I got the shakes

[Octaneforce]

My platform is 1993 fleetwood coronado class a p30 with rear disk brakes (p32?) and 454.

I put 6 new tires on it a few months ago and a shake developed as soon as i got it back from the tire shop, so i assumed it was the tires. They are sumihoto 8r19.5. They were not the cheapest tires i could get. I never cheap out on tires.
Anyway the rig has been back to the shop about a half a dozen times for this shake and it has not changed. They replace something say its fixed, and then the truck behaves exactly the same.
So far ive done 4 new bilstien shocks, bilstien steering stabilizer, supersteer trac bar upgrade, 2 new rims, 2 of the new tires replaced (warrantied). The front end is tight, springs and airbags are fairly new and i keep the bags at 80psi. Ive experimented with different bag pressures and never noticed a difference. If i continue to pour money into this pile of junk im going to change to non bag coil springs from supersteer. Thats would pretty much be the last thing i could think of. Unless my wheel cover simulators are making it shake, which i didnt think of until just now. The shake feels like an up and down shutter. It starts at 60 and gets worse as you accelerate. I will say the truck drives very steady and feels safe with all the new parts, it just shakes. Which is agonizing.

[Gjac]

Octaneforce wrote:


Some of the bags were whole like this

Did not see that in your first picture, but that would cause a problem. Hope the weights fix the problem permanently.

[Octaneforce]

Some of the bags were whole like this

[Octaneforce]

Gjac wrote:
The bags just break to allow the equal flow to the circumference of the tire. Your picture just shows broken bags so they did what they were suppose to do. Many would argue that fixed weights are better and equal could harden do to moisture and throw the balance off, but that does not appear to be your case. Hopefully your new tires and rims fix your problem.

I just dont see how the beads could distribute properly with the bag in the way. Its a cheap easy way to balance tires but from experience and research the bags are a gamble.

Anyway the truck drives MUCH better with the actual balance weights. I think my problem is solved. I’ll see how the next trip goes. Thank you and everyone else for the help!

[Gjac]

The bags just break to allow the equal flow to the circumference of the tire. Your picture just shows broken bags so they did what they were suppose to do. Many would argue that fixed weights are better and equal could harden do to moisture and throw the balance off, but that does not appear to be your case. Hopefully your new tires and rims fix your problem.

[Octaneforce]

Im at another truck tire shop having all the tires dismounted, cleaned of equal powder, and re mounted and roadforce balanced. We’ll see how it is on the drive home.



These equal bags never disintegrated in the tire. Theres a few thousand miles on these at this point. I dont see how this stuff could work.

[Octaneforce]

Gjac wrote:
I the shaking is felt in the seat I would supect your tire being out of round of rim bent.Front end problems (loose ball joints, worm tie rods, bell cranks etc) is felt in the steering wheel. Did you check for the tire being out of round? Or check to see if the wheel wobbles?

The tire shop who ive been dealing with warrantied the 2 driver rear tires and did 2 new rims. They said the tires werent seating correctly. The problem didnt change. If it is an out of round tire/rim, its the passenger side rear. Im about to buy 2 new rear rims and make them warranty 2 more tires just to confirm.

[Gjac]

I the shaking is felt in the seat I would supect your tire being out of round of rim bent.Front end problems (loose ball joints, worm tie rods, bell cranks etc) is felt in the steering wheel. Did you check for the tire being out of round? Or check to see if the wheel wobbles?

[Octaneforce]

DFord wrote:
Are you positive the shake is coming from the rear end? Those symptoms sure sound like there's excessive play in the front end. Worn balljoints or tierods or bushings are prime suspects. I'd see if a shop that works on Step Vans which are similar to your chassis would check it out for you. The "bell-cranks" on that chassis are notorious for loose, sloppy fits. https://www.amazon.com/SuperSteer-P3032-Bell-Crank/dp/B009WQQ64M These bell-cranks are expensive but are a positive fix to get that play out. GM should be forced to replace them on every "P" chassis ever made.

The shake is in the seat. It doesnt feel like steering wheel shake. I’ll crawl under with a bar later and check for play in the front end. I thought about doing bell cranks from supersteer when i learned how dangerous the stock ones are, but the truck never really had front end issues. It doesnt even jump around anymore like most of these p30’s do. Oh and also, im running out of money! Lol

[DFord]

Are you positive the shake is coming from the rear end? Those symptoms sure sound like there's excessive play in the front end. Worn balljoints or tierods or bushings are prime suspects. I'd see if a shop that works on Step Vans which are similar to your chassis would check it out for you. The "bell-cranks" on that chassis are notorious for loose, sloppy fits. https://www.amazon.com/SuperSteer-P3032-Bell-Crank/dp/B009WQQ64M These bell-cranks are expensive but are a positive fix to get that play out. GM should be forced to replace them on every "P" chassis ever made.

[Octaneforce]

DFord wrote:
Bent axle vibration will NOT come and GO. Look for another problem. Vibration like you're describing was common back 50 years ago when "loose" front end joints would cause oscillations that could only be stopped by slowing way down after they got started. Do you have a solid front axle with king pins and leaf springs or independent front suspension with coil springs/ball joints?

Its an independent front end. Typical chevy but with airbags inside the coil springs

[DFord]

Bent axle vibration will NOT come and GO. Look for another problem. Vibration like you're describing was common back 50 years ago when "loose" front end joints would cause oscillations that could only be stopped by slowing way down after they got started. Do you have a solid front axle with king pins and leaf springs or independent front suspension with coil springs/ball joints?

[Octaneforce]

wolfe10 wrote:
Octaneforce,

Just a quick, friendly suggestion: Fill out/modify your signature so we know what rig you are driving.

There are many here with decades of hands on suspension experience, but having to wade through 5 pages of posts to get info is "less than inviting".

Thanks.

Thanks for the advice. I did my best to create a signature. Its a little funky working this site from my phone

[wolfe10]

Octaneforce,

Just a quick, friendly suggestion: Fill out/modify your signature so we know what rig you are driving.

There are many here with decades of hands on suspension experience, but having to wade through 5 pages of posts to get info is "less than inviting".

Thanks.

[Octaneforce]

Bringing back this thread. I finally got around to installing centramatic rings on all 4 corners. The truck is now silky smooth below 60 and these rings really do stop vibrations, HOWEVER, as soon as i exceed 60mph the shake starts. With the rings its very easy now to identify the shake. Its more like a wobble, and im sure its coming from the rear.
The strange thing is, once the shake starts it doesnt go away, even when i slow down to 55. I have to slow all the way down to like 40 for it to “reset”. Im starting to think i have a bent axle. This issue is depressing. Whats funny is how awesome this thing drives now below 60 mph. Its like **** racecar with all these new parts. It just has shaking fits after that speed.