nasty vibration

[dlcss396]

hi guys- i was wondering if anyone can help--i drive a 87 chevy 1/2t 4x4--old style chevy-- developed a nasty vibration suddenly-here is what i have done so far to no avail--change front tire-swapped with some older ones i had-no fix-changed back- dial indicated rotors-found drivers to be out .015- also caliper sticky- changed rotors on both sides-checked wheel bearings-regreased-changed calipers and hoses-replace automatic hubs with superwinch-was having trouble with the automatics--dial indicated new rotors-pass side out .014- is that a lot??? checked tie rods-ball joints etc..HELP?????????

[bostoncan]

does it have a two piece drive shaft or a steady bearing in the center ? if it does check them .also check u-joints carefully.

[dlcss396]

it has a single shaft- - i drove it with the hubs out-so the front shaft wasn't turning-still there-i have owned these trucks since 1978-and have 4 now and never had this problem-gotta be something i'm missing-but i will ck the u-joints again tomarrow-any other ideas greatly appreciated

[bostoncan]

I have run into some that the steering box loosenes up where it bolts on the frame, also check the frame at the box area look for splits and broken welds caused from fatigue,also check the idler arm. good luck

[bdusted440]

I've run across this before on a couple of trucks if the steering dampener goes bad the front end will vibrate bad even if all the other components are good. Worth checking. http://checkmate-boats.com/6/ws/,s,8626072361/Graemlins/thumb.gif

[dlcss396]

ok- i checked the steering box-etc--all ok--checked the u-joints-look ok feel ok- have new rancho steering stabilizer from summit installed- gonna pull the rear driveshaft next-put it in 4 and see what happens-what a bitch!i hate to start replacing more parts- anyone know what acceptable run out is on a rotor?? it dialed out at around .015 total runout-didn't think that was too bad, but i want to keep going back to the brakes for some reason!! thanks again for the input any other ideas--go ahead-about ready to take it to the shop-which i have never done with any of my 4x4's.-just don't trust em!

[bdusted440]

When do you feel the vibration?
do you feel it in the steering wheel or in the brakes?At a certain speed?Need more info http://checkmate-boats.com/6/ws/,s,8626072361/Graemlins/brickwall.gif

[Checkm8fan]

dicss396;Have had a vibration for four years with a 1990 full size Blazer 4X4,it was eating u joints like crazy as well. The problem was that the U joint that was being sold for this vehicle was the wrong one. It was the most popular GM. one with the part number 3011 in actual fact we needed one with the number 534G it is about 60 thou. wider.This applies only if your rear yoke uses machined faces on the inside to lock against the snap rings.

[ckmate225]

Do you only feel the vibration when you apply the Brakes? If so you would feel it in the brake pedal ( a pulsation). If not It wouldn't be the rotors. Like 440 said do you feel it in your stearing wheel or do you feel it in you a$$ If you can isolate which end of the truck its coming from it may norrow it down a bit. I had a vibation in an old truck that drove me nuts untill I found some broken steel belts in the tire. Wear leathr glove and run you hand over the circumfrence of the tire and see if you have any steel wire poking out from the tread. Its worth a shot.
Good luck
Ckmate225

[dlcss396]

finally found it--- i pulled the rear drive shaft- while the truck was jacked up i noticed the drivers side rear tire didn't spin freely-- the f***ing parking brake was stuck on just a bit-- sanded drum- put it all together and wala- what a bitch-- anyway thanks all for the help it is greatly appreciated- knew it had to be something stupid- at leats i got new stabilizer and slotted rotors and new calipers- should be good till spring when i tear her down to regrease the bearings!!!

[ckmate225]

Ah,yes! the old parking brake stuck on a little trick!! That'll get you every time. Good you found the problem. The truck must feel like brand new now.
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