First post! Hello! Drive coupler replacement question...TIA

Hello fellow tractor owners!

First a little about myself. I'm a fan of all antique tractors but my faves are the old Fords and MFs. I have a Massey 135 Diesel that I rebuilt from the ground up, with help from a pro on the engine and hydraulics rebuild. Everything on her was either replaced or rebuilt /restored & repainted. I believe it's a 1965 model the same as me.

That was a little over ten years ago when I restored it. Time to go through it again now unfortunately after making the mistake of letting my brother use it one day after it'd been sitting too long, and I didn't make sure it had enough oil in it first.... grrrr.

Anyway that's another thing I'll be getting to as time allows. For now I have a question about another Massey a buddy let be borrow to bush hog and move some logs & dirt around with while mine is down. This one's a 231 and yesterday when I was using it I had it in fist gear, shifted from neutral to low speed after taking a break to reset my logging chain, then let out the clutch and forgot to take off the parking break. To my shock & awe I heard the telltale POP sound the drive coupler or "shear coupler" (as I've seen it called after some research here) makes when it goes. Now it won't move in any gear, forward or reverse.
Apparently this happens from time to time although I don't understand how the thing could be made so weak that a simple mistake like that could take it out of commission?

Now for my main question and thanks for reading through my introduction. I have seen different threads saying I can get it out and replace it going through the top, or from the side at the PTO lever cover plate. The side looks like much less of a hassle to do, especially out in the field. Can I do it this way on this particular model and does the fluid need to be drained first? I have ordered the new coupler this morning and it should get here by the weekend.
Thank you for any advice guys. I borrowed this tractor and want to be responsible and fix what I broke, intentionally or not. Wish I could say the same for my brother about my baby. :x
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Howdy from South Wales in the UK,
First of all you have not confirmed that the shear-tube is broken. The 'pop' as you have
described it is not likely to be the shear-tube breaking. Normally the tractor has to be
under immense loading and what you will hear is a loud BANG! I think that in this
instance the split pin has fallen out of the coupling which happens from time to time.
It is only a matter of time then for the tube to move rearwards until it disengages from
the output shaft in the gearbox. The 'pop' you refer to is likely to be the sound of
spline disengagement.
The transmission oil should be drained to at least the level of the bottom bolt of the
side cover. If the tractor has IPTO you will have less room to work inside. Disconnect
any pipework if fitted and remove the cover. You will be able to see inside using a
flashlight but refitment will be done more by feel that watching what you are doing. If
the tube has broken slide both pieces forward along the shaft. Engage high range and
withdraw the shaft and shear-tube. If the coupling has just moved rearward re-engage the
spline and slide it forward. Did you order a new splitpin with the coupler? The splitpin
is longer than most normal sizes so fitting the MF one is a lot easier.
Select a hole, it is normally the one in the most forward position. Insert the splitpin
right through. There should be minimal end float but NO tightness. If you cannot insert
the splitpin try the next hole back. When you have the right hole it is easier to
disconnect the shear-tube and turn it so that the chosen hole is north to south. Insert
the split pin from the top. It is easier to open the legs when they are at the bottom.
Bend them back as far as they will go.
Have a feel around in the oil in the hope of finding the old splitpin. If you can
retrieve it then it won't get caught in anything. Replace the sidecover and oil and
reconnect any pipework if fitted.
Let us know how you get on.
DavidP, South Wales.

Wow thank you very much David! I will do just as you have advised and hopefully the coupling tube has only lost the pin and not sheared in two. It was a pretty loud pop but It wasn't under a huge load or anything. The log I was pulling I had up on makeshift rollers and the brake shouldn't have put that kind of stress on it I didn't think. Will post my findings as soon as I get the cover off and inspect the situation. Did not think to order a new pin so hopefully the original is salvageable or I can find one locally that will work.

This tractor does have remote hydraulics so I hope that won't make it harder to get to it from the left side. I have one of Big Dean Austin's very informative CDs I bought 10 years ago for my 135 and it says the way to get to this would be through the top under the seat, at least for a 135 -w- remote hydraulics. Perhaps he will see this and even chime in as I respect his opinion greatly as well.

Hello,
Don't consider using the old pin. In straightening the legs you are likely to crack them
which could cause a future failure. Having the hydraulic cover removed is without doubt
easier but it's quite a bit of work.
DavidP

Well that went pretty smooth getting to it through the side cover. Sure enough that baby sheared right in half where it was designed to. Took a photo of it just before taking it out and will try to post it if I can as a new member?
Wish I'd thought to order the cotter pin too with the new tube. You'd think they would toss one in with every order since it's needed to keep it in place. They should at least suggest it to consumers. Oh well. I do have a 3/16" x 2" pin I got from the local home improvement store so maybe I can find the 2 1/2" one it needs somewhere local like Tractor Supply.

Trying a different way I guess...

Hi, nice photo. Now we know what the problem is.

Cheers

DavidP

Cheers and thank you very much for your time and replies. So glad this turned out to be an easy fix. Part is on the way!

On certain parts that have to ordered that don't cost a lot, or if I have some extra money I'll usually order a extra. Doesn't hurt to have a spare on hand.