already did wheel bearings, but getting vibration from front... struts? - Page 2

Obin Robinson · 07-05-2007, 06:11 PM

FWIW i looked at the pads when we removed them and they looked absoloutely fine. we actually took the time to inspect and clean the hubs and rotors when we did the bearings.

i'm really starting to wonder about the bushings and ball joints though. i'm going to put everything up in the air and take a really close look at them this weekend. for the cost of the entire assembly i am simply tempted to build up a "new" set using the control arms, bushings, and ball joints then just swap the old stuff out for the new ones. i bet it will make everything just a bit tighter.

offhand, how can i rule out that the noise is the strut bearings? do strut bearings make noise nonstop? they were like that in my VW Golf when they needed replacement. do they ever make noise only during heavy braking?

just to reiterate the symptoms:
- noise/vibration is ONLY under heavy braking. it's a "rrrrr" sound that reminds me of a bad wheel bearing. it isn't evident at speed.

- the car steering doesn't really feel "tight" as my 924 did. it feels good, but it seems like there is a little bit of "mushiness". i've attributed that to the power steering however. it's been YEARS since i've been behind the wheel of a 944-based race car but i can say though that the steering doesn't feel as tight as that. ball joints? suspension bushings?

thanks!

obin

nynor · 07-05-2007, 06:26 PM

loose caliper making the sound?

Icey1174 · 07-05-2007, 06:29 PM

Maybe the caliper hanging up. Might want to try cleaning them up so they move freely.

Obin Robinson · 07-05-2007, 06:31 PM

hmmm, good call. you know i think that all of these great suggestions are pointing in the same direction:

- i have to put the 944 on the lift and inspect it with a fine toothed comb!

the great thing about being active duty is the usage of the Hobby Shop. i was able last year to save myself $2,000 in labor fees by using the shop. last weekend we swapped transmissions and did a clutch job on my friend's Camaros. the cost of all the labor+ overnight stay for the car was under $30. you can't beat that at all.

i can put the 944 on the lift and analyze it for only $3 an hour. so far i'm going to look at:

ball joints
control arm bushings
brake components
strut bearings

...and anything else that people think could be causing this vibration.

obin

Icey1174 · 07-05-2007, 06:34 PM

All good things to look at.

flash968 · 07-05-2007, 06:41 PM

seriously, after checking your calipers, look for the shims and anti vibration inserts

then, if those are ok, skip the rotors (or at least spin them with some 200-400 sandpaper) and sand the pads - while it likely won't last, that will tell you if it's there or not - it's VERY hard to see deposits on either - i'm betting that it's there because you have no judder or wheel movement

Obin Robinson · 07-05-2007, 06:46 PM

the anti-vibration inserts? i'll tell you now that they looked like crap. you mean that little piece of metal that goes between the brake pins and the brake pads right?

thanks!

obin

Icey1174 · 07-05-2007, 06:50 PM

Mine look horriable too, but they work well, if that's what they are called.

flash968 · 07-06-2007, 07:34 AM

yeah, that flower shaped gadget that pops into the piston - there should also be a flat shim - these are bonded together when installed right - without that they can cause vibrations, rattles and buzzes

Obin Robinson · 07-08-2007, 07:37 AM

well i checked out the front suspension thoroughly and here's what i found:

1) the a-arm bushings look a little worn. one of them is really worn down.

2) the Weltmeister 220# springs are just a tiny bit short. when the suspension is fully unloaded they hang loose enough where you can wobble them with your hands and spin them freely. i actually spun them around a little bit so that they would fit better in the strut area.

3) the strut bearings don't look terrible, but i tempt to say that i am going to upgrade to the monoball ones later this year.

4) the ball joints were tight. they were old, but they were tight. VERY tight.

5) the caliper bolts needed to be torqued.

i got back on the road and noticed that most of the rrrrrrr sound had gone away under heavy braking. i am beginning to wonder if the sound has something to do with the slotted rotors themselves. is it possible that under heavy braking the slots in the rotors could be causing that sound?

thanks!

obin

Icey1174 · 07-08-2007, 07:59 AM

I would check into those springs. That's not normal, at least of what I know of. I have stock springs and they need to be compressed to install them. Maybe these aftermarket ones are different. How loose were the caliper bolts? That may have been some of the problem.

Obin Robinson · 07-08-2007, 08:06 AM

the caliper bolts were probably at only about 50 ft lbs or so. the proper torque is 63 ft lbs.

the springs are sport springs but they work at stock ride height. they are 220 lbs Stock Height Springs, Part Number: 904777
http://www.***************/ProductPage.aspx?pid=106765&vehicle=19040

obin

Icey1174 · 07-08-2007, 08:11 AM

Ask around and see if they are supposed to be compressed to install. I have never heard of a spring getting installed that was not under a load of some sort in any situation. I'm not sure that it would cause any noise of vibration though as the weight of the car then puts it under a load and braking adds even more load.

Obin Robinson · 07-08-2007, 08:16 AM

i'll call up automotion and see what they say.

offhand, here's the photos i took while i was under there:

http://ourdanka.com/obin/944/2007_07_08/

this looks like a good candidate for replacment:

ball joints ere dirty, but fine:

a-arms are rusty, but not cracked anywhere

obin

Icey1174 · 07-08-2007, 08:18 AM

Yes, the top pic looks like a replacement waiting.

I keep forgetting the early models have different control arms. Did you "pry" on your ball joints or just do a visual? Visual looks good. Boot looks good.

Obin Robinson · 07-08-2007, 08:28 AM

i got a prybar and i put a bit of effort into it. i put that "i'm going to pry this but if i push any harder i'm going to bust something" force into it. they were tight as possible and didn't budge an inch. i yanked and pushed at the tire from all sorts of angles and the ball joints still were tight.

the top pic is the outer sway bar bushing on the left side. i should probably replace those asap. i'm tempted to go with the poly ones but i fear they might be too tight for the street.

obin

Icey1174 · 07-08-2007, 08:31 AM

Sounds like the ball joints are good.

I have heard of people complain of the harder bushings and say they do not get that much out of them. I do not know for experience though.

Obin Robinson · 07-08-2007, 08:37 AM

so it's reasonable that i can eliminate:

- ball joints
- caliper bolts

that leaves me wondering about the strut bearings, the brake pads (didn't have a chance to check them today), and the a-arm bushings.

could the a-arm bushings cause that slight "rrrrr" under heavy braking? if you check the link you can see that they are indeed a bit on the worn side.
http://ourdanka.com/obin/944/2007_07_08/

thanks!

obin

Icey1174 · 07-08-2007, 08:41 AM

They could... The caliper is screwed to the steering knuckle and the steering knuckle is connected to the ball joint, and the ball joint is connected to the control arm and the control arm is connected to the body... so anything in the system that is not rigid could be the problem.

Obin Robinson · 07-08-2007, 09:17 AM

damn, i was hoping you wouldn't say that.

i tempt to say that my next task (after the water pump/timing belt/etc) will be new A-Arms complete with bushings, ball joints, etc.

i am getting a set of stainless brake lines so when i go in there to do the brakes i'm also going to put some more effort into tracking down this noise.

obin