Upgrade rear shocks to a monotube design?

[The Critic]

My dad's 92 Previa needs new ride control components...badly.

KYB offers their monotube gas-a-just shock for the rear, but not for the front. Their only option for the front is the twin-tube, OE replacement Excel-G/GR-2 model. They also have the Excel-G/GR-2 available for the rear, should I decide to have a matching design all around.

I like the idea of having an upgraded shock, but am a bit a concerned about having a stiffer shock in the rear. Will this cause handling issues? This van is a daily driver and never sees any towing, hauls to the dump, etc.

I've noticed that KYB has a tendency to only offer the Gas-A-Just on the rear for a number of cars, fwiw.

Thanks.

 

[Towncivilian]

For what it's worth, I'm running GR-2/Excel-G on the front struts of my Pathfinder (one of each, in fact; one is black and the other silver, heh) and Gas-A-Justs for the rear shocks. I can describe the ride as stiffer, yet smoother over the previous ~130k mile worn KYB OEM components. I think you should be fine with Gas-A-Justs on a car, but I have no first hand experience in such case.

 

[SteveSRT8]

More rear roll stiffness can dramatically change the handling, but I'm not sure just a shock can make much difference.

Sounds like a try it and see...

 

[PandaBear]

I once had only replaced the rear strut of my corolla and left the front alone (due to frugality) and it "handles like a sport car". My understanding is for a FWD car having significantly stiffer rear suspension than front could increase the chances of spin out.

If you are doing it just for durability purposes, I'd day no. Excel-G/GR2 should also have lifetime warranty if you do not lower the ride. I've done some motor control related work before and found that changing just the dampening without changing the spring rate can make the payload "shake like a duck" as our customer says.

 

[JHZR2]

We had that setup and it was fine.

 

[eagle23]

I'd be reluctant. The stiffer rear shocks do add to intial rear roll stiffness, i.e, a quick lane change, so it can feel more responsive. I've done that a couple of times through the years. It does help a front-driver understeer less, at least at initial turn-in.

But is that what you want for your dad? Is that what he would really want? I'm not saying he does or doesn't, just asking to hear what he wants and respecting that choice is probably best.

For a daily-use, 21 yr old grocery-getter, anything you use will be an improvement, one that he would likely appreciate. Unless he's one who likes to toss the van around, I'd stick with the matched set of four, which probably costs less anyway.

 

[GMBoy]

With the age of the vehicle and it's intended use I would just go with a lower priced Monroe sensa trac or similar all the way around. They have a lifetime warranty and anything you do is a big improvement over what he has now.

 

[another Todd]

Originally Posted By: GMBoy
With the age of the vehicle and it's intended use I would just go with a lower priced Monroe sensa trac or similar all the way around. They have a lifetime warranty and anything you do is a big improvement over what he has now.


+1

 

[mechanicx]

Originally Posted By: GMBoy
With the age of the vehicle and it's intended use I would just go with a lower priced Monroe sensa trac or similar all the way around. They have a lifetime warranty and anything you do is a big improvement over what he has now.


+2. Also isn't it getting around the time of year when you but 3 struts/shocks get 1 free or whatever rebate.

 

[The Critic]

Originally Posted By: eagle23
I'd be reluctant. The stiffer rear shocks do add to intial rear roll stiffness, i.e, a quick lane change, so it can feel more responsive. I've done that a couple of times through the years. It does help a front-driver understeer less, at least at initial turn-in.

But is that what you want for your dad? Is that what he would really want? I'm not saying he does or doesn't, just asking to hear what he wants and respecting that choice is probably best.

For a daily-use, 21 yr old grocery-getter, anything you use will be an improvement, one that he would likely appreciate. Unless he's one who likes to toss the van around, I'd stick with the matched set of four, which probably costs less anyway.


You do make good points about the needs of this van. Yes, installing the mono-tubes on the rear is more of a curiosity for me, and is also because of the nominal cost over the Excel-G units for the rear.

Also, the van is actually rear-wheel-drive; does this change your assessment about the effects of stiffer rear shocks?

Thanks!

 

[The Critic]

Side note, this project is not nearly as price as I had expected.

KYB Excel-G struts (front), KYB Gas-A-Just shocks (rear), & Monroe strut-mate mounting plates for the front = $223.

Front Upper spring insulators, Front Lower Spring Insulators, and Front Bump Stops = $95 shipped (dealer).

Is there anything else that I should replace? Any Previa experts want to chime in?

 

[The Critic]

Originally Posted By: GMBoy
With the age of the vehicle and it's intended use I would just go with a lower priced Monroe sensa trac or similar all the way around. They have a lifetime warranty and anything you do is a big improvement over what he has now.


I have some concerns about the durability of the Monroe Sensa-Tracs, as I've heard lots of negative feedback about their performance and durability, especially on iATN. I priced them out for this van and it would be $178 for all four corners, which, only saves me about $45.

 

[PandaBear]

You forgot alignment cost, and "maybe" a couple camber kit if the current alignment is off, and from my experience replacing struts there's always 1-2 tools / sockets that I don't have and need to have a quick run to Sears for.

