Front suspension & bearings are new - Sharp knock on bumps

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WBPDX

Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

Car is a 1979 Spider. Sharp knock is only on bumps, and definitely passenger side front. The knock is not felt in the steering.

I replaced all the bushings in the control arms, installed new ball joints upper and lower, tie rods (complete,) drag link, and wheel bearings and races. I also installed new shocks and cut the springs one coil. Also, new tires and new brake calipers. Everything has been checked for tightness\looseness 2-3 times.

I got an alignment.

After the work, the car drove great, but I had some front end noises. Then, I looked and saw that the passenger spring had tipped in the upper mount, and the spring was no longer seated properly. I fixed this, and now both springs\mounts seem correct, but the knock is still there. I then double checked the wheel bearings, and they are tight. All of the nuts seem torqued correctly to the best of my ability. The tie rods seem seated. I will mention, my only idea left is that the lower ball joint might not be totally seated, but I think it is a long shot...

I am running out of ideas and things to check - I don't expect anyone to tell me the solution, just help with ideas of things I may have missed.

Again, the knock is not felt in the steering, it is just a loud hollow sounding "wunk" that is definitely in the front, and definitely on the passenger side. It occurs only on bumps in the road; a man hole cover with a dip of 1/2"+, a pot hole, a speed bump, etc.

As of right now, this is really the only major reason I am not using the car regularly, and summer is running out FAST - Please, any help would be appreciated!
So Cal Mark

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by So Cal Mark »

can you bounce the car and duplicate the noise?
User avatar
FiatMac
Posts: 290
Joined: Sat Aug 01, 2009 1:14 pm
Your car is a: 1982 2000 Spider
Location: Salisbury, North Carolina

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by FiatMac »

I had a similar noise once. It turned out to be a missing rubber sway bar bushing at the connection to the passenger side lower control arm. The knocking noise was the sway bar end hitting the bushing mount.
Stan McConnell
Retired Mechanical Engineer
Salisbury, North Carolina
82 2000 Spider (driving)
78 124 Spider on the rotisserie
76 124 Spider parts car or possible Lemons racer
83 parts car
WBPDX

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

Sway bar end bushings are new too, and everything looks good with the sway bar.

I *can* reproduce the sound by bouncing hard on it. Sounds like I need to find a friend to bounce it while I watch\listen under the car.

Any more ideas?
User avatar
DocGraphics
Posts: 639
Joined: Sat Mar 19, 2011 6:43 pm
Your car is a: 1978 124 spider
Location: Coeur d'Alene Idaho

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by DocGraphics »

Check to make sure both ends of you shocks are tight (guessing)
Don Raugust
1978 Fiat 124 Spider "Fiona" - Burgundy/Tan
2011 pics: http://s918.photobucket.com/albums/ad22 ... 0Pictures/
2012 pics: http://s918.photobucket.com/albums/ad22 ... cs%202012/
WBPDX

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

DocGraphics wrote:Check to make sure both ends of you shocks are tight (guessing)
First thing I thought of, because that is distinctly what the sound sort of sounds like - All is well.
User avatar
124ADDHE
Posts: 365
Joined: Tue Oct 19, 2010 11:19 pm
Your car is a: 1974 Spider Amalgamation with C40 Solex
Location: Salmon Arm, BC, Canada

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by 124ADDHE »

What about the crossmember bolts? Idler bolts? engine mounts? ignition coil clamp?
Regards,
Keith Cox
1973 124 Spider
1973 John Deere 500c backhoe
1987 Jaguar VDP
2013 passat tdi
2015 cherokee
WBPDX

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

Crossmember Bolts - Checked when everything was apart
Idler bolts - Also checked on the passenger side while everything was apart
Engine mounts - Are brand new, and are also tight. Also not sure I could reproduce this one just by pushing down.

Now I just gotta find someone to push down on it while I crawl under... Nobody is around when you need them! :lol:
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by narfire »

My guess was going to be the sway bar ends. The nuts on mine kept backing off,not much but enough to thunk. Lock-tight and tightened...three years and no problems any more.
Chris
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
WBPDX

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

The bolts on the sway bar end did loosen up before, but I tightened them again. Maybe I need to check them again.

Last night I didn't really get anywhere. I couldn't find anyone to help! Maybe this weekend I guess...
majicwrench

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by majicwrench »

With the car up on ramps you should be able to crawl underneath and push/pull up and down and create the noise. I have a one-man auto repair shop and do it all the time. Also, you should be able to feel that noise as well as hear it, and sometimes it is easier to isolate the issue by using fingers hands to "feel" the noise.
Keith
ace124
Posts: 75
Joined: Mon Jun 07, 2010 9:38 pm
Your car is a: 1969 Fiat 124 Sports AC coupe

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by ace124 »

Check you exhaust down pipes are not too close to the crossmember. If the engine mounts are softish or a bit saggy or wrong height, then it will hit.
WBPDX

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

They aren't saggy, they are brand new. Lots of clearance.

Tried by myself, I can't generate quite enough force while lying down on the ground to make the knocking sound. Damn close, but not quite.
bark

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by bark »

If you have the plastic wheel well shields in place, check to make sure the lower control arm clears the edge of the shield. Makes a hell of a scary sound if it's barely " plucking" as the control arm travels past the edge. Ask me how I know! B-
WBPDX

Re: Front suspension & bearings are new - Sharp knock on bumps

Post by WBPDX »

It actually was the upper shock mount despite the fact that it was completely tight. I am still not totally sure how or why. I could not get it tight, so I took the shock all the way out, didn't change a darn thing, and put it back, this time with a lock washer to maybe put a little extra force on the rubber bushings. Knock is gone, even though I swear it is just as tight, and aligned in the exact same way.

I'm thinking the shock may have been bent\damaged when the spring slipped part way off it's perch at one point. If the knock ever comes back, I'll replace the shock.

What is funny about fixing these terrible noises, as soon as one noise is gone, you just notice other noises more. Now that the front end is quiet and smooth, it really stands out out bad the rear end is!!!
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