Morris Minor Owners Club

Ian - not manged to get these front tele dampers on yet ? They make a HUGE difference. The heavier oil in the standard dampers does help - but the additional tele dampers make the biggest improvement.

Roy. No not got round to fitting them yet . Still need inner wing sorting and have just paid out rather a lot for welding for test. It has been patched from underneath, hopefully ok for test but wouldnt have thought strong enough to fit shocker too.
Ian.

The general rule is that hydraulic oils and mineral oils (engine oil, axle oil etc..) should never be substituted as they are completely different animals.

ok - I'll ammend that to avoid confusion:

The general rule is that automotive hydraulic oils (hydraulic clutches etc..) and mineral oils (engine oil, axle oil etc..) should never be substituted as they are completely different animals
The exceptions are Citroen who use mineral oil for their hydraulics, however they are really the exception.

Anyway, as regards hydraulic jack oil being mineral based - that's nice to know.

its put my mind to rest!

Indeed - automotive hydraulic oil - as used in brakes and clutches - must never be substituted with engine type oil, or vice versa. The hydraulic oils used in industry are mineral type. Jack oil is indeed simply thin mineral oil.

Decided to fill my dampers, the passenger side was very low, so topped it up with 20w50, but it has started leaking out and really isnt riding properly. So i thought id flush out the nasty black oil and refresh it. However I don't want to remove the bottom bolt as i dont have a diagram. Does anyone have this diagram or could at least tell me what to do with whatever comes out?

I fthey are leaking at the main pivot then they fail the MOT and are best reconed.

I've just done a pair on the back and after sending the old ones back it should only have cost about £35

No theyre leaking from the bottom bolt, its just the nearside as that takes a real bashing from the pot holes round here.

I think the bottom bolt you refer to is the drain plug. It also holds in the actual valve so remove it carefully and all the black smelly oil will run out. If I remember correctly there is an aluminium washer on the plug, if it is missing or damaged just renew it.
Ian.

I thought you weren't allowed to unscrew the bottom plug? Just the top plug.

Be very careful if you do remove the bottom one
there is the plug-washer-spring-valve-spring if I remember correctly

talking rears btw, not sure if you are...

Of course it's allowed! But yes - take care to catch the valve bits and put them back in same order!! You can of course tighten up the pre-load on the valve and add some little washers under the spring too - but simply using 20w50 oil makes a worthwhile difference without the damper going stupidly hard.

Cheers ill do that now, the nearside is obviously not working properly as its leaking out the bottom and theres a horrible sludge in there so i will flush it with clean oil and fill with 20w50.

It may be beyond redemption - the black evil smelling sludge is the shredded remains of the long-chain molecules that used to be the oil ! But it may have damaged the seals.

Are the seals renewable? One of mine has a problem. It doesn't leak, but only damps on the down stroke, not up (or VV)

Why did you put in engine oil when ESM sell the correct oil for £3:95 part number MAC003.
Also I am even more confused by agreed remarks as stated above hydraulic oils & mineral oils should not be mixed, so are you saying that the original dampers didnt use a hydraulic oil, because I would have thought that hydraulic oil is not designed as a lubricant unlike engine oil, so they must both be made for different uses unless my interpretation is wrong.

Finished! Theres is a very noticeable difference in damping effect!

Kevin i realise ESM sell jack oil and theyre only 4 miles from me. However I used 20w50 on advive of BMCEcosse on the belief it would improve the damping effect, which it seems to have done although i havent taken it out yet, just up and down the drive and stopping sharply.

I believe the above information means that hydraulic fluids as used in the brakes are different from mineral oils. They should not be mixed, however the fluid in the hydraulic dampers is mineral oil so engine oil is suitable! I may be wrong but thats how i understand it.

But my point is that engine oil is designed as a lubricant, jack oil is not, and there have been reports in the past of strange things happening to the front dampers and mountings when engine oil has been used, like the bolts shearing and there has after all only been one poster on this site who advocates its use.
I also though that if you want to improve the damping rate you need improved dampers or just some new ones, sorry if I have got it wrong, but I dont design car suspension systems and prefer to use the correct parts.

I understand your point, but my dampers are far past their best and theres no way i can afford to replace them at the moment. As i understand it 20w50 is ok as the handbook states a 20w oil is a suitable replacement. However I apreciate the fact you wish to use the originally reccomended oil, but jack oil is not, armstong super thin oil is! It seems an issue of personal prefference. I also apreciate and trust the advice of BMCEcosse, for the short time ive been on this board i've always found it informative, reliable and useful.

Kevin wrote:But my point is that engine oil is designed as a lubricant, jack oil is not, and there have been reports in the past of strange things happening to the front dampers and mountings when engine oil has been used, like the bolts shearing and there has after all only been one poster on this site who advocates its use.
I also though that if you want to improve the damping rate you need improved dampers or just some new ones, sorry if I have got it wrong, but I dont design car suspension systems and prefer to use the correct parts.

I would imagine bolts shearing would be due to the greater than designed for load now being applied to most likely rather old and possibly fatigued fixings.

Surely in the case of shearing, oil thickness or uprated damper valve wouldn't make the slightest bit of difference, the bolts don't know why they're under more load do they?

Packedup wrote: I would imagine bolts shearing would be due to the greater than designed for load now being applied to most likely rather old and possibly fatigued fixings.

Surely in the case of shearing, oil thickness or uprated damper valve wouldn't make the slightest bit of difference, the bolts don't know why they're under more load do they?

The point is that the thicker oil presents more resistance to movement and so in the event of a rapid movement (hitting a pot-hole etc) then more of that energy is passed on to the shocker mountings.

Also, the effect of using a multi-grade oil is that when the shocker heats up through use (and overdamping through using thicker oil will increase this) then the oil gets thicker (a characteristic of a multigrade) which presents more resistance and more heat etc, etc. POTENTIALLY if the mountings are weak through age then the shear potential will be greater when using a thicker oil. This HAS been reported in the past.

The damping effort required and the oil specified was thought out by Morris engineers and the units were designed around those parameters. If you start drastically changing things, you can take the units outside of their design safety specification and it's a gamble.

It might well function well for many years (as in bmcecosse's case) or they might fail dramatically as has been reported elsewhere. It's your car and your gamble.