humming from front end

[yale329]

Lower srtut boots look pretty bad. Any chance the coil is cutting through the rubber touching metal?

[lorakew]

Originally Posted by yale329

Lower srtut boots look pretty bad. Any chance the coil is cutting through the rubber touching metal?

yeah, the rubber was worn pretty thin and was tearing at some parts where the spring could possibly touch metal.

When you take apart a strut, what would you normally replace while you have the whole thing taken apart.

[lorakew]

Originally Posted by Brian R.

When your car fell off the jack, was the wheel and tire on the car or off? Which side of the car fell (or both?) Was there any parts removed or loosened from the suspension or drivetrain when the car fell? Does it hum louder if you brake from 80 to 40 mph?

great question!


when my car fell off the jack the wheel and tire was off of the front drivers side. The front drivers side was jacked up with a sissor jack. the parking brake wasn't applied and the car rolled forward as my uncle pulled off the caliper from the rotor. when the car rolled forward, the (front driver side) rotor hit the pavement.

There were no parts loosened from the suspension or drivetrain. The only part taken off was the wheel on the drivers side. My uncle was trying to pull off the caliper without removing the 2 bolts. he's an idiot.

And when i brake from 80 to 40, it hums louder, but only at those 2 invervals (at 70 and 50 mph).

[yale329]

Just upper and lower rubber shells and of course upper stut Bearings. Hope that may be it for every dam bushing can cause a funny sound. Good luck

[Mike Gerber]

"when the car rolled forward, the (front driver side) rotor hit the pavement."

Have you ever checked the rotor for warpage or simply replaced it?

Mike

[yale329]

Don't no Mike, never happened to me, if the rotor touched the ground, you lost your wheel, or your rotor just cracked and fell out, WHILE PARKED. Wayne just adad and gran dad.

[lorakew]

Originally Posted by Mike Gerber

"when the car rolled forward, the (front driver side) rotor hit the pavement."

Have you ever checked the rotor for warpage or simply replaced it?

Mike

No i have never checked the rotor for warpage and i haven't replaced it either. A few months ago i didn't do my brake job in time and it scored that same rotor that hit the ground, so i plan on replacing the rotor eventually. Since it scored the rotor i've been having the pedal pulsate when i press the brake; so i know the rotor is now warped.

Do i have to replace the rotor in "pairs" or can i just replace that one that hit the ground.

And since the rotor hit the ground, do i have to replace the rotor or can i simply get it machined.

[Brian R.]

You can replace just one rotor if the other one is fairly similar. If it is in bad shape or machined down to the limit, then I would replace both. Replace the driver's side one, don't machine it.

I don't think that damage to the rotor is what is causing the humming. I bet that there is hidden damage to part of the drivetrain, like the splines of the driveshaft, hub, or outer CV joint. I would put my money on the hub. Check the straightness, length, and threads on the hub bolts. If one is stretched or bent, that may be the problem and it's an easy fix.

[lorakew]

Originally Posted by Brian R.

You can replace just one rotor if the other one is fairly similar. If it is in bad shape or machined down to the limit, then I would replace both. Replace the driver's side one, don't machine it.

I don't think that damage to the rotor is what is causing the humming. I bet that there is hidden damage to part of the drivetrain, like the splines of the driveshaft, hub, or outer CV joint. I would put my money on the hub. Check the straightness, length, and threads on the hub bolts. If one is stretched or bent, that may be the problem and it's an easy fix.

Do you think the hidden damage is on the same location that hit the ground? or do i have to take off all 4 wheels to look at every hub.

if it's just looking at the drivers side, i can easily take a look this week.

[yale329]

No, but rotors are cheap. Unless your racing do them both, teust me.

[Brian R.]

Originally Posted by lorakew

Do you think the hidden damage is on the same location that hit the ground? or do i have to take off all 4 wheels to look at every hub.

if it's just looking at the drivers side, i can easily take a look this week.

It almost has to be the wheel that hit the ground.

[lorakew]

hi brian,

i'm going to take a look at the hub next week and i wanted to go over a few things with you. I just took a look at the FSM suspension and axle. I see why you suggested the humming could be coming from either the hub, splines of the driveshaft, or cv. So next week when i take off the drivers side wheel, i'm going to check to see if the hub bolts are bent or damaged, and if they are, i should get a new hub assembly pressed in. I will also buy a new rotor, since the current one hit the ground.

But what if i don't see any damage to the hub bolts? Are there any tricks to knowing whether the splines on the driveshaft are damaged other than the obvious--- look and see if the grooves are damaged?

Do you think its smart to just replace driveshaft anyway? while i have everything removed with enough clearance. Napaonline.com has it refurbished for $47.89/core$11.00
i think the driveshaft is the part with the splines and the inner cv as well, correct me if i'm wrong.

