Do new struts need a break-in period?

[Rock_Hudstone]

1997 Olds Cutlass Supreme. I replaced the front strut cartridges because they were knocking, 114k miles on them, and the car had a bouncy ride. That fixed the knock but the bouncy ride remained.

So I replaced the rear Monroe gas-matics under warranty. Even though they were only about two years old, they were worn, especially the left side. Unfortunately, I don't really notice any improvement in the ride, still seems bouncy.

The car has 250,000 miles and the tranverse monoleaf rear supension. Could worn springs cause a bouncy/jittery ride even with new struts all around? The car always had a pretty smooth ride until lately.

 

[daves66nova]

never heard of struts needing to break in.

 

[Rock_Hudstone]

Originally Posted By: daves66nova
never heard of struts needing to break in.

Yeah, I didn't think so, just running out of things to replace.

 

[oilboy123]

I would have replaced springs automatically at that high of miles. The springs do get soft. The springs support the car, so if they are toast it makes it much harder for the struts/shocks to control the car.

I would find out your ride height from a manual at he library, or maybe online. This will tell you for sure.

 

[Chris142]

I put Monroe shocks on my jeep and removed them an hr later because they were way too soft. put gabrials on and its been fine ever since. those monroes would let it bottom out on small dips and bouncebouncebounce down the rd

 

[LeakySeals]

I use Gabriels too. No problems. No rattles. ReadyMounts. Just right (for me). KYB too stiff, Monroe too soft.

 

[Rock_Hudstone]

Originally Posted By: Chris142
I put Monroe shocks on my jeep and removed them an hr later because they were way too soft. put gabrials on and its been fine ever since. those monroes would let it bottom out on small dips and bouncebouncebounce down the rd
I can't really blame the Monroes as I used the Gas-matics on this vehicle for years and the bouncing is a recent development, so something else must be going on.

 

[mechtech2]

I'm sure the ride will stabilize in 100 miles.
There must be initial 'stiction' that will seat in.
But no special techniques are required.

 

[LeakySeals]

Could be the springs

 

[TFB1]

Originally Posted By: LeakySeals
Could be the springs


Maybe if it's bottoming out, but weak springs usually cause a noticeable decrease in ride height... Bouncy is generally too stiff of a spring for the damping action of the shock/strut, this is why the ride gets bouncy as the shock/struts age...

If the shocks are really stiff, then the suspension won't compress as it passes over bumps, giving a bumpy ride but not bouncy...

 

[hattaresguy]

Your in NJ you could have a broken spring.

 

[Rock_Hudstone]

Originally Posted By: TFB1
but weak springs usually cause a noticeable decrease in ride height... Bouncy is generally too stiff of a spring for the damping action of the shock/strut, this is why the ride gets bouncy as the shock/struts age...

Ride height appears to be the same as it always been, I've seen other w-body cars with clapped out, sagging springs and the decreased ride height is unsually obvious.

Its most noticeable on relatively smooth roads as the car does short quick bounces and jiggles over slight road surface imperfections.

 

[zzyzzx]

At that age, you should be using a quick strut.

 

[TFB1]

Originally Posted By: Rock_Hudstone


Its most noticeable on relatively smooth roads as the car does short quick bounces and jiggles over slight road surface imperfections.


Sounds like a combination of stiff sidewall tire and new struts that are stiff as well... They'll soften up, in uhhh, about 25K mi...

My '07 Grand Marquis is noticeably stiffer over small bumps with the new tires installed a couple months ago, car has 52K mi everything else orig...

 

[Jim Spahr]

Have you checked the monoleaf rear spring pads? They are a common problem because they wear out and cause all sorts of problems. Moog has a replacement 'problem solver' pad pn K6544 that is cheap and easy to install. You don't have to remove the spring, just jack up the spring a bit and slide the new pad in. Twenty dollars.

 

[Quest]

never heard of struts need breakin period. They will start deteriorating the moment you mount them and start using them. There's no "plateau" or breakin, just gradual deterioration.

The rate of deterioration depends on many different factors: from quality of manufacturing and materials, to assembling and quality control, to how the environment the struts have been exposed to.

Just like tires, they will eventually go.

Q.

 

[yonyon]

Originally Posted By: Rock_Hudstone
Originally Posted By: TFB1
but weak springs usually cause a noticeable decrease in ride height... Bouncy is generally too stiff of a spring for the damping action of the shock/strut, this is why the ride gets bouncy as the shock/struts age...

Ride height appears to be the same as it always been, I've seen other w-body cars with clapped out, sagging springs and the decreased ride height is unsually obvious.

Its most noticeable on relatively smooth roads as the car does short quick bounces and jiggles over slight road surface imperfections.


The W's are pretty jiggly things, especially Cutlass Supreme and Impala. They're almost into Sebring convertible territory. Monroes, especially their high line, tend to be jiggly as well.

When replacing cartridges be sure that the oil is full. Air is lower viscosity compared to any shock oil and will give less damping.

 

[Jim Spahr]

Many in the GM FWD W-body Gen 1 world use and rec. the KYB GR-2 struts. RockAuto carries them. They say the GR-2's are firmer and the Monroe's are too soft. and the Gabriel struts are in between.