87 gt - bad front bearings? (Page 1/1)
domer94 OCT 02, 04:36 PM
been out for a few cruises in the last days... the one before today , i started noticing a pulsing type rotational feel and sort of a knocking sound coming from the front end when turning to the left (30-45 mph on back roads). first faint , but today it became very pronounced to the point of starting to shimmy the wheel a bit and i took it easy on the way home. the car isnt pulling , it doesnt exibit this when braking in a straight line to stop. i just pulled the wheel , the lugs were tight , no visible cracks on the rotor. , the pads have an ok amount of meat on them and dont seem to have been overheated. im thinking hub bearing since it seems to happen when pressure is on the spindle in a turn. does that sound right? the ball joints look a bit older, but the car went down the road great , no wandering or anything like that...

also . ive seen videos of what seems to be the rotor and hub structure as one. is this the way it is? if i buy a rotor/ hub off rock auto does it come ready to go with bearings and all? ive also seen full hub assemblies that look like the rears but say they are for the front which accept seperate rotors. can both these configurations be used? or should i need to stay with the hub/rotor combo

[This message has been edited by domer94 (edited 10-02-2025).]

hobbywrench OCT 03, 11:17 AM
If your 87 is same as my 85 GT the front wheel bearings are tapered inner/out and replaceable, cheap and readily available. Also replace the races in the hub . Pack inner disc tunnel with grease. Preload on the tapered bearings after new installation is important and tricky. You may see "endplay" with a dial indicator shown, but that may not work. (clean, clean, clean).
Over tightening (preloading) will quickly burn up the bearings, while under tightening will result in "loose" wheel. The technique I have used is to tighten the hex nut while rotating by hand until drag is felt and then backing off to nearest cotter key opening. Murphy says this may not result in an opening. It is then possible to hand dress down the hex nut and/or washer to reach the golden spot (figure 8 with good emory cloth) . But then a satisfactory final check with the wheel off the ground is required. Grasp wheel 12 and 6 o' clock and rock very hard vertically. A barely discernible "click" is felt. If not I go back to above. Don't ask me how many purple bearings I have replaced.

BTW this little snipit is not meant to diagnose your problem, only if you elect to change bearings.
82-T/A [At Work] OCT 03, 06:19 PM
My daughter came up with a trick to diagnose a failing wheel hub (one that didn't even make a sound, but that just didn't feel right). It's NOT Fiero related, but the same process can be followed to test if it's going bad.





It's right at the beginning, my daughter basically puts painters tape on the wheel, and then also somewhere on the fender, and spins the wheel to see how many rotations she gets. On the wheel hub that was failing, it barely even did one. But on the one that I'd replaced the year before, it did like 3 or 4 or something.

It's a little different because we have literal wheel bearings, not a sealed hub... but it should still work.
Patrick OCT 03, 06:33 PM

quote
Originally posted by 82-T/A [At Work]:

...my daughter basically puts painters tape on the wheel, and then also somewhere on the fender, and spins the wheel to see how many rotations she gets. On the wheel hub that was failing, it barely even did one. But on the one that I'd replaced the year before, it did like 3 or 4 or something.



How was the possibility of a dragging caliper accounted for?
82-T/A [At Work] OCT 03, 10:02 PM

quote
Originally posted by Patrick:

How was the possibility of a dragging caliper accounted for?




She talks about that in the video.

In the case of this car, the brakes had both been completely serviced just a couple of months before, and there were no symptoms of sticking brakes.
domer94 OCT 04, 06:27 PM
ok , so i found the culprit... feel stupid right about now. the lugs were getting really loose on the drinkers side , one almost backed out! i pulled both wheels just to check everything , made sure the hub rings were good. re mounted and torqued. went out for a drive and everything is smooth as it should be! well now i have some more info about bearing failure!
Patrick OCT 04, 06:37 PM

quote
Originally posted by domer94:

the lugs were getting really loose on the drinkers side



Not a surprise!