The Mysterious Clunk and Adjustable Front Drop Links (long-ish)
07-15-2010, 02:02 AM
#4
Team Owner
its quite possible that the drop link heim joints were rubbing when the suspension moved a certain way and lengthening the rods changed the position of the joints relative to the control arms.
To set the links bolt one side up drive for a few miles to settle the suspension the attach the other side lower joint so there isnt any preload on the bar this is done with the car on the ground
To set the links bolt one side up drive for a few miles to settle the suspension the attach the other side lower joint so there isnt any preload on the bar this is done with the car on the ground
07-15-2010, 09:12 AM
#5
Team Owner
and thats why I included instructions for setting the sway bar setting procedure,
as it wasnt clear if thats how the links were set,
it may be perfect as is,
but its worth a check
as it wasnt clear if thats how the links were set,
it may be perfect as is,
but its worth a check
07-15-2010, 10:03 AM
#6
Rennlist Member
I have a similar light "clunk", at low-low speed, uneven surface (ie speed bump).
I think there are quite a few things which could cause a sound like that:
- Loose upper cross brace
- Loose lower cross member (just above steering rack, where the ends bolt to the chassis, check torque)
- Loose suspension mounts
- Loose sway bar mounts
- Loose lower coilover bolt
- Worn wheel bearing/spindle
- Worn upper lower/upper ball joint
- Twisting heim joint, if you have aftermarket style drop-links
- Sway bar "float"
Just think of anything that could move when the chassis flexes.
I think there are quite a few things which could cause a sound like that:
- Loose upper cross brace
- Loose lower cross member (just above steering rack, where the ends bolt to the chassis, check torque)
- Loose suspension mounts
- Loose sway bar mounts
- Loose lower coilover bolt
- Worn wheel bearing/spindle
- Worn upper lower/upper ball joint
- Twisting heim joint, if you have aftermarket style drop-links
- Sway bar "float"
Just think of anything that could move when the chassis flexes.
07-15-2010, 12:37 PM
#7
Team Owner
also if the motor mounts have been worked on,
the fingers of the limit pads can be contacting and it will make a noise that travels through the car
the fingers of the limit pads can be contacting and it will make a noise that travels through the car
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07-15-2010, 05:52 PM
#8
Rennlist Member
Mike,
I have that same clunk. I also have a mangled sway bar mount. I think that's exactly what I'm going to do when I get my Specialists swaybars. Thanks for sharing. I think you hit the proverbial "nail on the head".
Brian
I have that same clunk. I also have a mangled sway bar mount. I think that's exactly what I'm going to do when I get my Specialists swaybars. Thanks for sharing. I think you hit the proverbial "nail on the head".
Brian
07-15-2010, 06:40 PM
#9
Rennlist Member
I have the same clunk as well. its in the swaybar joint. It happens when things get a little worn, but there really is no slop in the system. pre load might help, but if you want the system to be set up with no preload, as I do, I over look the imperfection. devek swaybar? thats what mine is.
07-15-2010, 06:46 PM
#10
Rennlist Member
you have preloaded the system, ever so slightly. just lowering the swaybar mounts equal amounts, doesnt guarantee no preload. I finally nailed mine down to the swaybar by having someone jumping up and down on the door runner, while I was looking under the car and feeling around the swaybar joint. sure enough, that was it. preload by a few lbs, wont do much harm, but there will alway be an equalibrium point, so darting back and forth with the steering, you may find the click or clunk, again. 
When I bought my '87 (about three months ago), it had a little bit of a "clunk" in the front suspension when going over an uneven surface (like turning into the driveway at home -- slight curb -- one wheel hits the curb -- then "clunk" when the second wheel hits).
Buying my first 928, I was blind to the fact that it might be something serious (must have been 928 fever or something). I thought I would just figure it out later. I took it to get a wheel alignment (Sears, with a Hunter) and in the pre-inspection, the mechanic said that all looked good except for one of the rubber bushings on the passenger-side drop link. It was worn so that it needed replacing.
I thought "Aha! There is my clunk!" I installed the adjustable front drop links that 928 Motorsports sells, and followed the instructions about setting up a neutral setup.
Still had the exact same clunk.
Fast forward to today. I have a buddy who has been a mechanic by profession for almost 25 years. Nothing fancy at all -- he has worked in his dad's shop for the last 25 years wrenching on mostly American cars in our rural town (so rural that guys in their pickups seriously try to get me to race -- but that's another story).
We put it on one of his lifts, and he decided that the sway bar / drop link set-up was "too loose". So I just let him go at it. He unbolted both drop links at the bottoms. With the sway bar now held only by its bushings, he forced it lower by about one inch (using a pry bar). He then increased the lengths of both drop links by about an inch (using a crescent wrench and vice grips (because he "did not have metric wrenches that large" (gotta love him!), and reassembled.
The clunk is completely gone.
So, now that I am back from the land of vice grips and adjustable wrenches, what do you guys think about this "solution" to my clunking problem? Did he do the right thing? Any possible long term negative effects? I would love to hear what you guys think.
Buying my first 928, I was blind to the fact that it might be something serious (must have been 928 fever or something). I thought I would just figure it out later. I took it to get a wheel alignment (Sears, with a Hunter) and in the pre-inspection, the mechanic said that all looked good except for one of the rubber bushings on the passenger-side drop link. It was worn so that it needed replacing.
I thought "Aha! There is my clunk!" I installed the adjustable front drop links that 928 Motorsports sells, and followed the instructions about setting up a neutral setup.
Still had the exact same clunk.
Fast forward to today. I have a buddy who has been a mechanic by profession for almost 25 years. Nothing fancy at all -- he has worked in his dad's shop for the last 25 years wrenching on mostly American cars in our rural town (so rural that guys in their pickups seriously try to get me to race -- but that's another story).
We put it on one of his lifts, and he decided that the sway bar / drop link set-up was "too loose". So I just let him go at it. He unbolted both drop links at the bottoms. With the sway bar now held only by its bushings, he forced it lower by about one inch (using a pry bar). He then increased the lengths of both drop links by about an inch (using a crescent wrench and vice grips (because he "did not have metric wrenches that large" (gotta love him!), and reassembled.
The clunk is completely gone.
So, now that I am back from the land of vice grips and adjustable wrenches, what do you guys think about this "solution" to my clunking problem? Did he do the right thing? Any possible long term negative effects? I would love to hear what you guys think.
07-15-2010, 07:47 PM
#11
Former Sponsor
99.5% of the time, for us, the front end clunks are the bolt/nut that secures the drop link to the sway bar. They have to be uber tight not to make noise. If these are even remotely loose, the sway bar and drop link will rotate against each other, instead of the rubber bushing in the drop link loading up. Clunks over every bump where the front wheels move at different times. Hit a bump square on...no clunk.
07-15-2010, 08:52 PM
#12
Rennlist Member
99.5% of the time, for us, the front end clunks are the bolt/nut that secures the drop link to the sway bar. They have to be uber tight not to make noise. If these are even remotely loose, the sway bar and drop link will rotate against each other, instead of the rubber bushing in the drop link loading up. Clunks over every bump where the front wheels move at different times. Hit a bump square on...no clunk.
Now, I have the Ott drop links which have the "u-channel" where it mounts to the sway bar. Actually have to grind down the of the bar to make them fit.
I will check that bolt and make sure it' uber tight... but if it was not so tight, how could it "clunk" w/the "u-channel" around the bar end? Hmmmm.... will have to check.
