This week I am looking at the renewal of the wheel bearings, followed by the replacement of the stub axles on the old Snipe trailer. This model trailer had a transverse leaf spring as its method of suspension.
What I need is not just another pump of grease into the hub but to totally dismantle the hubs and tapered roller bearings. These bearings are a standard 1 inch stub axle with a taper so they can be adjusted by tightening up the ‘Castellated’ nuts which pushes the hub and bearing further onto the tapered shaft.
For this procedure make sure you have sufficient supports under the trailer when the trailer frame is jacked up. With the wheel off it’s then a straightforward process to remove the grease cap. This is where you will find the only nut that holds the hub together. The Castellated nut will have a split pin through its recesses. With this pin removed the nut will be easily wound off and then the hub complete can be pulled off.
With a little bit of cleaning we now have the old hub, bearings and tapered rings all quite worn. The option in this instance is to re-use the existing hubs and fit a new bearing kit, all readily available and not expensive.
The existing hub should be thoroughly cleaned in Paraffin with a small paint brush and dried with paper towel. Next you will no doubt notice any marks on the stub axle. This stub axle is a model with a rubber Indespension unit rather than my old Snipe trailer with a leaf spring and it’s bolted on stub axles. I have used a very fine Emery Paper to remove these marks, if one has ‘Score’ marks or ridges on the stub axle then you do have a problem and the stub axle and it’s complete rubber suspension unit will have to be changed.
However, the hub now is ready for the initial grease to be pumped in very lightly then slide the hub back on the shaft, then its large washer and castellated nut. It’s best to fit the wheel now before taking up the slack in the bearing. Lightly tighten the castellated nut and spin the wheel so it beds in. When it gets to the stage of a resistance and drag being felt, stop and fit the split pin through one of its external recesses. Complete the other side of the trailer, pump a good waterproof high resistant grease and take the boat trailer for a drive over several miles to bed the bearings in.
On return, jack up, take the grease cap off, remove the split pin and re-tighten, you will find the bearing has got a little slack. This can be checked by flexing the wheel from side to side; it’s good when there is no play in the wheel in the axle.
As an alternative to re-building the hubs with a bearing kit one can purchase a complete hub with fully fitted bearings. For Tiki I have opted for the new fully assembled hubs with the new stub axles, it’s a long tow down to the Greek Ionian Sea in mid April!
These Snipe trailers with the heavy transverse leaf springs (as opposed to the present Indespension compressed hard rubber units) I find are a much softer ride for the boat-laden trailer. The later models tends be a very hard bumpy ride and moreover it’s impossible to see inside these rubber units as to their state of ‘Compression’, very important in monitoring their state of road worthiness.
With the trailer fully jacked up and supported on axle stands, Steve my metal fabricator had the road wheels off and hubs removed exposing the stub axles. Then the matter of grinding off the old mild steel nuts which allowed the removal of the three bolts and the stub axle from the end of the spring.
The offending original stub axles were bolted on with mild steel M10 bolts and consequently the nuts were very badly decayed. Once ground off the bolts were easy to remove. With the stub axles removed I now have the end of the spring to check and clean. They are heavy duty 12 mm leaf springs and these are in good order. Do not be misled by the dull colour of these springs. In the high temperature process that’s needed to produce a spring from standard mild steel the colour and nature of the spring changes.
The old stub axles were a much lighter section to the new ones and from these original ones Steve was able to copy the hole positions and spacing onto the new axles. They were not in as bad a condition as I expected and with a clean up and new bolts would have been roadworthy for standard use and distances. However, with the 1850 miles in 5 days I felt it prudent to be safe rather than chancing it.
These bearing were certainly bad. The outer needle roller bearing was heavily marked and scored and evidence that salt water had entered the hub with deterioration of the cage that held the bearing together. The inner bearing on the right was in very much the same poor condition.
Both needle roller bearings travel up against the inner ‘Race Sleeve’, these surfaces were also badly marked and ‘pitted’. As a comparison this is the new hub showings its inner ‘Race Sleeve’.
This layout is the complete kit required to change the stub axles with bearings and new hubs. Not an expensive task but one which gives peace of mind when towing one’s beloved Drascombe to the waters edge and another adventure.
Returning briefly to the initial removal of the hub, firstly take out the split pin that holds the castellated nut on the shaft. Then you are able to wind the nut off the shaft followed by pulling the hub with bearings off the shaft. There are times that the bearings might be very firm on the shaft as I experienced on this one where the inner bearing was left on the shaft.
Returning back to the new hubs, with the bearings inserted I’m able to slide the hub unit onto the main shaft, place the outer large washer on before winding on the castellated nut.
With the nut on to a pressure that the hub is a firm fit but not locking the hub from rotating, grease is pumped in via the fitted small nipple. This nipple is also used to periodically top up the grease.
For the moment this is enough grease when it shows at the front of the hub and I can fit the grease cap to cover the bearing. With the wheel fitted, and from the back one can see the new stub axle and hub, a much healthier look compared to the old unit.
The final stage of adjusting the bearing I cannot document this week, I will have to take the trailer and boat for a 5 mile or so drive to bed in the bearing on the shaft. The process then is to re-jack up the trailer so the road wheel clears the floor, remove the grease cap and tighten the shaft nut. The tension one needs is to be able to spin the wheel freely and by checking the lateral play in the wheel for slackness – that’s from side to side. Once you have the right balance the split pin can be inserted.
For my trip to Greece I will repeat this last process of taking the trailer on a short road trip and another bearing adjustment. Again I must emphasise that this checking of the bearing tightness should be a regular consideration. Before leaving in April I will be applying more grease to the hub and with travelling over 380 miles each day I give them a short pump with the grease gun each day.
I do hope this has helped cover a topic that is very rarely mentioned, yet it’s so important for the safety of yourself, your boat and other road users.
My very best in you ongoing maintenance work on your Drascombe boat