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Hi,
I just replaced a rear air spring with Rebuild Master Tech aftermarket air spring. I cut the old air line at the point where it connect to the air fitting because I can't remove the old fitting with wrench (limited space). Then after put the new spring in place, I just push the hose into the new air fitting attached on the spring. The instruction says no need to unscrew the fitting, just push the line in.
I push the line in all the way until I can't push it no more. There's no click sound or anything. I tested the fit by pulling it out and the line came out with little resistance. Pump the air in and
soap the air fitting to see if it leak. Of course, found the leak bubble come out at the connector.
Not sure how the fitting works inside. Should unscrew the fitting and fit the line outside and then screw it back on? Don't wan't to do that in the first place because the instruction said no need.
The instructions should also have said not to cut.
a small 10mm wrench would have loosened the old line fitting
you have cut off the end where there is a groove that holds the brass collar in place. Without that brass collar gripping the line there’s nothing the nut can keep in place. It might reseat itself and cut a new groove if you try to force the line into the nipple until you can’t pull it out easily.
the other alternative is to take your old nipple apart and see how it is put together and how it seals.
The instruction state clearly to cut the line, so I went with it. I guess it's a bad decision. Even tried to call RMT to make sure the method but they said they don't have any technical support.
Now I'm debating if I should unscrew the fitting then reinstall the collar manually and screw it back. But since on the instruction say do not remove the fitting, I'm afraid that it might ruin the unit.
You mentioned about the cut the groove. Would you please advise how can I do that? I still have no idea what the inside the fitting look like. Don't event know if there's a collar just like the OE fitting.
You can sort of see it in fig. B in Arnott’s instructions - it forms a wedding band like seal around the air line by clamping onto it in two halves, riding in a circumferential groove.
Iirc there’s a special tool from Mercedes to cut the groove but you may get away with using the brass rings to cut a new groove as stated in these instructions.
unfortunately when you buy (what I assume to be) cheap Chinesium crap you also get ****ty instructions and no customer service.
again, look at your old fitting - unscrew it, take it apart; to see how it works. Don’t mess with your new fittings.
Thank you very much. Will look at the old fitting to get more understanding.
Another question. When I jack up the car the first time to replace the air spring. I jack up at the jack point near the rear wheel and the wheel is lifted up from the ground fine. However, when I lift the car the second time after get the new spring in and inflated it, I noticed that the rear wheel would not leave the ground even I lift the car higher then the first time. when took the all lug bolts off, the hub drop even further almost touch the inner rim. I need to place a jack at lower arm in order to lift the hub up to be able to re-install the wheel.
Not sure if it's because the inflated air spring push the lower arm down or something broken. is there anything I need to worry?
It sounds like they're using a typical push-lock fitting, similar to what would be used with PEX lines. Unless there's something wrong with the fitting, you probably just didn't push it in far enough. PEX lines are like that when pushing them into fittings - it feels like it is bottoming out when you first push the in, but a harder push allows it to go a bit further and fully seat. Ask RMT how far the line should go in and make a mark on the line so you know when it'd fully in... or... should it go as far in as the shipping nipple is long?
Inspect the fitting on the old air spring to get an idea of how the fitting operates (remove with 10mm wrench).
Mark the air line at the 1 cm mark (this is roughly the depth of the fitting). The hose should go in well beyond that point (and might require some effort to get passed the brass compression fitting). Once through, give it a good pull for the compression fitting to 'bite' into the hose and keep it in place - this can be a PITA sometimes.
If that still does not work for you, you CAN remove the fitting from the new spring, thread the line with the compression fitting, then reattach to the air spring. Just be careful not to over-tighten, or strip the threads.
02-24-2021, 03:51 PM
I guess it's a bad decision. Even tried to call RMT to make sure the method but they said they don't have any technical support.
