Z55 front shocks bad?

[juicedgsr95]

How do you tell if the front shocks of a Z55 suspension are bad? 2011 Suburban LTZ. I Have K02 tires that are 3k miles old and the fronts are cupping. Alignment was done when the tires were put on and running a front 1.75” level with the ride height brackets to keep them correct. The truck has 143k miles, and think I am just going to put some 5100’s on the front and get it aligned again. I’m hoping that fixes this issue.

The ride is fine, probably a little stiff compared to what a ‘luxury ride’ front strut should give I am guessing.

Any opinions?

 

[Joseph Garcia]

Have you put a scanner on it to see what the system components are doing?

 

[swathdiver]

How do you tell if the front shocks of a Z55 suspension are bad? 2011 Suburban LTZ. I Have K02 tires that are 3k miles old and the fronts are cupping. Alignment was done when the tires were put on and running a front 1.75” level with the ride height brackets to keep them correct. The truck has 143k miles, and think I am just going to put some 5100’s on the front and get it aligned again. I’m hoping that fixes this issue.

The ride is fine, probably a little stiff compared to what a ‘luxury ride’ front strut should give I am guessing.

Any opinions?

12 years old, the suspension could probably use some freshening up. If you have more than .5mm of play in your ball joints or 1mm of play in your tie rods, it is time for new ones.

Bilsteins are going to be a downgrade over what you have now.

Do you have access to a Tech-2 or similar tool? It can "talk" to your shocks and check their condition as Joe mentioned.

 

[juicedgsr95]

I don’t have a tech2. I am guessing they are shot because I wouldn’t call the ride any better (probably worse) than the bilstiens I put on my trail boss. I’ve decided to sway them but will check the tie rods and ball joints as well. Was hoping there was an easy way to check if they were actually working.

 

[91RS]

Failed shocks will not cause cupping. Worn bushings, ball joints, and tie-rods can though and if all that is original it is probably due for replacement. If you're lift is just a spacer lift, that also ruins the ball joint angles and is probably the main cause of your cupping. Tires like the K02 also do need to be rotated much more often (and cross the fronts going to the rear) to keep them in the best shape.

To answer your question, there are two ways to tell if the Auto/Mag ride shocks are failed. One is they're blown and leaking the other is they're locked up (best way to tell is to go over a steep speed bump).

 

[juicedgsr95]

Ok, so new upper control arms, and lower ball joints? Will I need a press for the lower ball joints? Rent a tool from AutoZone? I’ve decided I am installing the bilstiens (already have them in the rear) I’ll take out the spacer and use the bilstien to bring it back level.

Failed shocks will not cause cupping. Worn bushings, ball joints, and tie-rods can though and if all that is original it is probably due for replacement. If your lift is just a spacer lift, that also ruins the ball joint angles and is probably the main cause of your cupping. Tires like the K02 also do need to be rotated much more often (and cross the fronts going to the rear) to keep them in the best shape.

To answer your question, there are two ways to tell if the Auto/Mag ride shocks are failed. One is they're blown and leaking the other is they're locked up (best way to tell is to go over a steep speed bump).

 

[91RS]

I’d just replace the lower control arm. No press needed for that and comes with new bushings.

 

[juicedgsr95]

New tie rod ends, struts, upper and lower control arms and 36mm socket ordered. Will be a busy weekend. Hopefully being in the south and very little rust it all comes apart easily.

 

[juicedgsr95]

Replaced the shocks today with 5100’s. Instantly a better ride. One of the Z55 shocks busted open when removing it and spit oil everywhere. My guess is they were not performing correctly.

I have an appointment tomorrow to check the alignment and all ball joints. From my testing all ball joints and bushing looked good, no movement. I will have the. Tell me and I have upper/lower/tie rod belongs showing up Saturday. If they say it all looks good I will be returning those parts.

 

[91RS]

I would still install the new control arms. A 200lb guy pulling on the control arms will not reveal a worn bushing like a 5000lb SUV will when it is cornering. The ball joints can be squeezed with a big pair of pilers but that still isn't the same amount of force. If you bought good quality parts (OEM is best) that will probably make as big of a difference as the shocks.

