BMC 4/25 clutch

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Joined: Mon Dec 02, 2019 11:52 am
United States of America

BMC 4/25 clutch

Post by Dave1958007 » Mon Dec 02, 2019 5:18 pm

Hello new member here from US. I have a BMC 4/25 for past 25+years with loader and love the thing. It has served me well as we have a small horse farm. It's not the prettiest thing on the farm but the hardest working :D . I went to start it and the clutch pedal just falls to the bottom no resistance at all, so guess it's time to break her in half and look at the clutch. NOW poking around the WWW I found parts for Leyland/Neufield and BMC Mini and they all appear to be the same parts. I want to make sure I get the correct parts for the clutch and I am guessing that I'll need the release bearing, pilot bearing and while I am in there the clutch plate. It has also been running hot for a while and I have replaced the water pump, thermostat and it still runs hot, so I am not quite sure what to look for so any suggestions would be appreciated.


Posts: 187
Joined: Sun Apr 01, 2018 8:49 am
Great Britain

Re: BMC 4/25 clutch

Post by Nowtnew » Mon Dec 02, 2019 7:59 pm

Have a look at a couple of uk websites:


to see if the parts are common.
Nuffield 4/25 and Leyland 154 I would expect to be the same.
BMC mini not so sure. Clutch different diameter I think.

If 'Ley154’ sees your post he will give you the most comprehensive guidance.

As regards the overheating,, is it boiling or have you some other indication?. As a US tractor is it a petrol (gas) engine?


Posts: 102
Joined: Sun Apr 01, 2018 8:22 am
Location: Gloucestershire UK
Great Britain

Re: BMC 4/25 clutch

Post by Ley154 » Wed Dec 04, 2019 6:33 am

Hi Bondo. Just before you go removing the clutch check the tightness of the foot lever on its pivot. The pinch bolt that tightens the lever onto the plain clutch shaft has to exert a grip like a vice in order not to slip. Over the years this can relax and allows the lever to rotate on the shaft until all you feel is free play. If you don't have a manual I believe you can download the BMC Mini one free from this site. The method of adjusting the clutch free play is the same for all the lightweight tractor models. If the pinch bolt is not doing its work you may have to pull the lever off and increase the slot width by a mm or two. With a spanner on the flats provided on the end of the cross shaft you should be able to rotate the shaft clockwise against the return springs until you feel the release bearing touch the clutch cover. If you can't then something is wrong inside.
You say you have changed a few parts on the cooling system which should be fine. Two other things spring to mind but I'm aware of sending people down false alleys so to speak. Have you flushed the radiator? When the engine is hot does the whole of the matrix heat up - try it with your hand. There should be a gradual reduction in temp - hottest at the top of the rad and cooling as you go down to the bottom but if there are any cold patches the core is partially blocked.
False alley coming up: Does the engine sound the same as it always used to? If its gasoline there is the possibility that the advance mechanism in the distributor has seized (frozen) in the retarded position and this will cause hotter running. You should be able to rotate the rotor arm a few degrees with your hand and have it spring back with the action of the bob weight springs. You do clean and gap the points ? 15thou.
Hope this isn't misleading. Regards John Poulter.

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