OT, but still GM and unit bearing related

[GM Guy]

hey all,

my sister's 2000 Pontiac Bonneville with 265K miles is still going good (takes about 1 qt for every 10K oil change of full synthetic on the good ol 3800! ), but may be needing front wheel bearings IMO, and i wanted everyone elses opinion.

first off, should unit bearings have any slack whatsoever? just grabbing the top of the tire and jerking back and forth will net some slack. should I be jacking it up for a better feel?

second, I think I am correct in my diagnosis, but am not sure. there is a scraping noise from the front left brake, but it only occurs on a crowned road turning back to the left to hold it straight. let off the wheel, and the scraping stops. turn to the left, starts to scrape. is this a sloppy bearing allowing the brakes to drag when the spindle cocks in the hub?

Another reason i am leaning towards this is that the local GM parts man says its a pretty common issue, and they stock a pair of front bearings at all times.

is it best to replace in pairs?

will a bad bearing cause shaking and shuddering in the brakes, or is this more a warped rotor issue? on that note, does it hurt to re-use pad when changing a rotor? (we allready ordered some rotors for the rear).

any input appreciated, thanks!

 

[Will L.]

Jack it up and investigate further before buying parts. Yes the bearing could cause all that if it's warn enough. You could also have worn front and components as well as brake components, The only way to know is dig into it.

If the bearing is the culprit then absolutely change the other side, it's not going to be far behind.

 

[trouttrooper]

Hmm. Would almost consider myself an expert with that particular GM car.

No, there shouldn't be any play in the hub. If those are original then you got your money out of them. Jack tire off the ground and grab 12:00 and 6:00. If you can feel any up and down wiggle then the hub is bad. Some possible other indicators are if the ABS kicks on briefly when braking through a corner or bump, or traction control (if it has it) or ABS dash lights come on. Hubs aren't all that hard to replace, rust is usually the biggest issue. Rent or borrow a slide hammer and the world is a better place :thumbsup:

Shuddering when braking can happen if the hub is bad, but usually warped rotor. At that many miles they are probably due for replacement if they haven't been. As long as the pads are fine there's no reason to replace them too, some might disagree. Why do you need rear rotors?

At that age/mileage you should also consider replacing outer tie rods. Also as an FYI, I started going through drivers side CV axles on my 2000 Impala and couldn't figure it out for a long time. Ended up being worn out motor mounts were allowing too much flex. There is a funky hydraulic type lower mount that can "blow". I ended up paying a shop to replace that one just because I had no time to deal with it then. Upper dog bones are a piece of cake obviously.

I miss my 3.8

 

[btfarm]

X3 on the worn hub bearing test at 12 & 6 O'Clock. Any play is NG. Likely your scraping noise issue as you suspected. If they're cheap enough do both sides.

 

[GM Guy]

not exactly what one would call cheap.

we are needing to haul equipment out west, get machinery hauled home out of Nebraska, hit the spring auctions to get some more inventory, etc. so dad and I are pretty busy, so no time for sisters car. good thing she has money. works like a slave and still lives on the farm, so she can afford it.

I called in, and labor wasnt bad, 1 hour per side, and labor is around 76 bucks per hour. the parts, on the other hand, oh my. genuine GM, highest grade we can get, each one is over 300 bucks!!! :O

I flat out asked the service guy if they would be insulted if we shopped around and bought parts elsewhere, he said no problem. He understood, as he asked me if I was sitting down before he told me the price!

unfortunately the pontiac was here today and she took the Buick (90 Lesabre, 3800 powered of course its the one that started it all... ) and is taking the Pontiac tomorrow, so I cant mess with it till thurday or friday, or maybe even the weekend.


what has everyone had good luck with for front unit bearings? I assume Moog would be a good choice? I may try to stick with GM or AC Delco, but find a chepear price online.

thanks for all the help!

 

[NVW]

I bought Timkens for my 3500 from Rockautom $145 ea.

 

[trouttrooper]

For me the original GM hubs on my Impala went bad at 80k miles. I bought some made in china cheapos off ebay and they lasted 150,000 miles. The second set of el-cheapo hubs were still on the car when I got rid of it at 240K miles.

 

[btfarm]

Whatever Rockauto has as top of the line is what I would get. Also, you cannot go wrong with Timken.

 

[jrsavoie]

You can also google whatever part numbers you find or are recommended. I've gotten good prices from Amazon on parts. Often Amazon is cheaper than rockauto. I always price both anymore. Rockauto did beat Amazon on price on the AC Delco radio knobs though