LJ70 Build Thread!

[Ben]

Thanks Patrick.

 

[vegarwe]

Hello Ben.

First of all I want to congratulate you on an excellent thread an a great truck. I found it late and has been catching up during slow hours at work for months now (too few slow hours unfortunately). Nice job with the roof change. I had some problems with my own truck (see pic) and I just didn't dear straighten and weld it. So I bought another LJ70 with a faulty engine and just swapped over all the good parts from this one.


I've been meaning to ask about you experience with tires and tyre pressures and then I read this it gave me the perfect opportunity.

After struggling to get up the small rock steps I stopped and dropped all the tyres down from 35psi to 20psi. This meant the 12.5" wide tyres were now a few inches wider, giving me a nice big 14-15" wide foot print in the snow.

What is the deal with 20psi? I only offroad in Norway where there is a lot of snow, so maybe that's what's different. But here we typically air down to 8-10psi. In cold weather and light snow we often go down to 6psi and on my bead-locked 33x12.5 R15 I have gone as low as 3.5psi without problems.

What's your take on air pressure?

 

[vegarwe]

While packing my workshop up today I came across the damaged front ARB locker.

I intend on going to their head office in Melbourne with the damaged locker. I will explain to them that both the front and rear lockers have been fitted exactly to their instructions and both times the pinion has then hit the ARB locker causing damage.

I've seen the same kind of damage on at least three other ARB lockers mounted on LJ70. Seems to be rather typical and probably why ARB recommends grinding down the pinion wheel. But as Roger said, I don't like the idea of having to grind it down:

I do not like the idea of grinding the pinion teeth. Once the teeth on the pinion are machined, they are case hardened. If you then grind away part of the tooth, you destroy that area of the case hardening

Seems you have to be very careful not to heat up the metal too much and destroy the hardning.

 

[Ben]

Hi Vergarwi,

Thanks.

I could have bought another 70 here in the UK and swapped everything over, but.........................

Almost all the 70's for sale in the UK would have had rusty rear arches. So then I would have been back to cutting all the rot out, importing new panels from Germany and then spending weeks cutting and welding new panels in.

So I decided the easier and better option would be to change the roof.

I'm very pleased with how its turned out.

Apart from the seem of weld below the windscreen that still needs grinding down, filling and painting, its not easy to tell the roof has been changed. Its an almost invisible repair!

Tyre Pressures.

Tyre pressures are something that I think a lot of people overlook when off roading in the UK. The ozzies seem pretty clued up on it and seem only to quick to stop and drop the tyres a bit more. But here in the UK most people simply dont bother. They run road pressures all the time and never bother dropping them when they go off road.

In fact I'm sure a lot of them dont even bother checking their pressures very often/ever.

My suzuki mates who I go green laning with never drop their tyre pressures, the guys I was out with this weekend, didnt bother dropping theirs, people just dont seem to bother over here.

But I know it makes a huge difference!

Not just in sand or snow but in most off road situations.

I've always found in the UK if I drop below 10-15psi I often start rolling the tyre off the rim.

Of course bead locks would sort that, and thats something I will be looking at in the future.

ARB air lockers.

ARB only recommend grinding the pinion if you havnt got the clearance that they specify. When my locker was fitted we had more than the specified clearance. So as far as I am concerned the ARB instructions are wrong in that the clearance they specify isnt enough.

 

[Paddler Ed]

Hi Vergarwi,

Thanks.

I could have bought another 70 here in the UK and swapped everything over, but.........................

Almost all the 70's for sale in the UK would have had rusty rear arches. So then I would have been back to cutting all the rot out, importing new panels from Germany and then spending weeks cutting and welding new panels in.

So I decided the easier and better option would be to change the roof.

I'm very pleased with how its turned out.

Apart from the seem of weld below the windscreen that still needs grinding down, filling and painting, its not easy to tell the roof has been changed. Its an almost invisible repair!

Tyre Pressures.

Tyre pressures are something that I think a lot of people overlook when off roading in the UK. The ozzies seem pretty clued up on it and seem only to quick to stop and drop the tyres a bit more. But here in the UK most people simply dont bother. They run road pressures all the time and never bother dropping them when they go off road.

In fact I'm sure a lot of them dont even bother checking their pressures very often/ever.

