[Stlhotrod]

I have seen other threads on the front and flex. While going through my front end installing new bushing and ball joints I came across some things that made me scratch my head. Most cars using struts have the struts tied into the upper unibody frame rail and inner structure. They then go down to the spindle and mount to the spindle. Most set ups that I am familiar with don't even use an upper control arm they use the lower and the top of the strut all tied together as a triangulated suspension.

Ours uses both an upper and lower control arm with the spindle connecting the two. The strut connects to the lower control arm with a yoke that ties into the lower control arm through a rubber bushing in the control arm. The strut comes down and then attaches to the yoke. The yoke takes the line from straight downward to off set it to the front side of the A arm. The Strut mounts to this yoke with a collar and pinch bolt. The top of the strut mounts with a bushing plate with 2 studs that mount it to the frame. This is another thing not like most other strut applications. Most either have a plate with either 3 or 4 mounting bolts with slots for adjusting the top of the strut.

So my first question is could this yoke, off set lower mount and rubber bushing mounted stud for the lower mount be causing some flex in the front end? Next on a lot of cars the upper mounts or strut towers, if they have flex issues they will add either a cross brace across from one side to the other or if it is going to see a lot of abuse they will use a K type brace tying the strut towers into the firewall also. Now the upper strut mounts on our trucks are so low that to make a brace it would have to come up and over the engine and it would be so big that it would probably have too much flex to it to do any good.

Now the next thing that got me to wondering is the way our body is on the SSR. Most full frame vehicles have the cab and bolt on fenders with a front core support mounted on rubber bushings. This set up has no flex from the front end to the cab. Ours has welded upper inner frames and across the front at the core support area all welded to the cab structure. We also have the entire body and bed all as one unit. Could this big of a body structure be causing the flex to carry into the cab and felt in the steering wheel more? I know there were some old Ford pick ups that the cab and bed as one unit but back then people weren't using their trucks like we do.

Ok what do some of you guys who have worked on these over the years think?

 

[Autoprof]

I understand some of your confusion. This is caused by auto and auto part manufactures. They tend to call any shock with a spring mounted on it a strut.
It is NOT. Our trucks DO NOT have a McPherson strut suspension. A true McPherson strut suspension DOES NOT use an upper control arm. Honda and many others have been misleading consumers for years claiming to have McPherson strut suspension systems. Actually, they are a variation of a double wishbone type suspension. A design that is similar to ours. I believe that Monroe (along with others) adds to the confusion by selling a "quick strut" for suspension systems similar to ours.
So to remove some confusion you can't compare the the modifications between the two totally different types of suspensions.

 

[Texasbaehr]

Most vehicles with M strut or hybrid like the SSR benefit greatly adding a upper brace that ties the top of the spring towers together. The way the SSR is built it is nearly impossible to do that without some major mods.
My brother had a BMW Z3 that was pretty loose on a bumpy curvy road. We added a $200 tower brace and it was like a totally different car after.

 

[abadssr]

With the space between hood and engine a strut to strut brace wouldn’t work. It would have so many bends and turns

 

[Texasbaehr]

With the space between hood and engine a strut to strut brace wouldn’t work. It would have so many bends and turns

Exactly my point! At a minimum, would need a low profile manifold and the fuse box would need to be relocated, it sits on top of the left SHOCK mount.

 

[Autoprof]

Exactly my point! At a minimum, would need a low profile manifold and the fuse box would need to be relocated, it sits on top of the left strut mount.

Lets not add to the confusion --- It is a shock absorber NOT A STRUT

Sorry to be picky but I stress proper terminology to my students and it is stressed here when discussing the tonneau cover vs bed cover.

It is kind of like the term "tune-up". It hasn't existed on today's' cars since the turn of the century. You cannot tune a car without modifying the computer programming - it is not a maintenance item! I offer extra credit to my entry level students to find this term in any maintenance schedule for any cars sold in the US for the past 18 years. I have not had to give extra credit for this!

 

[Stlhotrod]

Ok my question is still could it be the yoke mounting into the lower control arm with the rubber bushing and the mount going into the damping system on the front end that is causing the shake in the wheel at times like going over railroad tracks?

I just find it hard to believe the frame is flexing. That frame is a big hunk of steel and formed very rigid.

I have to think it is either the front suspension or the body transferring the vibration and not frame flex.

 

[Mike in AZ]

Ok my question is still could it be the yoke mounting into the lower control arm with the rubber bushing and the mount going into the damping system on the front end that is causing the shake in the wheel at times like going over railroad tracks?

I just find it hard to believe the frame is flexing. That frame is a big hunk of steel and formed very rigid.

I have to think it is either the front suspension or the body transferring the vibration and not frame flex.

There are four players in this group, not just two.....

The resonant frequency of the front suspension is actually a bit too close to that of the body structure. The frame acts as the energy transfer media from the suspension to the body. The frame resonant frequency is also in the same realm as that of the body and suspension...... Changing the response of any one of the three will decrease the "shake" you speak of.

The easiest way to decrease the amount of "shake" that appears in the body is to change the resonant frequency of the frame, so that it is not so sympathetic to transferring energy. This is what the stiffening plate does.

The fourth player in the group is the set of body mounts. GM has actually tuned the mounts by using different rubber durometer, according to the location. A lot of math and testing went into the selection of these by GM, so I have chosen not to mess with them.

 

[Stlhotrod]

Thanks Mike I can understand that and now makes me have one more question. Will using the polyurethane bushings in the front help, hurt or make no difference?

