Are my Rancho shocks too short for a TB 3.5 lift?

[jake2077]

I replaced the factory leaf springs including a 3inch metal block/lift with Toms Bronco 3.5 11 leaf spring and no additional spacer/block. The Rancho RS55118 shocks that were on there are shot so replaced with the same model that notes, "Rear RAISED Height 2.0" to 4". I installed the leaf springs and when it came to the shocks they were about an inch too short of reaching the lower mount fully extended. I found that by putting load on the rear it compressed enough for me to mount them but they are still fully extended. Does this seem right? I would expect the leaf springs to settle in the future but not sure if this is something to be concerned about. Thanks.

https://photos.app.goo.gl/HmRTAzcaELhtNzVZ7

 

[spap]

Can’t tell with the boot on the shock
How much of the rod do you have showing

 

[jake2077]

It's fully extended showing almost all of the rod.

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[DirtDonk]

Then it's not right. Way too short.
There's no hard and fast rule that you need X amount of shaft in either direction, or that you must be half-way in it's travel, but half-way has been a nice goal sometimes.
I generally put them a little bit more compressed, but would not use one that was too close to bottoming out. And so I would not use one that is absolutely topped out like yours is.

Is the vehicle fully built and at it's full fighting weight? If so, measure between the top of the axle tube and the bottom of the frame rails in the rear and see what you find. It should be approx. 9.5 inches, give or take a half. So roughly between 9 and 10 inches.
If it's more, then your shocks are too short.
Notice Rancho's recommendation of 2-4 inches? That's pretty common among shocks, but yours is right near the top end of that range, so it's not unheard of for a shock to be too short or too long when it's near the range. Different brands use different lengths (slightly) so one might be too close to the limit.
Obviously though, since you had to compress the suspension just to get them to mount up, they're too short or you're too tall.

Paul

 

[DirtDonk]

Look up the thread by savage going through the same thing with springs. Ours have done it, Tom's have done it, and other brands as well. Doesn't make it right, but it does indicate that it has happened before.
Hence my recommendation to measure the ride height.

Back to fully the fully built question though, if yours is not then you can't judge anything yet. Any suspension determinations have to be done at full weight.

Paul

 

[DirtDonk]

I meant to ask too, did you look up that application yourself? I thought I remembered the 5118 shocks being the 0-2 inch lift version? I guess I'm wrong because that's just from ancient memory and we used that shock for almost everything. Even the small 4wd shops I worked at would stock 10 or 20 of them, because they fit so many rides. I might be thinking of stock height GM trucks instead of Broncos. And I've used them myself in the past on my Bronco.

But if it wasn't you that looked it up, maybe double check?

Paul

 

[jake2077]

The 5118s were on it before but with the original leafs springs and 3" block lifts. TB suggested after measuring the distance from axle to frame the 3.5 leafs would be equivalent. I agree on the load issue. The vehicle is down to bare body and frame about to be painted so maybe that will help when finished with a higher load? I'll upload more pictures this afternoon. Thanks fort your help!

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[jake2077]

I meant to ask too, did you look up that application yourself? I thought I remembered the 5118 shocks being the 0-2 inch lift version? I guess I'm wrong because that's just from ancient memory and we used that shock for almost everything. Even the small 4wd shops I worked at would stock 10 or 20 of them, because they fit so many rides. I might be thinking of stock height GM trucks instead of Broncos. And I've used them myself in the past on my Bronco.

But if it wasn't you that looked it up, maybe double check?

Paul

Just got home and I have 12 inches from axle to frame which seems way too much. I checked the front springs and they are Skyjacker 182s listed at 2" lift. I think I messed up and should have gone with the 2.5 instead of 3.5 leaf springs. From a distance the Bronco has a slight rake as well. If I try to return/swap the leaf springs with 2.5 I wonder if the shocks would fit enough to keep them in place.

 

[DirtDonk]

As you mentioned in your post number 7, you don't have a complete Bronco yet. So nothing is going to work in the rear until the weight is on it. That 12" is the equivalent of over 5 inches of lift, which is always going to be too high for shocks designed for 2 to 4 inches.
The only way you're going to know if the shocks are going to work once it's sitting at the expected ride height for a 3.5" lift is to compress the suspension down to make that gap measurement roughly 9 to 10 inches. Only then will you know if the shocks are sized correctly for yours.
And if they are, then they will also be fine for a 2.5" lift should you decide to go that route instead.

And rather than shipping springs back and forth (an expensive proposition as you probably already know!) I would first at least consider removing leaves. Of course that depends on just how far down you want to go, and how much weight is on the truck.
But the bottom line is still that you can't size your shocks based on an incomplete Bronco.

Or your driveshafts, or driveshaft angles, or your trackbar length, or other steering angles, or brake hose length, parking brake cable length, etc... And all that happy crap.
So first things first, compress the suspension. Use ratchet straps, or ten of your burliest friends sitting on the back. But get that suspension compressed or you're just whistling in the wind.

Paul

 

[jake2077]

As you mentioned in your post number 7, you don't have a complete Bronco yet. So nothing is going to work in the rear until the weight is on it. That 12" is the equivalent of over 5 inches of lift, which is always going to be too high for shocks designed for 2 to 4 inches.
The only way you're going to know if the shocks are going to work once it's sitting at the expected ride height for a 3.5" lift is to compress the suspension down to make that gap measurement roughly 9 to 10 inches. Only then will you know if the shocks are sized correctly for yours.
And if they are, then they will also be fine for a 2.5" lift should you decide to go that route instead.

