Violent shaking on 6% grade

[PenJoe]

Originally Posted by Super8mm

I thought my signature line was showing.

Truck is a 2011 GMC 2500 HD Duramax pulling a 2013 356 Puma toy hauler.

I had the same problem with a Sierra 1500. It would only act up on a downgrade. I took it in prior to a trip from Wisconsin to Florida and they told me there was nothing wrong with the brakes. Well, when I started down the grade coming into Chattanooga, it started to shake so bad, I thought the bug guard was going to fly off. One white knuckles ride down. Once we got down the grade, the brakes were good again.

When we got to Florida, I went to a dealer whom located a bulletin on the death wobble. GM had a bad run of front calipers and discs. They worked fine until they started to really heat up. The rotors would warp and cause the wobble, but then return to normal when they cooled down. Ya, I didn't that would happen either-once warped, they stayed warped. I found out differently. The dealer replaced both front rotors and calipers and that solved the problem. And, the dealer got GM to cover the repair. I wrote back to the dealer whom said the brakes were fine and got them to refund for their brake inspection.

[Super8mm]

Thanks guys,

My truck is all stock except the hitch with stock size tires.

They may have heated up when I came down a 6% grade from New Mexico going to Denver and the next 6% was on I-70 heading west out of Denver and it did feel like it was going to yank the steering wheel out of my hands. after that I got to the point if I could not see the road when going up hill I would slow to 40 mph and the 4 miles of real steep and 6% I slowed to 35 as that is the posted speed for vehicles of 26 K. figured it is was good for them it was good for me.

I have been running around Dillon and Breckenridge with out the trailer and all is good.

I'm just glad I am living to see this area, I will post some pics of my campsite in the other section in a bit.

[Lawrosa]

Originally Posted by philobeddoe

Dollars to doughnuts you have some out of round front brake rotors. Should that ultimately end up being the case, buy a new pair, don't bother with turning your current pair. If you tow a lot, shaving metal off of your rotors will likely only speed up the warping process.

There is no such thing as warping.... It does not happen ...


http://www.stoptech.com/technical-su...nd-other-myths

[325BH]

Originally Posted by Lawrosa

There is no such thing as warping.... It does not happen ...

I see you say this but don't know why you say that. Maybe you have a different definition of warping... but when the rotor no longer runs true (wobbles side-to-side), it is warped. I have seen that many times... usually because the manufacturer put inadequate sized rotors on the vehicle.

Saying metal cannot warp, especially due to heat, is silly.

[velorandy]

Originally Posted by bshort

Taking a wild guess here, but sounds like warped rotors on your TV.

I just had my 2013 F150 rotors turned. I only had vibration, shake, during harder braking or slowing down from higher speeds (above 55). Once the rotors were turned, all vibration ceased.

[gloryracing]

Originally Posted by 325BH

I see you say this but don't know why you say that. Maybe you have a different definition of warping... but when the rotor no longer runs true (wobbles side-to-side), it is warped. I have seen that many times... usually because the manufacturer put inadequate sized rotors on the vehicle.

Saying metal cannot warp, especially due to heat, is silly.

Ya just gotta let him have his statement and terminology. I am still betting on rotors that are not correct...for whatever reason/term preferred.

[aceinspp]

Another definition for warp use by another industry is twist same as warp. So this may be the issue. Later RJD

[Lawrosa]

Did ya ' all read this?

-Warped- Brake Disc and Other Myths

and this.

Brake rotors don't warp!! - Car and Driver Backfires

and here.

Raybestos Brake Tech School, Part One: Rotors Don't Warp | Hendon Publishing

There are many more.

IMO have an open mind and educate yourselves

Ask any true mechanic you know if there is such thing as warping. If he was learned by the myth then so be it.

But ask any race crew mechanic and they will tell you otherwise.

Believe what you want. Im just stating my opinion based on fact.

[Iwannacamp]

Many rotors warp.. some worse than others. I have turned many. Warped, out of round and both. When non vented rotors, composite rotors and over or abused rotors are out there they get warped easily.

Death wobble on 87 and down 2WD Chevrolet P/Us common problem. I.E. bad ball joints...changed some of them too.

Had an 06' Jeep Wrangler with death wobble...no it wasn't wore out 5K miles. Crappy Goodyear tires. Fixed.

[325BH]

Originally Posted by Lawrosa

Did ya ' all read this?



-Warped- Brake Disc and Other Myths



and this.



