90 740 Turbo - Major brake problems

Recently, my 1990 740 Turbo has begun to shake whenever I brake. At
highway speeds, its enough to make the steering wheel shake as well.
I recently took a short highway trip, and started to hear a high
pitched whine or squeal while coasting. This noise corresponded to
the wheel speed, not the engine speed. Almost a year and a half ago,
I had this problem corrected by resurfacing the front rotors. Should
this problem be cropping up again, so soon, after only 5K more miles?
Should I just have them resurfaced again?

I doubt that this has anything to do with anything, but I recently got
new front tires.

Advice? Diagnosis?

 

Front inner and outer wheel bearings?

Lift up front of car, remove tire and spin wheel hub: see if there is
wobble or deflection in the rotor.

Check for play / noise re: wheel bearings.

 

I will check that as soon as I find a working jack.

I should add that that there has been a repetitive "dink" or "ding"
sound that accompanies me wherever I drive, in addition to the
periodic whine that just started happening. Like the whine it is
dependent on wheel speed, not engine speed. Symptom of bad bearings
as well?

Thanks for the advice.

 

You probably have warped rotors that could have come from overheating
the brakes or from the wheels not being properly torqued when the
tires were replaced. Because the car is almost 20 years old the front-
end may be loose and minor rotor wobble could be magnified as a
result. Best to have a good Volvo mechanic take a look. If the
rotors are old and have been turned once there is an excellent chance
that they are too thin to be turned again.

 

were they new tyres or retreads were they balanced ?Is your braking system
sound of is a claiper sticking ?Do you thrash the car then leave the brakes
to cool down on one spot ?Do you leave your foot on the brakes just in case
you need them don't laugh I have seen it ?
If ever I needed to machien my brakes I would first let them heat up very
hot then let them cool slowly as I was driving then machine them other wise
you machine the high spots down and then when the get hot again the high
spots of previous become low spots where the metal was machined away ?
I have the same model car and found my pads made a difference cheap pads
caused problems .aLSO I bled the brakes correctly it made a difference .

 

The one problem I've had with my 740 which I've so far never been able to
solve is it's tendency to warp right-front rotors. Once it could be blamed
on siezed caliper slides, but those have since been fixed. Calipers were
replaced at one point, tried high quality PowerDisc rotors, since then I've
been using junkyard rotors and swapping when they warp. This summer I'm
thinking of replacing the rubber lines, blowing compressed air through the
steel lines to flush them out, and I may swap the ABS modulator since
they're cheap and easy to find used, I can't think of anything else it could
be that would affect just that one wheel.