My suzuki mates who I go green laning with never drop their tyre pressures, the guys I was out with this weekend, didnt bother dropping theirs, people just dont seem to bother over here.

But I know it makes a huge difference!

Not just in sand or snow but in most off road situations.

I've always found in the UK if I drop below 10-15psi I often start rolling the tyre off the rim.

Of course bead locks would sort that, and thats something I will be looking at in the future.

ARB air lockers.

ARB only recommend grinding the pinion if you havnt got the clearance that they specify. When my locker was fitted we had more than the specified clearance. So as far as I am concerned the ARB instructions are wrong in that the clearance they specify isnt enough.

Couple of other bits to add:

Without some dodgy VIN plate swapping you wouldn't have been able to take it to Aus with you, as you wouldn't have owned it for long enough.

Dropping tyre pressure can also help to reduce trail damage, as the load is spread more and there is less likelihood of spinning due to getting stuck.

Bead Locks are not ADR compliant IIRC... so can't be used on the road (and that includes things like the Canning Stock Route et al, as they are roads, as is the VIC high country trails) which is a bit of a problem!

 

[Ben]

Wrong!

Right!

Wrong!



On a truck with a separate chssis, the identification is with the chassis, not the body.

So you can change the body (well any part actually) just not the chassis, as thats what has the identity.

Dropping tyre pressures does do less damage to the trail.

Not all bead locks are illegal for road use!

You can get internal bead locks like the ones made by Staun, and their fully road legal.

That said their is loads of people running 35"+ tyres and bead locks in OZ. Totally illegal maybe, but people do it and get away with it.

Anyway................................................

Had enough of this bloody freezing weather now.

Another 12 days and I will be in my shorts enjoying the great Ozzy summer!

 

[vegarwe]

Tyre Pressures.

Tyre pressures are something that I think a lot of people overlook when off roading in the UK. The ozzies seem pretty clued up on it and seem only to quick to stop and drop the tyres a bit more. But here in the UK most people simply dont bother. They run road pressures all the time and never bother dropping them when they go off road.

I know it makes a huge difference!
Not just in sand or snow but in most off road situations.

When we get to a snowy and steep uphill I always try different things, one at a time to figure out what works best. 2wd vs 4wd, low range vs high range, airing down and different combinations of lockers. I've found that tire pressure is the most effective measure (after engaging 4wd of course). Lockers do not matter as much as tire pressure for driving on snow.

I've always found in the UK if I drop below 10-15psi I often start rolling the tyre off the rim.

Of course bead locks would sort that, and thats something I will be looking at in the future.

Like this you mean?

I did do that every once in a while when using only 31x10.5 tires. Never been a problem with 33x12.5. I've seen it on other peoples vehicles even with large tires, but usually only during recovery. E.g. with the anchor point for the winch being far right or left, causing much sideways force on the tire. The beadlocked tires of course never seems to come off.

ARB air lockers.

ARB only recommend grinding the pinion if you havnt got the clearance that they specify. When my locker was fitted we had more than the specified clearance. So as far as I am concerned the ARB instructions are wrong in that the clearance they specify isnt enough.

Hmmm, that is definitely something the guys at ARB should respond to then. I'm guessing most people, when they find that kind of damage, think they did something wrong during the setup and blames themselves.

With regards to the crown wheel cracking. That does seem to happen a lot on the 70 series. I've seen at least three broken diffs during offroading. For instance when trying to recover another vehicle by pulling in reverse. The front diff seems to be the weakest, and reversing is most problematic.

You had a theory about the metal from the ARB locker mixed in with the oil in the diff caused your crown wheel to fail, but I'm not sure a buy that. I think it's just a bit too weak for this kind of heavy duty use and will break every once in a while. Trail-Gear to the rescue...

 

[Ben]

Tyre pressures.

I find that very interesting that tyre pressures when trying to drive up snowy hills made the most difference.

We had a lot of problems when we were out this weekend (Hi-lux and suzuki) some of the hills they couldnt get up wernt even off road but tarmac roads with a lot of snow and ice on.

Rolling tyres off rims.

Yes just like that.

Normally its been in mud that I've rolled them off, which then means you cant just blow it back on the rim, youve first got to try and clean all the mud out or else the bead wont seat properly and be air tight.

Trail gear.

Have you any experience with the trail gear stuff, in particular the ring and pinion sets?

