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Post 30
December 2015

Mainshaft Assembly - Front Half

land rover series 3 bare mainshaft

Here is the bare mainshaft. There are two pegs. The peg shown in the picture prevents the spacer shown from rotating. There is another peg that stops the brass bush from rotating, and also prevents this spacer from coming off. In my case the second peg had been pulverised. So I guess you normally wouldn’t see the spacer like this.

land rover series 3 bare mainshaft

Here is the second peg. Normally you wouldn’t have to worry about this, but I had to install a new peg as the old one was missing (see post 29). The new peg was a fairly lose fit (it’s supposed to be a press fit). I guess the old peg had widened the hole as it was ripped out, or perhaps the replacement was just too small. Anyway, I roughed the inside half of the peg by pressing it between vice jaws and then hammered it in with a dose of loctite.

land rover series 3 mainshaft bush endplay

There are three endplays that have to be measured on the brass bush. 1st, the overall endplay of the bush between the spacer shown in the previous image and the washer held in by the devil circlip. Note that the new bush comes in two pieces, I’m measuring between the two, but this is effectively measuring the endplay of both combined. This was about right, no adjustment required.

land rover series 3 mainshaft gear endplay

2nd, the endplay of 2nd gear. The gear is held between the shoulder of the brass bush and the spacer. I had zero endplay, the bush needs to be slightly longer than the depth of the gear so everything can rotate freely.

land rover series 3 mainshaft bush adjustment

So the shoulder of the bush has to reduced in size, effectively lengthening the section of the bush that the gear spins on. I did this by cutting holes in a sheet of sandpaper, just the right circumference for the bush to slide through. Underneath the sheet of sandpaper is the old 2nd gear providing a hard surface, which is of course the perfect size for the bush to spin in. I spun the bush with a rubber handled screwdriver in a battery drill. It was bad for the screwdriver but worked a treat. I had to cut about 10 holes because the sandpaper will only last about 30 seconds in each spot.

All of the above probably doesn’t make much sense, but it will be obvious when you have to do it.

land rover series 3 mainshaft bush snap ring

Installing the annoying snap ring. Using the old bronze bush to tap it down the shaft into place. This needs to be installed to check the endplay on third gear. Order at least a couple of snap rings.

So that’s second gear at the bottom of the picture, and third gear on top. The synchro unit for third and fourth sits on top, but has to be installed when the mainshaft is sloted into the gearbox. So for now, the front half of the mainshaft is complete.

Parts

I replaced 2nd gear. Britpart. Seemed fine. Basically every component that has small synchro teeth, I replaced.

I had to replaced the bronze bush because it was chewed to pieces where the mainshaft pin had worked lose. The gearbox originally had a one piece bush with a shoulder in the middle, but these are unavailable, and now come as two separate pieces, but function the same. Britpart. The bronze bush didn’t have adequate length to provide end float for second gear and had to be worked as per above.

Snap Rings. Can't remember, either Britpart or Bearmach (genuine was ludicrously expensive from the site I ordered everything else from). Order a few because they stretch every time you have to test fit them. I used one for test fitting and kept a second untouched for final assembly.