Lastly, the third thing you suggested was damage to the CV. I haven't heard any clicking while driving/turning, and the last time i looked at it, the hard outer boot was in great shape (no cracks). Should i automatically rule out the CV?

my gut tells me it may be the splines on the driveshaft and the boots, because when i saw the car fall off the jack, the rotor was still on the hub. it didn't move at all, it was probably still rusted on. (everytime i replaced the wheel bearing the rotor is always rusted on, and it's a pain in the neck to take it off).

Well i'm moving to New York next week, and i will be driving my car from florida to new york. I will shoot myself if i have to hear humming during the entire drive.

[Brian R.]

Originally Posted by lorakew

hi brian,

i'm going to take a look at the hub next week and i wanted to go over a few things with you. I just took a look at the FSM suspension and axle. I see why you suggested the humming could be coming from either the hub, splines of the driveshaft, or cv. So next week when i take off the drivers side wheel, i'm going to check to see if the hub bolts are bent or damaged, and if they are, i should get a new hub assembly pressed in. I will also buy a new rotor, since the current one hit the ground.

But what if i don't see any damage to the hub bolts? Are there any tricks to knowing whether the splines on the driveshaft are damaged other than the obvious--- look and see if the grooves are damaged?

Do you think its smart to just replace driveshaft anyway? while i have everything removed with enough clearance. Napaonline.com has it refurbished for $47.89/core$11.00
i think the driveshaft is the part with the splines and the inner cv as well, correct me if i'm wrong.

Lastly, the third thing you suggested was damage to the CV. I haven't heard any clicking while driving/turning, and the last time i looked at it, the hard outer boot was in great shape (no cracks). Should i automatically rule out the CV?

my gut tells me it may be the splines on the driveshaft and the boots, because when i saw the car fall off the jack, the rotor was still on the hub. it didn't move at all, it was probably still rusted on. (everytime i replaced the wheel bearing the rotor is always rusted on, and it's a pain in the neck to take it off).

Well i'm moving to New York next week, and i will be driving my car from florida to new york. I will shoot myself if i have to hear humming during the entire drive.

I don't know any way of determining what shape the splines are in without inspection. I may be wrong, but I believe in general, splines are pretty difficult to damage in your situation. It is more likely that there is a crack somewhere in the area of the splines, rather than visual damage to the splines themselves. This is just a guess since your situation is unique. If you find damaged lug bolts, just replace them all. They are easy to press out and pull in from the rear with some washers and the lug nuts.

I am surprised that you have replaced the wheel bearing repeatedly. Is it possible you didn't preload the bearing correctly and a bad bearing is the source of the noise?

If you replace the half-shaft (which is probably a good idea since you don't yet know the source of the noise), don't forget that you can leave the portion of the half-shaft inside the differential and only replace the CV joint and outer part of the half-shaft. Getting the inner part of the shaft out of the differential can be a serious problem if it is the original. I doubt the CV joint is the source of the noise, but that doesn't make it a sure thing.

[lorakew]

Originally Posted by Brian R.

I am surprised that you have replaced the wheel bearing repeatedly. Is it possible you didn't preload the bearing correctly and a bad bearing is the source of the noise?

well i actually replaced both the drivers side and passengers side wheel bearing. I took off the knuckle with the hub and brought it to Napa and had them do the press work with new bearings (a few napa stores actually have a shop where they do stuff like presswork). the guys in the shop are really old fellas. they looked experienced, so i assumed they would have done the pre-load. the humming noise was still there after all that work.

You said the damaged lug bolts are easy to press out. I don't have a press, but you said i could use some washers and lug nuts? i'm trying to visualize how to press them out, but i don't understand where the washers and lug nuts are used. would a c-clamp or caliper compressor with a pad work?

And i always have problems getting the old rusted rotor off. i usually spray it down with PB, but even then, its still a killer to get it off. any ideas about getting this rusted rotor off. (when i take it into the shop i usually bring the knuckle w/hub and rusted rotor)lol.

[lorakew]

so here's a recap since this thread deals with different problems:

when my uncle was looking at my brakes the car fell off the jack. the drivers side wheel/tire was off and the rotor hit the ground. now when i'm driving there is a loud humming noise at 55mph and 70mph. In between those speeds the humming goes away. This happens when i'm driving straight. No humming specifically when i'm turning right or left. When i brake at 70mph the humming slows down a bit, but it still hums and it will eventually go away when the speed gets way below 70mph. If i'm driving at 70mph and i let off the gas and coast the humming is noticably louder as the car naturally slows itself down until the speed gets way below 70mph, then the noise will disappear.

I've had an alignment, tire balance, and when the tires were worn out, i had tires changed. the brakes are good, however my rotor that hit the ground is warped which i'll be replacing next week. i've changed the hub bearing on both the drivers side and passengers side, but the humming is still there. It's a loud hum, i have to talk louder to speak to the person next to me.