Shaking at 70-85mph

[Drjlambert]

97 gen2 5.9 2WD 118k miles ext cab 8’ bed. Have been dealing with significant shake 70-85mph. Not in steering wheel. Occurs more on acceleration and deceleration, seems to improve when steady state speed achieved. Done to this point: new tires, tires balanced, alignment, drive shaft balanced along with u joints replaced, BD steering stabilizer installed, Fluidampr installed. Fluidampr is awesome! However, problem still remains. Any help or suggestions from TDR nation would be appreciated.

 

[fest3er]

Check the rear brakes. My '98 had a tendency to shake *badly* up around those speeds (like severe rear wheel hop). It was a problem with the rear brakes.

 

[Drjlambert]

Unfortunately Chrysler no longer makes the rear drums. Ordered replacement parts from NAPA for a complete rebuild. Once old drums were finally removed, I decided to clean up mechanism and just install the new 13” drums. Pads had many miles remaining. Test drive was amazingly smooth! Fest3er, If I wasn’t a raging heterosexual I’d give you a big hug and kiss. Question now is should I continue with the rebuild or just return the parts? Thanks again for your wisdom.

 

[fest3er]

I would check for brake fluid leaking from the cylinders. IIRC, brake fluid can act like cutting oil. If the drums aren't 'perfectly' round, the shoes touching part of the drum should cause annoying shaking.

Aside, of course, after having an improperly balanced pintle-hitch trailer whip the rear end of the truck side-to-side (like 8' total) on the curvy WV turnpike, the excessive rear end hop caused by the brakes (at a later date) was nothing. The former caused a little sphincter pucker; the later latter was just, "Oh, I should look into that." First time (and hopefully last time) I ever saw cars and semis 1/8 mile behind me stand on their brakes that hard and quick. Fortunately, WVDOT up the road had a few sacks of quickcrete that had gotten wet; they were great ballast. Seven of those in the front of the trailer settled it down right proper; 70 MPH up and down hill it stayed nice and stable. (I was hauling Dad's 55' crank-up ham tower to my brother in MI, and didn't have enough weight forward of the trailer axle. This is why 60% of the weight must be forward of the axle.) Yes, my road trips (and even commutes) have often been adventures, even going back to '81 or so.

A hug and kiss wouldn't be inappropriate unless you're terrified of COVID-19. I'm not; I adhere to Mom's adage, "Expose me early, expose me often." I prolly had it back in November and may've had it a couple times more since. (Been going to the local watering hole 3-4 evenings a week all along; I play being the junior bar-back/stock-boy/maintenance-man.) Get it while it's weak. And keep getting it before it changes too much for my immune system to recognise it. Besides, my niece's husband is wont to hug and kiss us lads on her side, so I'm used to such, mmm, endearing behaviour. But it's OK; he's known for eating 5 lbs. of plain steak in a sitting washed down with a fine single malt. Come to think of it, he doesn't drink much of anything else, not even water.

 

[12valveZach]

Who balances your tires? Sometimes name brand places really don’t get it right... What kind of weights did they use? Also if you have a wheel that’s out of round you’ll have some vibration no-matter what. Thats an issue I have, If you know anyone with a tire machine you just hold a straight edge parallel with the inner surface of the wheel and look for a shortening and widening gap