Found rear caliper slide pins rusted in caliper bracket replaced brackets and pins seemed to make a difference, short road trip about 15 miles oneway, thought it was fixed.
I took it on a road trip today and did fine most of the way and then started again here and there, then on the way back nothing but the shakes. Maybe I need rotors replaced now, not for sure no pulsing brake pedal.
Don't really have the cash so might be a while before I update.
Think I will chk left front caliper for kicks since 3 outta 4 had issues, also gonna chk emergency brake pads to see if maybe not adjusted correctly.

 

FYI, Replaced all 4 shocks with Monroe Reflex they are alot stiffer than the Bilstiens, helped alot but still some shake on the highway occasionally, and at low speeds you feel it but it is not as pronounced as highway. Installed a new Moog idler this morning, looks alot beefier than the stock arm once I got the stock one off it is alot looser than the Moog is. Took a short trip no highway will post again to let everyone know. This problem is a trip just when you think you have it, it starts shaking again. I must say everything I have done has helped, before you know it everything will be new

 

Please keep this thread going.. I have the same issue and hope to hear you've found a final resolution. I'm going to put mine on jack stands like you did and compare mine to what you've found. Thanks for the info so far!

 

Sorry to keep you hanging took vehicle back to shop and had front end checked and aligned since I had done so much work on it, they said everything looked good. They did alignment and I had them rebalance again this is third time on tire balance.
Rotated cause they have 5k on em now took it for a ride about 15 miles highway and thats the best it ever drove.
Turned around to go home and slight shake but nothing like it was, so I think I'm gonna call it good enough for now, I have some other fish to fry.
I forgot to mention I also replace front stabilizer bar bushings and end links.
Sorry if I didn't have an answer for you, but like I said, everything I have done has helped. Good Luck!
And keep posting I'm all for trying something else.

 

I'm outta ideas!!! Took the Blazer on a road trip 100 miles one way, mild shake here and there, on the way back shook worse, inside door panel shaking center console shaking, sometimes you feel it more in your feet sometimes more in your seat, I don't know if wind direction is causing this issue or not, took the exact same trip in my Focus and smooth sailing so I know it's not the road it is a toll road and in very good shape.
Again the things I have done to this vehicle are:
New tires 5k on em now. Shook before I replaced.
Balanced 3 times
All new Moog balljoints and Moog idler arm
New front caliper pasenger side
New caliper brakets and pins on rear
Transmission mount
4 Monroe Reflex shocks
Moog stabilizer bushings and end links
Alignment and checked out at shop they said everything looks great.
63k total miles 2004 2wd
I'm starting to think this is a normal ride for these blazers.
So if there are any other suggestion I am open to all.

 

No that is not normal. I would tend to think its on the front end.
Its possible there is a driveshaft issues. Make sure there aren't any dings or dents in both shafts and the universals are good and not dry. Make sure the front hibs are tight and no noise when you spin them. Make sure the front CV's and shatfs are tight, no noise dings dents etc...
Make sure the brakes are not dragging, could be the rubber hose collapsing heating up the rotor.


Being in shot gun mode can get expensive. I would take it to a dealer and have them look at everything.

Before you take it anywhere...Check the caliper on the drive side. Make sure the piston isn't sticking at all. Should move smoothly. Open the bleeder when you compress the piston. Use a C-clamp, bar clamp etc.. See if any crap comes out.
Make sure the pins move freely, take them out clean and regrease them.
Make sure none of the brake line hoses look swollen or deteriorated as well.

 

ctyler,
Thanks 4 the reply I will check brake lines, pistons collapse and don't seem to stick all pins have been replaced and greased, front end checked by 2 different shops they gave it a clean bill of health.
No CV's on this vehicle it's 2wd

 

tvitale, please let me know if you come up with a reason for the shaking. Mine does the exact same thing. The second I go one over 65mph it starts with the shaking.

EDIT - Just found the post https://blazerforum.com/forum/steeri...e2/#post354388 which says the vibration is not fixable and is a known problem.

 

I just can't go along with it not being fixable.

 

tvitale.....This would be a longshot but can't hurt to check. Check the play in your steering box. I forget the nut size but the allen key is 3/16. Loosen the nut about a turn. Then turn the allen key until you feel some resitance, then back off 1/4 turn.
I had a loose steering and mild bucking issue in my 99 and that helped it.

A couple other things I'd do if it were me. Wait until the vehicle is all warmed up and you have your vibration. Pull over somewhere safe and temp all the rotors with a temp gun. See if one is significantly hotter that the others.

Same scenario but do this in your driveway or some other safe flat surface. Jack up the rear and and set the rear axle on jack stands. Chaulk both the front tires both sides firmly. Then put it in gear and see if anything is wobbling, bouncing has some runout etc... Also see if there is any play in the axle bearings etc.. If I didn't find anything I'd rotate the tires and start over.

Another long shot is to check the rotors on the hubs to make sure they center well.
the should be almost snug, no play. I just went thru this on my Cobalt with .030 of play causing vibration with several Mfg's. Personly I think Gm published a bad spec...another story and probaby why peeps are going thru hubs on them. I'd think it would shake all the time though at highway speeds....mine did.

Does it vibrate/shake any more or less braking, accelerating, left hand or right hand curves on the highway?