Cashwowud

Hi all,
2005 SL350 (UK)
The vario roof pump has started to make a double "thunk" sound about every 4 seconds, either with the engine running or with just the ignition on. I cannot see any oil leak and there is plenty of oil in the reservoir. The roof and roll bar are working fine. The wife and I are going on a big continental road trip in a month and don't want a car stranded with a half open roof! Any ideas what it might be please?
Thanks in advance,

cashwowud

Frederick NL

I don’t think I’m going to be of any use to you, but does this sound occur only while you’re opening or closing the roof?

Cashwowud

Hi Frederick and thanks for coming back. The noise is all the time when the ignition/engine is on - it's as if the pump is constantly trying to re-pressurise the system.
You must excuse me as I don't really know what I'm talking about! I've owned the car for about 13 years and apart from a new battery it's the first thing that (might) have gone wrong.

cashwowud

Frederick NL

Sounds more like your pneumatic pump, which sits straight under the hydraulic pump. If so, there’s an air leak, most commonly in the trunk lock. If so, you should be able to hear it hissing.

Cashwowud

Thanks again Frederick and yes you're right it is the pneumatic pump. I have listened with a plastic tube in my ear and can hear air escaping at the rearmost end of the pump but as it's 8.00 pm here in England I'll have to investigate tomorrow.
I'll come back later.

cashwowud

Frederick NL

If your trunk lock is leaking, here’s your fix. Cheap and very doable if you take your time.

https://mbworld.org/forums/sl-class-...w-fix-diy.html

Cashwowud

Hi anyone and Frederick in particular.
Of course the thread should have been titled "Noisy pneumatic pump"!
I have traced the leak to the pipe under the passenger (left side here in England) seat by removing the seat and peeling back the insulation where I found the pipe split. Any ideas to join them back together much appreciated

Frederick NL

Wow well done! I’m sure someone will have a brighter idea or more experience than me, about fixing that. I’d guess there would be simple plugs for that, but you would want to retain flexibility, as the chair obviously moves back and forth.

Cashwowud

OK, problem now fixed. I joined the pipe back together using a 2 inch piece of old plastic oil - pressure pipe used to connect the old non- electric gauges. The air pipe was a very tight sliding fit inside it and so no chance of leaks or coming apart.The hard part of the job is disconnecting the air pipe union from the plastic clip on the seat frame, after that easy peasy.

cashwowud

Frederick NL

Okay job done.. pay attention to not creating an ‘elbow’, where the brittle plastic will suffer from stress.

kemzo

I need this exact issue fix in my car, I can feel the tubes disconnected under my seat.