Axle cleaning and gear ratios?

[Jaybr]

Since the only thing left connected to my front axle was the brake line, I decided to go ahead and pull it out and clean and paint it. Then decided, while it’s out I might as well have it rebuilt and re-geared and maybe add a true-trac. I just keep digging this hole deeper and deeper

To my questions, what do you guys recommend for cleaning up the axle?

And for gear ratios, I’m running 33s and will eventually put in an overdrive tranny. I’m thinking 4:11 or 4:30?

456 if I decide to go to 35s?

Looks like the shafts are 31 spline and in good shape.

Motor wise, current plan is Blueprint 306 bronco crate motor with fuel injection but that may be a while.

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[DirtDonk]

The outside casings are pretty basic. Short of having some machine to do it, any standard de-greaser and a stiff brush (maybe even a wire brush) will do the job.
If keeping things less messy is your goal (I try not to make every big of dirt and grease I clean turn into another black spot on the pavement!) then start with the brush and scraper to get the big chunks off, the go to the brush and cleaning solution. Even soap and water can get the job done, but I like the nasty stuff better.

Keeping a disposable plastic sheet underneath, or cardboard, or whatever you have, does make cleaning up later easier.

It's just a big heavy chunk of steel, so once you have it cleaned and wiped off, some simple spray can black (usually satin, but up to you) will keep it looking good and rust-free for a long time.

If you meant the inside of the axle tubes, then I don't have the solution. Several clever ideas have been used over the years. From a half-round scraper on the end of a dowel or bar, pushed in and pulled out can scrape the dried up dirt out. Might be that Eastwood has some sort of "bottle brush" arrangement to clean axle tubes, like they do frame rails.
One member here even put small chain links on a threaded rod and used a drill motor to wail on the inner scale and dirt of a Bronco frame. Same concept could be used for the axle tubes.

Then paint, paint, paint to keep the rust down and let you just hose it out in the future since the oil seal is on the inside and junk is still going to get in there.

Good luck!

Paul

 

[Apogee]

I'd just degrease it as stated above and go after it with a braided wire wheel on my biggest angle grinder. As for the tubes, pull some kittens through them and you should be good to go.

For gear ratios, I would go 4.56 with 33" tires if the OD on the trans is in the range of .70:1, especially with a higher revving 306.

 

[Broncobowsher]

33s without overdrive. 4.11s have proven to be a great ratio.

Add overdrive and it changes. You didn't specify what overdrive, not all are the same ratio. But a good rule is to gear for about 2000 RPM at 60 MPH. The bigger the engine (not more powerful, actual displacement) and the smaller the tire (less drag overall) you can go with a little less RPM, 1900ish. But with small displacement and lots of drag you may want a little more RPM, 2200ish. Higher performance engines shift the torque a little higher in the RPM band as well.

2000 at 60 is what a lot of modern stuff runs. Try and go too low and you lug the engine and that is no fun to drive and gets bad mileage. Downshift and you just lost the reason for an overdrive. Shifting in and out of overdrive on every hill gets tiring in a stick and kills the 3rd/4th gear clutchs (they don't wear when locked, they wear when shifting, worse under load). 2000 at 60 isn't that much, its only 3000 at 90.

 

[DirtDonk]

And all that is why what you choose for your future fuel-injected and cammed crate motor is not what's going to keep your current stock(?) carbureted engine happy.

So choose wisely grasshoppa. Or you will either be hating life, or spending your hard earned money on the new engine a lot sooner than you had planned!

Paul

 

[Broncobowsher]

Paul, you forgot the 3rd option. Spend that hard earned money twice when you re-regear.

And count the splines again, you should only have 30 splines in the 44. Which is generally all you need. The small u-joints in the factory axles are way weaker than the splines. Even most upgraded large U-joint axles are still plenty strong in the splines.

 

[Jaybr]

And count the splines again, you should only have 30 splines in the 44.

I counted twice and got 30 both times but I kept seeing references to 31 splines and thought I miscounted

This one has an automatic, and I’ll upgrade to an automatic with OD. I haven’t done the research yet to determine which one will work best.

I don’t plan on wheeling it much if at all, maybe some logging roads getting to hunters to track once in a while but currently using my tundra for that. May take it on the beach occasionally.

What I’m really looking for is better drivability, not huge horsepower. Neither of my EBs have tachs yet, but they sound like I’m winding them out at 45 mph.




