Front Suspension Too Soft?

[richg]

Finally got on the highway today with my '73. Still sorting it out. Overall, it drives and tracks really well, but I hit a couple of sections on the road where the front end felt like it was just going up and down like a boat and it would not settle back out. To the point that it felt pretty unsafe.

I have no idea what springs are on it, but it has an extended travel setup front and rear (I measured 4" of lift). It has brand new JBG shocks (https://shop.broncograveyard.com/JBG-Front-55-Lift-66-77/productinfo/13437/). Current installed, loaded length of front springs is 15", and the distance from frame underside to upper spring perch is 8".

I did a quick compression/rebound check after I got it back home, the videos are here.

Front -

Rear -

The front is SUPER easy to get it to bounce, I can do it with one hand, and it takes several cycles for the shocks to get it back under control. The rear seems much stiffer, and settles down very quickly, it is basically stable after one cycle.

Is this simply all shock related? Or are the front springs too soft as well? Pics of front suspension setup attached.

 

[Rbuddy98]

Looks like a front shock issue.

 

[blubuckaroo]

I bought/installed a set of the yellow Bilstein shocks from one of our vendors, I took them off and sent them back. They were just too squishy for me. I was a bit surprised they took the return because I always paint my shocks black.
I've been very happy with the 70/30 shocks that most of our vendors sell.

 

[RODRIG3911]

Have you tried flipping them around and have the rubber dust guards up? Maybe the compression and rebound are backwards the way you mounted them. Toms site shows them mounted the other way

 

[richg]

Have you tried flipping them around and have the rubber dust guards up? Maybe the compression and rebound are backwards the way you mounted them. Toms site shows them mounted the other way

That's a good point, I swapped these on the same direction the old ones came off, and really didn't pay attention otherwise.

rich

 

[Slowleak]

From Bilstein: “You always want to install our application specific B6 4600 and B8 5100 shocks so the Bilstein labeled on the shock body is reading in the correct orientation. If your shocks have been installed with the stickers on upside down then the shocks should be flipped the other way.”

 

[Shimmy]

Whoa that front bounce is insane!! When you installed them were they easy to push in or did they somewhat bust out of the box?

 

[triracer67]

Concur with RichG. I bought a bronco with shocks upside down on front, it bounced like yours.

 

[richg]

The shocks I took off were totally blown , but the ones I put on were fine out of the box. They are gas charged so I had to compress them and be quick with the bolts. I can try flipping them around but I'm not sure if that will fix the problem (unless they are sensitive to gravity and hopefully I didn't damage them). No matter the orientation, they are in compression the same time the spring compresses and in rebound when the spring extends.

 

[DirtDonk]

Absolutely check them in the reversed position. It's not that compression and rebound change (compression is still compression and extension is still extension no matter which way the shock is placed) but the way any particular shock is designed can cause the piston-to-oil relationship inside to change. A gas-charged shock should not be as susceptible to this, but that does not mean it can't. It's all about the design.
If they are still soft after a reasonable time when you put them in the body-down position, then they're defective.

I doubt you would have have hurt anything by running them in the shaft-down position, but it might take some driving before they fully recover and get back to normal operation.
I've personally never experienced this with any shock run in the shaft-down position, but I can imagine it's very possible anyway.

Good luck. And definitely bounce them around a bit and let them sit in their new position for a bit before making a decision about their performance.

Paul

 

[toddz69]

The front shocks also look like they're too long for your application as well. There isn't much shaft extension at rest, which may cause the shocks to become bumpstops depending on your front suspension configuration.

Flip the shocks and they should immediately be better if the upside-down configuration is indeed the problem.

Ideal bounce on the front end after you let go is about 1/2 of a suspension cycle and then stop. That's known as critically damped and it's what you want.

Todd Z.

 

[ame]

If that is a twin tube shock then there is valving in the base of the body, with it up top it is sitting in an air pocket making it cavitate and useless thought as Todd mentioned they are wayyy too long as well. A shock with a IFP - Internal Floating Piston - separating the gas and oil can be mounted any way you want, a Twin tub / Emulsion must have the body down.

 

[Rustytruck]

wow you are a strong man.

 

[Apogee]

That video makes me think of the spring mounted "animals" on the little kid playgrounds that bounce around...but clearly there's an issue with your shocks and/or damping coefficients. I'm betting it would behave similarly if you removed the shocks entirely and tested it again.

 

[savage]

That video makes me think of the spring mounted "animals" on the little kid playgrounds that bounce around...but clearly there's an issue with your shocks and/or damping coefficients. I'm betting it would behave similarly if you removed the shocks entirely and tested it again.

That's exactly how my front end acted after I changed my arms. I was curious how much do the shocks stop the bouncing, so with out shocks, I grabbed the front and holy #### . Its amazing how much the springs bounced to the point it was getting close to the bum stops!!!;D

 

[brewchief]

When I swapped to deaver springs I still had some old doestch tech shocks that were pretty well junk, with a stiff spring you didn't notice how bad they were but with a soft spring they were about that bad. I replaced them with a 255/70 valved bilstein and it was better but still bouncy, a switch to a 360/80 valved bilstein has made it pretty good, probably as good as it will get with an off the self shock. I don't know what springs those are but they appear to be pretty soft so it will take a decent shock to control them.

Sent from my SM-T510 using Tapatalk

 

[richg]

Absolutely check them in the reversed position. It's not that compression and rebound change (compression is still compression and extension is still extension no matter which way the shock is placed) but the way any particular shock is designed can cause the piston-to-oil relationship inside to change. A gas-charged shock should not be as susceptible to this, but that does not mean it can't. It's all about the design.

I should be able to try to flip them this weekend. I sent a note off to JBG to ask if orientation matters on these shocks but hadn't heard back.

The front shocks also look like they're too long for your application as well. There isn't much shaft extension at rest, which may cause the shocks to become bumpstops depending on your front suspension configuration.

I checked with two different vendors when I was picking shocks for the length recommendations based upon my static measurements. Both ended up with about the same length shock recommendation, which gave about 5" compression and 7" extension. In hindsight if doing over again, I might go with a shorter shock and given up some on the extension to have more compression given how I mostly use the truck.

I have a feeling that even after flipping them, I'm going to end up swapping to a better shock.

rich

 

[needsmoarturbo]

Yeah, that must have some soft springs, BUT proper shocks should still be able to dampen it so it's not bouncy..

 

[toddz69]

Those look like they're probably WH springs, which aren't the softest coils out there. It's amazing how freely these coils move when there isn't a shock there to damp the motion.

Todd Z.

 

[richg]

When I took the shocks off, there were all these dead spots in their travel with no resistance. After flipping them the correct direction and then cycling them through their full travel a few times they started to act normal again. I let them sit a little while, then cycled them again, and they are back to normal. Re-installed and front end is back under control .