Volvo Portal Axles Under My HZJ78 Troopy (2 Viewers)

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Nov 14, 2008
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Rather than hijack Hulsty's build thread by rambling on in response to a question from Clint79 about a planned mod to my truck, I thought I'd start a build thread on this upcoming modification for my HZJ78 troopy...


SimonInAustralia said:
Nice snow photos, I'm looking forward to it again very soon, just need another couple of snow falls.

There still are a few tracks that don't get closed, where you can drive until you get stuck in it, that's why I'm going to put portal axles under my troopy.
The patrol kits around 18 g have marks adat made a cruiser kit yet

I asked Marks4WD a few months ago, and they said their cruiser portals were still in development, but I think were getting closer to being ready.

I think they said somthing about them being more expensive, maybe a couple or a few thousand more than the Patrol portals, due to the 70 series birfields or knuckles or something like that not being strong enough to cope with the portal boxes, and needing to be replaced, or braced, or something. Or maybe it was due to the 70 series knuckles that push/weld into the axle tube, or something like that, needing to be replaced with a bolt on flange on the axle tube, which they might not need on the Patrol version. Can't remember the full story.


There are a few other portal options that I considered along with the upcoming Marks4WD Land Cruiser portal conversion, such as second hand Unimog portals, new PortalTek portals, and the second hand Volvo portals that I decided to go with for a few reasons.


I have already paid for a set of Volvo C303 portal axles from someone in the UK, along with half of the shipping cost, and they are apparently ready to be shipped.

They have been de-bracketted, had bearings checked, Land Rover kingpin bearing conversion and a hub seal conversion installed to use cheaper and easier to find parts, new rubber boots/covers for the birfields and new vacuum diff lock diaphrams fitted, have been painted, and hopefully will be dropped off at the shipping company very soon...

axles.jpg



Once I get them in a couple of months, and have paid GST, import duty, and the rest I owe on the shipping, it will be probably six months to a year to get the money together to buy the extra bits, such as...
  • transmission handbrake ($1600AU for Hopper Stoppers kit, or something cheaper if I can find it and if it isn't too much of a drop in quality from the Hoppers Stoppers kit)
  • somehow integrate the Land Rover Series 3 drum brakes, that the Volvo portal axles have as standard, with my Troopy brake system ($?AU), or maybe do a disc brake conversion to the axles ($?AU)
  • standard 16x8 inch Volvo rims X5, with 8 stud pattern, ($600AU plus shipping, from a source within Australia), though not needed if getting disc brake conversion with 5 or 6 stud pattern before having axles fitted, and only if having the axle conversion engineered for registration purposes, to keep additional track width over standard to a minimum
  • custom 16x8 inch rims X5, with 5 or 6 stud pattern and full 8 inch backspacing/full positive offset as per standard Volvo rims, (maybe $400AU each), only needed if getting a disc brake conversion done with 5 or 6 stud pattern before having axles fitted, otherwise use standard Volvo rims as listed above, and only if having the axle conversion engineered for registration purposes, to keep additional track width over standard to a minimum
  • custom 16x10 inch rims X5, or X6, with 8 or 5/6 stud pattern depending on whether disc brake conversion, with 5 or 6 stud pattern, is done before having axles fitted, with maybe 7 inch backspace instead of the standard Volvo rim 8 inch backspace, depending on clearance between inside of tyre and steering/suspension after axles are fitted ($450AU each)
  • if getting it engineered for registration purposes, a set of 275 or 285 R16 tyres X5 to comply with maximum 50% increase in tyre width over standard 7.50/R16 tyres ($?AU each)
  • a set of 37 or 38 inch x 12.5 to 15.5 inch tyres X5, or X6 ($?AU each)
  • a box to modify the speedometer calibration ($?AU), to suit the new diff final ratio and other gearing changes, and switchable to work with both the 275/285 registration tyres as well as the 37/38 inch offroad tyres.
  • mods to guards/flares/wheel tubs, as/if required, so that the 37/38 inch tyres don't rub ($?AU)
  • something to activate the standard Volvo front/rear vacuum lockers, either tapping into existing vacuum system, installing new vacuum pump/tank/solenoids/system, or changing standard Volvo vacuum locker operation over to being air or cable activated ($?AU)
  • maybe a Marks4WD ($1825AU) or Terrain Tamer ($?AU) transfer case overdrive gearset, the Marks4WD version giving .92:1 (8%) high range overdrive and 2.81:1 (44%) low range reduction, and/or gearbox 5th gear swap ($?AU), to give increased overdrive to help deal with the Volvo 5.99:1 diff final ratio at highway speeds
  • possibly look at having any parts of the front drivetrain that can be balanced, balanced ($?AU), to help deal with the speed that the front of the drivetrain will be spinning at highway speeds with the 5.99:1 diff final ratio, due to no longer having locking hubs after the axle conversion
  • custom front and rear driveshafts ($?AU), balanced at least for the front due to no longer having locking hubs after the axle conversion, to help deal with the speed that the drivetrain will be spinning at highway speeds with the 5.99:1 diff final ratio
  • RHD tie rod and steering link (?UKP), custom made for the Volvo portal axles in the UK, or something custom made locally ($?AU), or a set of original Volvo RHD tie rod and steering link sourced from Malaysia ($?AU)
  • and then find someone who is a full time fabricator, with lots of diff swap/conversion experience, to fit them to my truck, hopefully doing a good/great job of it ($?AU), new coil hat/panhard rod/radius arm mounts on the front axles, new leaf spring perch/u-bolts/anti-wrap bar for the rear.
It is easier for me to afford portals for my Troopy this way, buying each part seperately, starting with second hand axles, rather than trying to get all the money together at once for something like a Marks4WD portal conversion, at possibly $20k+, or a new set of PortalTek axles, to start with. Though it will probably end up just as expensive as the Marks4WD conversion, or more so, doing it this way, after buying all the required extra bits and paying a good fulltime fabricator to fit them for me.


