how to know when to replace shocks, springs?

[bearandbee]

My vx is the bounciest car I've ever been in, speed bumps are jarring and I have a ton of rattles. How can I find out which pieces need to be fixed?

[RickOKC]

One of my rear bump stops was constantly in contact with the axle and there was about 1/4" of space between them on the other side. After putting on new(ish) springs & new stock spring insulators, both sides are even (about 1/2" gap.)

[samneil2000]

A lot of people cut the stock bump stops and have an improved ride. The jarring is when the axle hits the stops, which happens alot if there's only 1/2 inch of space. Cut the stock stop in half and you'll be happy.

[Scott Larson]

There seems to be so much difference between members rides, it really does make ya wonder about the handbuilt aspect of our VXs...I don't have any history on mine, but I do know that after two years of ownership, everything has checked out fine and that so many of the reported problems have not reared their ugly heads. That said, the suspension problems mentioned do not seem "normal". The space between bumpstops and axles is about an inch, and I see no signs of modifications? And no, I am not bragging; I do feel really lucky though...

[Mile High VX]

A lot of people cut the stock bump stops and have an improved ride. The jarring is when the axle hits the stops, which happens alot if there's only 1/2 inch of space. Cut the stock stop in half and you'll be happy.

X2...I got a set of bump stops from a Rodeo at the local salvage yard and cut those down and put them on the VX...rides much better and I still have my OEM stops if I ever want to put it back. Cost me about 5 bucks and a trip to the yard!

[VX KAT]

The VX suspension/ride quality is a very common topic of discussion on this forum. You should take some time and use the search function and some key words about suspension, shocks, jarring, etc...and take some time to read up on it since it's so well documented.

The OEM shocks are unique for a "passenger" car/truck as they have reservoirs to aid cooling.....that's not found on any other production car, at least as of when our VXs were built. It also has a VERY stiff/tight ride dialed in, that's the way it was intended.

If you read up about the VX suspension, and check out some of these pics, you'll better understand why the truck is so jarring and slamming....at least it really helped me understand why the ride was so harsh.

Many owners have bought the "Rancho XLS9000" 9-way adjustable shocks, (including me!). Allows you to set them differently using 9 different settings....obviously from softer to harder...MANY have said that the OEM shocks are still stiffer than the Ranchos on setting 9, the firmest.

I currently keep my Ranchos on 6/4 (F/R)...and with my rear bump stops cut in half, I'm very happy with the ride....it will STILL just about JIGGLE your teeth out on a rocky road...but that's much improved over what it was!
So don't ever expect a sedan or family car ride in a VX...never!

Hope this helps ya!


Here's some threads to get you started:
BUMP STOPS:
http://www.vehicross.info/forums/sho...ight=bump+stop

http://vehicross.info/forums/showthr...ight=bumpstops




DISCUSSIONS ABOUT SHOCKS, BRANDS:
http://vehicross.info/forums/showthr...ighlight=bruce

http://www.vehicross.info/forums/sho...62&postcount=6

http://vehicross.info/forums/showthr...ighlight=bruce



HERE'S A 3/4 VIEW PICTURE OF THE OEM REAR BUMPSTOP. IT'S THE BLACK THING WITH THE BEIGE MUD/DIRT ON THE BOTTOM. IT'S SHAPED LIKE A FIGURE "8", MADE OF SOME DENSE TYPE OF RUBBER.
** NOTICE HOW CLOSE THAT BOTTOM BEIGE PART IS TO THE AXLE...MAYBE 1/8" CLEARANCE...THIS ONE IS VIRTUALLY SITTING ON THE AXLE! EVERYTIME YOU HIT A BUMP, THE AXLE COMES UP AND SLAMS INTO THE HARD BUMPSTOP.




THIS IS A SIDE SHOT PIC AFTER I CUT THE BOTTOM HALF OFF OF THE "8", YOU CAN SEE THE REMAINING RUBBER STOP IS NOW A BLACK "O" SHAPE. IT GIVES AT LEAST 4" MORE CLEARANCE BETWEEN THE REAR AXLE AND THE BUMP STOP. THIS GREATLY REDUCES THE SEVERE "SLAMMING" EFFECT YOU HEAR AND FEEL WHEN HITTING A BUMP. IT MADE A HUGE DIFFERENCE IN THE RIDE ON ROUGH/DIRT/ROCKY ROADS, AND ON POTHOLES!