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[El Kabong]

Git yerself a ferret to clean those tubes. ;D

https://animals.howstuffworks.com/animal-facts/10-animals-with-better-jobs1.htm

In 1971, scientists at the National Accelerator Laboratory (NAL) had a problem. The NAL's new Meson Laboratory was nearing completion, but its piping — through which subatomic particles would fly — was dirty. And it needed to be spotless to work properly. Someone had to figure out how to remove the innumerable tiny steel particles, dust and other debris from the pipes' interior before they could be used. The first idea: Create a mechanical cleaner to wipe out the 12-inch (30-centimeter)-wide, 300-foot (91-meter)-long tubes. A good idea, but an expensive one. Then, visiting British physicist Robert Sheldon came up with another idea: a ferret [source: Fermilab].

Ferrets are small, curious creatures that love to duck into holes and burrows, which they'll zip along until they reach the end, just to see what's there. Sheldon recalled how, back home, ferrets were sent down rabbit holes to, um, ferret out bunnies. The scientists agreed to give the inexpensive option a try, and so the NAL purchased Felicia, a petite 15-inch (38-centimeter) ferret, for a mere $35. Employees taught Felicia to scurry down the piping while fitted with a special collar and string; as Felicia ran through the pipe, she pulled the string with her. When she emerged at the other end, workers fastened a tight-fitting swab soaked in cleaning fluid to the end of the string, then pulled it back through the pipe to clean it [source: Fermilab].

During her employment, Felicia made 12 runs through the tubes. Then, in a rather humiliating move, she was replaced by a mechanical ferret [source: Fermilab].

 

[blubuckaroo]

The seals are inboard in the pumpkin. The axle tubes are unsealed, so you won't believe how much mud and crap you'll find in there.
I've used a stiff bottle brush type thing I got from Harbor Fright attached to a piece of 1/2" EMT conduit.
Spray the inside of the tubes with engine degreaser, brush it really well, then hose it out with water. Then tape a ball of rags to the conduit and mop it out.
It's sort of like cleaning a cannon.

 

[idus25]

4.88's with 35's. Love it. Have 79 rear (31 splines).

 

[Jaybr]

Went with 456 and Truetrac

My axle guy has a power washer with extreme hot water and said he’d clean the axle for me


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[DirtDonk]

I counted twice and got 30 both times but I kept seeing references to 31 splines and thought I miscounted.

As you may have figured out, the constant mentions of 31-spline setups is strictly for the Ford rear end.
The front is a Dana and correct at 30.

This one has an automatic, and I’ll upgrade to an automatic with OD. I haven’t done the research yet to determine which one will work best.

The current go-to is the Ford 4R70w auto from later Explorers. But there are others if you're casting a wide look.

I don’t plan on wheeling it much if at all, maybe some logging roads getting to hunters to track once in a while but currently using my tundra for that. May take it on the beach occasionally.

Not a lot in there to recommend spending the extra money on a limited-slip differential then. However, the beach alone might justify the cost.
It's one of those decisions in the long list of many (like gear ratio in fact) that could go either way. You have to decide if it's worth it, and do it while the work is going on.

What I’m really looking for is better drivability, not huge horsepower.

Good. Broncos really benefit from low-speed characteristics of the engine. Built for throttle response, smooth idle, economy (within reason) and reasonably high torque numbers without going bonkers is a key to a happy owner. Unless you happen to thrive on burnouts and full-throttle high speed runs that is!

Neither of my EBs have tachs yet, but they sound like I’m winding them out at 45 mph.

Well, maybe they are. But most likely they're not and you're just used to how other vehicles sound. I was used to Broncos and I still thought mine sounded tapped out earlier than all the others I'd driven. It was 100% the exhaust in my case. How is yours set up?
And what size tires? You need to check your gearing now, because if you already have 4.11's or even something lower swapped in after it left the factory, you might as well know now.
You said you have this one apart, so just count the teeth on both gears and let us know what ratio you have. A 4.11 would mean it sucks to be you...;D
What I mean by that is that it would have been nice to be able to drive it with the new engine and transmission FIRST, before pulling it apart. That way you would know how it felt with the existing gearing.
Avoiding Broncobowsher's 3rd theory of Bronco-relativity.

Because it's apart you can't do this with the Bronco now, but what about the other one? Still driving it? Then put a tach on it temporarily just to see what it's doing in reality and compare that to the sound you're hearing. These things make a ton of noise from gear whine, big metal fans spinning under the hood, old bearings maybe, noisy tires, and just about anything else that can ring it's way through a tin can and into your head.

And for gear ratios, I’m running 33s and will eventually put in an overdrive tranny. I’m thinking 4:11 or 4:30?
456 if I decide to go to 35s?

Narrow 33's, or 12.50's?

