thing is to get the old stinking thin oil out (if there is any in there) and yes - SAE 40 is ideal. That's NOT 10W40 - it must be 'straight' 40 grade oil. I did use EP90 (final drive oil) in my Rally Minor - but actually - the viscosity rating of these oils is different - and it's pretty much the same as SAE 40 engine oil. Flush the new oil through the dampers at least once, before finally topping up - leaving a small air space under the fill port. As long as the dampers are not leaking - they will be fine with the new oil.

[MarkyB]

stop smoke sounds like STP oil treatment which is thicker than treacle!
I wouldn't use it for anything.

[droptheengineout]

Yes it is. That's what he said to use. Warm it in boiling water to soften it, then put it in. Mind you, he's not an expert on MM, so I thought I'd check with 'the pros'. I'm in Australia and the roads are fairly good here anyway.
Thanks for the advice. I think I'll go for the SAE40 or 50,

[leafie]

Yes it is. That's what he said to use. Warm it in boiling water to soften it, then put it in. Mind you, he's not an expert on MM, so I thought I'd check with 'the pros'.

Your absolutely right to check, the simple answer is don't do it, as Cam said you would be taking the dampers and their associated parts outside their development specification. When the Minor was designed the two holes that are not used by the side of the damper were there to accommodate a larger stiffer damper but it never happened.

It is fine for people on a race track to take things out of their design specification if they wish, they know the risks and wear a crash helmet. The public road really isn't the place to be carrying out "I thought it would be fine experiments".

Just realised 30 years working in a highways department has had an affect on me, going for a lie down

[bmcecosse]

You'll be well pleased with the SAE 40 oil in the dampers. It's easily the equal of the crummy 'bolt on' tele damper kits.... and a whole lot less expensive....

[droptheengineout]

The car hasn't been driven (significantly) since the early 80's, and I'm not actually sure what the condition of the dampers is (internally). I think he suggested such heavy oil in order to compensate for dampers which may not be in the best condition.

[bmcecosse]

Just try the 40 grade.... it'll be fine ! Do you know how to drain the old oil? One of the rears can be done in place - the other (with the top at an angle) will need to be loosened and swiveled round so the top is horizontal - then remount it when finished. May actually be easier to just take the rears off to do the job, then refit. That way you will be able to stroke the lever full distance to expel the old oil and refill the new. The fronts though should definitely be done on the car - just bounce the car up and down! Probably worth just checking the tightness of the mounting bolts while there.

[kennatt]

Just realised 30 years working in a highways department has had an affect on me, going for a lie down

Know exactly how you feel,even after15 years retired,I get a cold sweat on if I see a police car come into the estate,just incase they are coming to aks me to go back :
Got 40 grade in my s11. works fine,got mine from B&Q gardening section

[irmscher]

I always flush mine out before refilling

[samuria]

I always flush mine out before refilling

is that yourself lee or the dampers

[IaininTenbury]

I tried 30grade in my van (front obviously) and it was a fantastic improvement. A week later it had all leaked out again and I was back to a ride like a worn out 2CV but it was nice whilst it lasted. Must get some new ones....

[bmcecosse]

Yes - if the seals have gone....you either overhaul as per Declan's well documented process - or hope that 'exchange' ones have been properly overhauled for you......