 

[Mike in AZ]

Thanks Mike I can understand that and now makes me have one more question. Will using the polyurethane bushings in the front help, hurt or make no difference?

no difference

 

[RedHotSSR]

Thanks

Great post and comments,

I do have to ask this question. Is this a repair ALL R owners should anticipate, :crying: and if so when is this occurring? e.g. at ___________ many miles of driving?

Just asking. I have owned many cars with more than 100,000 miles that NEVER needed frontend repair / replacing. Alignments yes but upper and lower bushing, ball joints etc. NO.


"Long may you ALL run" :grin2:

 

[Stlhotrod]

Great post and comments,

I do have to ask this question. Is this a repair ALL R owners should anticipate, :crying: and if so when is this occurring? e.g. at ___________ many miles of driving?

Just asking. I have owned many cars with more than 100,000 miles that NEVER needed frontend repair / replacing. Alignments yes but upper and lower bushing, ball joints etc. NO.


"Long may you ALL run" :grin2:

The bushings are rubber so they are going to wear out. When, depends on your driving and climate conditions. Ball joints on most newer cars don't have a means to grease them and they are going to fail as well when the grease in them breaks down.

In my case it all started out I wanted to lower my 05. Well that requires pulling the shocks. If I am taking them off, I am going to put new ones back on. Now normally that would have been the end of the repair. But I was at my local pick a part salvage yard and they had a Trail Blazer that looked like someone had replaced the a arms recently so I pulled then and the spindles off it. I took my time and cleaned and repainted them. I got all new polyurethane bushings and ball joints and now have a complete front end in parts, all rebuilt and ready to go on the truck. With the updates I will be able to keep the ball joints lubricated and the bushing should last a long time. One other thing for me anyway. I have the tools for a job like this, I have a press at home and everything I need to do the job my self.


It is funny but usually with front end parts they wear out so gradually that people don't notice it and become used to the looser feeling of the ride. I would recommend checking the front end closely on anything over 50,000 miles.

 

[Ken Gutierrez]

Can you post pictures and what year trailblazer.
Sounds like something I would like to do.

 

[Topspin]

Lets not add to the confusion --- It is a shock absorber NOT A STRUT

Sorry to be picky but I stress proper terminology to my students and it is stressed here when discussing the tonneau cover vs bed cover.

It is kind of like the term "tune-up". It hasn't existed on today's' cars since the turn of the century. You cannot tune a car without modifying the computer programming - it is not a maintenance item! I offer extra credit to my entry level students to find this term in any maintenance schedule for any cars sold in the US for the past 18 years. I have not had to give extra credit for this!

If we're going to get real picky here, it's a coilover shock!

 

[Autoprof]

If we're going to get real picky here, it's a coilover shock!

Agreed!

 

[Stlhotrod]

Yes I agree it is not a strut system, it is a coil over shock system trying to look like a strut system. GM even makes references in their parts break down as a strut. That is part of my questioning. If it were more like a true strut system of a top strut mount that is used for adjustment on the suspension and the bottom tied into the spindle would it be a better system then what we have? I also questioned the way the lower shock mount is attached to the yoke that then curves over to the front of the lower control arm and attaches to a stud mounted through a rubber bushing. This just seems like it has room for unwanted flex and possible shaking of the front like going over rail road tracks.

And this is more for just throwing out ideas and questions than any real fix. I think a true strut front end would be better but the cost to make the changes would be cost prohibitive. The other issue would be finding a strut that would support the weight and confines of our trucks.

 

[Mike in AZ]

........ But I was at my local pick a part salvage yard and they had a Trail Blazer that looked like someone had replaced the a arms recently so I pulled then and the spindles off it. I took my time and cleaned and repainted them. I got all new polyurethane bushings and ball joints and now have a complete front end in parts, all rebuilt and ready to go on the truck. With the updates I will be able to keep the ball joints lubricated and the bushing should last a long time. One other thing for me anyway. I have the tools for a job like this, I have a press at home and everything I need to do the job my self.

.

Can you post pictures and what year trailblazer.
Sounds like something I would like to do.

Please be aware that if you install Trailblazer shocks on an SSR, you will have an increase in front end height. They change the front stance by about 3/4", due to the location of the lower spring mount on the shock. If you are looking to replace the shocks, be sure that the part number you are using is NOT the same as the part number for the Trailblazer.

My two cents,

Mike

 

[Stlhotrod]

I got my Bilsteins from Simple Engineering. Super fast shipping. And the guy knows his stuff on SSRs. Also got the bushings there as well.

 

[Mike in AZ]

I got my Bilsteins from Simple Engineering. Super fast shipping. And the guy knows his stuff on SSRs. Also got the bushings there as well.

Yes, and thank you for the endorsement......... I was just wanting to be clear about the front shocks....... I know where you got yours. I’ve seen the result of someone putting the wrong front shocks on......

Regards

 

[xoxoxoBruce]

Great post and comments,

I do have to ask this question. Is this a repair ALL R owners should anticipate, :crying: and if so when is this occurring? e.g. at ___________ many miles of driving?
Just asking. I have owned many cars with more than 100,000 miles that NEVER needed frontend repair / replacing. Alignments yes but upper and lower bushing, ball joints etc. NO.
"Long may you ALL run" :grin2:

I broke a rear upper control arm at less than 95,000 miles. I'm sure there are many trucks with much more mileage who have not had that problem.
So don't get all in a lather when someone posts a problem, because if someone does have a problem where else are they going to go with it?

Quite often we're not talking mandated repairs that everyone should do, we're talking upgrades that everyone can do.
By consensus we've agreed there are weak points like the radiator support, fan, and ignition switch, that many have swapped out as a precaution.
But there are others who haven't had a problem with those items.
I guess it boils down to your lifestyle, resources, and risk tolerance.