Sagging Roof bellows in hot weather - experiences

[WelshGas]

How do you get the drivers side one on if youve got the awning out?

Put it on before deploying the awning?

 

[Califan61]

There's lot's of posts on this one and a long one I created some time ago.

https://vwcaliforniaclub.com/thread...ng-bellows-roof-poptop-tpi.56210/#post-728126

Ours still sag too much for my liking and am thinking about having a new Hydraulic pump fitted. Apparently there is a new version of the pump in production now (I don't know when it hit production) but I'm keen to hear peoples experiences. It is rumoured there was a bad batch in late 2022 into 2023 so I'm keen to understand if any folks have the problem with T6.1s manufactured in 2024 or indeed T7s. I'm guessing they use the same pump, but only a guess.

Our Jan 24 Ocean has only experienced sacking once this summer and it was very hot and only to the point the fabric wasn’t as taught as normal, so only a minor issue. Any other use has been fine so I feel this is acceptable and is mentioned in handbook. I’m also happy to report no leaks from the 06S roof in a heavy downpour thunder storm

 

[sidepod]

Is it just hot weather that causes this?
We had 10 days in Austria last Christmas, warmest temp all trip was -5, coldest -13.
Roof sagged slightly after three days.

 

[WelshGas]

Is it just hot weather that causes this?
We had 10 days in Austria last Christmas, warmest temp all trip was -5, coldest -13.
Roof sagged slightly after three days.

It’s the temperature change that causes it.
At the higher temperature the hydraulic fluid expands the pressure goes up as the hydraulic rams containing the fluid don’t expand so much and so the excess pressure bleeds through a pressure relief valve. When the temperature drops the fluid contracts and the pressure drops so the rams will drop . That’s why the pump is supposed to re-pressurise the system at regular intervals once the pressure has dropped sufficiently.
Normally this occurs 10 hrs after Ignition off with roof up and thereafter on a regular basis only if there is sufficient pressure drop.

 

[myvanrodney]

It’s the temperature change that causes it.
At the higher temperature the hydraulic fluid expands the pressure goes up as the hydraulic rams containing the fluid don’t expand so much and so the excess pressure bleeds through a pressure relief valve. When the temperature drops the fluid contracts and the pressure drops so the rams will drop . That’s why the pump is supposed to re-pressurise the system at regular intervals once the pressure has dropped sufficiently.
Normally this occurs 10 hrs after Ignition off with roof up and thereafter on a regular basis only if there is sufficient pressure drop.

We get this too. I just resort to lowering the roof to the first stop (is the bed down prompt etc) and then press the open button. It's annoying, but not the end of the world. Your explanation helps me accept this. Thanks.

 

[sidepod]

That’s why the pump is supposed to re-pressurise the system at regular intervals once the pressure has dropped sufficiently.
Normally this occurs 10 hrs after Ignition off

I suspect there’s a caveat to this condition?
I always leave the keys in the ignition. At no point has the roof ever auto corrected.