PDA

View Full Version : Help w/ strange Front Susp KNOCK/Clunk/Crack when it Loads/Unloads Slightly



MavsFORMULA
11-10-2009, 03:07 PM
My new Z28 has had a list of problems I didn't know about when I bought it. The last one we have to sort, is this fairly consistent knock/clunk/crack or maybe pop that sounds like metal on metal/hard surface in the left/drivers front. It happens generally any time the front suspension loads or unloads slightly over uneven road or gradual bumps. We have had stethascopes all over it and cant track it down.. I should mention my front suspension/subframe is all BMR Tubular w/ one spherical rod end on each LCA.. It has LS1 brakes w/ Baer rotors. It also has Koni Single adjustable shocks and an Eibach/Ground Control Coil overs.
Now... So far we have had the brakes and upper mount out. The mount was replaced yesterday. The Spindles are powder coated and dont show any impact signs, along w/ either control arm. We added heater hose around the top of the coil spring, bc it had no isolator and wanted to be safe. Both ball joints have been greased along w/ the lot of the poly bushings. We can duplicate the sound when we jack the car up on the SFC and it unloads the suspension. My bolt in moly cage has a slight pop in it, but im pretty sure its not what were hearing much louder and to the front.. The only things left as suspects, my father and I imagine, are the ball joints, the Koni shock, and the spherical rod end. My uncle, who has managed GM dealers for years thought it was the upper strut mount(now replaced) and my father, who managed Toyota dealers for years, has never heard it before. We're stumped... Its consistant, somewhat loud, and very annoying. Im a perfectionist, someone please have experience w/ this and help me straiten this out... Thanks, to everyone, for your time!
Nick

AChotrod
11-10-2009, 03:14 PM
Worn out upper shock mount, or the top shock bolt could be loose allowing the shock to drop to far? I would check that next.

popo8
11-10-2009, 03:46 PM
X's 2 on upper bearing plate....

MavsFORMULA
11-11-2009, 01:01 AM
Thanks for the help guys..

I just replaced the upper strut mount and the sound remains. The LCA is tubular and there Isn't much to the lower shock mount, but we centered the shock and retightened everything. I just pulled the front sway bar and it may be a little less frequent, but it still persists.. All the front bushings are like under 500 mi new poly's that come w/ BMR parts..

I have put a wrench on every bolt/nut in the front of the car, including upper strut bolt, subframe, motor mounts, control arms, rod ends, roll cage, etc... and no change.

Any other Ideas?

tleed
11-11-2009, 09:27 PM
have u checked your motor mounts or trans mount?

MavsFORMULA
11-17-2009, 03:51 AM
It's left front, and started happening right front too. Must be that we found the poly bushings bone dry! Add it to the list.... we did check the motor mounts... Tightened them correctly, an they have about 400 mi BTW.. Tranny mount seems fine too. The noise went completely away when all my poly bushings were soaked in Mobil 1 grease, and came back as soon as I preassure washed my car/wheels. So we added grease fittings to each one of the poly bushing ends on my BMR Control Arms, and Im about to add some more! Be ready for this BS if your gonna buy tubular stuff for your car, or even put poly bushings in the stock stuff. But I think the tubular resonates/echos the sound?... Cause it can be loud! If I have to do this every week I will be unpleasantly suprised...

94Blackbird
11-28-2009, 12:35 PM
something that might also cause a noise similar to what you're describing is a hub going bad. It looks like you've already solved the problem, but I'm just throwing it out there. I recently replaced my right front when it started making similar noises, and that solved my problem

Fastbird
11-28-2009, 01:56 PM
My vote would be lower ball joints. IIRC Call911 had a similar issue and it was his lowers. greasing them made no difference but changed them and no more issues.

MavsFORMULA
12-05-2009, 01:03 AM
Good call Fastbird, Fixed it two days ago with lower ball joint!! I used to cringe over every bump and now she's back to amazing! Just wish I would've looked back on here after you posted. Would've been fixed a little quicker.

CALL911
12-18-2009, 06:32 PM
Sorry I didn't see this earlier either, as Fastbird was correct. Same was going on with my car, and finally fixed it after replacing the ball joints.

Fastbird
12-18-2009, 07:25 PM
Good call Fastbird, Fixed it two days ago with lower ball joint!! I used to cringe over every bump and now she's back to amazing! Just wish I would've looked back on here after you posted. Would've been fixed a little quicker.

Thank you thank you! The blind squirrel will be here all week! :D

CALL911
12-19-2009, 07:42 AM
Thank you thank you! The blind squirrel will be here all week! :D

You bastard... :shame:

... nevermind, I thought you were refferring to something else. :D