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Bilstein shock length

doogie928

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May 29, 2017
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I would like to purchase some new bilstein shocks for my 73. Not sure what is on there now or if they are the correct length. The guy I bought it from said it had a 3" suspension lift. I'm thinking it is either a 2 1/2 or 3 1/2. I am running stock shock positions. Anyone have any suggestions for correct compressed and extended length shocks for front and rear? Thanks!
 

JeepGuy

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Aug 24, 2006
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I would like to purchase some new bilstein shocks for my 73. Not sure what is on there now or if they are the correct length. The guy I bought it from said it had a 3" suspension lift. I'm thinking it is either a 2 1/2 or 3 1/2. I am running stock shock positions. Anyone have any suggestions for correct compressed and extended length shocks for front and rear? Thanks!

I can't help with the front, but the rear on mine in stock position with a 3 1/2" suspension lift. The rear shocks measure eye to eye 21 1/2" at ride height.

It's easy to measure, just take a tape measure and go from bottom bolt to top bolt on the rear shock. Of course that does not account for travel in either direction which is a whole other discussion.
 

DirtDonk

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You can also check the Bilstein applications for that height lift.
But first, because there is room for doubt, I would verify the lift.

Measure between the top of the axle tubes and the bottom of the frame rails front and rear. You can even do all four corners if you want, just to see if it's sitting evenly.
Your stock reading would be 7" in the front and 6" in the back. So whatever amount above those numbers is the amount of suspension lift.

There are 3" lifts out there by the way. Just not from the Bronco-specific vendors that I know of. A popular old-school lift was Rancho, which was 3" for Broncos. Red coil springs with big thick coil wire material.
Even modern lifts do not always keep the precise amount of lift initially, or over time. So knowing exactly what you're running is a helpful bit of info. And measuring your shock mount positions gives you the info you need to compare the recommended shock lengths to your exact needs.

Paul
 

DirtDonk

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Sorry, forgot to put the numbers that I know in that last answer.
In the older Bilstein catalog of several years ago (can't find my newer one at the moment) the front shocks in the 5100 series for a 2-4" lift on stock mounts are:
#24-065283. That would be a stem at the top and an eye at the bottom.
For the rear the 5100 series for 2-4 inches of lift is:
#33-186542 which has eyes at both ends.

We sell the set of four under our number #BIL88000 here: https://www.wildhorses4x4.com/produ...-77-Bronco-Stock-Mount/Bronco_Shock_Absorbers
You just choose the lift you want them to fit.

While they may be the exact same numbers as the old catalog, they may also be different due to our take on the proper lengths and valving for a Bronco. I'm sure most of them cross over to a recommended part by Bilstein, but some may not.

And speaking of that, you need to factor in what other mods have been made to your Bronco. For example, do you have big heavy bumpers, roll cage, gas tanks and all sorts of other equipment that might make yours heavier than a stock Bronco? If so, then you may choose to go with slightly stiffer valving. The recommended valving is excellent for most use with a standard weight Bronco, but can be too light for some tastes.

Paul
 
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doogie928

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May 29, 2017
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Thanks for the info! Will do some more investigating on the dimensions. I'm just running stock bumpers, but do plan on installing the 23 gal tank in the future.
 

JeepGuy

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Sorry, forgot to put the numbers that I know in that last answer.
In the older Bilstein catalog of several years ago (can't find my newer one at the moment) the front shocks in the 5100 series for a 2-4" lift on stock mounts are:
#24-065283. That would be a stem at the top and an eye at the bottom.
For the rear the 5100 series for 2-4 inches of lift is:
#33-186542 which has eyes at both ends.

We sell the set of four under our number #BIL88000 here: https://www.wildhorses4x4.com/produ...-77-Bronco-Stock-Mount/Bronco_Shock_Absorbers
You just choose the lift you want them to fit.

While they may be the exact same numbers as the old catalog, they may also be different due to our take on the proper lengths and valving for a Bronco. I'm sure most of them cross over to a recommended part by Bilstein, but some may not.

And speaking of that, you need to factor in what other mods have been made to your Bronco. For example, do you have big heavy bumpers, roll cage, gas tanks and all sorts of other equipment that might make yours heavier than a stock Bronco? If so, then you may choose to go with slightly stiffer valving. The recommended valving is excellent for most use with a standard weight Bronco, but can be too light for some tastes.

Paul

Paul you bring up a great point with all the add-on's. In your experience if you're running heavy bumpers, Bigger tires (33+) rear tire carrier, 23 gallon tank, full cage, etc... Is there a big difference in the 5100's or 7100's applications?

At the moment I'm stuck in deciding whether I'm going Bilstein, the new Duff Eibach's, or bumping up to FOX.
 

DirtDonk

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I'm just running stock bumpers, but do plan on installing the 23 gal tank in the future.

Luckily the rears are not as finicky. They're already valved much lighter than the fronts, but a few extra pounds right near the axle does not make a big enough difference to bring out any comments I don't think. Mostly the fronts, and mostly with a big winch bumper hanging way out there in front of the suspension.

Paul you bring up a great point with all the add-on's. In your experience if you're running heavy bumpers, Bigger tires (33+) rear tire carrier, 23 gallon tank, full cage, etc... Is there a big difference in the 5100's or 7100's applications?

Well, in off-the-shelf parts, there should be no discernible difference at all if the two shocks use the same valve ratings. The advantage to the 7100's (besides just being larger and possibly heavier duty construction) comes in the sheer number of custom valving options there are.
And if they still offer it, there is at least one free re-valve job that Bilstein will perform for you at their facility. So if you find that the one you bought is too soft, too stiff, or too "wrong" in one way or the other, they can help you out.
After that one you have to pay for future re-valves if needed, but it's still a nice bonus for the extra money.
And they are rebuildable if you wear them out.

I can't say for certain (because I have not looked) if the 5100's and 7100's share the same valve/piston types or not. But they are at least rated with the same numbering system which should equate to roughly the same feel. So a 255/70 (just a number example) 5100 I would expect to feel the same as a 255/70 7100 family shock.

The other advantage is the option of an external reservoir which the 5100 does not have. The external supply has two functions. Primarily it allows for more shaft/piston travel within a shock body of the same length because the displaced oil has somewhere to go. It also has the effect of better cooling under hard use because there is more fluid and at any given time some of it is in a cooler place where it can hopefully dissipate some more of the built up heat generated during use.

So the 7100's do have several advantages. But as to being a better performer in the usual categories (street comfort, road handling and off-road bounce control) I'd have to plead ignorance and say they'd be the same.

Paul
 

73azbronco

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I think I have a much easier way to ID the right shock length, measure sitting height distance between top and bottom of shock mounts.

Then go look at shock specs specifically extended and compressed numbers.

My fully compressed or "up" is really only 4-5 inches then I hit bump stops, so I'd like more down than that and I want my shock to sit right about 4-5 inches from fully compressed. So my Ranchos have about 5-7 down and 5 up.

BTW not really impressed with Rancho 9000, one front corner dives much faster when settings match. So little bump steer oversteer, and shock rebound issues makes for a fun drive.
 
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AZ73

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Does your Bronco have the F250 shock towers? check that too. Easy way to see it the factory tower uses a bolt at the top. F250's use a bolt through eyelets.
 

Madgyver

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Jul 30, 2001
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we did this a couple of nights ago... it's a 12" shock.
 

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