Repairing a Shimano Freehub on a Specialized Hardrock Disc 24 speed (2012) bike

The freehub on the back of my Specialized Hardrock Disc 24 speed (2012) bike is on the way out. It grinds when rotated and was full of rusty water when I sprayed it out with the old WD40. I removed it using a spline and a ratchet from the non-drive side of the wheel. 

I re-greased the what I could of the bearings but I reckon its time for a replacement. 




Im pretty sure that these Shimano freehubs are self-contained and have non-replaceable parts. I can just about see the non-drive side bearings on it if I remove the rubber side wall, but there is no obvious way to remove them. I cannot see the drive side bearings at all and again, I can see no obvious way to remove them. Some freehubs have press fitted cartridge ("sealed") bearings, some others have loose bearings. From looking at a photo of a Fast Forward 11 speed hub, https://www.evanscycles.com/fast-for...-body-EV192167, it looks like we can see the red sliver of the side of a bearing cartridge there alright. 

I came across a guide on servicing freehubs on the Park Tool website here: https://www.parktool.com/blog/repair...reehub-service . Comparing their images to the one I have, It looks like I have a Shimano or at least a Shimano type freehub. They said the following about these branded hubs:

"The common Shimano® freehub uses internal loose ball bearing, pawls and springs. Be aware that it is not recommend to completely dismantling the freehub itself. There are no parts available, such as the pawls or springs. The small ball bearings are available as replacement parts. However, if the bearings are worn out and require replacing, it is very likely the entire freehub is needing replacement. The blow-up image seen below is a ball bearing type freehub."

This is a pain, as it looks like I have to replace the whole hub. Id rather a more serviceable hub like the Fast Forward one. So ive narrowed my hub down to a Shimano. To recap, I have a 24 speed bike, or to put it another way, a 8 speed cassette. This website https://bike.bikegremlin.com/1259/bi...compatibility/ and this https://cdn.shopify.com/s/files/1/10...tion_Sheet.pdf appear to state that a 9 speed hub is also compatible with an 8 speed cassette

"9 speed cassette has narrower and more tightly spaced sprockets, so it has the same overall width as an 8 speed cassette"

After a bit more research, I found a freehub on this website that listed it as being compatiable with my Specilized bike. The part details are: 

Specialized S092100009 Joytech 9-Speed 135mm Q/R Sealed Freehub Body

My bike is 8 speed but from what I read earlier in this thread, the 8 or 9 speed freehubs are interchangeable as they are the same width. This is due to a 9 speed chain being thinner. 
I ended up emailing the "regular" bike parts sellers www.wiggle.co.uk and www.chainreactioncycles.com to see if they had it. They all came back to say that they did not have my freehub. So I went with the original website linked above. 

When it arrived, it looked pretty much identical to the original. 



I installed it and unfortunately found that it wouldn't freewheel  The base of it was about .5mm thinner than the the original. This caused it to be mounted too tight against the wheel hub. Luckily, I happened to have a washer from an old table saw that fit. When I sandwiched this between the freehub and the wheel hub and tightened it, it was able to freewheel. 



I put the whole wheel back together and the bike has been running great since. 


Out of interest, I had another go at opening the old Shimano freehub that I removed. I was able to remove the large rubber washer on the drive side exposing a cap that had a key on either side. I was able to unscrew this with a vice and the tool shown below: 




Inside, it was full of rusty water. There were about 20 tiny bearings on each end that looked to be a pain to try and get back together again. The spring on the pawls was rusted and broken. The bearing race channels were pitted. It was unfortunately beyond repair. 

Repairing fuel tank cap on Audi A4 B8

When I had the VCDS USB cable hooked up to the car to diagnose the cabin blower error, I came across a second issue. The VCDS software was reporting that the lock for the fuel cap was acting up. A print out of the error was as follows:

Address 46: Central Conv. (J393)       Labels: 8K0-907-064-46.clb
   Part No SW: 8K0 907 064 A    HW: 8K0 907 064 A
   Component: BCM2 1.1      H70 0134  
   Revision: 00002001    Serial number: 010967865308    
   Coding: 0100062000390040012001
   Shop #: WSC 06325 000 00000
   VCID: 2E4A198B2017BC72BDAC28D-807B

3 Faults Found:
02615 - Fuel Tank Cap; Lock 
            009 - Open or Short to Ground
             Freeze Frame:
                    Fault Status: 01101001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 128
                    Mileage: 264877 km
                    Time Indication: 0
                    Date: 2018.12.28
                    Time: 22:48:18

02616 - Fuel Tank Cap; Unlock 
            009 - Open or Short to Ground
             Freeze Frame:
                    Fault Status: 01101001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 128
                    Mileage: 264877 km
                    Time Indication: 0
                    Date: 2018.12.28
                    Time: 22:51:58

It appears thtat the fuel cap was not locking itself. Not really a problem, I mean, who siphons fuel to steal it these days. But it would be good to repair it nonetheless. I needed to have a look at the fuel cap lock to see what was wrong. If you open the cap, you will see a single screw that you can remove on the plastic panel.

Once this is done, using a spudger or blunt knife, remove the plastic panel. You will see the lock module on the left (model 8K0 862153 F). Slide this to the right and lift it out. It will be connected by a red plastic cable. Unclip this on the module side. Now you can remove it from the car.

If you are replacing the module, you can just follow the instructions in reverse to put it back in. I opened by module to see what the issue was. There are clips around the perimeter of the module.

