Trail Gear knuckle rebuild

[ModelMakerMan]

Im finally getting round to rebuilding the hubs and swivels on my KZJ70 with the parts I picked up from Trail gear whilst in the US last year:


The parts I got were:
Trail Safe Dual Lip Inner Axle seals - Supposedly better than OEM
Trail Safe Knuckle Ball wiper seals - Replaces the standard rubber and felt ball seals
Rock Rings - Replaces the metal rings which hold the rubber and felt seals on the back of the swivel
Creeper Breathers - An ingenious way of making your axles a completely sealed unit
Rock Assault Trunion bearing eliminator kit - Replaces the swivel bearings with a greasable king pin system. Kit includes a knuckle rebuild kit with all seals & gaskets etc.... more on this later

Ive also bought:
A load of high spec Silkolene waterproof red grease
Oils to replace those in the diffs, transfer and grearbox
New Koyo Wheel Bearings
Needle bearing upgrade to replace the brass bush in the spindle

So first the boring messy bit, the strip down. Im sure youve all seen/done a knuckle strip down so Ill let the pictures do the talking:





















So there you go one hub and knuckle strip down, well two actually but they are both the same pretty much.

FYI. The colour of the grease in the hubs isnt actually that bad as the grease I used when I last rebuilt the hubs (didnt do the swivels at the time... kind of wish I had now!) a couple of years back was a special water resistant grease which is a dark green/grey colour.

Onto the inspecting the damage:

Bearing (hehe!) in mind that there was no real signs of wear and tear/damage other than slightly leaky swivel ball seals and ingress of grease in the diff oil ie. the steering felt smooth and there was no signs of play I was surprised to find both lower swivel bearings were fubar!:

Offside

Nearside

The top bearings were worn but otherwise intact but the races top and bottom on both sides were a bit of a state:


Offside


Nearside
There were no shims at all on any of the bearing caps either which I thought was weird?

The knuckle balls were quite pitted but what I hadnt noticed till I got them stripped and cleaned was the relatively deep wear lines:



Pretty sure this must be due to the lower swivel bearing failures. There must have been some play there to cause this kind of wear but Im pretty thorough and check for play regularly and never found any excessive play. It hid it pretty well. Anyway I have a plan to remedy this situation. All will be revealed later.

Finally the CVs and shafts:



Offside
Pictures of Nearside to follow but its pretty similar if not slightly better.
Obviosly there has been some water ingress at some point and there is some surface rust on the exterior of the CVs but its nothing a little scotch pad wouldnt sort out and it doesnt seem to have got into the inner or ball bearings. Ill strip, inspect, re-build and re-pack the CVs to make sure everything is ok. Im thinking of swapping sides too. Is this a good idea?
Not sure how bad this wear is tbh as Ive not seen anything to compare it with. Any input welcome. I will be replacing the brass bushings with the roller bearing upgrade so dont think the wear on the CVs is too much to worry about?

And now onto the rebuild:

When I bought the Trail Gear Trunion Bearing eliminator kit they didnt have any information saying that the kit wont fit standard steering arms (they have since put this on the website). Im not too bothered as I have access to a machine shop to do the relevant mods to make them fit. My thinking behind fitting the kit is that it should be far stronger than the OEM bearing setup and if greased regularly with good quality grease should outlast bearings by a long shot meaning I hopefully wont have to do this job again (Please! ).

Here are the bearing eliminator king pins/swivel pins:

Next to the OEM steering arms (one is already at work ready to be modified):


As you can see the swivel pins need to be pressed into the steering arm caps so what will need to be done is chop off the bearing spigot and machine it flush then bore out the centre to allow the swivel pin to be pressed in.

So thats it for now. Going to be a busy few weeks. Any input welcome, this is the first time Ive done a knuckle rebuild (by the looks of it the first time anyone has on this truck!) and of course Im making it more complicated thatn it needs to be but thats just me; why rebuild it with the same stuff that broke in the first place when we can make it better .