Have spoken to an engineer, he likes the idea and is seeing if we can get around the registration department maximum allowed 50mm increase in wheel track, as the Volvo axles have a wheel track that is 105mm wider than the standard HZJ78 axle for the front and 120mm wider for the rear, but he thinks it is a good idea as it will make it safer with the wider track to counteract the 4.5 inches that the portals lift the axles/diff centre/truck.

Standard HZJ78 Front Axle Wheel Track: 1435mm
Standard HZJ78 Rear Axle Wheel Track: 1420mm

Volvo Portal Axle Wheel Track: 1540mm

Increase in Front Wheel Track Over Standard: 105mm
Increase in Rear Wheel Track Over Standard: 120mm

If I can't get it engineered with the standard Volvo axle wheel track, I might consider having the Volvo axle wheel track shortened, if that is even possible.

Or it might be possible that a disc brake conversion will result in a narrower track, I have read that some ways of doing it does reduce the track, but others have told me it increases the track.

Required Reduction in Front Wheel Track for Registration: 55mm (27.5mm per side)
Required Reduction in Rear Wheel Track for Registration: 70mm (35mm per side)
 
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wow mate
that sure is some seriously heavy duty conversions
im very interested in this
please keep up dated

are the volvo bits from a truck of some sort
if any bits break are they easy to get new supplys
 
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wow mate
that sure is some seriously heavy duty conversions
im very interested in this
please keep up dated

are the volvo bits from a truck of some sort
if any bits break are they easy to get new supplys

Yes, a pretty full on conversion, and will end up being pretty expensive overall as I don't have any fab skills to do the installation to the standard I would like, and will have to pay someone to (hopefully) do a good job of it.

The other option was to continue to mod my existing Toyota suspension/drivetrain, with a rear Harrop/Eaton E-Locker to match my front E-Locker, and a 4-5 inch suspension lift, but that would still keep the diff centre and axle tubes in pretty much the same position, depending on the tyre size increase, so I figured I would start putting that money towards the start of a portal axle conversion, that I have wanted for a while, instead.

Will keep up to date, but is going to be a long/slow process.


Yes, they are from a range of Volvo military/civillian forward control trucks, often referred to as C303, which was the civillian 4x4 version, also came in 6x6 as the C304/C306, the military models were TGB11/TGB13/TGB21/etc.

The C303 is rated at a GVM of 2500 to 3500 kilograms, which is pretty much the same as my HZJ78 troopy.


This is what they look like...

800px-Volvo_C303_front_q.jpg


304_Bogger01.jpg


304_Bogger04.jpg



In Dakar mode...

800px-Volvo_C_303_%281978%29.JPG



The Volvo portal axles are available with 3 different final ratios (5.99:1, 7.10:1, 7.55:1), and right hand side pumpkin offset or a more centred pumpkin offset, depending on what model they came from.


They seem to be a popular conversion for comp Land Rovers in the UK and Europe...

big-Defenders_report_02.jpg



There are a couple of 70 series Volvo portal conversions that I have seen, just a couple of photos though that I have found so far though, no real in depth info...

49.jpg


16.jpg


21.jpg



TiredIronGRB did a mud build thread on his 80 series Volvo portal axle conversion, which I think he has since sold...

https://forum.ih8mud.com/80-series-tech/59452-tiredirons-tlc-build-up.html

TLC_88.jpg



Ridgerunner on mud put them under an FJ55, which I think is now dismantled...

pig11se.jpg



Parts are not easy to find, though there is a little aftermarket support based on the UK/Europe comp scene, and some possible sources of parts from Malaysia, where they were manufactured in a RHD version, under license from Volvo, for the Mayasian military.