If upgrading to trail gear will give me a stronger, more reliable truck then I'm up for that! I'm very tempted to turn mine into a challenge truck and start competing in some competitions.

 

[Graham]

Hello Ben.

First of all I want to congratulate you on an excellent thread an a great truck. I found it late and has been catching up during slow hours at work for months now (too few slow hours unfortunately). Nice job with the roof change. I had some problems with my own truck (see pic) and I just didn't dear straighten and weld it. So I bought another LJ70 with a faulty engine and just swapped over all the good parts from this one.
View attachment 5420

I've been meaning to ask about you experience with tires and tyre pressures and then I read this it gave me the perfect opportunity.



What is the deal with 20psi? I only offroad in Norway where there is a lot of snow, so maybe that's what's different. But here we typically air down to 8-10psi. In cold weather and light snow we often go down to 6psi and on my bead-locked 33x12.5 R15 I have gone as low as 3.5psi without problems.

What's your take on air pressure?

.
Hi,

That truck looked good before the spill.

As far as air pressures go, I was told no less than 1 bar, which is about 14,5 psi.

I don't kow if I would dare let them down to 8 psi to 10 psi.
Also, no unnecessary turns, keep it strait as much as you can.

Gra.

 

[Roger Fairclough]

There is a relationship between tyre and rim width. If you fit a "narrow" tyre onto a "wide" rim, you will have trouble getting it to seat properly and there is a greater chance that the tyre will roll of the rim. Also the tread pattern will be compressed inwards so reducing it's effectiveness. If you go the other way, the tyre will not be supported properly and will have a tendency to sway on the rim. Normal beadlocks only work on the off-side, which leaves the inside edge unprotected. There are inside beadlocks which can be inflated once the tyre is fitted. These effectively force the beads against inner wheel rim. In my motorcycle trialling days, we used metal straps, fitted inside the tyre, to clamp the tyre to the rim. Tyre pressures for a 4X4 do not need to go below 10 psi. Any lower and tyre damage is inevitable. Trials cars can go to 2-3 psi at the back but this is for a big tyre/light car and is not applicable to a heavy 4X4.

I have never needed to lower my tyre pressures for green lane use. If a section is that "difficult" that lower tyre pressures would seem essential, then I would either find another route so that I did not create further damage, or I would winch through. I am not being patronising here but I have seen people powering through sections just to prove it can be done, when a simple and far less damaging winch pull, was all that was required.

Yes, the front diff. on the 70 series is a weak point. The damage on Ben's front, and to a lesser extent his rear ARB diff, is unacceptable and I will be interested in the result of Ben's visit to the ARB offices.

Roger

 

[Paddler Ed]

Wrong!

Right!

Wrong!



On a truck with a separate chassis, the identification is with the chassis, not the body.

So you can change the body (well any part actually) just not the chassis, as thats what has the identity.

Dropping tyre pressures does do less damage to the trail.

Not all bead locks are illegal for road use!

You can get internal bead locks like the ones made by Staun, and they're fully road legal.

That said their is loads of people running 35"+ tyres and bead locks in OZ. Totally illegal maybe, but people do it and get away with it.

Anyway................................................

Had enough of this bloody freezing weather now.

Another 12 days and I will be in my shorts enjoying the great Ozzy summer!

Got meself confussed there... I know that the Chassis number is stamped on the VIN Plate, along with the engine number, hence the expression matching numbers... but how does that relate to the body number (ie a LJ70RV, with the RV denoting RHD and Van doors)?

Hadn't thought of internal beadlocks; only thought of the external ones!

Watch out for the weather; the cyclones are beginning to reach FNQ, so the weather systems are coming back towards "normal" a bit more! Sydney's got Severe Weather warnings for Hail etc... normal Aussie summer then...

 

[Victor]

Gra, i am currently running 35x12.5-15 creepy crawlers on my lj70, on i think 8" wide rims, currently i air down to 0.5 bar and don have any problems... I do plan on getting beadlocks in the future though, just for safety

 

[Ben]

People say that the front diff's are weak, and I've broken a few ring and pinion's.

But why have I never broken a CV or half shaft?

My CV's have been clicking like mad for the past year or 2, and as far as I know they could well be original items so 150,000+ miles old.

I've driven my truck very hard at times the with the aggressive 37" tyres and both ARB air lockers engaged.

