Once I reach 75-80, the car starts slightly shaking and gets worse the faster I go. It's the type of shaking you get with unbalanced tires, but I just had the balance done a couple weeks ago. When I push the brake, the shaking increases. What could it be?

 

new roters maybe

 

Probably your rotors are warped. Does the brake pedal pulse up and down when you depress it?

 

how old are your tires? even balanced tires that are kind of old get tread separation on them sometimes. I had a car that I drove like 500 miles in a year (so it sat a lot) with new tires. I had them balanced and it still shook at high speed. One of the tires had the tread separate. I had to replace it.

It does sound like it's probably your rotors, though.

Also, sometimes at high speeds a car will shake if it's a little out of alignment.

 

you may need to balance your tires

 

The brake pedal feels fine. The brakes are ok when going normal speed. When I said "the shaking gets worse when I push the brake", I was referring to 75+ mph. I did take a closer look at the tires today and the inside edge of the front tires is worn out. It looks like the alignment is messed up as you suggested, red. I'll have that checked out tomorrow. One question, when the car gets out of alignment for whatever reason, does it stay in that position or does it even get worse over time?

 

it usually gets worse over-time... but not really fast. But the longer you go without aligning those wheels the more you are kicking the crap outa your tires

 

The front tires are trash. There goes my paycheck.

Thanks guys. I'll let you know what it was.

 

well if you plan on keep ya max just kick out the money for a lifetime alignment @ firestone or sears. never have to pay for another alignment on that car and you just have to deal with tires. I got one for like $113 @ firestone. just a thought???

 

Update: the tires were changed and the vehicle needed alignment badly although there was just a slight pull to the right. Turned out that the rack and pinion was dead. Hence no alignment could be performed. I'll update that issue in the other thread I started.