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Discussion Starter #1 (Edited)
Meritor RF611/ford 9" axle build

What would pirate build? Which center section (9", sterling 10.25, dana 70, 14 bolt, etc) would you use to build these axles (matching front & rear steering)?

The axles are the Meritor RF 611 planetary, I choose these because its a 2:1 reduction at the hub, there is a local supplier that I can drive to, parts are plentiful and the axles are cheap. What I will use is everything from the inner C out & the inner & outer axles. It will require some creative welding & fab work, but the housings are weldable, and other than time, it's more than doable. I have the parts lined up, just waiting on the old parts to sell to free up cash.

The issue is weight, the factory Meritor's are big & heavy, and the end goal is to get the weight down as much as possible & keep the price for the center section as affordable as possible, using as many junkyard/over the counter parts as possible.

Locker would be a spool or welded, I do not want or need a locker of any sorts, this is a mud bog/tuff truck type of application, no trail riding or DD duties at all. The stock meritor axles will be re-splined to 1.5" 35 spl to fit the center section. Tires are either 42" skinny boggers or 44-48" skinny ag tires.

My initial though is go with a sterling 10.25 (or would a dana 70 be better)? The trade off here is a heavier center section that is basically free, with an end cost of ~2g for the pair (less steering components/brakes & my time).

I blame the monster buggy for this change of direction, watched him compete at havoc and was sold on planetaries, but the weight is killer.
 

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Master of none.
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Cody, before going with the Axletechs I was going to use a hybrid planetary/14 bolt combo, I chose the 14 bolt for a number of reasons, the biggest reason was the 1.75" pinion, & 3rd pinion bearing,
Also like the 9" & F-106, the pinion support lends itself well for pinion brake brackets,
I love the Ford 9", & tho it shares some similarities with the 14 bolt, I just think it would cost to much to make one live in my rig,
you may get away with it in a mostly mud application,

What is the end ratio you are shooting for? (end as in final ratio)
 

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I too have been considering RF-611 hybrids. These axles are awesome, other than the chem-resistant paint and ductile cast-iron housing (while is weldable, from my slight grasp on metallurgy it takes a little special treatment). For a while now I wanted to do something with a removable 3rd member and make a sheetmetal housing to use these knuckles/outers. My initial preference would be an Eaton H072 for the removable center section, third pinion bearing and load bolt; draw backs would be lack of available, shallow gear ratios (although transfer case gearing would be able to be reduced or tire size increased) and some parts availability issues possibly. A D70 or 14bolt would be a good choice as well; with the hub reduction you may be able to get a 9" to work decently but you'd probably have to lighten the vehicle and still have to stuff it full of aftermarket pieces.

If you can, please acquire and share as much as you can for these Meritors (ie. shaft lengths, spline counts and diameters). I have searched high and low on the internet and can't find much more than a Meritor advertisement.
 

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Tires are either 42" skinny boggers or 44-48" skinny ag tires.

My initial though is go with a sterling 10.25 (or would a dana 70 be better)?

Front - Currie RJ70
Rear - D70 w/Jana 87 kit
 

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Discussion Starter #6 (Edited)
No dropping any coin on an aftermarket housing like rock jocks, to much cost up front.

Looking at the jana 87, that might be a good option, but I'm looking to stick with a 3.00 (or as close to it as possible) ratio, otherwise the end ratio will get to slow. Looking to stay as close to 6.0 as possible.

I'm debating the 14 bolt, but in terms of parts and diffs, I have none vs the sterlings and the dana 70's (I really like the 3.07 sterling ratio). Like I said I'd like to stick to 6.0 as best as possible (or even numerically lower). I'd love to go with a removable 3rd, and the 9" would be great, but to make it survive would be $$.

For the welding to ductile cast iron, heres some information, it's very similar as if you are welding to nodular cast iron (ie hp dana 60 front), in summary, high preheat, small quick & low heat input welds, followed by a post weld heat & slow cooling and some peening:

Guidelines for Welding Cast Iron

I was thinking to do a flanged end like you see in the monster trucks & such. I have access to high grade pipeline flanges, and would get some 300lb blind flanges bored out to the necessary ID's, machine the meritor knuckle to press fit onto the flange, have it beveled out enough on one side to get a near full penetration weld, grind out the backside to sound metal & complete the full pen. weld. I would then gusset as required & bolt it up nice & tight. This joint would be as close to the king pins as I could get it, basically right where the "ball" starts.

