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RA Drop Brackets, does brand matter?

Shimmy

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1977 Bronco
Joined
Jun 20, 2021
Messages
338
Loc.
Maple Valley
Bronco is at at the shop and it doesn't look like we'll get enough caster out of the 7* bushings (3.5") lift. I was looking at the big "4" brands and curious what everyone is running. The WH, JBG and TBP look identical, maybe one offers more drop than the other? The Duff bracket looks pretty sweet, but not sure i need the adjustability?

Whats everyone's thoughts? I'm a little under 1* caster and the D44 knuckle bushings aren't helping enough.

I'll need to ditch the 7* C bushings too right? and what degree bushing do you recommend i get?
 

DirtDonk

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You have other issues that are not really surmountable with bolt-ons.

I don't think you really have much of a choice in C bushings.
If you drop all the way to 2° and lose 5 and only gain four back with the drop brackets you’ve just lost your 1° of caster.
If you drop down to 4° bushings you’re losing three and then gaining back four with the drop brackets. That’s a lot of work for just one degree bringing you back to a grand total of 2°
Using the drop brackets in addition to the 7° bushings will basically net you 5° of caster.
A very nice setting, but with other headaches to overcome.

Basically you won’t be able to use four-wheel-drive very effectively with that kind of compensation. Between the lift and 11 degrees of correction your u-joint angle will be so severe that you’ll very likely get binding.
If the driveshaft will even turn in the first place!

There is a reason that 7° is the maximum correction factor available in bushings. That’s because if you twist the axle any further you start to run into pinion angle problems and u-joint bind.

So I’ll say it right off the bat here, that the only way you’re going to have your cake and eat it too is to cut and turn the steering yokes.
It’s a little more work, and even possibly the kind of thing you don’t want to do yourself if you don’t have the equipment. But it’s the best of both worlds.
Literally the only way to correct pinion angle AND positive caster.
 
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Shimmy

Shimmy

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1977 Bronco
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Messages
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Ugh! just not sure i'm ready to go that far. And, i don't have the equipment or skills to weld. :( Its always been one of those skills i've wanted to learn though.

Normally I would say numbers don't lie, but these broncos are so strange! i could very well get drop brackets and 4* bushing and voila! its at within 3-5! lol:LOL:

I'm almost wondering if the alignment shop adjusted the knuckle bushings correctly? Seems that those should have helped dial in the caster too.
 
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DirtDonk

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If the knuckle bushings are the ball joint eccentrics, they are only capable of up to 1 1/2° at the most anyway.
It’s also well known that Broncos up to about 76 didn’t have much caster to begin with. Usually much less than expected.

Adding the drop brackets will definitely give you the caster you expect. It’s just that as I mentioned it’s extremely likely you won’t be able to use four-wheel-drive.
 

savage

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Renton
I prefer the James duff adjustable drop brackets, its nice that you have three different degree of adjustment. That said, Paul is is wright on the money with the pinion angle!!!
I have a 3.5 inch lift with 4 degree-bushings , with duff drop brackets, but I also have the duff T-REX arms that give me even more caster and the pion angle is giving me trouble!! I'm where you are and don't have the skill to turn the knuckle's, so I'm going to adjust the radiuses arm with the duff brackets and lose some caster to point the pion up so I can use four wheel drive till I can have someone turn the knuckles.
 

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Oldtimer

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What does the current drive shaft to pinion angle look like?
Any photos?
 
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Shimmy

Shimmy

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1977 Bronco
Joined
Jun 20, 2021
Messages
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Loc.
Maple Valley
I prefer the James duff adjustable drop brackets, its nice that you have three different degree of adjustment. That said, Paul is is wright on the money with the pinion angle!!!
I have a 3.5 inch lift with 4 degree-bushings , with duff drop brackets, but I also have the duff T-REX arms that give me even more caster and the pion angle is giving me trouble!! I'm where you are and don't have the skill to turn the knuckle's, so I'm going to adjust the radiuses arm with the duff brackets and lose some caster to point the pion up so I can use four wheel drive till I can have someone turn the knuckles.

What is your caster (official alignment) at now with the binding?
 

savage

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I don't have alignment number yet. I talk to Tomwoods drive line and they said the driveline numbers were not where they like them. Here is the numbers I sent them. I did look into installing a high angle driveline, but not sure if I want to go that route.
 

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Rustytruck

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Are you sure your 7 degree bushings are not installed upside down. from the factory the 77 axles have better castor numbers that your getting with the added 7 degree bushings you are installing. My understanding is you should be getting 5 degrees more than what ever the stock caster was. 5 added degrees. for 7 total.
 
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Shimmy

Shimmy

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1977 Bronco
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Are you sure your 7 degree bushings are not installed upside down. from the factory the 77 axles have better castor numbers that your getting with the added 7 degree bushings you are installing. My understanding is you should be getting 5 degrees more than what ever the stock caster was. 5 added degrees. for 7 total.
100% certain, triple checked. what i don't recall was seeing a 7* labeled on it tho
 

DirtDonk

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yeah, that's a shortcoming that I've been moaning about for decades now. most, if not all of the C-bushing companies don't bother to put any kind of indicator on the outside where you can see it once installed.
Most of them do mold a degree rating into them on the inside. Where it gets wiped off almost immediately upon installation of course. So even when you remove them you can't always read the old markings.