Motor wise, current plan is Blueprint 306 bronco crate motor with fuel injection but that may be a while.

Got a link to the exact one you're contemplating? Just curious what it's power ratings and curves are. This is good stuff for you to study too, to help in the ultimate gear selection.
As mentioned, mine is at one extreme with 4.56 and 31's. This gearing is actually pretty sweet for off-road, but while not optimum for highway, is very usable still with the Explorer engine. With the overdrive 4R70w trans, I'm still spinning the engine much less than my 4.11 and 32" combination.
I know without doubt this thing would be sweet-on-the-street with the dreaded 3.50's and the 31's and I'm going to test that someday. Even though that would put my cruising rpm way below what is normally recommended for a Bronco and carbureted stock-ish engine.
Which is the point I'm finally trying to reiterate. What's good for one engine may be intolerably dull for another.

Which is why the "good luck" has a lot of meaning here.;D

Paul

 

[Jaybr]

Great info DirtDonk, thanks!

Current tires are 33x12.50 MIckey Thompson MTs. I plan to switch to an AT and may even go up to a 35. Once I get it all back together I’ll drive it some with the 33s and new gearing and decide then. 35s would fill the wheel wells and look better IMO.

The motor I’m contemplating is the Blueprint 306 Bronco motor. I guess I’m assuming this is the Max Lider version and would be setup best for typical Truck uses.

The other bronco is all stock.


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[Jaybr]

And for the Trutrac, I know with my planned uses I may never need it. We have a saying in my industry “future proofing” and it applies here. I’m afraid the day may come when I wished I had put them in. There is no labor cost to install it with the new gears so figured best to just go ahead and do it now.


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[DirtDonk]

Sounds reasonable. In my case that's always why I say yes to a traction differential for myself, or for someone that uses their Bronco in more varied situations and conditions. It may very well come in handy. At least I hope I still use my Broncos in that way!
But it's still always good to at least suggest that it might never been needed/used, and let the person contemplating it have more to chew on before pulling the trigger.

The motor I’m contemplating is the Blueprint 306 Bronco motor.

That's why I asked. There are 9 listings for just 306ci engines.
Now that I look though, I see only two are shown with EFI, and one does say Bronco in the description.
The other one is 370hp/350tq (which does not sound like a good Bronco candidate for you). The "Bronco" version is a 365/365 which is still a potent engine, but with perhaps a lower rpm torque peak.

I could not find a dyno chart this time though. Is there one on their site, or do you have one?

Paul

 

[Jaybr]

I could not find a dyno chart this time though. Is there one on their site, or do you have one?



Paul

I couldn’t find one either, but I’d certainly want to see one before I made a purchase.


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[DirtDonk]

I think they call it the Bronco because several people from here on classic have inquired and purchased what sounds like a reasonable engine for a performance truck. They just took it and made a category out of it perhaps.
With all the Broncos being built right now, I would not be surprised if that had something to do with it.

I remember seeing plenty of dyno charts during the discussions about Blueprint Engines over the last three or four years, but don't remember one specifically for this. Might turn up in a search, or you might spend a day and a half checking out every discussion of Blueprint!

Anyway, if you do happen to find out they have one, post it up if you can.

Thanks

Paul

 

[Jaybr]

Here’s an article on that motor http://www.fourwheeler.com/how-to/engine/1809-blueprint-engines-306ci-bronco-edition-crate-engine

And a picture of a dyno chart, can’t read great but looks like a pretty flat torque curve.

I should probably start another thread on the engine


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[DirtDonk]

Cool, thanks for finding and posting that.
I'm interested to know who makes that distributor. I like the small(er) cap, and angled vacuum port for the advance canister.
I wonder if it's a Holley?

You can see the nice flat torque curve, but at that lower end it's starting to really plummet! I'll put it down to the vagaries of dyno testing though, where it's hard to test below 2500 rpm for most setups as I understand it.
Even if not, that steep drop off is from a much higher peak than any stock Bronco engine ever had, so very likely still feels strong down low. And based on the article's text, that's how it felt to the testers.

Curious too, what history that Bronco has. It's got a Jeep or Scout hub on it, so I'm guessing someone did a disc swap years ago and sourced those parts instead of the now common GM version.

Interesting stuff.

Paul

 

[Nothing Special]

.... I was used to Broncos and I still thought mine sounded tapped out earlier than all the others I'd driven. It was 100% the exhaust in my case....

Intake can make a lot of difference in engine noise too. The "hot air intakes" (open element air filters) that so many of us have on top of our carbs make it a real mouth-breather. An enclosed air cleaner with ducting to the grill will be a lot quieter (and probably give more power too).