Rattling and clunk

[cessna]

Hello all I have a 93 lumina z34 it seems there is a rattle coming from underneath kinda makes you think exhaust is loose but thats not the case I don't have a lift to put it up high enough to really get a good look underneath the rattle feels like right under floorboard on drivers side, sometimes I get a hard clunk when I stop which I feel in the floorboard, ball joints seem to be fine as well as tie rod ends the car has 80.000 miles on it what else should I be looking at sub frame bushing seem to be intact from what I see ......any help 

[Imp558]

if the subframe isn't loose look at the trailing arm pocket in the back. that will make a pretty good racket when you drive down the road. just the same it would be worth it to jack up the car and see if the subframe isn't loose to be on the safe side.

[cessna]

Hey imp558 I was thinking about sub frame being loose also I have owned this car since it was new  I kinda peaked under the car and was looking to make sure the bushing were in place and not broken or so forth  from what I saw they were in decent shape is there an upper bushing also on the sub-frame that maybe I did not see from a glance I will try to get it up on stands this weekend and really take a hard look just wanted to see if there was any particular area that would cause this clunk on hard stops and the rattle sounds as tho something is loose like exhaust but it is not ....... .thanks I will also check the trailing arm  too 

[Imp558]

if you get down on one knee next to the car and reach in front of the rear wheel you can grab the trailing arm and give it a shake. You'll know right away if that trailing arm pocket is rotted

[Dark Ride]

Yup what imp said check your subframe, particularly the rear bolts/mounts as they can rust out and where the trailing arm bolts to the body are a very common issue. It could be bad dogbone or motor mounts but that doesn't fit your clunking when braking hard issue as well.

[cessna]

I jacked the car up and pulled up and down on the wheel checked the side to side play seems tight need to get under car and check sub frame, would loose or bad  struts cause this issue they seem to perform find with the normal bounce test rebound is minimum and no noise, just wondering if they could be loose and rattling but the clunk has me baffled it wont do it all the time seems sporadic but have noticed on hard braking at the end of the stop its a snapping  clunk thats why i was thinking ball joint ?

[Imp558]

Checking subframe: Jack car up and support it. Use a pry bar between the subframe and the body to pry down on the subframe right next to the suspected bushing and watch for movement.

 

Checking Trailing arm pocket: With vehicle on the ground is fine. Kneeling down in front of the rear wheel reach in and firmly take hold of the trailing arm. (Trailing arm goes from the wheel spindle assembly to a metal pocket that is welded to the car body) Try to move in, out, up, and down. If it clatters on the body side the pocket is likely rotted and loose inside the body. This can be repaired by a weld shop, don't panic.

Edited April 15, 2017 by Imp558

[Schurkey]

Sway bar rubber bushing rotted/missing.  There's four of them in front, I don't remember how many in the rear.

 

Control arm bushings rotted/missing.

[cessna]

thanks for the ideas, wanted to check it out this weekend but was kindly reminded by the other half that we have plans for easter weekend ...so this will be on next weekends agenda, thanks again for all the suggestions and some i can check rather easily so those might get a look at soon .I'm always open for any suggestions it seems more to me like maybe a sub frame bushing because I can feel it in the floor board on the drive side sometimes but I will check all of them out 

[cessna]

just wanted to drop an update got under car and started checking things out sub frame bushings in great shape no problem there still look new no rust no bad or worn bushing,sway bar bushings all in tack looks good ,tried to move ball joints up and down kinda felt small movement but no clunk still looking for the culprit might just go ahead and change all joints to be safe though,would be nice to find the rattling and the snap that happens at some hard stops thinking may be ball joint on the way out ? can feel the rattle on the drive side floor board it seems but nothing underneath seems to be showing me any signs but when I do get to the root of it I will drop back.

[55trucker]

what sort of lever did you push in between the ball joint & the lower control arm to pry on the ball joints?

[Imp558]

what sort of lever did you push in between the ball joint & the lower control arm to pry on the ball joints?

Exactly what I was thinking, you want to have the weight of the car on the wheel, on a ramp or on the ground with the wheel turned so you can get a look at it. Then pry between the a-arm and spindle with something tough and a couple feet long. you can do it with the wheel off and the vehicle supported by the subframe. It's just that when you do it that way you're fighting the spring in order to see movement.

[cessna]

Yea I had the wheel off the ground with car supported there is movement very little but could be enough, so I thought i would change them out anyway car has 80k on it bought it new in 93 always been in the garage so never been abused or modified just cant seem to get a handle on the rattle tho, replaced the struts about a year ago will see what happens after i get new joints and get them installed.Yes imp555 that is a good idea I will take another look this weekend just to see how much it is moving .thanks  

[95GS]

Hello all I have a 93 lumina z34 it seems there is a rattle coming from underneath 

 

I've got a similar problem - took it to a garage for inspection on lift when I couldn't find the trouble myself.

