Reply To: Ransomes Motor Triple Mk4 Clutch

[trusty220]

It will definitely be something amiss inside the main drive clutch. The two large nuts that you’ve removed hold the shoe pivot posts to the backplate and did not need to come off- they stay attached at all times.

There used to be a special tool supplied by Ransomes for removing the drive clutch. You can make one quite easily- it was 1″ thick steel bar, about 2″ wide with three holes drilled through it. The centre one was tapped for (I think) 1/2″ UNF with a long-ish bolt through it, the outer two holes were plain with no thread but drilled for a clearance to allow two 3/8″ bolts to pass through. The two threaded holes in the clutch backplate are tapped 3/8″ UNF, so you need two bolts long enough to pass through the puller and give at least eight complete turns through the backplate. All you do then is to take the centre bolt out, remove all of the washers and re-insert it to give something for the puller to push against. It should then be a simple matter of winding the 3/8″ bolts in, then tensioning the centre bolt to withdraw the clutch evenly. I’ve never had to hit it with a hammer to release it but there’s always a first time!

What you are most likely to find inside is one broken return spring out of the pair. The part number is MBA3474 and you really need to replace them in matched pairs. If you put one new one in and leave the old one in place you will find that the clutch will not engage evenly and you run the risk of having the old spring break in the same way that the first one has!

When refitting the shoes pay attention to the direction of rotation- centrifugal clutch shoes should always be fitted in a trailing position, that is with the fixed end leading and the floating end trailing. This is to allow the shoes to disengage when the revs drop; if you fit them the wrong way around (as you would in a drum brake) they will drive and they will “bite” but they won’t disengage.

I doubt that Ransomes dealers will have the parts you need but try Bartrums Mowers, I think they bought all of the Ransomes stock of Motor Triple parts when they had a clear out.

Let us know how you get on.