Drivetrain rumble??!

[2002WRXSTi]

Yeah so anyway I wish it was obvious where the problem was coming from but I was just thinking of something I didn't do that it may be?

Anyway I did a 4:10 swap along with a 93' solid driveshaft at the same time. The car had a bit of rumble at the 80 to 110mph range. Just lately it has come on big time! Had a friend in the car going up Rt22 2 nights ago and he was like what the hell is wrong with your car

It rumbles the entire car now and you know it. The thing is it just started doing it pretty much and I was trying to figure out what could have triggered it? Then I remembered that I did just put new rear tires on it and I didn't balance them Still I wouldn't think unbalanced tires would make a rumble at that frequency

 

[Roadboss]

Our cars are exrtemely sensitive and I would not settle for any run of the mill balance. I now have been getting Road Force Balances from the shop in the next town that has the Hunter Machine. It has the capability to simulate tire load and indicates wheel runout as well. Get it on all 4 corners.

 

[Woof47]

Whenever I do tires on my Mark, I tell them: "It's normal for me to drive 85-95 mph; quite often over 110mph. I need the best balance job I you can give me." after I take the car for a test drive, if I like it, I give the guy that did the balance job a $20.00. If I don't like it I make them do it over. When it's the way I want it, then the guy gets his extra 20. It's worth the extra money to me to get an exceptional balance job. The guy takes the extra time to do a good job. It makes a difference. Only once did he have to do it twice.

 

[MarkVIII93]

I balance all tires for customers so there is less than .05oz imbalance on the assembly. It's funny because the factory balances have been imbalanced in excess of .25oz

 

[2002WRXSTi]

Well couple problems, one being I do all my work so I can balance them myself when I get around to it. Other problem is it is not a wheel balance thing. I remember when I had out of balance wheels in the rear and how it made it feel. That was no where near the vibration frequency and also it changes with throttle

So how many people have had real bad rear wheel bearings and do you remember what they felt like at all loads and speeds

 

[XLRVIII]

I'd check the wheel nut on both sides and the pinion nut.

 

[2002WRXSTi]

I'd check the wheel nut on both sides and the pinion nut.

When I did the shocks yesterday I got under the car and checked the Pinion and Driveshaft to see if there was anything loose or bent/out of balance. All was solid as when I installed it and I had noticed when I grabbed the back tire I was able to get a clunk out of it pulling from side to side.

I didn't take the rear rotors off to get a look at the swing arm bearing assembly tho cause I was more into getting the shocks done at the time.

So how many people have replaced the rear bearings and how do they come out? You take off the stub axle nut and the flange off and then how is the bearing held into the swing arm? That and anyone know the rear axle nut torque specks off hand

 

[XLRVIII]

when you did the gear swap, did you take the axle nuts off?
did you replace them or reuse them?
how tight did you tighten them?

I dont recall the exact torque spec for the rear axle nut.
but when we did my gear swap I do recall it was a significant amount of torque.

your not supposed to reuse the rear axle nuts, but I did and got away with it
*shruggs*

 

[2002WRXSTi]

Didn't take them off. I dropped the 8.8 down and the axles came out and then I reversed the procedure putting the 4:10 unit in. So they are the original bearings in the rear and in 300 miles they will be @200,000 :shifty:

I am thinking the torque would be 150 like the fronts

 

[Aquabrit]

I am thinking the torque would be 150 like the fronts

From my 93's Ford service manual:

Since the bearing cannot be adjusted, the hub nut retainer must not be backed off after reaching the required torque of 188-254 lb-ft during installation.

 

[2002WRXSTi]

From my 93's Ford service manual:

Since the bearing cannot be adjusted, the hub nut retainer must not be backed off after reaching the required torque of 188-254 lb-ft during installation.

Yeah that explains why I had to buy a new torque wrench cause my old one only went to 150

 

[2002WRXSTi]

Amazingly got it all done in one day! Started around 1pm or so and took off the rear spindles or uprights if ya wanna call them that. Looked them and figured no way am I going to try to press these old bearings out.

Took them back to Autozone and of course they say we don't do any work at all. Of course I was thinking "Yeah I thought so ". So I go to PDQ in Manville and they where like yeah no problem but those are the wrong bearings they sold you over at Autozone. He pulls out the right one and of course it is twice the size of the GM bearings they sold me AND it was about $3 cheaper

They got them done in about 45 minutes and it took me less then an hour to get them back on my car and taking a test drive around the block. Could only hit about 65 in the traffic on 202 but it felt better. Taking a shower and then I'll head for White Castle in Green Brook on 22 so I can hit 75 or 80 to see how it feels?

 

[AbrahamLincoln]

awesome I would like to do this to my car so I can have a vast array of used wheels to purchase from Craigslist

 

[2002WRXSTi]

awesome I would like to do this to my car so I can have a vast array of used wheels to purchase from Craigslist

Do what? I still have a Mark VIII bolt pattern.

It was a ton smoother but now there is deff a drive shaft harmonic. I already have a 93' shaft so I was hoping it was gonna be smooth. Guess not

 

[AbrahamLincoln]

oh woops! i saw hubs off the car so I jumped to conclusions... There a good right up about our chasis and vibrations out there somewhere if you search. I know tires have a HUGE impact. I got new tires and it changed the whole car. I have 4.10's and stock driveshaft no complaints here, its a little annoying but it goes away after 100. But i've been getting some play when my car shift, not sure what thats about im going to my driveline guy this week to get the diff inspected and fluids replaced.

 

[wood_e]