Rear suspension bottoming out on rough roads.... where to start?

Hi all,

So, the 2008 Jimny I bought recently came with +2" suspension and 235/75/15s. On smooth roads it drives okay, but on rough roads/lanes it seems to bottom out very easily at the rear. Much more easily than any other 4x4 I've owned. This is my first Jimny incidentally. 

Before I start ripping into things, is this kind of bottoming out "normal" for a lifted Jimny, or is there an issue with the lifted suspension? I don't know the make of the suspension fitted, but it does seem quite soft on the springs - I guess its possible the shocks are reaching full compression before the axle hits the bump stops? 

Any thoughts/advice very welcome! Thanks guys. 

I would remove both shocks and check they have pressure/resistance when pushed by hand 

Once they are off also measure the damper travel and check against vehicle articulation.
As you indicated it's possible it's damper travel especially as you don't know what's fitted. I would suggest it's not normal, so start investigating.

Okay - quick update. Looks like the lift kit is likely Pro Comp judging by the shocks. I believe it was a matching kit (springs and shocks).

However... the previous owner also fitted shock extenders on the back axle - net result, the upwards movement of the shocks was only about 1 1/2 inches before the shocks were fully compressed - nowhere near the bumpstops of course. So I'm pretty confident that was the issue. The shocks themselves still have pressure, albeit not as much as I would expect, so they may well be on their way out. I've never had much faith in Pro Comp stuff previously TBH, ran it on a couple of Landies and had frequent shock failures before I gave up and moved onto other manufactures (e.g. running Pedders now on the Cruiser).

Anyway, I've removed the shock extenders and it does seem to have reduced the bottoming out issue, however its increased the tendency for the tyres to foul the arches when hitting fast bumps! The tyres are SImex copies with big side lugs, and at 235/75/15 are pushing the envelope on a +2" kit despite trimming the inner arches etc.

Need to sleep on it and decide next steps... Thanks again for the comments Jack and Scimike.

Get some 50mm extend bump stops 
Jimnybits sell them 

Thanks - yeah I was thinking about that - also wondered whether I should just bite the bullet and get a new full +2" kit (Black Raptor maybe?).

QQ - can anyone give me a measurement to check how much lift I've actually got on the current set up? Say from the centre of the hub to the wheel arch? I'm suspicious the current springs have sagged somewhat, as well as the shocks being tired.

Thanks guys!!