Was almost sure it was ball joints - hard rattles & knocks - but no, they're fine.

The problem is a front swaybar mount.

The sway bar is connected at 4 places with rubber bushings,

one at each end, two inboard on the front subframe.

 

The inboard sway bar mount on the driver's side is knocking around loose

because that small section of the subframe is rotted out.

 

So the clamp & rubber bushing & bolts are attached to the sway bar, but floating free.

This part of my subframe was not sprayed with oil apparently, the other side seems ok.

 

I will need to bolt in or weld a plate to the top of the subframe, to replace the mounting surface.

Hoping I can do this without too much disassembly.

 

Could someone post a photo of the top surface of a 1st gen front subframe (removed from car)?

[95GS]

This thread speaks to the same problem:

 

http://www.w-body.com/topic/52404-removalinstallation-front-subframe/

[cessna]

Hey 95gs can you actually see the inboard bushings if they are broke from looking underneath, Im hoping to get this car up on a lift so I can check it out further but the similarity's that you mention seem to be right on point I believe schurkey mentioned the same thing earlier in the post, thank all of you for the inputs to this problem  

[95GS]

cessna,

 

One can see the inboard bushings with the car on the ground.

For driver's side, crank steering wheel hard right turn,

you'll see the swaybar clamped by the upside down U-bracket w/ rubber bushing - supposedly all bolted to the subframe underneath it.

(Will try to follow later - next 48 hours - with a photo)

 

You MAY be able to see if it's detached (torn out) from that position - could require flashlight and mirror.

Not sure if one can get a pry bar between the sway bar (above) and sub-frame (below) from that position.

You may need to get under the car where the sway bar lies on top of the subframe for about 2-3 feet.

 

Anyway, the sway bar should not move relative to the sub-frame when pried.

If it does, the bushing bolts are not holding, or worse, the sub-frame there is rotted out.

 

On mine, one can see the rot from below, looking through the access holes for the nuts with a flashlight. (Car on ramps)

 

Not sure how to fix this - Ideas welcome.

 

Might have a neighbor weld a small plate on top of the subframe - but finished job should be at the same level. Hmm.

 

Would like to do this with minimum disassembly, without a lift. Removal or loosening of sway bar is probably required.

 

Your thoughts?

[Imp558]

Support the drivetrain with an engine crane and replace the subframe.

[cessna]

Hey 95gs I'm looking at about a week before I can get it up off the ground to take a closer look, when I see it then I will try to help you with some suggestions,IMP558 might have a good point there..... its awful tight under there I remember 2 years ago doing my alternator .........fun stuff . 

[Imp558]

You're probably looking at lowering your subframe in the rear to reach with a welder.

[95GS]

Thanks, Imp. I'm hoping to avoid replacing the subframe, at least for the moment. 

If I go that far, I'll want to do a lot more. Not time or facilities at present to get deep.

I think the rest is in good or at least better shape than this trouble spot. No apparent signs of deep rust.

 

May have to lower it to weld, maybe not.

How many attachment points for the subframe to body/engine?

Two are plainly visible at the rear.

Is there a thread on this - I've searched but not found yet.

[95GS]

cessna,

 

These shots might help you target the trouble.

 

Overall view - driver wheelwell. Hakkapeliitta snow at left.  

Pointer shows rubber bushing in U-bracket over stabilizer bar.

 

 

 

 

 

 

Closer view of bracket - note separation (lifting) from subframe.

 

 

 

 

 

 

 

Another view of lifting bracket & torn out bolt.

 

[95GS]

cessna, as a temp. fix to stop rattle and wear for next two days until I can fix this,

I'll try to bind the stabilizer bar to the sub-frame using web & ratchet...just to stabilize it...lol

 

Does anyone know the hardware dimensions here? Bolt diameter & length. Are these hardened?

 

What's involved in removing the stabilizer bar?

Can the car be driven around the block without the bar?

[cessna]

nice shots of problem GS, just wondering if you can go all the way threw subframe with bolt and maybe place a plate underside? if the frame is not rotted out at top completely that is just from looking at the pics not really sure but like I said I need to get under my vehicle and check this area also 

[Imp558]

nice shots of problem GS, just wondering if you can go all the way threw subframe with bolt and maybe place a plate underside? if the frame is not rotted out at top completely that is just from looking at the pics not really sure but like I said I need to get under my vehicle and check this area also

wow that's a really good idea maybe have a machine shop make up a couple of plates for underneath the bracket out of 1/8" plate. then drove through to the bottom and just use longer grade 8 bolts on it. I can see that working without any problem for quite a while anyway