Axle shaft information:

inner Shaft dia at splines 1.64", 32 spline

inner Shaft dia 1.5"

inner Seal surface 1.88"

Stub dia at splines 1.84", 36 spline

Stub dia 1.70"

stub shaft Seal surface 1.88"

the Meritor U- joint is the same as a 2.5 ton axle U joint


EDIT** pictures aren't working, I'll try to get them up later.


It's also tempting to say screw it and just run these as they are with pinion brakes. Or adapt the planetaries to another axle. The cheapest way (2g total) may be to just run the as is and deal with the 6-800lb penalty. Truck will still be lighter than the other rigs though.
 

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Flanges welded to the end of the inner kingpin would do the trick.

Do you plan on rear steer? From the little I've seen the rear housings already have a bolt on flange/spindle for the reduction hubs. If you don't have to have rear steer or can come across a cheap Meritor rear that could be an option.
 

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You aern't explaining your overall goal very well. Hard to guess what;

Do you have a weight on these axles? Steering angle? what do the outers weigh?
Do you have a overall axle target weight?
How much Horsepower do they need to handle?
What is the vehicle target Wheelbase, Tire size, Overall Weight, Track width.
Are you shooting for centered difs, offset difs?
How many degree's of steering?
 

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Discussion Starter #9 (Edited)
You aern't explaining your overall goal very well. Hard to guess what;

Do you have a weight on these axles? Steering angle? what do the outers weigh? Weight of the factory axle is ~1000lbs less brakes, steering angle 35*, not sure on weight of outers
Do you have a overall axle target weight? as light as funds will allow, if I can get them to 700 less steering & brakes I'll call it a win, and judging by the housing & 3rd member I should be able to do this
How much Horsepower do they need to handle? 800hp is what I'm at now
What is the vehicle target Wheelbase, Tire size, Overall Weight, Track width.
Are you shooting for centered difs, offset difs? 115" ish; tire size is above, I think the ones I want are 46; overall weight I was hoping to hit 3000lbs but now it will likely be 4000lb, keep in mind this is a bare bones rig; track width: 90" not set in stone though can vary +/-6", offset diffs with the same offset as these come factory with, so 6" to the driver side
How many degree's of steering? what these provide factory is fine, not great but it will work.
See my response to your questions in red. I already have a pair of steering Meritor axles lined up. The spindles are removable from the knuckle, there's a thread I bumped a few days ago where a guy has taken these planetaries, built his own spindle, and built a pair of 9" diffs for sled pulling.
 

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I wish you were closer, or at least would have known about this project.
I have a lot of parts for this project if you decide to go 14 bolt,
(3.21:1 R&P, 2 set up kits, 2 high angle drive line pinion flanges, 2 detubed 14 bolt housings, 6 ft of 3.5x.375 wall tube) & could have hauled it all up just a couple weeks ago. :laughing:
 

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See my response to your questions in red. I already have a pair of steering Meritor axles lined up.
If your making 800hp no way would I be trying to put that through a 9" differential unless you plan on throwing some coin at it. Factory housings are also something I wouldn't bother with.

Skippidlink nailed it with the 14bolt centers, Plus cheap.

how much machining experience do you have and do you have access to machines?

if not, or none, check out your local technical college and talk to the instructors or students to see about help. Its a Cool project sounds like fun.

here are my thoughts

Your target weight is going to require pinion brakes for the weight savings.

14bolts Carriers will bore out just fine for the 1.64 Dia inner shafts and sides of the carrier. I would go 1.670" dia. for clearance. You could also have spools or locker side parts edm'd fairly easiliy.

I would consider turning down the inner seal surface as it will make finding seals easier.

Crane inner seal retainers are easy but you can make your own using factory parts, a seal book, and a little ingenuity.

I would try flanges welded to the 14 bolt tubes similar to what Russ Gearheart and others do. Machine the Knuckle side axle tube if there is enough thickness to get the holes drilled and tapped with a shoulder and o-ring groove. 14bolt tubes are not very round wich is why I would go this route.



35° of steering, thats a bummer but shoud be fine with front and rear.

3000 is a lofty goal my guess is 4500+ but best of luck to you.

Best advice I have is to get out wheeling and have fun. If you want to change it up later, do so but don't let that greatest upgrade sideline you from having fun for to long, you'll regret it in the long run.
 

