Damper draining

[ronnie]

Help !!! I'm trying to drain an refill my front dampers. I've removed the bottom drain bolt and valve and pumped the suspension not a lot came out. I've removed the top plate and it's full of oil (fresh ) so how do I get it out it's not moving when I pump it !!

[bmcecosse]

I wouldn't take the whole top plate off - just take the fill plug out. It should run out the hole where the valve assembly came out.....is any of the valve left inside?? Someone may have already filled them with more viscous oil.......

[brucek]

You may also want to try bouncing each corner to 'pump' out the old oil. Best done with the top plate in place, of course

[ronnie]

Hi. I've tried pumping it 1st Heavyly on each wing with just the drain plug out and what I think was the whole valve assembly and only a small amount came out. So I took of the top plate and the oil was flush with the damper what do I do now to totally drain it apart from soaking what I can with rags ????

[bmcecosse]

No idea really - mine ran out like water - and was nasty smelly stuff too! Suck it out with a syringe?? Not a lot of work to pop the top trunnion off the damper arm - and you will then be able to move the damper over the full stroke range.

[ronnie]

I suppose I could suck it out or at least as much s I can with the draper pump I have . As I said the oil was pretty fresh and seems about the same viscosity as the new oil I have . Would I disconnect the damper at the trunion and pump it from there ??

[bmcecosse]

That's the idea.......

[Trickydicky]

Hi,

You need to follow this method, remove the bottom plug and the valve assembly, rock the car untill no more oil comes out, replace the valve assembly and the plug, rock the car again and the damper will firm up again. Repeat removing the plug and valve assembly, rocking the car untill all the oil comes out as many times as is required to remove all the old oil.
When it is all out the damper wont "damp" the arm will just move up and down.
Basiclly you need to move the oil from the top of the damper down to the drain plug.
Again to flush out the damper when you replace the oil you will have to follow the same method. Its eaisier on the rears as they are off the car and you can make the damper arm move further thus removing more oil.

Hope this helps

Richard

[ronnie]

Thanks guys will keep at it , by the way Roy I've never seen you use the phrase ::: No idea ::: lol

[bmcecosse]

Richard - the problem is that the oil is not 'running out' when the car is rocked.......... and yes - you have me stumped there Ronnie !

[Trickydicky]

Can only assume then that the valve assembly on top of the damper piston is either stuck or broken. From memory Declan Burns article on how the damper assembly works will explain it better than I can.
http://www.mmoc.org.uk/viewtopic.php?f=4&t=36349

If it is the valve assembly that is not working on the damper then the only option will be to replace the damper.

Are you able to remove all the oil from the other damper or does it show the same symptoms?

Richard

[bmcecosse]

The top valves are just little balls with springs to each give one way damping - I doubt they could jam.

[ronnie]

Both dampers are the same the oil sits level at the top . Should maybe drain what I can and flush with maybe parifan or diesel , although the damping on the offside is bouncing easy and the near side still feels dampened

[Trickydicky]

Hi,

I think my next step then would be to disconect the damper arm and "manualy" move the arms to see if you can drain the oil from the dampers. I was advised not to use parrafin or diesel to flush the dampers, best just to flush with oil rather than parrafin or diesel.

I cant understand though that if oil cannot move from the top of the damper to the drain plug how the valve on top of the piston is not working correctlly? From how I understand the way the damper works, the valves on the top of the pistons allow oil to move between the piston bores thus creating the damping motion? The pistons are set in opposition to each other with the valves helping to create the damping action.

Richard

[bmcecosse]

The top valves just ensure oil can refill the bore that is NOT damping while the other one IS damping. The restriction comes from the tiny holes in the valve assembly - with the valve able to lift off it's seat and allow oil to bypass when a heavy bump is encountered - otherwise something would break!

[mike.perry]

My suggestion, have not tried it yet, is to support the front corners of the chassis on axle stands, remove the wheels, jack up the lower suspension arm with a trolley jack until the chassis almost lifts of the stands then release the trolley jack. The fast lowering of the suspension should pump the fluid out. That's my theory

[ronnie]

Thanks mike . It's been laying all night and the oil level is still flush with the top of the damper so got to try something

[bmcecosse]

Syringe......

[ronnie]

Hi Roy , I've sucked out all the oil put on the top plate and drain plug and filled with new oil but what I'm worried about is if the fresh oil is getting all the way through the damper

[bmcecosse]

It will do if you work the arm through full range. Hence my suggestion that you pull the arm off the top trunnion. Then you can stroke it out.