One other possibility besides warped rotors.

You said there is a spare on one side?

Is it the same diameter?

If one tire is off a bit in size, the ABS can act weird, and create a pulsing feeling.

But most likely, it's warped rotors.

 

it's a used tire that's the same diameter but the tread is a little less than the others. My other 3 tires (used to be all 4) were the same tread, about 2/3 of original. Then when the sidewall got cut, I had to get a used tire, and it has about 1/2 original tread.

 

Get good new quality rotors. If your rotor has warped check for a sticking caliper or the problem could repeat. If they warped by them selves turning them may help but this makes them thinner and will likely warp faster than before.

 

I have had new rotors that were warped. You can have them checked for trueness at Oreilly's or Napa when you buy them. Should not cost you for them to check. Note also of your shaking is felt in the whole truck or more in the steering. The whole truck shakes when the rear brakes are bad, you will feel it first and most in the steering wheel if it is the front brakes.

 

I hope it's not my rear brakes...I just replaced the brake shoes, springs/clips, and drums about 3 weeks ago. Although it was less than 20 degrees outside, I was able to change my front rotors this past weekend. Re-greased the wheel bearings and had to go buy a 3/8" allen head socket (all mine were metric). Got the rotors replaced fairly easily following Haynes instructions. Good news is that the vibration has gone. I looked at the caliper but didn't note anything that was obvious. Only time will tell if it was the rotors. Unfortunately, I didn't see your note until after they were already installed. Everything appears to be working well, although now I can definitely tell that I need front shocks. I can feel every pebble in the road.

 

It's the rotors causing this 98.5% of the time that I've seen it happen. Usually if the rear brakes cause any vibration you can feel that it's in the rear. In your case since it went away it was probably just the front rotors.

 

something isn't right. I'm not sure what it is. But it's still bouncing when I'm pressing my brakes. I'm not sure how it could be the rear...I've replaced the brake shoes, springs, clips, and drums. I didn't replace the front brakes or calipers, but i did replace the rotors. I know I need new front shocks. Could that cause my truck to shake when pressing the brakes? The emergency brake cable must have been stretched. I ended up having to use a brake cheater clip to get it tight enough to work, but now it works fine. None of this happened until I replaced the rear end due to my gears being jacked up. Any suggestions? What are other possibilities? Rear shocks? Ball joints? tie rods? steering sector? I'm just throwing darts now, but I don't want to keep replacing parts until I figure it out. There has to be a way to narrow down until I figure it out.

 

have a look at your tires...... they showing any odd wear? (cupped.....) That may give you a shake.

 

3 of them are about half worn, and the wear looks even. They were on the truck when I purchased it in June 2014. The 4th is a used tire that I purchased from a used tire shop when I found a cut in the sidewall of my tire one day before I was going to take my truck and trailer 300 miles to Alabama to pick up bunk beds for my son. I was in a hurry and couldn't shop around. There is only about 1/4 tread left on that tire, so it has noticeably less tread than the other 3. It is located on the front passenger rim.

It's raining today. I just came back from lunch, and I park in a 8 floor parking deck. I rolled down my window and listened. Everytime I turn the wheel, something squeaks. I assumed that this was a rubber part that is wet or possibly may still have coolant on it from when my head gasket blew and coolant spewed out of the res tank. Now I'm wondering if it may be more. The truck, when going slow, feels like it's surging a little (hard to describe...not the transmission, but like it's rolling over something small, like a bubble in a tire or something, but I haven't found anything).

 

Run your hand around the tires. You may not be able to see it, but, you should be able to feel it.