My observation is that people like softer suspension wouldn't mind SensaTrac, but those who like a firmer / sportier ride would think SensaTrac wear out too quick. Don't go anything cheaper, like Monromatic, those don't last long.

 

[eagle23]

Originally Posted By: The Critic
Originally Posted By: eagle23
I'd be reluctant. The stiffer rear shocks do add to intial rear roll stiffness, i.e, a quick lane change, so it can feel more responsive. I've done that a couple of times through the years. It does help a front-driver understeer less, at least at initial turn-in.

But is that what you want for your dad? Is that what he would really want? I'm not saying he does or doesn't, just asking to hear what he wants and respecting that choice is probably best.

For a daily-use, 21 yr old grocery-getter, anything you use will be an improvement, one that he would likely appreciate. Unless he's one who likes to toss the van around, I'd stick with the matched set of four, which probably costs less anyway.


You do make good points about the needs of this van. Yes, installing the mono-tubes on the rear is more of a curiosity for me, and is also because of the nominal cost over the Excel-G units for the rear.

Also, the van is actually rear-wheel-drive; does this change your assessment about the effects of stiffer rear shocks?

Thanks!


I had forgotten the Previa is rear drive; it's been a while

But yes, the same point holds. It will effectvely stiffen the rear suspension initial roll response. I doubt it would toss him into the weeds

but then I don't know what kind of driver he is.

I understand your curiousity, and am only encouraging asking him what he wants vs. your experimenting. But then if he isn't happy and you're willing to R&R the new rear shocks with something more to his liking, then....

 

[SteveSRT8]

Originally Posted By: eagle23
I'd be reluctant. The stiffer rear shocks do add to intial rear roll stiffness, i.e, a quick lane change, so it can feel more responsive. I've done that a couple of times through the years. It does help a front-driver understeer less, at least at initial turn-in.


Sounds familiar!

 

[ChrisW]

If i recall correctly, the front brake lines go through a small section of hard line mounted on the front strut body, you'll have to disco this when replacing the front struts. Maybe do the front hoses at the same time since the system will be open? And something about the lower front ball joint sometimes wears out as well; easy bolt on design and not pressed in. I'd go with Moog for the ball joint. Maybe think about the front lower control arm bushings, I could imagine rubber rot at that age.

Had a '92 previa in the family before, thing was a tank! Except for when the ignition rotor fell off the post from a loose rotor screw, lesson learned there is to use loctite on that screw can't trust the split lock washer to keep tension. Luckily it just chewed the cap/rotor a bit and didn't mess up the distributor. Changing spark plugs is fun on the previa!

 

[The Critic]

I went ahead and ordered the Excel-G struts for the front and Gas-A-Just shocks for the rear. With a coupon, the whole thing was only $160 shipped from Justsuspension...what a deal!

I went with Moog front strut mounts. The bump stop, dust cover, upper spring insulator and lower spring insulator will be replaced with OE parts.

Altogether, it will be about $340 plus the alignment, which is a bit more than I was hoping to spend...but at least the job will be done correctly.

Originally Posted By: ChrisW
If i recall correctly, the front brake lines go through a small section of hard line mounted on the front strut body, you'll have to disco this when replacing the front struts. Maybe do the front hoses at the same time since the system will be open? And something about the lower front ball joint sometimes wears out as well; easy bolt on design and not pressed in. I'd go with Moog for the ball joint. Maybe think about the front lower control arm bushings, I could imagine rubber rot at that age.

Had a '92 previa in the family before, thing was a tank! Except for when the ignition rotor fell off the post from a loose rotor screw, lesson learned there is to use loctite on that screw can't trust the split lock washer to keep tension. Luckily it just chewed the cap/rotor a bit and didn't mess up the distributor. Changing spark plugs is fun on the previa!


The spark plugs actually weren't that bad. I thought it was much easier than doing an Infiniti G35.

Yeah, the hoses do have to be disconnected. However, I am reluctant to replace any components that seem OK since the service life of the parts on that car have been incredible. I have a feeling that the stuff on the aftermarket today may be inferior to what is on there now.

I'll check the front-end, thanks for reminding me. I have been meaning to do that for a while.

 

[The Critic]

Just an update.

I checked over the front suspension per ChrisW, and found the sway bar bar bushings to be shot (bar squeaks when you wiggle while it is loaded), and one of the sway bar end links is leaking grease. So, I've gotten all new Moog components for that ($80, ouch).

I went ahead and did the rear shocks for now, with the KYB Gas-A-Justs. Much to my disappointment, the Gas-a-Just shocks were made in malaysia, but the Excel-Gs for the front are made in japan.

The Gas-A-Justs shocks are STIFF! When priming the shock prior to install, after 4-5 cycles, I could barely compress the shock despite all of my force onto it. Post-install test drive showed that the new rear shocks deliver a stiff/choppy ride for a 3rd row passenger, but for the driver, the stiff ride is not very noticeable.

 

[martinq]

Aren't Gas-A-Justs adjustable?

 

[The Critic]

Originally Posted By: martinq
Aren't Gas-A-Justs adjustable?


AGX are. Gas-a-just and Monomax are not.