And rather than shipping springs back and forth (an expensive proposition as you probably already know!) I would first at least consider removing leaves. Of course that depends on just how far down you want to go, and how much weight is on the truck.
But the bottom line is still that you can't size your shocks based on an incomplete Bronco.

Or your driveshafts, or driveshaft angles, or your trackbar length, or other steering angles, or brake hose length, parking brake cable length, etc... And all that happy crap.
So first things first, compress the suspension. Use ratchet straps, or ten of your burliest friends sitting on the back. But get that suspension compressed or you're just whistling in the wind.

Paul

Thanks, that makes since. I've read about removing the third from the top leaf spring to net 1-1.5" and that may help it feel more even but I'll wait until it's closer to being complete and do a compression test to see where the shock sits. It's nice to know there's an option besides spending money on shipping back and forth! I'm new to this but glad to have you and others providing advise and feedback, really appreciate it.

 

[DirtDonk]

Glad to help Jake.
Of course, it might be steering you wrong if you end up needing to return them after all. Because once you've taken them apart (and frankly, once you've installed them sometimes!) you probably can't return them.
The good news of course is that if these springs just don't work out even with removing leaves, they can still be sold on for a good price because there's a lot of demand for Bronco rear leaves.

But we won't go there yet. Chances are very good you'll be able to use these one way or the other.
In the meantime check out savage's thread about it too, to keep track of how his goes.

And let us see pics of your overall Bronco-project progress too!

Paul

 

[sprdv1]

Thanks, that makes since. I've read about removing the third from the top leaf spring to net 1-1.5" and that may help it feel more even but I'll wait until it's closer to being complete and do a compression test to see where the shock sits. It's nice to know there's an option besides spending money on shipping back and forth! I'm new to this but glad to have you and others providing advise and feedback, really appreciate it.

wealth of knowledge on here, never hesitate to ask

 

[sprdv1]

Glad to help Jake.
Of course, it might be steering you wrong if you end up needing to return them after all. Because once you've taken them apart (and frankly, once you've installed them sometimes!) you probably can't return them.
The good news of course is that if these springs just don't work out even with removing leaves, they can still be sold on for a good price because there's a lot of demand for Bronco rear leaves.

But we won't go there yet. Chances are very good you'll be able to use these one way or the other.
In the meantime check out savage's thread about it too, to keep track of how his goes.

And let us see pics of your overall Bronco-project progress too!

we love pics for sure...

 

[sprdv1]

Look up the thread by savage going through the same thing with springs. Ours have done it, Tom's have done it, and other brands as well. Doesn't make it right, but it does indicate that it has happened before.
Hence my recommendation to measure the ride height.

Back to fully the fully built question though, if yours is not then you can't judge anything yet. Any suspension determinations have to be done at full weight.

this one?

https://classicbroncos.com/forums/showthread.php?t=309897

 

[Rustytruck]

you can buy shock extensions if you love your shocks.

 

[savage]

Yes,I'm going through the same scenario. I have Tom's 3.5 inch 9 leave pack and after installing it, it measured at 12 inches, I don't run a top, doors, or sparetirer, so what I decided to do is simulate the weight with sandbags and drive it that way to break in the springs then take the weight out to see if it settled.at all. I ended up using 6 sand bags that gave me 360 lbs, and it now measures at 10.5 inches, so it lowered it by 1.5 inches. I'm going to wait on buying shocks, so I pick up shock extenders to use my old shocks for now . I thought the same thing should I've gone 2.5 inch instead of 3.5,but figured it's easier to remove leaves then having to used blocks ,which I hate.
Dave

 

[Nikko Long]

Well, if those shocks do not work for you in the long run, you may go for Bilstein shocks instead. Not only are they affordable, but they're top of the line as well.

 

[jake2077]

Hi all, I'm revisiting this thread and hoping for more advice. I now have the Bronco with powertrain installed, and engine fully installed. The front has dropped down so there is a rake with the back end trending upwards. I had wife and son sit in the rear of the Bronco to simulate weight and it did level out but without anyone in there it resumes the slanted look. Guess I could take another leaf out or would I risk having it sunken too much with passengers on board? Also, for fun the drive shaft does not reach now that everything has been reassembled {sigh}. I used the 6 degree shims in the rear and re-aligned the springs over the rear axle with no change. There is at least 1/2 to 3/4 inch gap. It worked before but guessing the springs were worn and allowed it to just reach fully extended. Even if I could get it connected it would be at maximum and that seems concerning. I did order a new rear drive shaft measuring 37 inches from TB and think that will give me the travel needed without stressing the u-joints etc.. Pictures for reference..

 

[DirtDonk]

I’m sorry you ordered a new driveshaft based on an incorrect ride height issue. If you ever correct your ride height you will now have a spare shaft to sell.
You still need to address the initial issue which is ride height being too high in the rear. Not to mention the pinion angle still being incorrect at least based on the visual cues in that picture.
It should have risen up but perhaps due to the overall lift height, it’s beyond what the 6° shim could compensate for.
The pinion still looks a little low.

Are you saying you did take a leaf out already? Or are the springs still as delivered?

 

[jake2077]

I had taken a leaf spring out already some time ago and the stance is still slightly raked. Wondering which of the leafs I should remove this time around? If I do review another leaf, would that help with the pinion angle?

Yeah, I'm not happy about buying the drive shaft but after doing some cleaning of the other I discovered metal degradation on the splines and it was packed full of dirt. This build keeps offering surprises at every turn.

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