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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:

  1. This can be dismantled, cleaned out, re-greased and put back
  2. If the bit with the pawls in it can be replaced?
  3. Or if the whole freehub should be replaced and wheel rebuilt around it?
  4. 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

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    youtu.be/X9gIEG1db0s – Daniel R Hicks Apr 19 at 19:22
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    FYI shimano freehub bodies are not designed to be serviced. Never stopped me trying, but I'd suggest you order a replacement, and have a go at servicing the existing one. – Criggie Apr 19 at 22:28
  • FYI, WD40 as the standard product is not a lubricant but a water displacement spray (and is also an effective degreaser!). WD40 as a brand does sell bike lubricants and are clearly marked as such on the packaging. So I hope you had one of those. – Superman.Lopez Apr 23 at 3:18
  • Nope @Superman.Lopez, I just used WD40 but live and learn and I say! Will see about getting some better lube when I order the other parts! Thanks – Jamie G Apr 23 at 10:32
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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).

Shimano 105 5800 freehub body image from sjscycles.co.uk

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&A on a retailer's website that it is a 10mm hex.

enter image description here

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.

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    Just to add to Swifty's answer: I've done 1. last year with my circa '94 Shimano Alivio MC10 freehub. Beyond the chain whip and cassette lock ring tool to get the cassette off, and cone wrenches to get your axle out, you need another tool to remove the inner piece that conceals the pawls. In my case I made my own by grinding a socket that by coincidence I never needed. See RJ the Bike Guy's video: youtube.com/watch?v=1qBk5pePGRg Mine was a slightly different size than in the video, but you have to get to this point before you commit to making the tool. – Gaston Apr 19 at 19:44
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    Another thing: there's also some type of dust cap that you remove before you remove the internal part that conceals the pawls. So there are definitely many steps to get to the end goal, but I never had any experience with working on bikes until last year, and with the excellent information available online, I'm fairly certain anyone that really wants to get it done, can be successful with it. – Gaston Apr 19 at 19:49
  • Many thanks Swifty, I'm definitely heading option 2 direction then, but, your follow up questions aren't exactly right... My follow up question is: "How do I know what Shimano 105 hub I have in the first place, let alone what hub body replacement to order!?". I was hoping someone might be able to tell me the model from my videos, but perhaps that's not realistic. Presumably to find out I'll need to buy the tools, take it off, find a serial and then try to order a replacement body that fits? – Jamie G Apr 19 at 20:54
  • @JamieG You'll find any series codes before disassembly, they won't be hidden. See what numbers you can see on the hub body, and report back, editing in new info, numbers, photos, is fine. I do wonder if the 5600 and 5700 bodies are directly interchangeable, I'm afraid I don't know, though it wouldn't surprise me. That could be a reasonable other question (try not to add more questions to this existing one but do feel free to ask new ones). – Swifty Apr 19 at 21:11
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    Amazing @Swifty no idea how I missed that this was here, but yeah - clearly printed FH-5800 (I updated initial question with this). Searching Amazon shows a compatible part Y31F98070 which I'll be buying along with some tools to do option 2. Wish me luck! – Jamie G Apr 20 at 8:01
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WD40 is a water displacement product, not a lubricant and not oil. It actually dries to a sticky mess. I know mechanics who use it to put on MTB grips, because they slide on while it is wet, then when it dries to become tacky, it holds the grips on nicely.

It is highly likely that you have a mess of WD40 inside your freehub preventing it from engaging. If you do not have tools to disassemble, you may try soaking your freehub in some sort of solvent, then relubricating with actual oil (this will lead to other issues down the road). Freehubs are generally packed with some sort of grease that is intended to lubricate and prevent moisture intrusion. If you contaminated it with pressurized WD40, you'll need to find a way to clean that mess out. Ideally you will clean out the contaminated grease and lubricate it with new appropriate grease.

Unless you are running a very cheap wheel, I am guessing it would be least expensive to find a shop that will repack your freehub with appropriate grease. Shimano's freehubs are not meant to be disassembled and repacked. However, many cyclists that ride in colder tempeatures (like folks racing fat bikes in January) do take apart their freehubs to winterize them with winter weight grease. You might be able to find such a mechanic with some searching.

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The few times this has happened to me, it was because 2 of the 3 pawls were cracked and the last one was sticky, which is normal but not noticeable unless there’s only one. They’re not that hard to replace if you can get spares and grease.

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  • Thanks, I'll definitely replace but have a look see if i can service the old one too! – Jamie G Apr 23 at 10:33

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