What have I done?? (Front wheel bearings)

79targa · 12-20-2002, 07:30 AM

About a week and a half ago a friend and I changed out the stock tie rods with new turbo tire rods we bought from PP. Since we were working in that area we decided to pickup new wheel bearings (also from PP) and change those out at the same time. It was an afternoon of work and at the time things seemed fine. The steering was much tighter. A couple of days later the car was taken in for a professional alignment.

A couple of days after that my wife started noticing a noise at slow speed coming from the front. After sometime I heard it too. I checked the front wheels by grabbing the tire and pulling hard from side to side and there seems to be play in both wheels. I used my Bently guide to adjust front wheel bearing play as they say but it doesn't seem to help. I even tightned the bearing nut (U-shaped nut) over tight just to see if that would take out the play, it didn't. The steering still feel tight so I don't know that its any problem with the new tie rods.

I'm not sure whats going on here. Anybody have suggestions for me to try please?

Dr. CS

911nut · 911nut's Garage

According to the Bentley manual you must press out the old bearing races and shrink the new ones in. Did you do this or did you just replace the bearings only? .

Jdub · 12-20-2002, 07:58 AM

Are you simply feeling the inherent play of old struts? There was a thread about this very thing recently wherein the poster found that the play he felt was not at the wheel bearing but rather further "in," at the strut/insert.

Go carefully with those bearings: adjust them so that they are not too tight and then work from there. You wouldn't want to screw up the good work you have already done by burning the races now.

John

79targa · 12-20-2002, 07:59 AM

Hmm, I have to admit the shortcut. we just changed the inside bearings and and reused the races as they looked so good. Once we got started in the process it was obvious the bearings had been recently changed so we made an assumption that reusing the race would be fine. We may have made an incorrect assumption.

Chuck Moreland · 12-20-2002, 08:00 AM

Is the noise from rotation of the wheels, or from turning the steering wheel, or not correlated to anything?

79targa · 12-20-2002, 08:08 AM

Quote:

Originally posted by Chuck Moreland
Is the noise from rotation of the wheels, or from turning the steering wheel, or not correlated to anything?

The noise is brake pad. In rotating the rotor around part of the rotation would have the rotor lightly hitting the pad. The noise didn't sound like bearings at all.

grant lyon · grant lyon's Garage

i spend some time with precision bearings (another application) and for high quality bearings you typically do not want to mix parts from different bearings ie. different bearing lots. also, proper handling at installation with shrink fits is critical to preserving bearing form.

you can find threads on PP with specific expert opinions on wheel bearings for 911s. i believe the Haynes 911 manual recommends not mixing bearing sets.

79targa · 12-20-2002, 01:07 PM

Quote:

Originally posted by grant lyon
i spend some time with precision bearings (another application) and for high quality bearings you typically do not want to mix parts from different bearings ie. different bearing lots. also, proper handling at installation with shrink fits is critical to preserving bearing form.

Makes since. I don't have a press which was another reason for using the old race.

Question, I will take the hubs in and get the old races pressed out and the races that came with the new bearings fitted. Can I still use the bearings with about 250 miles on them or should I toss all and get a new set of bearings/races. Of course new seals too.

tmctguer · tmctguer's Garage

Front wheel bearing races

check this thread for my experiences changing out races at home. it can be done, but it is a project involving spousal cooperation.

grant lyon · grant lyon's Garage

>A couple of days after that my wife started noticing a noise at slow speed coming from the front

Sorry to say, sounds (sorry for pun) as if the damage is done. If you're going to the trouble to have someone heat the hubs and press in the parts, the bearings are relatively inexpensive. Even if you do the heating and press fit yourself, I'd replace the bearing set (complete sets). Make sure you don't even swap the rings from one set to the other ie inner ring and rollers with (other) outer ring.

FWIW, I'm a bit bothered about having bearing grease products in the home oven. Unless you have a non-food related oven, I'd console yourself that having the job done outside may well make better sense for your dinning pleasure if not for your health.

The post just before this message by tmctguer is the good thread I had in mind.

dickster · 12-21-2002, 12:57 AM

agreed - you can't mix and match!

heres my experience
front wheel bearing replacement-don't try this at home!

911nut · 911nut's Garage

Quote:

Originally posted by grant lyon

FWIW, I'm a bit bothered about having bearing grease products in the home oven. Unless you have a non-food related oven, I'd console yourself that having the job done outside may well make better sense for your dinning pleasure if not for your health.

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Put the races in the freezer overnight to shrink them. Then press them in. It's easier to skrink the races then to heat the rotor.

dickster · 12-21-2002, 04:16 AM

911nut,

have you done it??

i understood heating was the "proper" way, and freezing helps the process. i used the kitchen oven

Chuck Moreland · 12-21-2002, 07:43 AM

I heat the hubs and cool the races. I use the same oven to heat that hubs that prepares dinner and cures paint. Of course they are clean of grease before going in.

No problems yet except I've developed a nervous tick a nervous tick

Even with the heat/cold they still take a good bit of force to fit together.

911nut · 911nut's Garage

Quote:

Originally posted by dickster
911nut,

have you done it??

i understood heating was the "proper" way, and freezing helps the process. i used the kitchen oven

Yes, Dickster, on machinery using tapered roller bearings. The principal remains the same on a car.
The coefficient of expansion works both ways and I think most people overlook that. Depending on the amount of interference fit the race will be chilled and the orifice will be heated. One would need i.d. and o.d. micrometers to determine interference fit they're looking at. If it's .001 in. or less freezing the o.d. part alone would be enough.
According to Chuck the interference is greater than that, therefore heating and cooling are required.

dickster · 12-21-2002, 08:51 AM

yeah, it would be great if freezing was enough!

79targa · 12-27-2002, 07:02 AM

Update. Took the car in Monday to have new front bearings and RACES installed. Replacing all the bearing work I had done a couple of weeks before. It then snowed Monday afternoon with another coating of snow on Thursday. The guy was very nice to keep it indoors for us through the weather. I'm just now getting the car back.

With the new bearings there is now no slop in the wheels. He showed me one of the races he pulled and it was starting to look real bad (looked great two weeks ago). So the lesson I have learned "always change the races and never mix bearing/race of different manufacture". If I had known parts and labor were only going to be $90 I would have let him do it from the start.

O-well, I learned some things and no harm done.

Dr. CS