How to change the cutter belt on a Cox Stockman 4000 Hydro

How to change the cutter belt on a Cox Stockman 4000 Hydro.

I searched high and low for advice on changing the cutter belt on a Cox Stockman 4000 Hydro drive rideon mower, to no avail. Having talked to the people at Cox (, and being unable to to find a mechanic to do it for me, I decided to give it a go. It’s a bit of a pain in the arse.

This is what I did.

Lower the cutter deck to its lowest setting. Look under the mower, at the rear of the cutter deck and find the rear hanger. Remove the R clip that retains it and swing out of the way of the belt.

Loosen all 4 engine mounting bolts (13mm). The engine needs to move towards the rear just a little. Remove the drive belt from the engine pulley.

At the back of the mower, you’ll see an inspection plate with 2×10 mm bolts. Remove the bolts and the cover.

Lift the seat and the flap that covers the hydro drive. There are 4×13 mm bolts holding the perforated steel fan cover which Cox call the “PTO Sub Assembly” ( 1 below). Remove all 4. The left and right “belt guides” ( 17 & 18 below) will probably fall away. The 4 bolts screw into these.

You should now be able to remove both belts from the PTO Sub Assembly pulleys and remove the PTO Sub Assembly from the machine.

6/ Remove the belt. You’ll notice a couple of bent metal belt keepers at the deck pulley, that might hinder removal of the belt. I used a spanner to just bend them out of the way enough to get the belt off.

7/ Replace with a new belt and perform all the above tasks in reverse order.

I did this on a hot day, out in the sun. I was used to changing the belt on Husqvarna and John Deere mowers previously, both of which were a 10 minute job. It’s not so straight forward with the Cox, but in its defence, it has done a fair bit of mowing on pretty rough grass over the last 18 months and this is its first belt change. Good luck.