Dampers, are you protecting yours?

[tomwood]

My car has failed its first MOT on the basis of a leaking rear damper. With this being after just 2,500 total miles I'm obviously interested to know why.

One suggested reason that came from the garage was that, if the shock picks up a load of crud on the shaft, and you happen to go over a particularly large bump and compress the suspension more than normal, a sharp bit of it could make its way down to the dampers seal and end up knackering it.

suggestion therefore being to fit some kind of damper sock to stop the crud going in there in the first place. Seems sensible so just wondered if others were doing this in their cars?

ive had a look about, Deamon Teaks do them. Call me tight though but at something like £20 per corner it seems very expensive. I'm half inclined to butcher an old pair of socks

[Jonathan Kay]

I don't, reminds me of Shirley Conran's comment on stuffing mushrooms.

There's a discussion of suitable socks somewhere in the archives. IIRC products for bikes were suggested.

Jonathan

[SM25T]

No problem for 14 years and 87.5k miles. Risk is that a sock keeps stuff trapped inside too !

[ScottR400D]

I checked my, unprotected 3500 mile, dampers after seeing your earlier posts. They're all perfectly clean and dry. 

 

[Simon.Rogers]

Tosh ! As in the one sudden longer stroke.

There will be at least 2 seals on the shaft.  The one you see is only a scraper seal to remove the crud as the shaft enters the bearing to protect the main seal inside.

Its just a failure that should not have happened.  Not seen many but it does happen.  The smallest nick in a seal or o ring can cause the oil to pass. 

Just sitting there its going to be at 150psi.  This will increase as the damper goes through its stroke.

There could be any number of reasons for the fail.  A nick on the shaft from road debris which then damages the seals is the usual.

Interestingly the Penske's do not seal as tight as others and when I first fitted them thought they were leaking.  They were - intentionally.  The seal is designed to bring out a very very small volume of oil each time to ensure the inner seal and the scraper seal are cleaned each time.

There is sufficient spare capacity of oil in the damper to allow for this.  

The oil brought out is very very small volume.

[tomwood]

So, it's now been repaired and sent back to me. I asked the guy who rebuilt it what he thought. No obvious scoring on the shaft led him to suggest that I was just unlucky in this case and that he couldn't say what had caused it.

[Simon.Rogers]

Sounds about right.  It does just happen.

Hope it lasts.