After watching a lot of your restoration vids. I have learned a load of useful information, just need to put it all to good use!

I have the Green one. A lovely model but the design flaw in the motor boogie mounting screw cutting into the armature is an annoying issue. The trick is not to tighten the screw all the way. In every other respect Airfix were a forward thinking maker of popular OO model locos for the time.

Great upload. Nice to see someone caring for a model that I couldn’t afford in 1975. Great stuff!

What a game changer was the Airfix class 31? Five pole motor ! Super powerful and generally very reliable and bomb proof! Not seen one as bad as yours before? Shame is there are no spares ,no brushes available and trial and error for traction tyres!

Morning Bill. It’s absolutely fantastic watching you fix up these old locomotives 🤩 With the extortionate price of new models it’s good seeing that you can have a smooth running model with some TLC 😂 Your channel is so important showing how you can do it simply with some tools & scoosh cleaner lol 😆 and patience of course 👍🏻

Tanks for sharing 00Bill always a great expierience... "Happy Rails". GMan

Hi Bill, my Airfix 31 sounded like a bag of spanners, followed your video, checking the play in the armature, moved the worm gear for a nice smooth fit, reassembled, couldn't believe what a difference it made, 100% improvement. Keep up the brilliant work. Tom

Bill, I'm one of your subscribers from over in the U.S. Although the motors you work with are often different than the old open frame 5-pole motors of most of my old locos, I have learned much from watching you think through problems. I am currently on a binge building old locos from the 1950's - 1980's from kits that I've had on the shelf. It is satisfying getting these old locos assembled and running - as noisy as some of them are.

Blimey Bill you had so many cocktail sticks stuck in there to release those clips I thought you were going to stick lumps of cheese & pineapple on them and use it in a buffet. Another brilliantly informative video though, there is something I love about those old airfix models

Been following your channel for about 6 months now Bill, I have just changed over to 00 and bought a shed load of none runners which now run thanks to your great channel. I purchased a class 31 for £20.00 which didnt run, runs great now same level of quiet both directions I found that the magnet mounts vibrated in one direction tried all sorts to sort it found that by loosening the magnet and lifting the magnet a touch and putting a piece of paper under the magnet then tightening down the sounds level became the same in both directions now got a great sounding fully serviced class 31 thanks 00Bill.

super to see her running nicely mate... The memories of the Airfix class 31... cheers Neil

I thought my Airfix 31 was noisy until you backed that one into the shed! Service to follow once I've watched the master. Cheers

Sometimes when watching these if you're like me you're glad they are being filmed so you can tell how they go back together :-)

I've subscribed to many Model Railway channels, I have to say, this is the best for knowledge, delivered in a very watchable way. Are you recording any of your layout modifications?

I had one of these a few years ago , bought used from eBay , got it running quieter but performance was generally poor . I found the two plates either side of the armature would catch after use , I thought someone head possibly changed the magnet previously but it looked exactly like the one you have there . Gave up on it and sold it on eBay and bought a Lima , much better runner .

Hi Bill, I have had an air fix class 31 since the mid 80’s, before I got married in fact, but in the last 6 months I have converted it to EM Gauge using em gauge society axles and Alan Gibson wheels. I have reused the motor and gears, but it runs fine with loads of grease on the worm drives, although still a bit noisy. The em gauge society have a data sheet on how to convert, which discusses the motor noise and how to minimise.

Nice video Bill the airfix class 31 was my first locomotive I’ve still got it and it runs sweetly they all have this distinct sound. I’ve got several of them you might like the BR green one as well.

Thanks - I bought one of these in the 70s and it was never a favourite with my son and I. It always sounded like a Kenwood food mixer.

Well done for getting this running again. You inspIred me to take a look at my GP40-2 as the front lights had stopped working. I found out that the led was not working, but it was getting power. A bought a whole selection of led’s and it took about five minutes to fit the replacement. Works very well, but a lot brighter than the old one - safety upgrade is what I say.

Great stuff and good knowledge.from old model enjoyer

I recall that Mike from Model Railways Unlimited serviced his old Airfix Class 31. He discovered that the vertical brass screw on the rear of the power bogie needed backing off slightly or a bit filed off as when it was fully screwed in , it was slightly touching the worm drive causing the noise. Might be worth a try Bill. Great video as usual . Cheers.

You legend.

Have a couple of these myself now, one green one blue. They are fine models and run great in both DC & DCC.

It was a Class 31 porcupine for a wee while there. I must say Bill, it looks great on your layout! Cheers, Andrew 👍🇨🇦

Common fault with these is that the screw that is used to guide the motor bogie is sometimes screwed in too far and it rubs on the worm gear. You can back it out a couple of turns but the best thing is to shorten it.

Really interesting one this time Bill, my Lima deltic is the same, loads louder in one direction

A lot of the noise comes from the screw on the motor bogie interfering with the worm gear. If you chop it back by 1 - 1.5mm it quietens down. I've got two of these and need to see where the contacts go against the brushes.

good vid on the channel thanks lee

Hi Bill, I have got an Airfix class 31 but not quite as old as yours. Runs well will cleaning and careful lubrication from the outside. Haven’t been bold enough to open her up yet and using the motto if she works, don’t stuff around with it! Interesting how you have tried to quieten her down. I have just embraced the noise and convinced myself it is a realistic growl!?