Surely an already clicking, worn CV should be weaker than a ring and pinion?

When me an Roger removed my original front diff we found the ring gear had a crack in it. Had I caused that, or was it a faulty ring gear?

Definitely time for an upgrade I think!

 

[Roger Fairclough]

Gra, i am currently running 35x12.5-15 creepy crawlers on my lj70, on i think 8" wide rims, currently i air down to 0.5 bar and don have any problems... I do plan on getting beadlocks in the future though, just for safety

The measuring rim (the size of rim used to determine the size characteristics of the tyre ) for a 12.5" tyre is 10". The permitted rims are 8.5", 9", 10" and 11". By using an 8" rim, you are squeezing the tyre inwards and opening up the tread. This will create tyre squirm on the road but will attempt to stop the tyre rolling of the rim.

Roger

 

[Ben]

I run my 35 x 15 x 12.5 tyres on 10J rims and they usually have to use a bead cheat to get the tyre seated.

 

[Roger Fairclough]

I run my 35 x 15 x 12.5 tyres on 10J rims and they usually have to use a bead cheat to get the tyre seated.

Out in the wilds, you will need a strap around the tyre to compress it before attempting to inflate it. In Iceland they squirt WD40 inside the tyre and then ignite it. This will either seat the beads to the rim or blow the tyre out from the rim. It looks spectacular but it is bloody dangerous.

Roger

 

[Mud_dog]

Ben , I have only ever heard bad things about trail gear, very noisy when fitted and have a habit of braking the r and p's in reverse under load, look up a company called nitro, they cost the same as trail gear but have far greater feed back. Hope this helps and good luck with the move, I would be in oz tomorrow giving the chance to .

 

[vegarwe]

Trail gear.

Have you any experience with the trail gear stuff, in particular the ring and pinion sets?

If upgrading to trail gear will give me a stronger, more reliable truck then I'm up for that! I'm very tempted to turn mine into a challenge truck and start competing in some competitions.

I don't personally have any experience with Trail-Gear pinion/ring gears. However, people say there definitely is a difference. I do have a set of Trail-Gear CV joints, because just as yours, mine are ticking and generally indicating that they are about to fail.

I bought the stronger CV joins, but I wanted to wait with the change until the bad ones actually failed. Just liked to see how long they lasted. That's now almost a year ago...

But why have I never broken a CV or half shaft?

My CV's have been clicking like mad for the past year or 2, and as far as I know they could well be original items so 150,000+ miles old.

I've driven my truck very hard at times the with the aggressive 37" tyres and both ARB air lockers engaged.

Surely an already clicking, worn CV should be weaker than a ring and pinion?

If you get stronger gears in the diff then the CV joint will probably be the next weakest link in the chain... ^_^

 

[vegarwe]

That truck looked good before the spill.

Thanks, yes. That was an '85 model and I couldn't find any rust on it anywhere...

As far as air pressures go, I was told no less than 1 bar, which is about 14,5 psi.

I don't know if I would dare let them down to 8 psi to 10 psi.
Also, no unnecessary turns, keep it strait as much as you can.

10psi really is no problem at all with 12.5" or wider tires. You wouldn't drive fast of course, but low range and first through third gear is just fine.

Whether there is a huge difference between 14.5psi and 8psi with regards to traction I really cannot say. But in deep snow it's really important to float on top.

 

[vegarwe]

Normal beadlocks only work on the off-side, which leaves the inside edge unprotected. There are inside beadlocks which can be inflated once the tyre is fitted. These effectively force the beads against inner wheel rim.

The Hummer rims have a double beadlock system. Read a great review by Bill Ansell[1]. That does seem like the best solution.

[1] http://www.pirate4x4.com/tech/billavista/PR-Hummer_Rims/

I have never needed to lower my tyre pressures for green lane use. If a section is that "difficult" that lower tyre pressures would seem essential, then I would either find another route so that I did not create further damage, or I would winch through. I am not being patronising here but I have seen people powering through sections just to prove it can be done, when a simple and far less damaging winch pull, was all that was required.

I do agree about the track damage. That is something every offroader should care more about. I know ARB use that as a sales pitch for their lockers. Luckily, track damage is less of an issue when the ground is frozen solid and there is 80-100cm of snow on top ^_^