Brake rotors don't warp!! - Car and Driver Backfires



and here.



Raybestos Brake Tech School, Part One: Rotors Don't Warp | Hendon Publishing



There are many more.



IMO have an open mind and educate yourselves



Ask any true mechanic you know if there is such thing as warping. If he was learned by the myth then so be it.



But ask any race crew mechanic and they will tell you otherwise.



Believe what you want. Im just stating my opinion based on fact.

OK. So we'll just call it "disc rotor have deformed and moves side-to-side because it got too hot".

LOL. When you throw a rotor on a lathe and moves left-to-right, that isn't brake pad material... that is warped , er, um, I mean "deformed".

Might as well say "metal doesn't bend/warp when heated!"

[gloryracing]

Many of the public use the word 'warped' to explain a 'bad' rotor. Been this way for many years/discussions. We are not saying that you are wrong...we are saying that we think the OP may have 'bad' (warped)rotors causing the problem.
Thanx for the info.


What do you think the problem may be? That could be helpful too.

[Iwannacamp]

Originally Posted by Lawrosa

Did ya ' all read this?

-Warped- Brake Disc and Other Myths

and this.

Brake rotors don't warp!! - Car and Driver Backfires

and here.

Raybestos Brake Tech School, Part One: Rotors Don't Warp | Hendon Publishing

There are many more.

IMO have an open mind and educate yourselves

Ask any true mechanic you know if there is such thing as warping. If he was learned by the myth then so be it.

But ask any race crew mechanic and they will tell you otherwise.

Believe what you want. Im just stating my opinion based on fact.

Learn something everyday. I know most of the time when you put the rotor in the lathe one side cuts more than the other and and one face will cut one side as it rotates and then cuts the other side. You can see the run-out(out of round) Sold these things 25+ years. Been to dozens of brake schools/clinics. Now more about proper brake jobs than I want to. Never heard this, but I have been out for 11 years.

[Wobbles]

The life expectancy of thread is?

[Wally21]

Just a thought from a B.C rv tower. Many of pur roads are waved from large heavy semis applying brakes on downnhill grades. You do the same on these damaged roads and your rig will buck. You should feel warped rotors through your brake pedal not the whole vehicle unless they are really warped and your brakeing way too hard. Trueness of the rotor can be checked at any shop or do it yourself by brakeing on a non-grade, if your rotors are warped ypu will still get a shudder

[Sterlingsilver]

His truck is a GMC and like my Chevy the brakes cook when you ride them on long grades. Then you get a whole lot of shaking going on. Nothing is wrong that needs fixing. Lay off the brakes until they cool down or buy super duty pads and even then, all you get is more braking until they over heat.

[Scrapper]

You can warp a rotor by improper tightening of the lug nuts. Start with one lug nut, tighten it down all the way, then do the others. I've seen tire shops do this.

[gloryracing]

Originally Posted by Scrapper

You can RUIN a rotor by improper tightening of the lug nuts. Start with one lug nut, tighten it down all the way, then do the others. I've seen tire shops do this.

Fixed it for ya! :-)

[PenJoe]

Originally Posted by Wally21

Just a thought from a B.C rv tower. Many of pur roads are waved from large heavy semis applying brakes on downnhill grades. You do the same on these damaged roads and your rig will buck. You should feel warped rotors through your brake pedal not the whole vehicle unless they are really warped and your brakeing way too hard. Trueness of the rotor can be checked at any shop or do it yourself by brakeing on a non-grade, if your rotors are warped ypu will still get a shudder

Or factory defective. The shuddering on the Sierra was violent on downhill braking. GM had a bulletin to address the problem. It was not how I was braking but what I had to brake with. Once the front brake pads and rotors were replaced, no problem.

[QCFR]

Old trucker mantra: Never. Never. Never go down in a gear faster than the gear it took you you to climb. (Let your transmission work in unison with your electric brakes.) The death wobble will make you a believer.

[TheWolfPaq82]

Originally Posted by QCFR

Old trucker mantra: Never. Never. Never go down in a gear faster than the gear it took you you to climb. (Let your transmission work in unison with your electric brakes.) The death wobble will make you a believer.

I remember my dad (R.I.P 7-11-14) telling me that in the early 70's before I could drive. He was one of the few that didn't have to stop at the check points coming down Pikes Peak...quick check and they waved him on. I can still see cars lined up at the checks...with smoke coming off the wheels.