Substantial shaking under downhill braking

so, this started yesterday and i need a little input.

downhill sections of freeway, 6-8% grades and 50-70mph, truck was shaking substantially under braking. shaking increased with brake pressure. mainly came up through the steering wheel but there was some vibration in other areas of the truck.

my first thought was warped rotors however, it does not occur on flatter sections of road either on the freeway or off. nor does it occur going uphill. also, the shaking from warped rotors tends to subside with more brake pressure. mine increased until speed dropped below 40ish.

it did not appear to occur while we were in the dirt yesterday.

truck is just shy of 24k. lift and 35s have been on for roughly 10k miles. it's been aligned once.

looking for ideas on possible causes and what to check. i have not yet crawled under it as everything was a little too hot yesterday afternoon. might try to get under it this morning before things heat up.

 

Empty bed?
Have the tires been rotated every 5k?

 

bed is not empty. there's a topper and drawer system with full drawers plus an aftermarket bumper with a full size spare.

yes, tires have been rotated every oil change. i do a 5 wheel pattern to rotate in the spare.

 

Still sounds like warped rotors. Maybe only start to warp when really heated up, like sustained downhill, not enough time to cool.
Only reason I’m thinking this is I have a diamond blade in a chop saw,(wet/dry) was doing great no issues. Cutting pavers for backyard. When I made a few cuts back to back the blade warped bad. I thought I’d have to go get a new blade for two more cuts to be done. Well me being a cheap ass figured I could go slow and get two more cuts.
By the time I got to them the blade had cooled and was nice and straight again.
So, might still be warped rotors. For what it’s worth.

 

thanks

 

i'll give that a shot one evening this week. thanks.

 

Thanks for posting this Sean. I had this happen on my '07 and never figured it out. It wasn't a frequent issue so I never fixed it. Thanks @ColoradoTJ, now I'll know what to try should the issue arise again on the '16.

 

Maybe a slightly loose caliper? More weight shifted to the front because you're going down hill at speed.

 

Also check your front wheel bearings

 

I had this happen on my Tacoma...Toyota replaced the rotors under warranty. Big difference between the two brake systems but symptoms are the same: hard to replicate on flat ground by shook like crazy when going downhill in the mountains.

 

ok, so, i went through the steps that @ColoradoTJ outlined. last week we drove to telluride and back. traffic on 285 and over monarch wasn't heavy and moved steadily. as soon as the brakes got hot, everything started shaking. spent a lot of time cruising downhill in second and third.

i'll be replacing pads and rotors. considering the following: powerstop z36 front/rear kit and ebc's stage 3 truck kit w/ greenstuff pads for front and rear.

there is a significant price difference but, whatever, i want the truck to stop. especially when the girls are with me.

i put powerstop on wifey's Q7 and they are holding up well with a significant improvement over stock. no noise. no dust. i had ebc on my FJ and was happy. Amazon reviews on the z36 kit are mix of positive and negative with a few mentioning warped rotors before 10k miles. reviews on summit are all positive. kinda sorta leaning towards the ebc setup but thought i'd pose yet another brake question to the tundra geeks and fanatics.

so, what say you?

 

Yup, just replaced mines. No more shakes.

 

Mine are doing the same thing on my 19 CM. Will be changing out to the powerstop z36 system as soon as I have time and money

 

I’ve had the best luck with new oem rotors. Turning them or replacing with after market or performance rotors have always led to one thing...warped again and way too soon.

 

Warp rotors. 110%. Get new ones problem solved 120%

 

Stick with new OEM sounds like the better route then?

 

+ 1 warped rotors
+1 stick with OEM

 

Can you the the rotors. Or just get new ones?

 

yeah sounds like a braking issue not tires. rotors could have hot spots so uneven spots where maybe you came to a complete stop when the brakes were super hot. or they're warped.

 

best recommendation is when you change rotors change the pads too. then look into doing some light bedding of the brakes and try to prevent coming to a complete stop when they're super hot (ie. a long downhill that requires plenty of braking).

 

This.. I always change them together. Pads are cheap!
I've had good experience with "powerstop" slotted brands, does better than OEM for my Subaru. But that's just me.

Above..

 

Ok, I will change out rotors with OEM again and new pads. Descending Teton pass often eats breaks even when gearing down. Shake getting bad.

 

I had a 2015 SR5, and currently a 2019 TRD Pro. I also live near the mountains. When coming down the passes I get the same thing if I overheat them. I avoid it by not letting the rotors overheat by using trans braking, though sometimes I still experience it to a smaller degree.

While not 100% sure of the cause, rotors don't usually warp in the sense we think they do.

What we sense as a warp is usually uneven transfer of material to the rotor from the pad. The "warp" is actually a sticky spot in the rotor that the pad grabs onto. I've saved a few rotors in my day by sanding the pad transfer material off, replacing the pads and re-bedding the pads correctly.

If your rotors were truly warped or worn uneven, it would happen all the time. It sounds to me like they're getting really hot and you got one area of uneven pad transfer that is being exaggerated by the heat and becomes extra "sticky".

If you have the money to throw around then by all means, replace them and re-bed.

If not, you can sand off the pad transfer material with a DA sander and re-bed.

This guy walks you thru it.

https://youtu.be/5qB-jnANdTw

 

That 10% grade downhill by Jackson hole it's notorious for killing brakes.. if you mean that route

 

Yes I drive it 4 days a week. 5 in the winter. A lot of gearing down. Tourist don’t know how to drive the pass and ride there breaks all the way down. Seen a few run aways with big trucks. Now that scary. Generally the pass is safer in the Winter.