Need to get all this done before Lincomb.

 

[hairyguy4]

with the lack of shims on the knuckles worried me aswell but did some asking around and every kzj70 owner I asked said theres had no shims either? must be designed that way?

 

[Ben]

Great thread Dave.

There were no shims on my 70 the 1st time I stripped the front axle either.

Hoping to rebuild my front axle over the next week or 2.

 

[Victor]

I had shims on my -87 lj70 when i stripped it down..

 

[ModelMakerMan]

OK quick update; a bigger update will come after this weekend once Ive finished refurbishing the swivel balls:

Those of you who have seen Ben's build thread will see that both Ben and I made the same mistake in assuming the axles on HiLux and LJ/KZJ70 were the same. Unfortunately this isnt the case so the Trail Gear swivel ball wiper seals and inner axle seals dont fit . Time to source OEM parts then! Ill have to try and sell on the seals to someone with a Hilux. Fortunately the Trunion Bearing eliminators do still fit the the machining of the steering arms continues and Ill update the thread once they are further along.

Stripped down the CVs today. Having only ever seen exploded CVs Im not sure what counts as acceptable wear:
Offside:

The ball bearings are pitted but still round and the pitting hasnt made the balls rough...if that makes sense? Ive orientated the balls showing the worst pitting so the pitting isnt as bad all the way round.







Nearside:

The ball bearings on this side are better than the offside but still slightly pitted.






So whats the verdict? Im really hoping Im worrying over nothing and everyone will say they are fine so I can re-install them as I cant really afford the expense of two new CVs on top of everything else and Im pretty sure if I do need to replace them I wont be able to get it finished before Lincomb.

 

[Roger Fairclough]

Hi Dave.

The wear mark on the swivel ball is normal and is the result of grit getting under the seal edge and rubbing on the ball as you do slight steering changes in normal driving.

If the tracks on the CV joints are stained as against worn, then try changing the ball bearings.

Roger

 

[ModelMakerMan]

Swivel balls refurbished :

Start with a before picture:



Make sure to remove any trace of dirt, grease and oil from the balls before you start. I used copious amounts of tissue and brake cleaner remove the worst of the grease then used a blow torch to heat up the balls and burn off any grease/oil left in the pitting and trapped in the bearing races (obviously best the drain the oil out of the axle before you do this!) then finally wiped them down with thinners.


This is what I used to fill the pitted holes and level out the worn sections. Its really useful stuff, its basically an epoxy resin with metal particles in, once cured its hard as nails but still easily sandable. FYI this can be used to fill parts which you will be powdercoating where normal filler wont work.


Its really difficult to put a smooth even layer onto a spherical object. The first coat was a bit thick and uneven.


I used a file to remove any excess and high spots then sanded it back with 120grit paper leaving just the low points with the filler in.


The second layer went on a lot more even as I worked out the best way to do it was to use an artists flexible pallet knife and flex it round the curve of the sphere. I then sanded this layer back with 180grit leaving a very thin (almost translucent) layer over the entire surface of the ball.



Then gave it a coat of acid etch primer. This should only be a very thin layer but the acid etch helps the adhesion of the next layer of paint to the metal substrate.



First coat of 2k high build primer. 2k is a polyurethane catalyst cured resin so once its cured its really tough BUT its incredibly bad for you so always spray in well ventilated areas and always wear a decent fitting respirator with the correct filters.



Wet sanded it back with 400grit being careful not to sand through the etch primer layer.



One final coat and there they are good as new!

Just need to knock out the old bearing races and fit the races for the trunion eliminators.


Had a fun day cleaning and degreasing all the parts in between sanding and waiting for paint to dry. I now stink of petrol and so does my garage!

Should get the steering arm machining finished one evening this week then I can start rebuilding it all. Problem is most evenings are booked up with training for my kayak coaching and the next free weekend I have is the one before Lincomb... going to be tight this one.

