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?
Printable View
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?
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.)
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.
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...:yeso:
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!Quote:
Originally Posted by samneil2000
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! :freek:
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.
http://i1099.photobucket.com/albums/...DSCN0435-1.jpg
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.
http://i1099.photobucket.com/albums/...908111658b.jpg
http://i1099.photobucket.com/albums/...908111658c.jpg
http://i1099.photobucket.com/albums/...8111649d-1.jpg
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.
http://i1099.photobucket.com/albums/...908111657b.jpg
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!
It means we remove them for the summer, fall and winter? :happyfaceQuote:
Originally Posted by blacksambo
srry
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.
Quote:
Originally Posted by blacksambo
Quote:
Originally Posted by blacksambo
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
http://www.trademotion.com/schematic...al/F669130.gif
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.
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.
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.
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!!!! :bgwb: 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.
[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.
Sambo, if your bump stops/"spring helpers" are contacting your axle at all times during forward motion, something is seriously wrong with your setup.
Test it out. Put some powder on the axle underneath the stop, drive around the block, (assuming you don't live in an overly bumpy potholed neighborhood) and see if there's been contact.
EDIT: Also, I just picked up full set of Rancho 9000XLs from Summit (finally!). They're having a special where Rancho will rebate you the cost of one unit when you purchase a set of four.
I don't think so. There is only, per factory specs, a quarter to half an inch open space there (between the spring helper and the axel rest plate), which easily colapses to zero with the forward inertia of a two-ton vehicle. Our springs are strong, but not two tons at 30mph and only a quarter of an inch margin strong.
so what is this "add nitrogen" you speak of?? my ride has become quite the bouncy mess in past few months, and i chalked it up as needing shocks.Quote:
Originally Posted by SlowPro48
You can refil the OEM shocks with nitrogen to help restore performance. Bike repair shops seem to do this service.
...and I just dropped 4 bills on new Ranchos. Ahh, it's all good I guess. I'm pretty sure the bike shop wouldn't rebuild my 14 year-old, never-serviced OEM shocks anyay. Plus, I've been dying to see what all the fuss is about with the 9000XLs! Hopefully Summit gets 'em to me by the weekend.Quote:
Originally Posted by blacksambo
I've got that pre-season madness going on now to get her in game shape for the winter. ;)
hmm ok thanks sambo Ill look into it
There's a guy named Bruce that's rebuilt our OEM shocks.
http://www.brucessuspension.com/
At least 2 owners have had him do it (Little Beast, VR4-QUEST)
Here's some old threads on it, including recharging them with nitrogen.
http://vehicross.info/forums/showthr...ighlight=bruce
http://vehicross.info/forums/showpos...1&postcount=12
http://vehicross.info/forums/showthr...s+shocks+bruce
http://vehicross.info/forums/showthr...ighlight=bruce
http://vehicross.info/forums/showpos...9&postcount=14
Thanks Kat! (How ya been, lady?)
I'll be reaching out to Bruce once my OEM's come off.
Anyone have any data on the life expectancy of the Rancho 9000XLs?
-V
Quote:
Originally Posted by blacksambo
Sambo, I'm getting too old and tired to argue anymore. Nowadays I like to agree with people. I'm curious though - exactly how do you think the spring helper insulates the axle housing from the frame by being in contact with it? Do you know how a mechanic's stethoscope works?
Will you agree with me that the axle housing is attached to the frame via a center link, a lateral link and two trailing links, which provide a pathway for vibration (sound) to be transmitted to the frame?
Will you agree with me that the shocks and coil springs also provide a pathway for vibration?
Will you agree with me that these pathways exist whether the spring helpers are touching the axle housing or not?
Will you agree with me that when the frame-mounted spring helpers are NOT in contact with the axle housing it is physically impossible for them to transmit the vibration from said axle housing to the frame?
And finally, will you agree with me that when the spring helpers ARE touching the axle housing, they do not insulate but rather provide an ADDITIONAL pathway for noise from the axle housing to reach the frame?
Fortunately, they don't provide much of a pathway because rubber does not transmit vibration very well. That's why the links and shocks are rubber bushed and there are rubber donuts between the springs and the frame.
The spring helpers may damp some vibration/harmonics in the frame and maybe even in the axle housing simply due to the fact that they have mass and are bolted to the frame/touch the axle housing - like play-doh on a tuning fork or a string silencer on a hunting bow - but they in no way acoustically isolate the frame from the axle housing by making contact with it. I wish they did because I would appreciate a little less whining from my differential.
Hey maybe I should bolt six or eight more spring helpers onto the backof the VX to quiet things down a bit!