Great service Bill It would be interesting to know how much noise they make when new Nick Australia

I was looking forward to this when I saw it come up, wondering what one of the diesels looked like inside. Airfix certainly didn't do things the easy way but they made nice models. Their coaches are really good. It's a shame they didn't stay in business long enough to iron out the bugs and finesse their mechanical designs. I have two 14xx locos, a spare chassis and a very attractive autocoach. Once the locos are cleaned and not over oiled, they are nice runners and do look pretty, as long as you don't have to take them apart too often 😊

I still have my identical model. It was a really poor runner from new in the 1980s ,I had nothing but problems with it, it’s now a none runner

Rather nice for a free gift. I used to have the Airfix Class 31.

Love my airfix class 31 but never want to strip it down again.😆

A friend had one with a couple of Mk 2d coaches and some track when we were in our teens, his was never quiet or particularly smooth, I think it's just how they came out of the factory, it might be the one model that thwarts any attempt to quieten down, but it looks like an easy candidate for a home DCC conversion.

Have 3 of these all a bit noisy but top runners.😀

These old airfix 31s are noisy buggers and very fussy on how they want to be put together, coming from a lad who has one running on his branchline! Usually those bearings are very springy and like to cause the rattle and noise these things have but once you hit a sweet spot they can run nice and quiet, one fault of the noise can be that screw that helps the bogie not swing out too far is rattling against the worm and making a racket. There's also replacement couplings out there to change out those old arifix ines so they can work much smoother with other stock, Hornby does both a NEM and standard D tension lock if you find any

Dear OOBill, 1 / excellent video, and I have been watching a few via my TV of late, so my questions are of a general nature. 2 / is there a reason why you do NOT install thrust washers ? In a number of videos you comment about the armature shaft moving back and forth, and whilst I understand that you are rightly reluctant to be "heavy handed"in an attempt to rectify a this problem on a repair, would not the addition of thrust washers be a less invasive alternative ? 3 / gear meshing seems to be a problem with some locomotives, and modern, high fidelity models appear to be difficult to add packing under the motor, unlike the older 1960s are open frame motor equipped locomotives, 3 / some locomotives definitely run better with additional pick ups, yet as far as I am aware, you do not add additional pick ups, which on non powered tenders, is relatively easy to add, is there a reason for not doing so ? 4 / really enjoying your videos, very instructive, Best wishes and regards from Australia

Off topic for this video.... a while back you wanted a 3rd HST 125 mk 3 coach. I picked up restaurant buffet and it looks great, so I wondered if you might go for that for your set. Some go for silly prices but as with eBay, patience is the word, .... less than £20 is good.

hi bill yet another great repair video.i have learnt loads from you,i have been donated the same loco with couplings ,buffers, and body screws missing do know were i would be able to purchase these from i would b greatfull, please keep the great videos coming:-)🙂

Hi OOBill - great video, very helpful as I'm refurbing 2x - so very useful. Can you tell us where you got your vice/puller tool from as it looks very useful? thanks a lot!

Hi Bill acquired an AIRFIX 54100-6 Class 31 in blue No. 31401 with both coupling ends broken missing. Any suggestions as to what I could fit in their place to make this loco haulable would be appreciated. Great video. Have overhauled the above easily, thanks to yourself. 👌

Bill I have to say your channel is fantastic, I’m learning loads. One question, do you repair peoples locos as I find ring pole motors fine but this type not

Like many of the comments Bill, these are noisy even after servicing, I think it makes a realistic engine sound, DC sound fitted lol ! I have 2 of these in BR green but I cant run them double headed as it trips the gaugemaster controller.

Hi, I acquired one last weekend and runs well and quiet on DC , but won’t run at more than a crawl on dcc.any ideas!?

watch that screw on the power bogie it has been known to foul the worm gear.nice one bill.jpj

Never had an Airfix diesel but looking at the design of models from that era they were very cheap. I always wondered why they never went with cast metal chassis/underframe with a centrally mounted motor driving to both bogies, similar to Athearn in US. All wheel drive and pickup makes a world of difference.

Hi Bill could you please tell me where you got your remagnetizer from kind regards Craig

The motor bogie is in Fact the Front of the loco. In most cases the Front of UK Diesels is where the roof fan is!

Wrong button sent too soon now since resurrection of trains in COVID for grandchildren the 31 was a non runner and not having experience of Airfix still is. But thanks to a host of cocktail sticks I am inspired to not just renovate but improve.

Bill, you're gonna need a bigger layout soon with all your loco's and rolling stock you have. Any plans in the pipeline for that?

A interesting video - thank you. Just one minor point about the Airfix Mk2D coach. It is the same moulding as the Hornby Mk2D coach. Airfix model railways were sold to Palitoy (ie. Mainline), who later got into financial trouble and sold some of the former Airfix models to Dapol, including these coaches. Hornby acquired them from Dapol in the mid 1990s. If anything the Hornby ones should be nicer (better quality paintwork and moden metal wheels). On the other hand, many of the Airfix ones came with those nice mini tension lock coupling (as on the loco you repaired).

Love the Airfix 31. That five pole motor is smooth and reasonably quiet at realistic speeds. Looks nicer than the Triang one too.

No need for DCC sound with an Airfix 31 !!