But a 7 degree is pretty easy to tell at a glance once you've seen a few. It's got quite a bit of offset.
And obviously i was not paying attention. Once again Rustytruck brought up a good point. You can see I mentioned "pre-'76" axles in a previous post, but since yours is a '77 it should almost certainly have good caster numbers. I wonder if someone swapped in an earlier 44 at some point, for some reason?

When you get a chance, take some close-up photos of the sides of your C-bushings. Maybe we can verify that they're 7's just by looking.
Can't always, but if you can see the offset lugs inside from the side view, you can probably tell.

Paul
 
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Shimmy

Shimmy

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1977 Bronco
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here's pics of my c bushings
52E11E6C-C1B9-4A11-B70E-E21AC3777CE6.jpeg
 

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Shimmy

Shimmy

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1977 Bronco
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and my pinion angle. i realize angles are difficult to see in pics
 

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DirtDonk

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Fantastic. Very good pics.
The bushings do look like 7° models.

You’re right about angles being hard to determine, but at least from this viewpoint your current angle looks at least still usable.
But it’s far enough now that I think the additional caster correction is going to do what we were afraid of and put it out of range.
 
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Shimmy

Shimmy

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1977 Bronco
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Fantastic. Very good pics.
The bushings do look like 7° models.

You’re right about angles being hard to determine, but at least from this viewpoint your current angle looks at least still usable.
But it’s far enough now that I think the additional caster correction is going to do what we were afraid of and put it out of range.

my bronco is a street rig, so at this point, i'm thinking i should go DBs or LAs and if my pinion angle is whack then i'll remove the front driveshaft for the time being. I wont miss 4wd. Then the bronco will at least be back on the road until i can figure out a plan to turn the knuckles.

any advice on LA or DBs? i know the DBs will be cheaper, but i plan to keep this baby forever so $$ doesn't matter in the end. I've had LAs on my jeep and it made a world of a difference vs DBs, on and off road. Just way smoother. I know LAs aren't needed for a street rig, but they are so much "cooler" than DBs. haha!
 

DirtDonk

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Didn't you already mention changing the arms to something else? Or was I just remembering the pics posted by savage with the Duff arms?
Street OR trail, I'd opt for long arms over drop brackets every time. More expensive, but more versatile and beneficial.

The only downside I can think of is making it more prone to leaning into corners while driving. But firmer shocks and/or springs can help with that a bit at least. Or anti-sway bars. Or nothing, as there are plenty of Broncos driven around on long arms with no complaints.
Depends on your threshold I guess.

As you pointed out, the long arms are just cooler as well. Drop brackets are very effective, but add more leverage and twisting potential to the frame at that point, hang down low for a ground clearance loss (not an issue on the street of course) and look funny hanging down there.
But they do work.

Paul
 

savage

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Didn't you already mention changing the arms to something else? Or was I just remembering the pics posted by savage with the Duff arms?
Street OR trail, I'd opt for long arms over drop brackets every time. More expensive, but more versatile and beneficial.

The only downside I can think of is making it more prone to leaning into corners while driving. But firmer shocks and/or springs can help with that a bit at least. Or anti-sway bars. Or nothing, as there are plenty of Broncos driven around on long arms with no complaints.
Depends on your threshold I guess.

As you pointed out, the long arms are just cooler as well. Drop brackets are very effective, but add more leverage and twisting potential to the frame at that point, hang down low for a ground clearance loss (not an issue on the street of course) and look funny hanging down there.
But they do work.

Paul
The duff drop brackets will help with his coil spring bulge. I don't have the long arms from Duff, I have the T-REX arms from Duff. But will LONG ARMS HELP WITH coil s bulge ? The T-rex arms are stock length but still have the same bend and C'S as the long arms just shorter.
 
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Shimmy

Shimmy

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1977 Bronco
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got my hands on the actual alignment specs... wondering if i should try another alignment shop? i have 1.5* knuckle bushings and i'm thinking i sacrifice camber for more caster. i'm no alignment tech but feels like they could have rotated the bushings the other way for favorable caster.
 

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DirtDonk

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Yeah, that’s kind of what it looks like.
Looks like when they used the eccentrics and didn’t utilize the entire 1.5 degrees to correct camber, the leftover got pushed to the back and reduced your caster.
Might not have been enough to be a miracle cure, or dealbreaker, but it would’ve at least been better.
 

DirtDonk

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But will LONG ARMS HELP WITH coil s bulge? The T-rex arms are stock length but still have the same bend and C'S as the long arms just shorter.
Sorry, forgot to answer this question.
And the answer is I’m not sure.

It’s all about the angle of the top deck where the lower spring cup mounts. Of course it has to do with its location front to rear and side to side, but that is assumed to be centered under the spring tower.
If the heads of your arms appear to be tilted in such a way that the cup surface is relatively flat, or horizontal to the ground, then yes they should reduce spring bow.
 
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