KDL

Would be grateful for any ideas about the following. My car has been sinking pretty substantially in the rear when I don't run it for more than a day or two. When I start the car up, the compressor refills the springs and I'm good to go (although probably killing the compressor). I assumed that I had a leak in one or both rear air springs, and took the car to my (reliable) mechanic. He said he tested everything, and found no issue with the rear springs, the lines or any of the assembly. I asked him to leave the car overnight, and he found that the FRONT was shot. A year ago I replaced the front air springs with Arnott Gen II, and within days of the replacement, I needed to replace the replacements. This would be my third set of Arnotts in the front. Mechanic and supplier both said they're not surprised and that the Arnotts have been problematic. Anyway, a few questions:

1. I know there's something wrong with the rear because I have seen the problem occur for the past few weeks, but the mechanic isn't able to replicate my experience and can't find a leak. Any thoughts about what the issue could be? Faulty air line or O ring?

2. It seems weird to me that I brought the car in because of a problem with the rear, and they instead found a problem with the front. Any ideas? Could one thing be related to another?

3. Has anyone else had problems with Arnott Gen II air springs? I am on my third set in less than a year. Mechanic had recommended a more expensive option (Blau, maybe?) and I went for the Arnotts because they get a lot of love around here and are cheaper.

Many thanks for any insights you can share.

PaperToast

more info about your ar would be helpful, year, mileage, if the rear bags are oem from the factory.

could be a bad valve block, just throwing that idea out

Torsti Tenhunen

There's quite many leak options that you have to check. If rear is going down, the leak is there.

1. Air spring top cap and its o-ring (inside the body, impossible to check without taking the spring down)
2. O-ring between spring and shock (checking also means dismantling the package)
3. The air bag itself
4. Airlines to the spring and to the shock.
5. The load valve in the shock
6. Valve block and its connectors

What I would do?

1. I's put the car higher (level 3 or 4) when parking and checking if still goes down. If not, the leak is definitely in the bag - the leaking hole is at the area of rubber bending back. If the car still goes down, the leak can be in the bag or somewhere else.
2. I'd shut of the shock air line - to eliminate faulty air line and load valve in the shock.
3. Check all the air connectors in the valve block.
4. If no help, replacing the air springs both sides, especially if they are original.

Probability of leaking bag / faulty valve block is about 5/2 so I'd start by replacing the bags if they are original. I still have originals (car 2002) but usually, if the bags are not cleaned regularly, go after 10 years. In Finland where we change tyres twice a year, I clean the bags every time.

I'd also shut the load valve in the shock for good. For that I have made DIY for the forum. Much firmer ride after that.