Help, I've messed up my rear suspension :(

[hiro]

Only had the bike a couple of weeks (Haibike Fullseven LT4.0) and had a day off today so decided to do as I'd been advised to and set up my suspension before going for a ride in the rare bit of sunshine.. When I measured the rear sag it was closer to 50% than the 25% recommended in the manual so I decided to add some air. I guessed a bike pump wouldn't do this so used a small portable car tyre compressor rated up to 100psi. As soon as I began screwing the pump onto the shock valve it immediately let all the air out in one blast, leaving the shock bottomed out. I put the maximum I could get in, which was about 90psi, but as soon as I start unscrewing I lose all the air again in one quick whoosh. The bike is currently unrideable unless I lock up the rear shock, how do I fix this? Do I need a special shock pump that will go higher than 90psi? (The specs say max pressure 300psi)
As you will have guessed I'm a complete newb to mountain bikes of any sort, so go easy

 

[leverleg]

you need a special shock pump mate yes

 

[hiro]

Thanks, I've been googling some more and I see now I needed way more than 90psi. There's a Halfords not too far from my work and I see they do one so could get that tomorrow, is the one they do ok? If not then I'll need to order one online, any recommendations?

 

[ggx]

Yes, u need a shock/sus pump.
Doesn´t mean that u can´t use a tyre pump (I´ve done it in an emergency), but u can´t tune the pressure/sag.
1st advise : Get help in a store (maybe the one u bought the bike) .

 

[steve_sordy]

One of these.
Wiggle | Topeak Pocket Shock DXG Pump | Shock Pumps

 

[Doomanic]

The Hellfrauds pump is generic pump used by many and branded as own-brand by several manufacturers including Trek. It'll do the job just fine.

 

[hiro]

Thanks all, I've ordered that one from Wiggle and it's being delivered to work tomorrow, saves me having to find the time to get out to Halfords

 

[steve_sordy]

Thanks all, I've ordered that one from Wiggle and it's being delivered to work tomorrow, saves me having to find the time to get out to Halfords

That is the one that is supposed to ensure that no air leaks from the shock when disconnecting the pump.

 

[Doomanic]

My generic Trek pump also does that.

 

[R120]

I have had/used the Halfords one for years with no probs - and never put a compressor on to a shock, could end in tears!

 

[Gofurtherfaster]

I go mouth to mouth so to speak

 

[hiro]

I go mouth to mouth so to speak

Crikey you have stronger lungs than me!

The pump has arrived but I'm not at home til Tues so I'll follow the setup guide then and see if I can get it right