silky

I think I have a problem with my suspension- more in the rear than front. I'm wondering if my shocks are bad.

What are the signs of bad/old shocks? How do you know it's time to replace or upgrade?

GS400 '98 with 43K. Thanks

RON430

The old test used to be to get the car bouncing and watch it settle out. If you press up and down on the fender to get the car bouncing and then stop, it should damp out in one oscillation. I personally don't think this is very useful any more with modern suspensions. Probably the best indication is to get under the car and look at the shock (or strut or cartridge or whatever). If you see something that looks like a water stain on the body, it means the oil has leaked out and it is one dead puppy. Don't know what Lexus would say but I have a very low opinion of any OEM shocks and 43K is probably long past when they have gone out on you.

rominl

iTrader: (4)

yip, either look for leak, or try to drive the car on bouncy roads. if it keeps on going up and down, it'sdead

mooretorque

The stock units are insufficiently damped to begin with, so a sort of bouncy, whoopsy ride is not unusual, even with shocks that have not yet worn out. Since (unless they start to leak and fail very quickly) the change in handling and ride is so gradual, it can be hard to decide if your car is wobbling around more. I agree with RON that the old "push the bumper down" test is not useful any longer. And if the shock isn't leaking, there will be no stains on it.

At 43k, you've gotten more than enough use out of them and, even if they haven't failed completely, will certainly not perform as well as when new. May I suggest something in, say, an L-Tuned shock/spring combination?? 1.25" drop, much better controlled ride motions, almost no change in comfort (maybe even an increase if current shocks are shot) and slightly less body roll. (I know L-Tuned has/is going away, but the parts are still available thru TRD; your dealer can order or you can get them from Steve Ganz at Carson Toyota for about 12% less than list.) Certainly there are other alternatives but I think it may be time to retire the old set!!

silky

Thanks for the feedback guys. I sure hope replacing the shocks will help with the harshness over road irregularities that I still feel even with new tires--Sumi HTR+

Two new questions now--
1. if oem shocks are not good but I'm not sure I want to lower my car, what would be a good choice of shock. It seems that the l-tuned shocks (and Springs) automatically lower things. Right??

2. What about my springs? Is it time to replace them too if only replacement shocks rather than the l-tuned system is used?? When, if ever, do springs wear out?

Thanks.

JacobT

The springs are the components that affect your ride height. You can rplace the shocks w/o affecting the ride height. You can get L-tuned shocks to replace the stock shockswithout losing any ride quality.

RON430

silky - In the olden days it was a lot easier to describe what a shock did and what a spring did, now things are blurred somewhat. Originally, the shock, which was referred to as a dampener was there to damp out the oscillations of the spring as it returned to its rest position after experiencing some suspension movement. However, now the shock is used to tune the handling and response of the spring as much as the spring is. The spring is a very robust unit that gets its property from the material and the winding with a long life. One of your comments gives me a little concern and that is that your complaint is ride harshness. When a shock goes away, the ride is normally very soft and inevitably, putting new shocks on will firm up the ride quite a bit. If your ride harshness is because even small bumps are causing large excursions in the wheel/tire (and transmitting that to the car) then shocks will certainly help. I have bilsteins and am a strong supporter of them, as has been posted. Other posts indicate that the L tuned shocks are also excellent. I have a hard time believing your springs are shot but if you want to have the ability to adjust ride height later, one of the coilovers might be a good approach. Most of the guys here are talking about expensive systems but bilstein also makes a coilover that isn't too bad on price. What is a coilover? Basically a shock with an adjustable spring perch that allows you to adjust static ride height by running one of the spring perches up and down. Hope this helps.

silky

Thanks guys. I'm going to try new shocks for sure. I'd hoped the new tires would take care of my ride problem and they do cruise very nicely but I still feel real thumps that resonate up into the cabin--very un-Lexus like--on large ruts etc.

I have Daizen sway bushings (not the bars) that I will install as well as the shocks.

I like the look of my black 400 with 17" oem silver wheels and probably won't lower it. So I just need to choose between L-tuned and Bilsteins --keeping the original springs.

Can you think of any other source of my loud thumping --almost banging--sound? I know I'll do a four wheel alighnment also. Could bad alighnment contibute to my problem?

I just bought this car a couple of months ago from a Lexus dealer--it's Certified--and have not had a chance to see it up on a rack yet.

RON430

Awfully difficult to diagnose sounds over the internet. Only other thing that comes to mind is the possible problem with the sway bar brackets loosening up. Some guys have reported some real loud noises, I just got a creaking noise from mine. Probably going to have to take it one step at a time.

mooretorque

silky, that impact harshness is likely another symptom of worn out shocks; had the same thing on my (previous) car, an SC 5spd in which, I am ashamed to admit, I let the shocks go so long that the CD player (trunk mount) would skip over interstate expansion joints. In my defense, I can only say that this sort of failure is very gradual as the internal valving wears out and one sort of becomes accustomed to the change because it IS so gradual.

I agree with RON; springs pretty much don't wear out, certainly not as quickly as this. You might also look at your front sway bar mounting brackets; the GS has a known problem with the mounting bolts loosening. It's not a dangerous, suspension-failure type of problem, but it's loud and it's very annoying, but very easy to fix.

Also, can't go wrong with those Bilsteins if you aren't going to do springs (and the only reason to change springs realistically is to alter ride height - I assume you don't plan to formally race the car on a track).

silky

You guys have given me hope--I love everything about the car except that harsh ride. I even love washing it.