What's best for rescuing a Shimano freehub?

It's a Deore 525 hub. It's not slipping, it just sounds really rough. I've flushed it out with WD40 and all seems fine. Should I

a) just leave it with WD40
b) douse and drain GT85
c) soak in engine oil
d) the last of my sample of Squirt lube?

Not worth replacing it as it's a spare wheel which will probably not see the light of day for a long time. I remember trying chain lube many moons ago but it just drained out and thinned the grease.

Any good ideas out there?

In the past I have taken the freehub off the wheel, carefully prised the rubber seal out and fushed all the old grease and crap out with de-greaser – blown it dry with an air gun and then put a bit of light oil back in before re-assembling. Quite satisfying but it was seven speed and I never used it again, so I don't know whether it's worth the hassle.

Think I'd drop a bit of oil in it and leave it at that.

That's what I was thinking but when I've tried it with chain lube, it's too thin and runs into the grease.

Do the rubber seal off thing then run wd40 or similar through it, then light oil, then heavier oil, and do each process until the clean stuff of whatever you use runs out of the end. Works quite well.

Or, get a tub of grease from Halfords with the funny plastic extruding ring bit in, stick your thumb in the axle hole bit from the hub side of the freehub and press down hard; fills the freehub with grease…

I used a heavyish gear oil last time I experimented with salvageing one, think it was EP90, worked ok but if I had to buy some i'd try some 130.

cheers guys. I really like the extrusion idea. Is that something you've tried in the past or is it just a really bright idea?

I'm now tempted to buy a donor hub and use all the bits out of that and then build up the knackered parts from this hub with the new shell and drop it in the back end when cleaning the bike. Only thing is, the race on this shell is a bit manky looking.

Not done this myself, but was once told that heating up some grease in an old saucepan till it liquifies and then dropping the freehub into it, so that the liquid grease fills the free hub. Once cool, it should solidify and you'll have a freshly greased hub. Note that heating grease isn't the best idea, but if done very carefully in a well vented space, should be ok.

Grease may make pawls stick.

I've managed to dismantle and rebuild a deore freehub in the past. Once removed you should be able to lever off the thin metal bearing cover carefully as its quite soft. This gives access to the main bearing race which can be unscrew via the two notches in the top, i used a 27mm wood spade drill bit for this. once undone you get access to the pawls and freehub bearing races (lots of small bearings so be careful).

I tried the extrusion method. It didn't work. The grease just came up the side of the pot instead of through the hole. So, I guess what I have it WD40, mostly dried off and sealed both ends with loads of grease. I tried to get as much grease as possible into the bearings under the rubber seal. Guess time will tell!

Grease might stick the ratchet pawls down and stop it from engaging. I had this problem with a non-shimano freehub. I have revived XT ones in the past by filling an aerosol cap with oil, remove oil seal, immerse and whizz it round, drain out the dirty oil, repeat…