Front end vibrations, and SES Light

Okay. Here is my newest dilemma.

=====Brakes, in more detail:
Background: I recently replaced the drivers side front wheel bearing. There
was a broken bold on the caliper, replaced both of those with new ones. The
pads and rotor seemed quite fine. Before this, the front end would shake
when I'd brake heavy; brake pedal would move almost to the floor before
gaining any brake force and then it'd require more pressure. I had the pads
and rotors replaced almost exactly a year ago.

After the procedure, I had the front end realigned. The brakes immediately
were no longer spongy. Now I've noticed that the pulsing has increased -
hinting that a rotor is warped [on the passenger side?]. Question: I suspect
that the drivers side brake wasn't really functioning as the pad looked
relatively unworn after a year; I haven't inspected the passenger side rotor
or pads, in fear of breaking another bolt and being without (nor have I had
the time.) When braking the car pulls to the drivers side, and I get a "grip
and slip" feeling in the steering and car itself almost like antilock but
not as smooth or controlled.

If it's the passenger rotor/pads, should I just replace that side? Should I
get new pads for both while I'm at it? Is there any brand of rotors that
wont warp [or as badly] for 1997 SC2's?

======= SES Light:
Also, The rear oxygen sensor is done for since I suspect transmission fluid
got into the connection between it and the computer. I have a new sensor, a
socket for the sensor, yet I cannot get it out no matter how much force I
can try. I have a picture of the sensor here:
http://i9.photobucket.com/albums/a66/Hypercube33/Dsc03466u.jpg
I have noticed that in the service manuals that there is no "guard" that my
car has, and the guard appears to be home brewed. Is there any way I can get
this beast out without cutting the exhaust system to hell? Note: I don't own
a torch!

Major thanks, and this time I am awake enough to actually be capable of
spelling!
-Brian

 

Brakes: Bleed the fluid until it runs clear. Have both front discs
resurfaced. Check the caliper pistons are not siezed. Repair/replace as
required. Usually done in sets! Replacing rotor or pads on one side is just
asking for trouble.
Bolts do break, it's a fact of life with mechanical systems. You can
minimize breakage with the right tools and techniques. Use a good
penetrating fluid (NOT WD-40), let it soak for a while and then try to break
it loose. Impact wrench is preferred as it tends to shatter the brittle rust
bond. When the bolt starts to move a little, don't force it. Go forward and
back, all the while applying more penetrating fluid. In extreme situations,
a flame wrench (torch) is used with great care. I know you said that you
don't have a torch but even a turbo torch running mapp gas is better than
nothing.

Sensor - if the sensor has to be replaced anyway, cut the cable and use a
deep socket on the sensor. You can also buy special O2 sensor sockets that
have an open slot for the wire. Try first with a breaker bar or an impact
wrench. Here, heat IS your friend. If you can't get the sensor loose, heat
it at the screw base to a dull red and try to work it back and forth. If you
can't heat it, take it for a drive up a hill and try again while it's still
hot.
Oppie

 

I agree. Brake fluid is hygroscopic (absorbs moisture from air) which leads
to galvanic corrosion of iron and aluminum brake parts. IMHO, brakes should
be bled periodically in order to change the fluid and remove any
contaminants. Use only fluid from a new sealed can and do not use fluid
from an opened and resealed container.

IMHO, resurfacing rotors is a waste of time and money. It leaves the rotors
with reduced thickness which can allow them to warp again more easily. IMHE
the far more expensive Saturn OEM rotors are no better and IMHE are actually
much worse than cheap offshore rotors which cost only a little more than the
normal charge for resurfacing. Using new rotors also saves a trip to the
machine shop, and you can buy them before your car is dissasembled. Use
only good quality pads.

Often due to corrosion caused by contaminated brake fluid.

I agree, always do both wheels on any axle at the same time.

Used caution when working a siezed bolt back and forward as it can cause
galling of the threads if the lubricant has not penetrated properly and this
problem is worse when the threads are hot. If there is any evidence of
galling then the bolt should be replaced with new and always use anti-sieze
thread lubricant for assembly.

IMHO, A low heat torch is often too slow and will expand the bolt as fast as
the housing, the secret to using a torch is to use OA because it is very hot
and the small very hot flaame can be properly directed to expand the housing
faster than the bolt.

IMHO it is essential to use an anti-sieze thread lubricant on the threads of
ALL bolts, use a high heat type for all brake work.

The caliper must slide on the mounting bolts when in use and any binding can
cause uneven application pressure and incomplete release. Incomplete
application or release will cause the pads to drag more on one side of the
rotor which contributes to rotor warping and pad wear and increased fuel
consumption. IMHO the holes and bolts should be properly cleaned and the
shaft of these bolts should be lubricated with anti-sieze lubricant.
..

 

I would replace both rotors.. soundslike one or both are warped.. easy
to do if you ever did a panic stop especially if they were ever turned
down.
As far as the sensor you can try some penetrating oil and leave it
over night without driving and then give it a go in the am.

 

I've already got a wrench for the sensor. Also, I let the thing sit for 4
days, spraying it heavily. No dice. It almost looks like someone actually
welded it in and put that angle iron on there to keep it from being struck
off? I'm ready to
A. take a sawzall to it and then a drill, or
B. Have someone else deal with it.

 

It is always harder to diagnose problems that someone else has worked on
previously, and this is very common after purchasing a used car or one that
has incomplete maintenance records and log. This is one of the reasons why
I keep a complete fuel and maintenance log for all my vehicles as my memory
is not perfect and the log allows me to make notes about any problem and its
symptoms.

I doubt that your sensor connector has been damaged by transmission fluid,
but after looking at your photo, I agree that does appear like someone has
welded the sensor into the cat. I am not familiar with the guard and cannot
comment on its source but it does appear to have a funny bend and notch next
to the weld. I also notice that the bolts appear to be non OEM replacements
and are installed reversed and with what appears to be a new gasket. An
inspection of the exhaust system downstream of the cat may reveal more new
bolts or hangers or clamps.

It would be difficult to weld the sensor without removing it to weld over
the top and I suspect that it was removed for repair. It does appear to be
a nice weld, but welding on the sensor may have something to do with its
failure. YMMV.

Since you seem to have done all the easy stuff, I suspect you will need to
remove the cat for replacement or correct repair by welding on a new
threaded boss so the sensor can be screwed in place (using high temp sensor
safe anti-seize or Teflon tape). I suspect that the original repair was
caused by either an impact on the sensor or more likely by damage caused
when trying to remove one that was seized.

I suspect that a new cat will be expensive and you will have trouble finding
a used one at a wrecker as they contain precious metals and are usually
removed for metal recovery long before the wreck hits the yard.

One of the inconvenient truths of mechanical repair is that improper repairs
usually need to be repaired properly later.

Good luck, YMMV