Fixed Problem, but came right back

Hello,

Problem 1
I have a horrible braking problem that shakes the entire truck. Been happening for awhile, tried to fix it once by having all 4 brakes changed...came back. So, I left it until last week I brought it to another mechanic and they swapped the rear drums. Fixed the problem for a day or two and then it came back. During the "fix time" the braking felt like it was mainly coming from the rear. Called them back and he swore they adjusted them right. The mechanic has a good reputation and just wondering if it could be something else as I'm determined to get this fixed.

Problem 2
CEL came on for 0420 and they replaced the AF sensor and it cleared the light. Now, my ultraguage says it has a pending alarm for the same thing. From what I read, these trucks are very sensitive about having Denso sensors. I haven't been able to check it yet, but would that be the issue or something else?

Thanks for any help guys as I'm hoping to get this all straightened out when I get back from training in Georgia.

-Brad

 

0420 is either the air fuel ratio or the 02 sensor, the brake issue sounds like warped rotors

 

Had all the brakes replaced last year...Drums, rotors and all pads came back in a week or two that time.

 

you just braking too hard?

 

ask your mechanic to check the rotor run out, and drum runout, if they are out of spec i reccomend upgrading the rotors and drums as well as the pads

does it happen only when applying brakes? also how hard are you are the brakes, a sticky wheel cylander or caliper could easily cause the brakes to drag, overheat and warp again.

also any circumstances where youre brakes were hot and rapidly cooled (IE lots of high speed stop and go then go to a car wash with cold water?)

 

I would get your tires balanced.

 

what do you mean the drums rotors and pads came back? did the problem come back? when did the shaking start? sounds like some warped rotors to me. if the rotors are warped and you change only the pads, the new pads will wear fast and your problem will return.

 

I'm no expert but I believe if you replace the rotors/drums you should replace the pads at the same time.

For instance in your case, say the problem was in the rear drum. You replaced the pads and it came back, so your pads are ruined again. Then replaced the drums, but your pads are still bad so the problem comes right back.

 

-Drums, rotors, and all pads we changed last year...problem came back within 2 weeks
-New tires couple months ago-balanced...pretty much ruled that out
-Last week changed rear drums...problem came back in two days.
-I don't brake unusually hard, most of the time and it'd been dry lately.

Would a sticky cylinder or caliper cause them to warp in two days?

Any more ideas?

 

yes, especially if it overheats the rotor/drum, you had any pulling?

 

I haven't noticed any huge pulling. Just a slight to the left.

 

might be a sticky caliper on the right side causing the rotor to overheat and warp

 

Here's the deal so far. They're replaced the drums and pads today (for free). They said they found a sticky caliper pistons on one (maybe both I don't remember), but anyways they're replacing both calipers, rotors and pads tomorrow. Hope that fixes the shaking issue. I'll keep this updated when I find out, no use in having a thread without answers right?

The pending code went away. Just didn't give enough time for the code to totally clear.

 

Ok the shaking is back again. Both calipers were replaced and I'm not doing any heavy braking. It seems to happen more at highway speeds and I've pulled the e brake to check the drums and it seems the drums are warped again.

Because it's been shaking for awhile, I wonder what was messed up to cause the symptoms to return. Any help?

 

Not having your lug nuts torqued correctly can warp rotors. Run them down and then torque in a star pattern with a torque wrench.

 

Something MAJOR out of wack?? Leaf Springs broken, bent U bolt, or a bad proportioning valve? Hell, bad wheel berrings at the rear end? There are so many ways to look at this. Can you lift rearend and see if there is play in the wheel/tire combo? (Just like looking for a bad ball joint or tie rod end in the front, grab top and bottom of wheel and see if there is any give and take there ) If the wheel on the rear deflects in or out then I would look there first.

 

What about ABS system if so equipped its caused more than a few problems within the brake environment..just throwing it out there..

 

Don't have ABS and I just replaced the leafs a couple weeks ago. When doing so I didn't notice anything completely out of wack. I'll left the back up and play with the wheels later today. I've played with the front and didn't notice anything though.