Well, if they are standard height springs (assume they are) if you jack the truck up, put an axel stand under the chassis and take the wheel off, you may be lucky and be able to take the spring out without compressing. Perhaps take the anti-roll bars off while you do this to get extra axle droop. Alternitivly nip to halfords, spring compressors are only £10-£15. A few people have managed using ratchet straps, so could give that a go. If your just going to hit them stand well back, lol, not sure it'll work, but if it does rather you than me :-P And if its hard to hammer them out, it'll be even harder to hammer them in!