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Over on Audiworld forum several have installed a new Chinese bladder and o-rings to fix their Bilstein air struts. One member is distributing some o-rings that have repaired a couple units.
I do not see the air bladders for Jaguar on eBay. The air struts are very close.
Has anyone tried to repair the air leaks? I remember someone was working on the top part here.
While the air bag itself can fail the main failure is the top seal
Air leaks around this and escapes at the metal top hat
I have repaired 2 units by welding in a ring between the top hat and the metal ring which connects the cats
That being said its not as easy as it sounds to pull off.
You need to tig weld the ring in as other methods will put too much heat into the rubber parts.
When I did the rings I first tacked the ring in at 6 points, 3 inner and 3 outer
I then put the whole unit in ice water so that just the minimum amount of the top hat was out of out of the ice water. To do this I used to top mount bolts, bolting on some flat bar to suspend the unit.
I then proceeded to tig the rings, just doing a small amount at a time, quenching the area and moving on. This took some time to do but was successful on both units.
I haven't been able to do this on any more units as I have not had access to more fulty ones to test. All in all I did about 5000km on the repair. I managed to get sport B4's , to replace these units which I swapped in a front set.
SO if you have the welding skill and access to a TIG. Thats how to fix it.
PS I made the rings from 4mm steel. It does not need to be that thick, but I had some scrap the right size in 4mm at the time. I made the ring on a metal lathe. If I was to do it again Id make 2 rings and use 2 or 3mm. Id also place the ring above the top hat and make a spacer for the inner ring.
I have been following your weld a spacer(s) suggestion. Why not just add a washer with another o-ring? Would the added pressure do it or are your welded parts creating a new seal?
The leaks come from the rubber which is at the top of the strut assembly
The air escapes around the rubber and under the top hat (the metal part that has the mount bolts)
Welding in a ring between the top hat and damper ring (where the cats cable connects) creates a new seal.
You need to be careful you dont damage the rubber of the airbag. This is why it needs to be tig'd. Even with a tig weld you still need to control the heat
I would also like to see an image of your handy work. I have been giving this some thought as mine are bound to leak soon and I have been following most of the posts on the matter. Of especial interest was Reyesl's cut away photos which I have used for this post.
My original idea of a washer would not work without some modifications. My idea is to fill the space around the leak area with some sort of compound. As the outside has a lip, yellow arrow from Reyesl photo.
and the inner has a lip it seems that filling the area would be feasible. If the two holes (one is cut away and the other is just outside the "308" in the photo) need to be present a vent tube can be installed prior to filling. Looking at the inner workings I don't think it is a vent.
Why wouldn't this work? If the fear is air will still pass and/or the air pressure would push up causing a leak then my second idea would be to place an inner and outer o-ring which extends past the lips and then fill the area or fill the area and embed the o-rings into the compound. Then use a "washer" to push down to keep the seal. This can be done by tapping and/or tig welding two threaded rods into the two above mentioned holes and making corresponding holes in the "washer" to hold it in place and maintain the seal.
A third approach would extend the collet (black nut in photo upper left, tinker with some fittings and use this central location as the source of pressure for the "washer" seal.
34by151 and I have corresponded on this topic and I've been kicking around an idea similar to yours involving a sealant. The best candidate I've found so far is Copaltite, good for at least 2,000 psi and with a working temperature range of -315° F to 1500° F:
It might be helpful to pull a slight vacuum in the air spring while applying the sealant to draw it into the leak as deeply as possible. We'd have to be careful because too much vacuum could damage the air bladder.
After the first application of sealant was (hopefully) drawn into the leak, a second application would form a nice bead around the gap to reinforce the seal. That's my theory anyway!
If one was to insert a tube first to keep the connector area from getting contaminated and then fill the entire area with epoxy that should work.
I do have reservations about the epoxy cracking though - I suppose the cheaper 5 minute type is more flexible.
I will reach out to some smart people to see if they have some sealant ideas. I looked up the Copaltite and it is unclear if it is the proper sealant. I will do some more digging.
I do have reservations about the epoxy cracking though....
That's my concern, too, since the top seal appears to be a flexible bushing. That's why I'm considering a flexible sealant like Copaltite. Our leak is apparently very small and only opens up in cold temperatures (usually 40F or below), so I've just been living with it.
After looking at the photos and reading the problems the MB owners have I think the problem is the seal shown below in Reyesl's photo.
This appears to be the only seal that stops air from escaping up the sides in the areas owners are complaining of leaks.
Under this theory the solution would be to 1) try to seal the sides with a very thin liquid sealant that will flow down the sides; 2) try to seal the top area entirely forming another seal (including adding tig welded washers); 3) both 1 and 2; 4) try to bend the upper metal lips so that they exert more pressure on the seal or 5) figure out a way to add a cap with two O-rings.
After some reading I don't think using normal epoxy will work as it will crack.
I'm getting a used one to take apart and see which parts need to be re-made or replaced as an attempt at fixing them. I have a machine shop so most of it shouldn't be difficult. If it's just a matter of fixing the seal on top, maybe a Urethan adhesive/sealant would work? It's used to hold panels together to form frames so it should be suitable. Any advice you can give before I attempt this is more than welcomed!
Just adding info on my "experiment" with a failed strut. I had a rear strut fail (a Arnott strut btw) after doing my brakes. Carefully jacking and lowering, but a large leak occurred, would not inflate at all. Had a spare which I installed. But I thought I would try something. I bought a bottle of Green Slime TUBE sealant, emptied the bottle in the bladder and coated the internals as best I could, then drained over night. Next day filled to 100 psi and it held, for a week. Then drained and stored it. About a year later I filled again , 100 psi, it still held. Of course this is in a static condition, and in no way recommending this to anybody. But next time I have a leak I will try this. Cheers.
Hi Bucktooth,
Thanks for the info; that's interesting... My left rear failed after getting new tires put on the car. I know they were worn but I was hoping to get some more life out of them. How old was the Arnott shock?
After a decade or more of service, attempting to repair a module doesn't take into account that just like tires, the rubber airbag has a limited life. In fact, the service manual specifically states that you should never install a new replacement module that is older than 7 months from its manufacture date. Why? Because of its limited lifespan. And this also includes NOS inventory. Just like tires, dry rot and certainly shock performance decreases with mileage and time. It's a safety issue as well. A rupture in the airbag while at speed on the highway places not only your life, but also the life of other motorists at risk if a collision happens from loss of control.
I purchased a set of XJR shocks pulled from a low mileage 2004. Installed all four on my car. In a year all had started to leak. Have not had a failure using RMT rebuilds on these shocks.