Unclip these and remove the cover. Inside is a motor and lock mechanism.

To remove the motor, pull out the two pins in the plug (like above, with a needle nosed pliers) . Then you can wiggle the motor out of the module housing. I removed the motor and attempted to spin it with a 12 v power supply. I would spin, but only after a push. Monitoring the power supply, I notices that it current limiting was it was pulling more than 2 amps at certain angles of the armature. This is a sign that the coil was shorted or burnt out.

I doubt that I would be able to get a similiar motor, and it would be a pain to remove the gear and put it onto a new one, so I just bought a replacement module for about 30e.

Repairing a faulty cabin blower in an Audi A4 B8

While driving I noticed that the fan in the cabin of the Audi A4 was becomming tempermental. 50% of the time when I would press on the button to demist the front windshield it would fail to start up. I hate having to wipe the glass as it leaves streaks, so I was forced to drive with the windows wound down to get enough air through the cabin to clear the glass. Not the safest of options.

I got the laptop out, connected the VCDS cable and ran the software. I got the following error related to the Heating, ventilation, and air conditioning (HVAC) module in the car.

Address 08: Auto HVAC (J255)       Labels: None
   Part No SW: 8T2 820 043 K    HW: 8T2 820 043 K
   Component: KLIMA 1 ZONE  H05 0120  
   Revision: B0000000    Serial number: 0126.02.080837
   Coding: 34040000
   Shop #: WSC 06325 000 00000
   VCID: 3A6225DBEC5F60D2112454D-806F

2 Faults Found:
01273 - Fresh Air Blower (V2) 
            003 - Mechanical Failure - Intermittent
             Freeze Frame:
                    Fault Status: 00100011
                    Fault Priority: 3
                    Fault Frequency: 55
                    Reset counter: 179
                    Mileage: 264877 km
                    Time Indication: 0
                    Date: 2018.12.29
                    Time: 16:27:51

             Freeze Frame:
                    Temperature: 11.0°C
                    Speed: 0.0 km/h
                    Load: 0.0 %
                    Load: 8.5 %

01273 - Fresh Air Blower (V2) 
            006 - Short to Plus - Intermittent
             Freeze Frame:
                    Fault Status: 00100110
                    Fault Priority: 3
                    Fault Frequency: 14
                    Reset counter: 179
                    Mileage: 264877 km
                    Time Indication: 0
                    Date: 2018.12.29
                    Time: 16:27:53

             Freeze Frame:
                    Temperature: 11.0°C
                    Speed: 0.0 km/h
                    Load: 0.0 %
                    Load: 32.5 %
                    Voltage: 11.60 V

Googling keywords from the issue informed me that the fan/blower motor had to be replaced. New, this part is about 120e off ebay. To do this, I would need the part number to look for. So I would have to take it out to have a look at it.
I roughly followed this guide here to remove the glove compartment. https://www.youtube.com/watch?v=9d3zL-7kJBQ Note, some guides will advise you to remove the Radio to get at some bolts. I did this, but found that there were no bolts that needed removing. So dont do that.
there are about 5 screws to remove from the glove compartment. Two on top, about two on bottom, and one under the panel to the left of the compartment inside the door. Once removed, you will need to disconnect a cable going from the car to the airbag enable/disable switch in the glove compartment. Once this is removed, put the glove compartment aside. You will see the power resistor for the fan and the fan itself. One screw holds the fan. Remove this, and then with two hands, firmly twist the fan housing to remove the whole fan. The blower/fan will look like the following:

I cleaned out the cage for any debris. I spun the fan by hand and found that it was very stiff, only spinning for less than one second before stopping again.

I hooked it up to a 12v power supply limited at 2 amps and found that it turned slowly.

Looking at the part number, it is 8k2 820 021. This is not meant to be a user serviceable part, but as I had nothing to loose, I decided to open it.
I removed the back cover, it is held in place by two screws

I bent back the two copper gates holding spring for the carbon brushes in place. This allowed me to remove the spring and spray some WD40 into them to make sure that they came in and out freely. The brushes had about half their life left. Leave the springs out along with the brushes pulled out.

I then sprayed the bushing closest to the cage too

Next, I decided to have a look at the rear bearing and the commutator. To do this, we have to remove the back piece of metal covering the rear bearing. This is held in place against the main housing by a few crimps in the metal. These can be teased up by a flat screwdriver. Unfortunately, I do not have any photos or video of this.
You will now be able to see the commutator. You can see that there is alot of carbon buildup on the copper, along with wear patterns from the brushes.

This can be cleaned with a bit of sandpaper. I put the cage end into the chuck of an electric drill, held the sandpaper against the commutator, and spun it to smooth and clean it.

Then I used a dental pick to clean between the copper contacts on the commutator for any bits of copper or carbon that might short it.

The rear bushing got spray of wd40 too. I pressed the rear metal housing back into place again. This will require a few goes and some patience. A few taps of a small hammer bent the crimps back into place.

Screw the rear black plastic housing back into place again. I tested it with the power supply again and it appeared to spin with more speed. Manually spinning the cage resulted in it continuing to spin for 2-3 seconds before coming to a stop. Not great, but definitely better than before.

I installed it back into the car. VCDS along with the cable was used to reset the all errors on the car. After a month of use, the fan works now as expected, and there are no errors showing up on VCDS. Success!