Shimano 105 freehub FH-5800 - pawls not engaging, repair or replace? After a thorough clean and (over) oiling with WD40, my Shimano 105 FH-5800 freehub stopped engaging. Sounds like a common fail: I had previously thought that more oil = better. Live and learn!

Bike is just over 10 years old but in good condition otherwise. I don't know if:


This can be dismantled, cleaned out, re-greased and put back
If the bit with the pawls in it can be replaced?
Or if the whole freehub should be replaced and wheel rebuilt around it?
Any other options?


I've looked at countless guides online to do with all three, but I just can't work out what applies to me  and my kit and what doesn't.

I'm also not sure what I'd attempt myself and what I'd need a shop for. I certainly wouldn't attempt (3), but would considering (1) and (2) with solid advice. I would need to buy the Shimano tool and a chain whip first though - until this happened I'd never heard of freehub, cassette, pawl or Sheldon Brown for that matter - I'm getting a good education here! 

Here's the back wheel when going wrong:
https://photos.app.goo.gl/8p3vnYAyxyndNtoz5

https://photos.app.goo.gl/CYjnuzZFZSuhisDM6

(apologies for the poor backing track )

Update: https://photos.app.goo.gl/oBSpGwfBUpxfyxDJA (additional photo of hub model)

Happy to send more images, but as far as I'm aware, unless I get the tools I can't currently get the cassette off to see more.

Thanks all
It should be possible to do one of 1. or 2. but the way Shimano hubs are, the pawls are contained in the freehub body, which is pictured below.

So that means option 2. is that bit more achievable than option 1 (but costs more in parts). You'd take the cassette off with tool and chainwhip, then disassemble the cup and cone hub using a cone spanner and regular 17mm, before the freehub body is removed with a big Allen key. You could always investigate inside the freehub body first and see if it just needs degunking. I doubt that WD40 penetrates all the way inside, it might just need it's overdue 10-year clean (jks that's not a thing).



Here is an image of a random Shimano rear hub exploded diagram, that I stole off of eBay. Part number 15 is a large bolt that you have to access to remove the freehub (Part Y3BL03000 for many hubs incl FH5800). I believe from Q&amp;A on a retailer's website that it is a 10mm hex.



Doing 3. is a possibility, don't be afraid of giving it a go, but that might be 'running' whereas option 2. is 'walking'. Arguably.

Option 4. is buying a new wheel. Doesn't have to be that expensive, but would be more costly than option 2 and less fun.

Your next questions might include: 

"how do I turn the 10mm Allen key with force now the long end is in the hub?" (Use a spanner)

"help, I took apart my hub and can't get it back together!" (see diagram, see How do I reassemble this Quando rear hub?)

and, "something, something, Darkside" (see a counsellor).



You should check the rim wear and overall health of the wheel before spending any money on spare parts, or even tools. If the rim is old and worn down near its limits then replacement parts wouldn't be the most economical way to go, you could put that money towards a new wheel. Tools are fun and useful going forwards though.