Trailer Disc Brakes & Wheel Bearings

[Mik]

Next is to replace the grease cap. There are a multitude of different grease cap configurations out there, so if yours differs from what I'm showing here you may need to speak to someone else to get the low down on yours if it proves to be tricky.

Mine is a knock in type with a spring, seal arrangement (Rubber disc & 1 O'Ring) grease nipple & plate and one circlip.

Remove the circlip (Once you have the pliers engaged, place your free hand over the assembly to prevent the circlip flying off into outer space if it slips from the pliers)

Pull the spring out & the seal / disc. The seals are in two pieces on mine, make sure you remember which way they came out. Give the whole thing a good clean & inspect the seals. Replace them if required & also the spring & circlip if they are affected by rust.

Reassemble the unit & pop it back onto the wheel hub.

Giving it nice gentle taps insert the cap back into the hub. Keep it as straight as possible.

Clean off any muck & pump some grease into it. Once you see the disc being forced outwards thats enough grease.

Now you can replace the rubber or plastic cover cap & tape it up.

TIP – Apply the tape in the opposite direction to the forward rotation of the tyre. This will help keep it in place rather than the wind getting under the end of the tape & unravelling it on you.

Right, the new pads can now be fitted.

Put the push plate back in. Holding the calliper up so that the lever arm allows the push pad to be fitted flush inside the hole. Then fit the new pad in reverse of taking them out.

Now, this next bit is kinda tricky, watch your fingers as you do this, blood on the brake discs isn't good for them.

Before you start, clean the calliper bolt threads with a wire brush & apply some anti-seize. This stuff is available at most hardware stores, grease is nowhere near as good. Its also a good idea to put some on the bolt sleeve / spacer. The trick with anti-seize is to apply it with the brush the wipe the excess off with a rag. Too much is just plain messy & it does sometimes cause a hydraulic locking action in the bolt hole, making things difficult.

NOTE – if you value your marriage take care NOT to get this stuff everywhere, it really does get onto everything.

As an example. Once on a remote construction site we were told that anti-seize was banned from site (Dunno why, they just didn't want to use it) so all bolts went in dry. We snuck a bottle into camp & did a little test / bet. We put one dob of anti-seize on a handrail on the site (About the size of a 50 cent peice) and then put the bottle in the first vehicle leaving camp. After 3 days there were smudges of silver in the wet & dry messes, in the showers & toilets of the camp and the silver team (Betting group) scored $10 for each mark we found away from the site. I think we ended up with about $140.

Keeping the pads apart, slip the calliper assembly over the disc. Start at the bottom & get the disc between the pads. Once you have it started it should slide on fairly easy. Just keep checking that the push pad is in its right place as you go.

Now, before you go anywhere, double check that the brake arm lever & cables are in the right position & not tangled around anything. Unless there is some damage to the cable it doesn't need to come off during disassembly.

Now, by rotating the calliper around the disc slightly, you can fit the spacers / sleeves to the calliper bolt holes, then add the bolts. Some callipers may require you to fit these BEFORE you fit the calliper to the disc or you can't get them in. If that's the case you need to make sure the bolts are inside the holes only enough to allow the calliper to be fitted & not foul on the disc.

Tighten the bolts & give everything a good shake. The calliper should have movement when the bolts are tight. That's normal. Give the disc a spin & ensure things are free. Remember the bearings are still tight, so this will hold things a little, as long as the pads are not locked to the disc your all good.

Now fit the return spring to the arm. This can be a difficult job in confined quarters, if its at all possible fit the spring before you fit the calliper to the disc, but I have found most cases this isn't possible because the spring just keeps falling out.

Adjust the brake arm lever until the arm only has about 5 to 10mm gap. If there is no gap the brakes will be permanently on & your lovely new discs will be dust in no time.

OK, replace the wheel, give it a spin & your done, all that remains is brake adjustment.

Drop the trailer off the jack & give each brake lever & wiggle to ensure they have movement. Now tighten the cable at the front adjuster until the cable has only a slight sag in it along its full length. Test it by pulling on the hand brake. It should pull up firm well before the hand brake lever is at full stroke. It should also fall slightly slack again on release of the hand brake. Handbrake movement should only be about 10-15mm max.

Double check the adjustment by measuring the gap between the inertia pin at the front (Tow hitch end) and the gap between the handbrake & the inertia pin end. The gap at the front should be more than the gap between the handbrake o0r the brakes won't apply when the pin is pushed backwards by inertia. As you can see, mine needs a little more tension on the cable as the handbrake gap is too much.

That's better.

Now you can grab your man balls in one hand & grunt. (Clean you hands first, a big greasy paw mark on your crutch make start some rumours in your neighbourhood)

Take the trailer for a quick test spin round the block. Check the brakes at low speed. A good way to test that they come on is to reverse a little without the reversing plate on the inertia pin being flipped over. The brakes should come on & your all sweet.

Now, take a drive at low speeds (under 60klms) for a few blocks, then return & quickly check the temperature of the wheel hubs with your hand. There will be some heat there but it should not be so much that you can't keep your hand on the hub. If you touch it & immediatley have to remove your hand (Unless your a real girl, in which case congratulations on getting this far at all!!!) then the temperature is over 80 degrees. Whilst that may be normal for a hot summers day after a 1000 klm trip, its not for your little test drive. If its really hot or god forbid, smoke is coming off the assembly, you need to back the lock nut off. If it continues to get hot then you'd best strip it all back & start again.

Hopfully it all went smoothly & your ready to brag to the missus that you won't be able to do the ironing from now on as you have man things to do.

Good luck & tight lines (Fishing lines, not brake lines!)

[Chris 55]

Excellent article Mik

nice to see you passing on the secret's of the shed

bearing blue on the ear piece of a phone is fun too

BTW do you still have Fanta Pants or has she been passed over

after you upgraded

Chris

[Mik]

Ah good 'ol Fanta, she rests quietly under the house.

The day one of my sons asks to take Pog out on his own is the day I say, "Mate, your boats under the house, get to work!"

[1975]

thanks for that

i'll try it at the end of the season.

billy

[yockman]

Best write up on this I've seen - top stuff.

"Smack it like you'd smack Bin Ladens head"

[GordoRetired]

Was "Googling" for info and came across this article. Thanks for taking the time to write it up, I have read through it a couple of times and am now 1/2 way through putting new bearings on my trailer in preparation for a drive down to Jindabyne.

Reading through gave me the confidence to do the job myself rather than pay someone. Thanks again.

 

Update: Job now finished. Took the rig for a 45k run to make sure everything was OK. When I got home one of the bearing buddies was too hot to hold so backed off the nut 1 notch.  When I tried to move the wheel there is no play, all seems nice and tight and turning smoothly.

Now sitting with beer in hand while typing this update.. Cheers :-)

 

Edited May 6, 2018 by GordoRetired
Update