 

[BRE Fabrications LTD]

That looks really good! What a great idea.

 

[ModelMakerMan]

Finished machining the bearing caps/steering arms!



Got busy with the hack saw and cut the bearing pins off


Mounted them in the mill vice using a DTI clock to ensure they were flat, level and square in the vice (got them all to within 0.02mm) then machined the faces flat but making sure to remove as little material as possible (0.05mm at most). I then used the DTI to find the exact centre of the machined face and drilled a pilot hole using a centre drill the opened the hole using a series of increasingly larger drill bits and finally a reamer to get the perfect toleranced fit for the trunion eliminator pins to fit into. I then pressed the pins into the caps/arms using a hydraulic press.


And here they are fresh from the machine shop.

 

[ModelMakerMan]

On to the build up now then:

Knocked the old bearing races out of the swivels using a drift



Pressed the trunion eliminator races in using the seal/race installation tool and a copper hammer



Installed new oil seals


Cleaned and treadlocked all the steering arm/bearing cap studs and holes and re-installed the studs into the hubs




Trail Gear supply the trunion bearing eliminators with these low profile grease nipples which require a needle attachment on the grease gun.


I dont have a needle attachment for my grease gun and Id prefer to keep all the grease nipples on the truck the same so I can quickly whip round with the same gun so I swapped them out with standard Zerk fittings. They stick up (or down) less than the studs/nuts on the knuckles/caps anyway so I dont think them being a little higher will be a problem really.


Tested the grease nipples out



Now comes the long tedious bit:

I greased up the swivels and races and installed the knuckels onto the swivels and fitted the steering arms and bearing caps with the eliminators. I measured the height between the bearing face and mating surface on the
lower steering arms before machining them then compared that to the measurement with the eliminators fitted. There is a 0.5mm difference so I installed 0.5mm shims between the knuckle and lower arms to compensate. This should keep the axle shaft central in the housing and seal.



I then started the tedious task of setting the preload using shims between the knuckle housing and the top cap/arm. This took a lot of time adding or removing shims, tightening and torquing bolts, measuring the preload and taking it all apart again to add or remove shims again. I now have a deep hatred of cone washers!




I ended up with 1.75mm in the Offside top with 8kg preload and 1.7mm in the nearside top with 6kg preload. Trail gear specify preloads between 7kg to 11kg but after reading a few threads on other forums about the eliminators it was advised that 4.5kg to 8kg gives best results. The eliminators are a bit of a pain to setup and a 0.05mm makes a huge difference; for example the offside had a preload of 11.5kg with 1.75mm shims but switch out to 1.7mm out and it went down to 6kg!

So once all preloads were set I threadlocked all the nuts and torqued them up.




Ill get the rest of the build up later this week.

 

[Ben]

Great update Dave.

 

[ModelMakerMan]

And finally:

Bolted up the swivel seals


Rebuilt and repacked the CVs with grease, installed the drive shafts with new snap rings. NB: I swapped the CVs around so the Offside one is now in the Nearside and visa-versa. The wear on them didnt seem too bad to me and they weren’t making any noises prior to this rebuild so I think they should be fine. Ive heard swapping them is a good idea to get extra life from them as it evens out the wear on the surfaces.


The reinstalled them into the axle and packed them with grease



Used a bearing puller to remove the old brass bushes from the spindles



Then pressed in the needle bearing upgrade making sure the bearing was fully primed with grease


Followed by the brass flange


Greased up the flange, bearing and inside the spindle, installed a new gasket


As well as a new gasket and hub seal on the brake sheild


And bolted it all up


Installed new bearing races, bearings and seal to the hub and greased it all up






The bolted it up and set the preload using Julian V's method


Rebuilt and installed the free wheeling hubs and brake callipers


Re-connect steering and relay rods, all the brake lines, bleed the brakes refill axle with oil then its all done!

