Some Damper Questions....

[geoberni]

I've read through the posts I could find on dampers, and most of them seem to be about oil, flushing & cleaning, dismantling and the like, but I have questions about what the Manual says.

For the rear it seems a bit misleading.
So the caption to Fig L1 says

The rear dampers should be removed from their brackets on the rear springs before being replenished

So just off the springs, not removed totally from the car...

Then in the text where it talks of thoroughly cleaning the tops it says that's easily done on the fronts, but...

in the case of the rear dampers, which must be removed from the car for this attention.

Their use of the bold text.


So perhaps the 1970s weren't too precise on the meaning of words but Should and Must are quite different. The first on has a strong element of 'well we recommend it, but its down to you'.

Then when you have a rear wheel off, the rear damper is very accessible and easily seen to clean the top, no different to the front.

So what do people do? Remove or not?


My 2nd point concerns the final part of Section L, about Modified dampers. From Car no 24067 the DAS8/R Damper replace the DAS8.
Am I right to think that 24067 is back in the midst of early MM production?

The new front dampers are identified by a spot of green paint and the rear ones by the valve, which is now horizontal below the bump piston.

I can't imagine anyone can find a spot of green paint these days.

I do wonder what the damper oil is going to be like in the rear ones as the paint looks unbroken around the filler cap.

20210711_113255.jpg (731.41 KiB) Viewed 2063 times

Do I remove it or take a look while it's on the car?

[philthehill]

Take a look at the fluid level whilst the damper is on the car.
If it is low and requires topping up you should as a minimum disconnect the link to the body and exercise the damper arm to clear any air from inside the damper mechanism before and after topping up the fluid.
If the fluid smells ripe it is time for a fluid change especially if it has been in the damper for some considerable time.

[taupe]

I would take them off, clean and refurbish them on the bench.....

If you have a few spares try doing one of those first as practice!!!!


Taupe

[geoberni]

Thanks guys.
I've taken the RH one off since after cleaning them both externally, I took the filler caps off each to check the level and I couldn't see any oil in either, nor when dipping a length of twisted blue paper did I get any damp mark.
However, now it's off it's pretty stiff to move and I can see some oil when I tip it over. It also looks clean and doesn't smell strange.
So I'm off into town to get some SAE30 from Tool Station.
They sell it as Engine Oil for petrol Mowers etc.
https://www.toolstation.com/engine-oil-1l/p77571

If it is low and requires topping up you should as a minimum disconnect the link to the body and exercise the damper arm to clear any air from inside the damper mechanism before and after topping up the fluid.

I've seen this mentioned before about the rear damper, but if that's the case, why is it not necessary on the Front?
Is it because of the different mounting angle?
The manual is quite poorly worded about it, in that it says

When fluid has been added the lever arm should be worked throughout it's full stroke to expel any air that might be present in the operating chamber

But doesn't say anything about releasing the link on the front....

[philthehill]

You do not have to release the front link because as you say the angle of the damper and the ease of which you can 'bounce' the car to expel any trapped air.

[Trickydicky]

If the dampers are low on oil when you inspect them then I would expect them to leak when you refill them. The seals don’t appreciate being dry.

[geoberni]

If the dampers are low on oil when you inspect them then I would expect them to leak when you refill them. The seals don’t appreciate being dry.

Well, lets see what happens . Each one took about 18-20mls, going from the markings on the syringe I was using, but there was oil in there to move about so hopefully the seals stayed damp.
I don't think the rears had been touched since they were fitted, because the grey paint was intact under the underseal that was sprayed everywhere. The fronts however are fine for oil level and you can see that the filler covers have tool marks from being removed.

[Trickydicky]

Didn’t want to sound harsh Berni, just that from my own experience of working with dampers, if they run dry then the seals will fail.
I would remove the rears and make a jig to bolt the damper to and place it in a vice to prevent damaging the casing. This will allow you to remove the drain plug and move the arm through its full motion to drain them. Then you can refill them upright to the correct level and pump oil through the pistons and valves. You will feel them get more resistance as you pump the oil through.
When I first got my car I had a clunk on the drivers side suspension, investigations revealed the connecting link between the pistons in the damper had broken so the damper was not functioning. I replaced it and followed the same method above to refill but the force required to move the oil in the front dampers is so great it was impossible as the pressure mounts.
The only way to replace the oil in the front dampers is on the car as you can bounce the suspension.

[geoberni]

Trickydicky

There was some oil in there, it just wasn't obvious when fitted to the car.
I didn't drain it as it was clean and it didn't smell 'ripe' to quote Phil.
I topped it up and did all the required range of movement exercises to expel any air.
They feel OK, with a similar resistance each.
It's just a case of wait and see if they leak.

[geoberni]

I thought I'd add some comment about the condition of the rubber top hats on the Links.
I already had some ready to fit as they looked really deteriorated.
When I got the links off I was pleasantly surprised to find the insides were good and still doing their job.
They were quite firmly stuck in place, one of the 'body side' ones I had to actually cut off in bits with a sharp blade.
Here's a pic of the outside deterioration compared with the insides.

20210712_094312.jpg (2.73 MiB) Viewed 1931 times

[philthehill]

The condition of the two rubber bushes makes the case for fitting good quality poly bushes.
A grease nipple fitted to the top trunnion bush eye would not go amiss either so keeping the poly bushes in tip top condition.

[Timdiver1966]

Hi.
Because they're so easy to remove, I took the rear dampers off, gave them a really good clean with Gunk, then dried them off and drained the old oil out by clamping them gently in the vice and working the arms up and down. I then replenished them with oil (car jack oil from Halfords was recommended) and refitted them.
With the fronts, again I cleaned the units but left them in-situ to refill.

I've treated myself to a set of new van rims and am off to order my new tyres this weekend!!

[myoldjalopy]

Did you remove the vave assembly at the bottom so the old oil could be drained?

[geoberni]

Did you remove the vave assembly at the bottom so the old oil could be drained?

Are you talking to me or Timdiver1966??
As I already said I didn't a couple of post above..

Hi.
Because they're so easy to remove, I took the rear dampers off, gave them a really good clean with Gunk, then dried them off and drained the old oil out by clamping them gently in the vice and working the arms up and down.

Tim
I measured the angle the Rears are mounted at (55 deg) and then drilled 2 holes in a length of MDF so I could mount them at the right angle, as required by the Workshop Manual.
Simple jig that took me a couple of minuted to make.

[jagnut66]

Hi Berni,
Just wanted to add that I keep a couple of rear dampers on standby, that I have already refurbished, as it speeds up the process and gets your car back on the road quicker.
You can then refurbish the ones you've taken off at your leasure.
Best wishes,
Mike.