I would classify my truck and driving style as mountain touring, to get me into the backcountry, on/in deep snow (by Australian standards), for snowboarding missions, not comp or rock driving, so hopefully I will not stress them too hard.


The plan is to hopefully avoid situations where I am stuck in the snow on my chassis and other bits under the truck, with all 4 wheels spinning and going nowhere, as it takes a little too long, and a little too much effort, to deal with by myself on solo missions, like this...

_MG_0398b.jpg


...though a rear mounted electric winch, or hand winch, would have made things a little easier, so that I could have pulled myself out backwards, both of which are planned for future purchases/mods.


The main advantage of the portal axles, for me at least, is that the bottom of the diff pumpkin and axle tubes are raised approx. 4.5 inches, so that the bottom of the diff pumpkin is pretty much in line with the centre of the wheels, giving much more under diff clearance than you get with standard axles.
 
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good luck, great axle choice, they are hard to find for sure. I am planning a 'mog axle conversion for my 80 in the near future. portals are the deal....:popcorn:
 
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good luck, great axle choice, they are hard to find for sure. I am planning a 'mog axle conversion for my 80 in the near future. portals are the deal....:popcorn:

I considered Unimog portals, but for a few reasons went with the Volvos instead.

The more commonly available, and cheaper, Unimog 404 axle has a 7.56:1 final ratio, while the C303/'fast' option Volvo 5.99:1 final ratio makes it easier to get the gearing back close to normal/standard (along with transfer gear overdrive and/or a 5th gear with more overdrive, and tyres around 37/38 inch), which will better suit my use as I will be doing a lot of highway km's at 110/120 kph to get to where I want to go offroad.

Not sure if there are other 'faster' ratios available for the Unimog 404 axles, via different rings/pinions, or if you need to go to larger/heavier/more expensive 406/416 axles to get the faster ratios (6.5:1 standard, 6.0:1 and 5.3:1 also available). And if the 406/416 axles have the factory 406/416 disc brakes, you need to use a 20 inch rim to clear them.

There might be some aftermarket portal gears to give a 6.9:1 final ratio in the 404s, or you might be able to use gears from the earlier versions of the smaller 411 Unimog to give a faster final ratio.

Another issue is the diff pumpkin location, I think that the Unimog has it on the left, while the Volvo is on the right. The Unimogs can be flipped or retubed or somthing to get the pumpkin on the right, maybe with shortened/custom axles, but more hassle and expense than the Volvos for my needs. And the Unimog axles have the long torque tube, which is still long when converted to a pinion.

One site recommends a hybrid Unimog axle in these situations, using something like a Ford 9 inch diff centre with the Unimog portal boxes, not sure what those would cost.

I plan to put the Volvo portals under my truck using the standard mounting points on the truck, and suspension setup, so that I can 'easily' swap back to the original axles if needed for something like rego inspections, or if I sold it later on and wanted to keep the portal axles.

Overall, the Volvo axles are lighter, and cheaper once fitted, than the Unimogs in my application, and are a much easier bolt in replacement for my standard Toyota axles.

If I was building a comp truck that didn't need to be driven on the highway, with more money to throw at it for getting the Unimog axles modded to suit and/or modified suspension to handle the extra size/weight, then I might consider the Unimog axles, but for my non-comp/touring use the Volvos are a better choice for my truck in the situations I will be using it.
 
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Hi simon,

I do not like this conversion :doh:

The unimog axles are too big and heavy for a 4x4 (expedition, traveling, etc)

Between Volvo Axles and Toyota Axles reliability, I would not change the toyota axles... ;)

Many components of the volvo axles are strong, but the axles-shafts are weak (like a Land Rover Axles or Dana 44) :hillbilly:

I have two friends here in Spain, they have broken many shafts-axles on 4x4 events (Rainforest, Extreme Trial, etc etc etc), they carry volvo axles in their 4x4


Sorry, is my opinion. :hmm:


Good Luck! :cheers:
 
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I do not like this conversion :doh:

Between Volvo Axles and Toyota Axles reliability, I would not change the toyota axles... ;)

Many components of the volvo axles are strong, but the axles-shafts are weak (like a Land Rover Axles or Dana 44) :hillbilly:

I have two friends here in Spain, they have broken many shafts-axles on 4x4 events (Rainforest, Extreme Trial, etc etc etc), they carry volvo axles in their 4x4

Sorry, is my opinion. :hmm:

That's OK lulo, I was fully prepared for some negative opinions on my choice of Volvo portals for the troopy.

I know they are a little fragile, but I am commited to giving them a go, having already purchased the axles, and doing so with that knowledge in advance.