NOTE THE BLACK SHINY SQUARE AREA, THAT'S WHERE THE BUMP STOP ACTUALLY COMES INTO CONTACT WITH THE AXLE.








THIS IS A FRONT BUMP STOP. IT'S DIRECTLY TO THE RIGHT OF THE BRIGHT RED BRAKE LINE. THEY'RE A SQUARE PAD ABOUT 3" x 3", and about 1.5 - 2" thick. YOU CAN SEE THE CLEANER BLACK SPOT ON THE FRONT AXLE WHERE THEY COME INTO CONTACT WITH IT.
THEY'RE NOT AS CLOSE TO THE AXLE AS THE REARS, DON'T KNOW ANY ONE HAS CUT THESE, USUALLY THEY REPLACE THEM WITH SOME PROTHANE ONES.

[blacksambo]

We've been around this block before (hate to remind everyone).
Those black rubber figure eight things are not bump stops!

They are technically spring helpers. What does that mean?

They stop body roll and quiet the ride. They are supposed to be about one-half inch above the rear axel, at rest.

So, where does that leave us? if you shorten them they will not stop body roll or help deaden sound. That's all..........? You can remove them permanently, and your VX will stiil move forward....but without the factory ride, safety and quiet the VX was mean't to offer. (Remember 1996? Isuzu was sued by Consumer Reports for excessive body roll. Neither side won but the seeds were planted in Isuzu's mind on what to do next.) It's your choice. Nuff said!

[Grif]

They are technically spring helpers. What does that mean?

It means we remove them for the summer, fall and winter?

srry

[Grif]

So... that leaves us with nothing but telling us not to alter the spring helpers even as it may help our ride. Does not address the original post.

SHOULD the spring helpers sit on the axle? If they do or dont, does it mean we need new springs or shocks or adjustments?

Mine do not rest on the axle and my ride feels springy, but on large bumps will get jarring fairly easily.

So in the spirit of the original post, how can we tell??? What is the proper clearance? How much energy should the proper springs and/or shocks absorb and how can a layman determine that easily?

Not sure if anyone here has a pat answer to that.

We've been around this block before (hate to remind everyone).
Those black rubber figure eight things are not bump stops!

They are technically spring helpers. What does that mean?

They stop body roll and quiet the ride. They are supposed to be about one-half inch above the rear axel, at rest.

So, where does that leave us? if you shorten them they will not stop body roll or help deaden sound. That's all..........? You can remove them permanently, and your VX will stiil move forward....but without the factory ride, safety and quiet the VX was mean't to offer. (Remember 1996? Isuzu was sued by Consumer Reports for excessive body roll. Neither side won but the seeds were planted in Isuzu's mind on what to do next.) It's your choice. Nuff said!

[VX KAT]

We've been around this block before (hate to remind everyone).
Those black rubber figure eight things are not bump stops!

They are technically spring helpers. What does that mean?

They stop body roll and quiet the ride. They are supposed to be about one-half inch above the rear axel, at rest.

So, where does that leave us? if you shorten them they will not stop body roll or help deaden sound. That's all..........? You can remove them permanently, and your VX will stiil move forward....but without the factory ride, safety and quiet the VX was mean't to offer. (Remember 1996? Isuzu was sued by Consumer Reports for excessive body roll. Neither side won but the seeds were planted in Isuzu's mind on what to do next.) It's your choice. Nuff said!

IMHO, what they're called isn't as important as understanding what they do and trying to give the initial poster some background info and detail on them.

I've found they often come in contact with the axle at rest and cause an extremely jarring ride on bumps.....many other owners have said their "black rubber figure 8 thing" is actually resting on the axle (as in my picture).....Other SUVs I own have between 4-6" clearance. That may well be because they aren't marketed as a "PUV" like the VX was.

Based on the comments in the thread below, I really think we're describing the same "function"........the nature of the ride, the very similar "jarring", insulate frame from body, insulate vibration, prevent metal on metal contact, noise reduction.... You says they also help in cornering.

If cutting them in half increases coil compression and changes the spring rate from OEM....I'll still take it and any consequences that may cause, because the improvement in the ride is worth it to me.