Just think about it...
Oh and to the OP: If your shocks aren't leaking fluid, just take them off the vehicle, pop the metal cap off the reservoir and clean everything up - especially inside the schrader valve. Take the shocks to a motorcycle shop or tire shop that has nitrogen and tell them you want 250psi. Then go to Lowes/Home Depot/Grainger/any plumbing supply place and get rubber caps and jubilee clips to replace the metal caps you destroyed. Put the shocks back on the VX and see if it helped.
If not, you can get them rebuilt as long as the shaft isn't bent or dinged up. But a lot of times, just pumping them back up will do the trick. It's the same principal that allows the water in your radiator to go well over 212 degrees without boiling - only at about 20 times the pressure. If the shocks aren't pressurized enough, the fluid will cavitate when forced through the shim stacks and you end up with a bunch of air bubbles in the fluid. It's like boiling water in a pot except it's caused by pulling a localized vacuum on the fluid instead of having the vapor pressure of the fluid exceed atmospheric pressure due to heating. But the end result is the same - bubbly, frothy fluid that offers no resistance when forced through the piston/shims and therefore shocks that don't damp.
Give the nitrogen a try - it's a cheap gamble...
P.S. you can use a drill and slide hammer to remove the caps or they're thin enough to just hammer an awl in and pry the cap off - but do your drilling/punching off center! The shrader valve is in the center!
I just installed a set of moog 784 springs in my vx. You just have to cut off the pig tail and they are perfect for the isuzu. Depending on how much you cut off you get between about 3" lift to low rider I supose.
I am running 315 75 16 tires, so I went with 3". The ride is so much better than stock. It is like a new vehicle. I imagine that if you cut them so you had 1.5" it would still ride nice and you wouldn't have much lift. I got mine from Advance auto for $79 delivered.
http://i219.photobucket.com/albums/c.../Photo0512.jpg
[QUOTE=SlowPro48;265437]Sambo, I'm getting too old and tired to argue anymore. Nowadays I like to agree with people. I'm curious though - exactly how do you think the spring helper insulates the axle housing from the frame by being in contact with it? Do you know how a mechanic's stethoscope works?
Will you agree with me that the axle housing is attached to the frame via a center link, a lateral link and two trailing links, which provide a pathway for vibration (sound) to be transmitted to the frame?
Will you agree with me that the shocks and coil springs also provide a pathway for vibration?
Will you agree with me that these pathways exist whether the spring helpers are touching the axle housing or not?
I think you said it with the tuning fork analogy. The spring helper blends all these contact points into a balanced resonance and thus makes the clatter from this symphony of metal arms less prevalent .
I can attest from personal experience that it works this way. And my wife who has no particular mechanical expertise mentioned it first...."what did you do to quiet this thing down." Installed the missing spring helpers....simple.
These were my OEMs when I replaced them with Ranchos 9000XLSQuote:
Originally Posted by SlowPro48
I'm curious, is the rusty looking crudy end cap/piece in the first 2 pics indicative of them leaking something?
oh...and Hi V!...I'm hangin'....:wave:
http://www.vehicross.info/gallery/data/500/DSC_0071.jpg
http://www.vehicross.info/gallery/data/500/DSC_0075.jpg
http://www.vehicross.info/gallery/data/500/DSC_0074.jpg
http://www.vehicross.info/gallery/data/500/DSC_0076.jpg
http://www.vehicross.info/gallery/data/500/DSC_0070.jpg
http://www.vehicross.info/gallery/data/500/DSC_0059.jpg
Thanks for pics and help Kat
Really recommend anyone looking to reduce bounciness, jarring ride, etc. take a look at this thread:
Recommendations for Leveling Out Suspension
Pricier than Moog or even OEM springs but they're adjustable based on your load and they shouldn't wear out as quickly. It smoothed the ride in my VX while maintaining sharp handling, and when we couldn't find replacement springs for my wife's Axiom we had these installed instead. Probably handles better than the day we bought it.
Good stuff regardless of the answer to the "spring helper" / bump stop debate.
(Btw Isuzu calls those "rubber stoppers" on the Axiom, so there's a 3rd name for them. :p)
Geez, that makes at least the 4th name Isuzu uses for the same part!Quote:
Originally Posted by vt_maverick
http://www.vehicross.info/forums/sho...8&postcount=15
Different vehicles, different uses, that's being efficient.
That's right, I forgot Isuzu makes no mistakes. I think RamAirZ said it best back in the day:
http://t2.gstatic.com/images?q=tbn:A...gkNxUqwgXBJadN