As mentioned earlier, I don't think that I drive as hard as someone would in a comp truck, so might not put as much stress on them, and I might avoid breakages. I'm willing to give it a go and see what happens.

As you agree, the Unimog axles are a little too large and heavy, and are more expensive to get to work easily on my truck. The PortalTek axles are probably stronger than the Volvo portals, as I assume they are an improved/stronger version of them, but they are not really proven as there don't seem to be many around, and are more expensive up front. Some sort of custom hybrid Unimog/Ford type diff would be more expensive up front as well.

There really isn't any other portal options that I am aware of, and the Volvo portals are a similar size, and closer in weight, to the original axles, so are easier for a straight swap.

I'll keep the original Toyota axles, with minimal modification to the original suspension and mounts on the truck. If there are issues with the Volvo portals then I will swap back to the original axles or try something else later on like PortalTek, or a hybrid Unimog, or something else if there is anything stonger and small enough, that is if the portals improve the on snow ability and I want to keep going with them.
 
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Simon

let me know what help u need from Malaysia I may be able yo help u more than u realise.

Disc conversions are done here as the drum brakes on a volvo are real bad to say the least. Every trip requires shoes to be replaced. Portal axles are very heavy you Could have bought rhd here and shipped cheaper.

They are very heavy is correct. I believe they take a pounding from what I have seen 15bt running 21 psi hammering them and 2jzs etc yes axles break but man u gotta be giving them some serious punishment to break them.



More news next week for you
 
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Simon

let me know what help u need from Malaysia I may be able yo help u more than u realise.

Disc conversions are done here as the drum brakes on a volvo are real bad to say the least. Every trip requires shoes to be replaced. Portal axles are very heavy you Could have bought rhd here and shipped cheaper.

They are very heavy is correct. I believe they take a pounding from what I have seen 15bt running 21 psi hammering them and 2jzs etc yes axles break but man u gotta be giving them some serious punishment to break them.

More news next week for you

Hey Cicak,

Yes, it is unfortunate that I had to go to the UK to source them, as I did try to find someone in Malaysia to help, but I just don't know anyone over there, and couldn't find anyone to help source them.

I did send you a PM on 27th of December, when I was nearly ready to buy these axles, to ask if you had any sources for these axles in Malaysia, but I didn't get a reply from you, so assumed you were not interested in helping out.

Since buying them from the UK, I have also found a source within Australia that uses Volvo portals, and who has a contact in Malaysia for axles and parts.

Wish I would have known that before buying from the UK, could have saved some money, but that's OK as I had no other choice at the time, and they are paid for now so no use in worrying about it.


Anyway, I would be interesed if you do talk to anyone that has Volvo portal parts, to find out what a RHD tie rod/steering link set would cost, that I can fit to my LHD axles, with tie rod ends in as good a condition as possible, considering they will be second hand.

I would also be interested in the best way to go for a disc brake conversion, taking into account the my truck is probably around 3000-3500kg. I'd like to know what parts are used, as well as what cost is involved.


Thanks,
Simon
Canberra
AUSTRALIA
 
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I think that the hole/socket for the tie rod end in the Volvo axles has a particular taper to it, which has to be drilled out for normal tie rod ends, or something like that.

I have a contact in the UK who has tie rod ends with the correct taper, he just needs to find time to make up a set of rods, which he plans to do for his own axles, and his axles are RHD, so I'll probably get him to make up some for me while he is at it.

The original Volvo tie rod also has a bend in it, to clear the pumpkin I think, which needs to be replicated, and the steering link connects to a bracket along with one end of the tie rod, so that there is a single connection point on that side of the axle for both tie rod and steering link.

Might source a 2nd hand original set as a spare, and one of these custom replacement sets to use on the truck. I think it is better not to modify the axles to accept non-Volvo tie rod ends, and possibly good to have them made by someone that has a lot of experience in competing with Volvo axles.
 
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This is the Volvo parts diagram, showing how the steering link connects to the tie rod, then tie rod to axle...

PartCatalogue20-Steering1.jpg



...and this shows how the tie rod ends need to curve in around the portal bits, these are someone else's custom tie rods for Volvo portals...

P7170024.jpg



Probably no reason why I couldn't get someone here to make them up, but might be better to use tie rod ends that fit the axles without needing to modify the tie rod 'sockets/holes' on the axles.
 
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fair enough I guess I just come from th school of modify the non consumable parts to fit off the shelf easy to come by parts. Reaming tapers is probably one of the easier mods to do, I know DJR96 just posted some info on his truck conversion in relation to reaming.

I hear what you are saying about getting Volvo expeienced guys to do stuff, just keep in mind that a lot of countries have different standards for approval and Australia in one of the tougher ones when it comes to getting thing road legal.
 

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