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Discussion Starter #12
I wish you were closer, or at least would have known about this project.
I have a lot of parts for this project if you decide to go 14 bolt,
(3.21:1 R&P, 2 set up kits, 2 high angle drive line pinion flanges, 2 detubed 14 bolt housings, 6 ft of 3.5x.375 wall tube) & could have hauled it all up just a couple weeks ago.
Yeah I was only thinking about this, never actually going to go through with it as I don't have a source for cheap axles, then western Canadian Rockwell parts spoke up on EMF last week and we got to talking, and well the rest is history and I have the axle build I've always wanted to do. I may be in touch with you on these parts.

So it looks like the 14bolt is the favorite, did they ever come in ratios numerically lower than 3.21?

how much machining experience do you have and do you have access to machines?
I don't do any myself, but have a couple good sources that will work for beer.

here are my thoughts

Your target weight is going to require pinion brakes for the weight savings.
Yeah that is my thoughts and current plans, but I may have to compromise on this pending some of the racing rules & reg's (ie I may have to have wheel brakes), we'll put this as a TBD item, if the weight puts me over that 700lb limit, well I guess I'll be SOL, but I'm still going to try.

14bolts Carriers will bore out just fine for the 1.64 Dia inner shafts and sides of the carrier. I would go 1.670" dia. for clearance. You could also have spools or locker side parts edm'd fairly easiliy.

I would consider turning down the inner seal surface as it will make finding seals easier.

Crane inner seal retainers are easy but you can make your own using factory parts, a seal book, and a little ingenuity.
EDM is easy to do, but $$$, I'll respline the shafts and carry a complete set of cryo'd spares front and rear for what it costs, the meritor shafts neck down to 1.5" as well (pm'd tech tim on this the other day, and dean at performance cryo for the shaft work, it was around 1000 for the edm work and 500ish for the shafts with cryo). Also, the meritor shafts have the seals at the housing end, there is no seal surface at the third member, its all at the knuckle, makes the resplining process a little easier, also means with keeping the housing ends I can use stock meritor parts, no machine work or odd ball seals.

I would try flanges welded to the 14 bolt tubes similar to what Russ Gearheart and others do. Machine the Knuckle side axle tube if there is enough thickness to get the holes drilled and tapped with a shoulder and o-ring groove. 14bolt tubes are not very round wich is why I would go this route.
That's a good idea, I know the housings will have the diameter, it will a question of whether there is enough material to work with, otherwise I'll a flanged end on the knuckle as well.

35° of steering, thats a bummer but shoud be fine with front and rear.
My thoughts as well

3000 is a lofty goal my guess is 4500+ but best of luck to you.
Before this plan with these axles, I was on my way to the 3000lb goal, now with the bigger diffs, 4-4500 is my goal. This truck is simple, this is a racing rig, if I don't need it, it's not going on. Winches are only going on receiver hitches when I'm racing events that need it, no spare parts or tools carried, one small battery, only run enough fuel for the events, and so on. I want to keep the power to weight ratio up there as I race against 1000hp big blocks, and well they can't be beating me.
 

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with the 2:1 reduction at the wheel ends, I could see a spooled 9" center living long enough.

Easier to find 3:1 range ratios in as opposed to tonner rearends, as well.
 

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what ratio are the axles currently?

Given that the ujoint is the same, I would consider looking at a F106/C103 center section. They will be heavier than a ton axle, but removable third, variance in ratios, and then you could build them to run 2.5 ton lockers/spools/shafts/etc.

edit: these axles also arent likely going to get you to the end ratio you are wanting.

Other option to me would be 14b or d80, but the 80 is typically higher price.
 

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Discussion Starter #19 (Edited)
I think the Meritor's are between 6.0-6.5, can't remember off the top of my head. For the center, I want to keep to a 3.0 or lower (numerically) if possible. Dana 80 is possible, but then I'm getting up there weight wise and nearly better off to stick with the meritor 3rd. You are right, the F106 will not get me the ratio I want, and the 3rd is probably similar size to the factory one. Also, the factory shafts in these are essentially the same as a rock 2.5t, they use the same joints with minor shaft differences.

The fab'd housing is a possibility, I would have to look at the 3rd member & housing and see if its worth it, If the 3rd member weight is similar to the other center chunks mentioned, it might be the better way to go.

Snowracer, yeah Neil is pretty good to work with, prices are really good as well, cheaper than a semi built dana 60.
 

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You just want the strength of the planetary or what? I feel like I'm missing something with all the jumping through hoops to end up with a 6:1 ratio which is commercially available already (and damn close to a stock rock, really)
 
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