Post #9 by Ericn » Sat Jul 11, 2020 2:09 am
Hi all, just updating this thread, I decided to tackle the halfshafts and try and fix the leaks on our jcb 3c mk2 10 speed manual, I dissasembled the left halfshaft today after removing it from our jcb yesterday, overall the job wasnt too bad however it does take some time and patience especially in removing the 3 bolts that hold the chassis to the half shaft housings, these bolts are 1 1/8'' and I had to use a torque multiplier and large 1 inch drive socket to break mine loose, removal of the floor panel was necessary to gain access to the halfshaft housing bolts, there is also a spring connected to the bottom of this floor panel only visible from underneath the machine so you must undo that before attempting to lift the panel out, you will also need to remove the brake unit housing if you want to remove the halfshaft housing to give you enough clearance between the chassis and gearbox to disengage the spline drive shaft from the differential in the gearbox housing, I ran into trouble with seized clevis pins on my brake unit which wouldnt allow me to remove the brake actuator from the housing so I had to completely undo the brake adjuster nut and disconnect the actuator from the pedal and linkage that way, a 19mm spanner fits this nut, do not breathe in dust from your brakes, I wore a respirator when doing mine as it was full of dust, it wouldnt be a bad idea to wet it down with a spray bottle of water to prevent rising too much, inside the brake unit there bolts which hold the brake unit housing to the gearbox, remove these and be careful when lifting the housing off past the splined shaft as there is a oil seal pressed into the housing which could be damaged if handled roughly, after removing the brake unit and chassis/halfshaft housing bolts, I used a block and tackle slung from a steel beam ran accross both sides of the chassis to support the half shaft housing, it is very heavy i would guess around 100-120kg with the halfshaft installed in it and it would be wise to have 2 people for the hoisting out procedure, 1 person inside the cab undoing the housing to gearbox bolts (15mm bolts if i can remember correctly) and guiding the halfshaft out and the second person near the wheel hub, we used a strap to support the outer end of the halfshaft housing by wrapping it around the beam of steel overhanging the mudguard that the block and tackle inside the cab was hanging off, as our gearbox had leaked most of its oil out it wasnt necessary to open the drain plugs on the bottoms of the halfshaft housings to drain the gearbox oil however if your gearbox is fairly full of oil get 2 25 litre drums to drain off your gearbox this will remove most of the oil, after removing the halfshaft housing to gearbox bolts working my way from the bottom of the housing to the top after removing the bolts i used the 2 threaded holes in the housing and 2 of the bolts i removed to jack the housing from the gearbox, these may be full of dirt/grease so make sure to clean them well with a pick or something similar to avoid damaging the threads, abit of grease on the bolts helps too, you should be able to jack the housing out nearly half an inch and then the bolts will get tight, this is the bolts bottoming out in the threads, back them off and put a jaw of a big spanner between the bolt and housing to act as packing and repeat this for both jacking bolts alternating between the 2 until the housing comes about an inch out from the gearbox, use a pry bar with some tape wrapped around the end to prevent damaging the mating flanges of the gearbox and housing to encourage the spline drive shaft out of the gearbox, the bearing it runs through is self aligning which does make this process slightly easier but care must be taken not to pinch shaft against the outer bearing race too hard, its diffcult as the housing is top heavy and wants to fall towards the back of the tractor, lower the outer end of the halfshaft housing down slightly and pull outwards and downwards guiding the splined shaft out through the cutout in the chassis as you pull the housing away from the gearbox, the differential is supported inside the gearbox by carrier bearings and wont fall out of alignment, and thats the removal process that worked for me anyways! dissasembly of the halfshaft housing wasnt too bad, I included some photos above, to remove the halfshaft remove the cotter pin and nut (mine was handtight) roughly mark where the nut was for bearing preload on re assembly, the driven gear is supposed to go on one way, the inner splines extend more on the side towards the gearbox, my inner bearing wouldnt just slide off so i removed the 3 bolts holding the halfshaft outer cover to the halfshaft housing (put a small file mark or cut to the cover and housing to make sure its clocked at the original position when re-installing) i used a small hammer and loosened the cover with a few taps then beat the back of the halfshaft flange to remove the shaft from the housing, when doing this, make sure the large nut that was cotterpinned on the halfshaft is loosed off to near the end of its threads, this allows you to pull the shaft out enough to allow the inner bearing to fall free however prevents the bearing from hitting the floor, when pulling the halfshaft out take care not to bang it against the bearing cones in the housing, i used the youtuber Montegosons method of removing the halfshaft outer bearing and seals shown in his video about leyland/nuffield halfshaft seals and it worked like a charm using a chisel and small hammer the bearing was removed and in re-usable condition and the wear ring was removed shortly after, see pictures above where the oil seals had worn a groove in mine, there are 2 types of these wear rings as far as i know, a 41mm wide one and a 44mm wide one, i measured mine after removal it was around 43.6mm so im assuming its the 44mm ring my halfshaft takes, they're around 30 pounds excluding vat and shipping, for anyone wondering the both the inner and outer halfshaft support bearings are the same, I cant remember the part number off the top of my head but if anyone wants it feel free to ask and il find out for you, sorry for the long post, I thought a detailed description of the whole process would be handy for anyone wanting to attempt this process, the torque multiplier i mentioned above works brilliant for removing the wheel studs and without it i dont think i couldve removed the chassis bolts without it, i picked it up on ebay for around 60 euros new and another 30 euros for the dog of a socket you need for the nuts on the bolts, hope this guide helps anyone attempting to remove the housings, il post back here with an installation guide once ive put it back together, feel free to ask any questions below and il try my best to answer them
on our jcb the gearbox was dry when we bought it, the original owner said it wasnt holding oil, the seams where the half shaft housings mate against the differential housing look caked in oil/dirt and appear to be leaking from the gaskets there, my question is has anyone ever replaced the half shaft housings on a 3c mk2 and if so is it a very difficult job requiring special tools? is it necessary to open up the transmission brake packs to disconnect or remove anything before pulling the housings or would just removing the half shaft retaining nut and half shaft housing nuts allow removal to replace the gaskets? 
