My Reverb compresses when sat on by about 1 cm, googling it sounds like there is an air gap in the damper, is this something the full service will sort out or does it need sending off? The RS video suggests it does but the service looks pretty comprehensive. £75 + p&p sounds like a lot to service something that you can get new for £190.

Definitely got it pumped up to exactly 250psi? (no more, no less)

A service does usually sort it out.
It’s not cheap to service them because of how long they take to do-they’re fiddly things to work on.

I checked it and it was just below 250, added a bit of air but my shock pump isn’t great and I may have lost some air, will this affect it? It raises to full height but the last section has a bit of a clunk.

How old is it? Under two years? If so its under warranty, I’m on my fourth right now all of the previous had this fault and were replaced under warranty. Seal issue between oil and air chamber

Its two and a half years old so past warranty.

Give the poor thing a service if it’s that old & not been touched!
Your forks wouldn’t be working too well after that time scale, a dropper post is no different.

Service it is then. Possible to do yourself looking at the youtube vid, depends if you can be bothered. Not cheap though

It’s not really the sort of service you can do by yourself. If it feels gritty then you can clean it out/lube but the OP’s problem is with the IFP position. I believe that adjusting this requires a special IFP tool and the shaft bleed kit.

One option is to GOI of course. Mine’s had 10mm of squishiness for a year or more now – it doesn’t really bother me enough to warrant sending it back.

Mine has done this about 3 times now. Unfortunately it came on a bike I bought so no warranty. First time I fixed it with a 2 pence O ring from my big box of O-rings from Aldi. It lasted about 3 months. Then I bought a reverb seal kit and changed all the seals and replaced the O ring again (it was the same one and had suffered the same obvious damage as the first one. The Proper O-ring from the kit lasted about 6 weeks!! So once again I replaced it with a cheap 2 pence O-ring from my Aldi kit and it has now been fine for 6 months of hard riding.

What I have noticed is that on the 3 previous occasions when the o-ring has gone the big silver nut on the reverb has worked loose. The last time I fixed it I used a bit of thread lock on it and it has stayed tight since and I am assuming this is where the problem lies.

Stripping and rebuilding the post is pretty straightforward (if a little daunting the first time) but you need a soft jawed vice and a circlip pliers as a minimum.

Note that old Reverbs have an upgrade available to what they have in the newer ones which have less issues with the seals I think. Not sure which year that happened. Under warranty they usually upgrade them I think.

Get it serviced, I had same issue sorted under warranty

From bike-discount.de actually who were awesome with the whole thing

I had mine replaced under warranty last year for the same issue, new one has had no issues.

I will probably get it serviced then, shame the SRAM Tech Centre don’t do consumer work as I only live 5 miles away!

I had mine warrantied by bike discount for the same issue ,they swapped the oem one I originally brought for a brand new retail boxed one with all the extras 🙂 was really fast too:)