 

[dkad260]

I would like to add to this as I'm suspecting my front's may be bad also.

I have the Z55 in my 2012 XL Denali and I recently replaced the rear shocks with Arnott but the front is still OE with 117K miles.

Do you have access to a Tech-2 or similar tool? It can "talk" to your shocks and check their condition as Joe mentioned.

I do have a Tech 2, could you elaborate on this procedure?

One is they're blown and leaking the other is they're locked up (best way to tell is to go over a steep speed bump).

When I roll over a small speed bump, straight on, at even a low speed, the front will "land hard" on the backside of the speed bump with a sharp hit.

Normal driving the front feels like I have 50 PSI in my front tires and they are Defender LTX with over 80% of tread remaining.

I do have the 22" wheels from GM as well.

I'm fine with replacing the front shocks/struts with OE GM. I just hope the new GM units play well with the rear Arnott.

Wanted to add, the front behaved like this before I replaced the rears, but the rear rides very nice now.

 

[dkad260]

The ball joints can be squeezed with a big pair of pilers but that still isn't the same amount of force

One method is to jack up the control arm so the tire is about an inch off the ground, then take a prybar under the tire and try to lift up, the lower ball joint should not compress when lifting the tire.

You can't really test this with the suspension hanging, needs to be under normal resting load.

 

[swathdiver]

I would like to add to this as I'm suspecting my front's may be bad also.

I have the Z55 in my 2012 XL Denali and I recently replaced the rear shocks with Arnott but the front is still OE with 117K miles.



I do have a Tech 2, could you elaborate on this procedure?

When I roll over a small speed bump, straight on, at even a low speed, the front will "land hard" on the backside of the speed bump with a sharp hit.

Normal driving the front feels like I have 50 PSI in my front tires and they are Defender LTX with over 80% of tread remaining.

I do have the 22" wheels from GM as well.

I'm fine with replacing the front shocks/struts with OE GM. I just hope the new GM units play well with the rear Arnott.

Wanted to add, the front behaved like this before I replaced the rears, but the rear rides very nice now.

No, I don't have that suspension on mine so the menus are not there for me to look at. @gooffeyguy @Joseph Garcia

If there's more than .50 millimeters of play in either the upper or lower ball joint, they are out of spec.

We jack up one side on the frame. Then put a floor jack on the control arm and lift it up about an inch and use the dial indicator to see how much it moved, if any.

 

[Joseph Garcia]

Were your front shocks stiff before you replaced the rear shocks?

 

[dkad260]

Were your front shocks stiff before you replaced the rear shocks?

Pretty much yes. Not bone-jarring stiff but you feel just about every ripple in the road.

 

[dkad260]

Were your front shocks stiff before you replaced the rear shocks?

Now that I think about it, I don't know if it was the same or worse after the rear shock change. Ride height is pretty much perfectly level, no issues there.

It does feel like the front is way over damped.

 

[Joseph Garcia]

Now that I think about it, I don't know if it was the same or worse after the rear shock change. Ride height is pretty much perfectly level, no issues there.

It does feel like the front is way over damped.

OK. Just trying to determine if the work on the rear shocks were some how potentially related to the stiff shocks in the front.

A bi-directional scanner would be helpful in seeing just what is occurring in the dampers on the front shocks.

 

[dkad260]

A bi-directional scanner would be helpful in seeing just what is occurring in the dampers on the front shocks.

I do have a Tech 2, just unsure of where this field is populated, or what the values should be.

 

[Joseph Garcia]

This document may help you.

 

[dkad260]

My update on this, I cannot find anything in the Tech 2 on the health of the suspension, I will chalk that up to user error at this time.

Secondly, I'm trying to locate the front strut cartridges, based on my VIN, the 2 dealers I called gave me: 19420494 and they also verified I have the computer controlled suspension.

Are these correct? Searching these parts I don't see the electrical connector at the top.


This is a pic of my front strut, safe bet these are OE with 120K miles....ouch.

I purchased this with 92K on the clock and these have been on my to do list.