Activa Rams

Unread post by **Dommo** » 11 Feb 2010, 13:21

Sorry about the delay but I've had a lot on. I'm about to go and take some photos for you now.

Unread post by **Dommo** » 11 Feb 2010, 14:48

Right, after an argument with my digital camera, here are the pictures, they don't show loads but I had an 'ahh right' moment:

So here's my ram with the gaiter pulled up, the next bit you should see is that black thing (will be referred to quite a few times in this post) that on mine has silicone on the end, however on mine I'd already moved this thing, I didn't want to put it back just for the photo

Here's all the silicone goop (not as bad an idea as it first seems!) You can also see some teeth type things just down the ram from the silicone. What we did was put a rag around this and used some stilsons to try and undo the black thing, after a few turns we realised it seems to be just a push fit, not a screw fit, but I think you need to do the screw-ness to loosen its grip so you can then pull it off.

As you can see here, the black thing you pull up sits on this part of the return spigot

These next two show you what the ram looks like, unfortunatly no circlips or anything to show servicability. Judging by the change of colour towards the top of the ram, it looks as though this bit may be smacked and/or heated into place. Actually that dimple you can see in the darker coloured section could be what the black part that I removed with stilsons sits in??

These next three show you can move the return spigot up the ram to the shaft, and you can see a little channel from between the black thing and the ram (there are no holes/ports on the part of the ram that the spigot sits on), so the only fluid the return spigot should get is what is between the black thing and the goldey coloured part of the ram, ie, what leaks passed the main seal.

So it seems that even if the main seal is leaky, the outer seal (on the black part) should stop it getting out, and if it does the LHM SHOULD return up the return spigot, assuming the return spigot is healthy, but some silicone sealant should sort that if it isn't. Presumably this black part seal wasn't working as it should or someone wouldn't have put silicone sealant on it. In theory if you had a nozzle long enough you could possibly put sealant on the inside up the black part to seal around there, unlikely but worth trying on an otherwise knackered ram? PS - the play in this ram really is minimal, there's some, but not a lot. At full extension there's probably 1mm of movement at the ball joint end.

Unread post by **CitroJim** » 11 Feb 2010, 15:49

Thanks Dom

Those pictures are like gold-dust to me...

The from tram is constructed in a very similar fashion. Jolly interesting on the leakage return seal.

Looks like my heat-shrink idea may work then

Unread post by **Dommo** » 11 Feb 2010, 15:51

CitroJim wrote:Thanks Dom

Those pictures are like gold-dust to me...

The from tram is constructed in a very similar fashion. Jolly interesting on the leakage return seal.

Looks like my heat-shrink idea may work then

That is the front ram that I've pictured, or am I missing something

But yes, I fully expected the return spigot to return LHM from within the ram, not what leaks passed the main seal!

We had thought of silicone sealant and heat shrink to seal the return spigot, just heat shrink on it's own may not be enough because of where the spigot usually cracks, ie right on the inside of the bend!

Unread post by **CitroJim** » 11 Feb 2010, 16:05

Dommo wrote: That is the front ram that I've pictured, or am I missing something

No, but I am

I'm suffering a terrible bout of 'flu and find it incredibly hard to make sense and concentrate...

I meant to say words to the effect that the construction of the front and rear rams are substantially the same...

So what is good for the front one should be good for the rear...

Unread post by **Dommo** » 11 Feb 2010, 16:15

Ahh, no problem Jim, hope you get better soon!

What is interesting is that for the return spigot to get all the LHM it should be at the lowest point of the ram, however on a rear ram the return spigot is situated at the bottom of the ram, pointing up towards the undercarriage of the car.

This could explain why all rear rams appear to be damp, but not exactly leaky.

addo · Unread post by **addo** » 12 Feb 2010, 12:45

Good pictures - ta immensely for that effort.

From one photo, it looks like the rams may be a ZF part (circular logo on body casting). Perhaps a cast body with ported steel sleeve welded or pressed in, then honed.

The ram's open end appears swaged closed - this will challenge rebuilders as it would probably need turning off and an adaptor collar TIG-welded in after rebuild. Not a deal-breaker by any stretch, just a sidestep to get it back together properly.

Positioning of the catch collar and return spigot appears designed to promote a "wet" environment inside the gaiter; the pulsing action of ram operation should pump out any excess beyond a threshold level.

Regards, Adam.

Unread post by **Dommo** » 12 Feb 2010, 12:56

addo wrote:Good pictures - ta immensely for that effort.

From one photo, it looks like the rams may be a ZF part (circular logo on body casting). Perhaps a cast body with ported steel sleeve welded or pressed in, then honed.

The ram's open end appears swaged closed - this will challenge rebuilders as it would probably need turning off and an adaptor collar TIG-welded in after rebuild. Not a deal-breaker by any stretch, just a sidestep to get it back together properly.

Positioning of the catch collar and return spigot appears designed to promote a "wet" environment inside the gaiter; the pulsing action of ram operation should pump out any excess beyond a threshold level.

Regards, Adam.

That's a good point about the spigot, I hadn't really thought about the ram movement forcing fluid up the spigot. Although in theory the black part shouldn't move so the only thing that should force fluid up the spigot is more LHM leaking passed the main seal?

Also that circular stamp on the ram body is simply a manufacture date. 12 98 I think mine says, so December 98, safe to say it's never been changed before!

My next task is to see if the top ball joint arrangement unscrews off the shaft, I dont really know how to hold the shaft without damaging it though. It's not as stupid as it sounds either, my rear shock on my mountain bike (Fox shocks if you've heard of them, a very good make) has a shaft end bit where the spring sits that unscrews, as I found when it somehow did and shat shock oil all over my legs!

addo · Unread post by **addo** » 12 Feb 2010, 13:05

I would see the gaiter as working like a pump to push that fluid out. The base of it is tightly sealed; when the ram pushes down the top neck seals against the eye fitting and creates air pressure.

Only things I can think of, to hold the ram's honed rod, would be stuff like UHMW plastic vee blocks in a bloody tight vice. Make sure that top's not welded on!

Unread post by **Dommo** » 12 Feb 2010, 13:10

I was thinking of something like that addo, something to grab it but not crush it, two pieces of wood with a groove that's slightly less than the ram shaft size in a vice might work.

The thing is with that theory is that as long as the black thing seals correctly the gaiter shouldn't make any odds, but if it doesn't seal correctly then what you say does make sense...

addo · Unread post by **addo** » 12 Feb 2010, 13:23

Just be aware that even the tiniest scratch is game over for the pushrod - the internal fluid is that pressurised it will leak from there on, and rapidly get worse. Maybe wrap it with gaffer tape first, then use the vee blocks.