Here's the thread from a few months ago Black Sambo started about them, and a couple highlights of comments:
http://vehicross.info/forums/showthr...spring+helpers

• They stop coil compression and isolate the frame from the body. Mine rusted away sometime back. Maybe way back? But replacing them really really helps stabilize the ride and reduces the noise factor, significantly.

• These "helpers" take the body and insulate it from the frame. Without them you're talking metal to metal contact between the frame and the body, and that means noise. If you study a VX underside you'll see rubber isolaters at all the mounting points. These spring helpers do just that, they help the spring and shock mounting points avoid a metal to metal ride in the rear. Renew yours and and you'll immediately hear the difference.

• ironing out the vehicle vibrations and undulations.

• they more gently "stop" your compression on up travel so that it is not a sudden "bump" when your springs(or shocks) reach max compression, or when the top of your tire contacts with the bottom of your rear cladding (wheel well).

• Using Merlin's St. Charles Isuzu parts site, they're PART #10 in the schematic, and are called "BUMPERS, VEHICROSS", MSRP $50.64, PRICE $43.04.

• Using "myisuzuparts.com", they're called "RR SPR HELPER RUBBER", PART #8-94374-448-1

[bearandbee]

Thanks for all the info everyone! I ll roll up my sleeves and get ready for another project once I learn what needs to be done. At least I don't need to buy shocks, springs at this point.

[Maddawg]

I'm not disagreeing with the body roll concept of the rubber "stops", BUT, that's what the sway bar does. The frame doesn't contact the rear axle without the rubber so I don't understand what that has to do with noise.

[blacksambo]

The OEM VX spring helpers contact the rear axel at all times when the vehicle is in forward motion. You can check this by looking at the '97 JDM phanton view in the sales brochure. You'll notice the spring helper at rest is only about a quarter of an inch off the axel plate. It was the intended design, to help insulate the axel from the frame, as well as to help the springs absorb energy and counteract the natural roll-over tendency of such a tall vehicle. That's all the magic there is to it.

[SlowPro48]

You're right, Maddawg - they've got nothing to do with noise. The spring helpers may provide a small, coincidental measure of sound damping due to the fact that they have mass and are bolted to the frame and thus attenuate some vibes but they in no way insulate the axle from the frame. The exact same axle/frame contact points exist whether the spring helpers are there or not. Sound damping is not their reason for existence. The spring helpers take advantage of the hysteresis of rubber in order to provide rollover protection.

Yes, the sway bar helps limit body roll but, being a torsion bar (i.e., steel spring), it offers the same resistance whether it's being twisted slowly or rapidly and it also returns almost all of the energy it stores. This applies to the coil springs too. Without spring helpers present, the shocks would provide the only damping to control rapid oscillations such as would be seen in a high speed avoidance maneuver - and the engineers apparently decided stiff shocks and springs weren't enough to prevent rollovers and the attorneys and bean counters decided spring helpers were cheaper than settlements, thus we have spring helpers instead of bump stops.

Due to the elastic hysteresis inherent in rubber, the faster the spring helper is compressed, the more resistance it offers, and it doesn't store and return all of that energy but rather converts it to heat. This gives us some rollover protection from botched avoidance maneuvers but the ignorant little chunks of rubber can't tell the difference between a frost heave and a swerve to avoid a deer so we have to put up with a harsh ride if we want avail ourselves of the full measure of safety designed into the VX.

Or one can roll the dice, chop the chunks and roll over square edged bumps in relative comfort - and hope one doesn’t roll over in any other way!

Anyway - the original question was which pieces need to be fixed when the boinging starts. The answer is.... THE SHOCKS!!!! But if it's just a harsh ride you're talking about then that's normal. If you're getting a lot of brake dive and pogoing then the dampers are no longer damping. If you've still got the OEMs, you might want to try just adding nitrogen. If that doesn't work, they can be rebuilt. If you've got worn out aftermarket shocks then it's time to replace.

[blacksambo]

[QUOTE=SlowPro48;265236] The exact same axle/frame contact points exist whether the spring helpers are there or not.

I'm not trying to be argumentative here but....the spring helpers do touch the axel at all times when the VX is in forward motion, so therefore they are constantly insulating the axel from the frame, thus causing a noise deadening effect.

I can also attest that this is one of the benefits I immediately noticed upon putting mine back in play after a period of abscence. My wife also noticed this benefit.