thumping coming from front when turning, NWF swap - Suspension and Brake Forum

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thumping coming from front when turning, NWF swap
Friday, September 07, 2007 2:10 PM
Ok, so I have the front NWF swap (well, I'm using G/W/C calipers instead of the F calipers, but it doesn't matter).

My issue is that when doing a long sweeping slight right (like a soft on ramp), I get a thumping sound coming from the front. This isn't a clicking, its a thumping, and it only happens around 30mph and above and when doing a slight right (sometimes, it'll do it when doing a slight left). It doesn't do it when going straight, turning onto another street, turning lock to lock, or at low speeds.

What I've changed:

Hub bearings - new, both, because one of them had a bad wheel sensor.
Outer Axles - first with yard axles, then replaced with remans from Advance, both, because I had a "clicking" noise coming from the front when going straight. Now it thumps on slight long turns. Has new boots and clamps. Clamps are not rubbing the swaybar endlink.
A-arm bushings - both, poly from carcustoms
Ball joints - new from Mac Auto so they fit the N-knuckles

I've checked everything for rubbing, tightness, and just "not supposed to do that"-ness, and nothing. The only thing the I can think of are:

A) One of the reman outer axles, the CV joint is bad. But wouldn't it click, instead of thump? This is thumping, like something large is hitting; I thought that bad CV's click (the whole reason for changing it the first time).
B) Perhaps one of the inner axle tripod joints is bad? Would that cause the thumping on slight turns? If so, why doesn't it do it when going lock to lock, and why did it only start doing it after changing the axles again?

Sigh..........



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- Sold my beloved J in April 2010 -

Re: thumping coming from front when turning, NWF swap
Tuesday, September 11, 2007 5:58 PM
n-e-bady....



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- Sold my beloved J in April 2010 -
Re: thumping coming from front when turning, NWF swap
Tuesday, September 11, 2007 6:59 PM
my 01 cavy was doin the same thing. did u take anything on the suspension off. if so thats wat i bet is wrong. i lost some bushings above the springs and it did the same thing.


finders keepers losers suck!!
Re: thumping coming from front when turning, NWF swap
Tuesday, September 11, 2007 7:02 PM
get someone to get in your car and crnk it up and turn the wheel while you watch the suspension


finders keepers losers suck!!
Re: thumping coming from front when turning, NWF swap
Thursday, September 13, 2007 10:04 PM
2 things that come to mind...

me personally... I would put it up on a rack at work and get the thing going at speed in the air and check for noises.. The next thing I would do is balance the tires (we have a road force machine so I would do that). while the tires were off I would look at the wheel speed sensors.. I don't knwo how they go in on your setup but I'm seen a VW that came in becasue of a noise when turning right and braking, the wheel speed sensor doesn't just sit in there, you can move it, it was moved in to far and rubbing if the angle was just right and hitting the brakes..

The way you describe it you make it sound like a rotational noise, like the noise goes at the vehicle speed... is that the case? If so there are only so many things it could be.. axles, bearings, bubble in a tire, broken belt in a tire, a wheel weight hiting the caliper, somehtign stuck inside the rotor making noise when it spins... hell I've seen a car come in with a with a broken off end of an allen wrench that pierced the tire and made its way inside, someone just tossed a plug in it and the allen wrench inside was making noise at low speeds. I've seen a car with a load clunck that you could feel in the floor from when backing up and turning after the cars been sitting for hours... it wasn't a bad wheel bearing the problem was when wheel bearings on VW's get replaced they come with a little tube of greese. If you don't spread the greese on the outside of the bearing before pressing it into the hub the bearing will shift slightly in its bore, just enough to make a clunk noise with no free play.

My point is if you've checked/replaced the obvious and your confident all is well then its time to start looking into the not so obvious.



Re: thumping coming from front when turning, NWF swap
Thursday, September 13, 2007 10:57 PM
putting it up in the air doesn't really help cuz it changes the angles of the axles. that, and the axle when fully raised would hit my swaybar endlink. not an issue when normal ride height.

tires have been rebalanced TWICE.

wheel speed sensors are inside the bearings. bearings are brand new. no tube-o-grease necessary.

noise is rotational, but it only occurs above 30 mph or so, when doing a soft sweeping right turn (like an on ramp). not going straight, or turning onto another street, or going slow, nothing.

no bubbles in the tire, although broken belt in tire is the only thing i haven't looked into, except, that i should probably hear that more often.

impossible for wheel weights to hit caliper.

i debated if there is something inside the tires, but when i took them off i shook them in the air in all directions and heard nothing.

only other things like i said i can think of is the cv joint (that is currently new) is a dud. or, the inner tripod CV coming out of the tranny is binding or is just plain messed up.



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- Sold my beloved J in April 2010 -
Re: thumping coming from front when turning, NWF swap
Sunday, September 16, 2007 6:39 AM
Viper98912 wrote:wheel speed sensors are inside the bearings.

Actually, they're not. The reluctor wheel is part of the axle outter shaft, and the sensor is on the spindle. Check it to make sure. I can't remember how exactly the sensor is mounted. I'd go out to my garage to check, but it's 2000 miles away right now.

Good luck with this man. You have had so many problems with that swap, I hope you get it worked out.






Re: thumping coming from front when turning, NWF swap
Sunday, September 16, 2007 7:36 AM
No, on the N-body outer axle there is no tooth wheel and the wiring connector can be mounted anywhere. As said, the speed sensor is inside the wheel bearing.



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- Sold my beloved J in April 2010 -
Re: thumping coming from front when turning, NWF swap
Sunday, September 16, 2007 7:00 PM
Viper98912 wrote:No, on the N-body outer axle there is no tooth wheel and the wiring connector can be mounted anywhere. As said, the speed sensor is inside the wheel bearing.

I must be smoking crack.
Now that you mention it, I can remember when I was fiddling with the Grand Prix spindle and hub to see if they were interchangeable, the pigtail was on the hub. I must have been thinking about the J unit.

Just out of curiosity, did you use the N-body axle, or just the outter on the J-body inner? Someone said that they compared the hybrid and an N-body axle side by side and the hybrid was a little longer, not shorter as was originally thought. I'm wondering if somehow suspension travel during a corner could be causing binding or something? Just a thought.






Re: thumping coming from front when turning, NWF swap
Sunday, September 16, 2007 7:24 PM
Hybrid. The problem w/ the other one is that the axle is 1/2" shorter, while the spindle is set outwards 1/2". This could all be relative theory, but what this tells me (from what others have said) is that there is a 1" difference in completely using the N axles. Not good.

My only problem is that this seems to have only started happening recently, not since the beginning.



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- Sold my beloved J in April 2010 -
Re: thumping coming from front when turning, NWF swap
Monday, June 16, 2008 11:33 AM
i have read your posts in the swap thread. you put poly bushings in???? definatly going to get more nhv

Re: thumping coming from front when turning, NWF swap
Monday, June 16, 2008 1:00 PM
sounds like an axle problem to me......but i would still check things like your link pins and such.

you could still put your car in the air......on an alignment rack, which i would recomend for visually checking.

You could also use a chassis ear to narrow it down. I have one if you need it, just send me a heafty security deposit, or if you wanna buy it...hit me up.



Re: thumping coming from front when turning, NWF swap
Monday, June 16, 2008 3:21 PM
I ended up changing the axle, and now it might be worse. So I'm thinking its either the other axle, or I got a bad axle, which stinks. For now though, I'm just gonna run it and hope nothing breaks.



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- Sold my beloved J in April 2010 -
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