One thing I did notice when re connecting the brake hoses was the top grease nipples for the trunion bearing eliminators were obscured by the brake hoses making it very difficult to get a grease gun in there so I switched them out for some 45° angled ones


Took the truck for a test drive today and the only issue so far is the steering feels a little vague in the straight ahead position and it is not returning to centre very well (it never has returned to centre that well since I lifted it but its now a little worse).I think I need to have another play with the shims and see it I can lower the preload in the offside knuckle to about 5-6kg.

Also the steering went a little vague when I fitted the lifted suspension but it wasnt too bad, I intended to fit some castor compensation bushes to hopefully rectify this but I havent got around to fitting any yet so maybe this will help too?

All in all its not been too difficult a project and with a little more fiddling with the shims and preloads I think I can get it setup so no one would be able to tell the difference between my truck and an identical one with the standard bearings BUT as long as the eliminators are greased regularly (every 5000miles or so) they should last longer and be much stronger than any bearings.

 

[Roger Fairclough]

Without the castor correction bushes, it's likely that your steering will feel vague.

Pedders do a bush that is styled on the original type i.e. properly moulded rubber.

Roger

 

[Ben]

Nice work.

Whats Julian V's method for setting bearing pre load? Have you got a link?

 

[ModelMakerMan]

Here you go Ben: Julian V's Method

@ Roger; I saw the rubber Pedders bushes a while ago and those are the ones Im planning to fit as they look like they are well thought out and designed for purpose rather than just a urethane puck with an offset hole like some of the others.

 

[Ben]

Thanks.

Just spotted your signature. WTF?

 

[ModelMakerMan]

Just spotted your signature. WTF?

Yeah Ill put a post up in the for sale section once Ive got everything working properly. Its similar to Jimbo's reasons really; recently bought a house and I have too many hobbies and not enough time and money so sustain them all. Ive got massively into kayaking over the last couple of years and I spend most of my time and money on that so the Cruiser sees little use (mainly Lincomb, couple of green lane trips and a week or so of snow a year). Out of all my hobbies the Cruiser is the one that I spend the most money on and use the least so logically its the one that needs to go.

Im not enthusiastic about selling it and Ill only sell it to someone who will look after it, continue the project and use it for what it was built for. I know what its worth to me and Im in no rush to sell so Im happy to wait for the right buyer and finish off a few little tinkering bits in the meantime. Ill be very sorry to se it go and I know I will miss it (especially when Im at Lincomb cooking and watching everyone else) but Im sure Ill get another 4x4 at some point in the future when funds and time allow.

So if anyone knows of someone looking for a KZJ70 then without blowing my own trumpet I cant imagine youll find another in as good mechanical condition. There are a few bits of rust on the body in the usual places but nothing someone with even basic fabrication skills couldnt sort out in a couple of days.

Anyway this is turning into a for sale post now so Ill leave it there. Dont worry Im not going anywhere even if my truck does.

 

[stumog]

shame its a lovely one should try to keep hold of it. I cant see my wife driving it to work though.
stu

 

[Ben]

Good luck with everything Dave. I'm glad you will still be sticking around.

 

[Macc_70]

Dave - I'm on the rebuild phase for my kZJ70 after following your info, which has been a great help. I do have a question regarding the often controversial correct fitting of the birfield components, specifically, the cage orientation. My cage looks identical to yours having the six holes that help contain the ball bearings and the long axis sides of each hole have a slightly different shape, one side flat the other is more curved in at the corners / oblong shaped. My question is, did you fit the cage in the birfield with curved cage holes side facing out towards the wheel or in towards the diff? There's little difference in measurements of the so called thin/thick sides of the cage between the six holes long axis and outside of the cage and also the diameter of the two large holes through which you insert the star / race. The curved side was facing the diff when I took it all apart but the star / race was in the wrong way round so I'm not too confident that it was assembled properly in the first place. Regards