Braking in reverse- drums sticking?

Hi friends, this is my first post on here after months of snooping around this forum. You guys are super knowledgeable, and I’m not sure if I’ve seen anybody else mention a problem like this-
I’ve had my truck since June of last year and a few months ago I started noticing that, occasionally, when I first start the truck on a cold morning, back out of my driveway and hit the brakes, there’s a loud almost shuddering/jittering. To me it seems like my brakes are locking up. This only happens in reverse, seemingly randomly. I’ve been planning to jack the truck up and see what’s going on, as I understand that these trucks have a “self adjusting” brake system that works in tandem with the e brake. After learning that I know I’ll also need to adjust and tighten the cables as I also have squishy brakes (The front pads have been recently replaced) Before I check the rear drums I wanted to see if anybody else has experienced this problem and what should I look for when I take the wheels off. Thanks!
-also wanted to note my left rear wheel having a rubbing sound when cruising that I originally suspected to be a wheel bearing but after reading on here I’m wondering if it has something to do with what I’m experiencing when I reverse.

 

Has anything been replaced?
Have you tried a brake fluid flush?

Squishy is a poorly bled system. Just because the rear is "self adjusting" doesn't mean you don't HAVE to bleed the rears and LSPV

 

And you're sure it's specifically when braking?

I ask because shudder in reverse, namely while turning, is also a sympom of incompatible rear diff fluid, aka "chatter". This will happen if your truck is equipped with LSD rear, and you try to use certain brands of synthetic rear diff oil.

 

@FishNinja I haven’t bled the brakes yet. I was told by my dad’s friend who did the front brakes that they don’t need to be bled because they’re hydraulic? I know that’s not right and If you have any tips on how to bleed them correctly it would help a ton. Nothing has been messed with yet in the rear- I need to rip the bandaid and see how it’s looking. It’s my only vehicle so I need to get a good weekend for everything.

 

@shifty` There’s a chance that there’s some incorrect diff fluid from a shotty oil change place in there. I tried to take the easy route with those guys and I think I’m learning my lesson from it now lol. I can’t say for certain that that’s what’s causing it because it happened again this morning and I pulled over and just hit reverse and backed up straight and there was still a little chatter. I guess my best bet is to start with bleeding the brakes and putting some Toyota Diff fluid?

 

Welcome

Along with any/all the above comments, take a few minutes and read thru the below linked thread by @Aerindel, it'll definitely help with your “self adjusting” brake system.

Rear Brake Adjustment, theory and practice. | Toyota Tundra Forum

While you're at it, take a look at the other Sticky threads at top of Forum while you're at it.

 

Also something I wanted to mention was that sometimes when I disengage the brake I hear a little squeal from my left rear side maybe a second or so after I release the pedal. I don’t feel any kind of dragging when that happens, maybe it’s just from age and I’m nitpicking but I thought I should note it. I don’t have a lot of experience working on my own car but I’m willing to poke around and learn as I go.

 

@BubbaW Thanks! I’ll be sure to check that out

 

Not necessarily Toyota Diff fluid. If you have the LSD diff (if not rusty, there should be a sticker identifying it near the fill plug), the only full synthetics I've seen work and not cause chatter is from Valvoline, and the Amsoil Severe Gear. Any conventional will work fine, I made the mistake of not heeding this warning and put Mobil1 full synthetic in mine, and sure enough, chatter. It required more slip additive than I was comfortable using to get rid of most of the chatter, so I took advice here, installed Lucas 80w90 (conventional, non-synthetic) and no problems since.

Chatter, I felt it primarily in reverse. How to explain ... As I started rolling backwards, it was almost like something was skipping, stammering while backing up. A shudder, maybe you'd describe it. And it only happens at low speeds. It's stronger when turning in reverse.

If it's happening when rolling forward, at speeds higher than 5mph, it's probably not chatter.

That said, I take it you've seen the warnings on here about how your ABS sensors can get crud on them and cause ABS to pulse/engage too, right?

 

And as for the screech you describe. It's not unusual to hear a little groan when the calipers and drums let loose. Screech is different story.

On my side, I was dealing with a pesky screech only when cold and backing out of the garage. It ended up being the stupidest shit ever. Read about my my experience with that one.

There are a couple of other threads on the topic also.

https://www.tundras.com/threads/brake-screech-in-reverse-only.148482/

https://www.tundras.com/threads/met...iper-or-wheel-bearing-videos-attached.145025/

 

damn. Don't EVER go to that guy ever again.

wtf.

you should ask him "then why the FUCK are there bleeders on every caliper?"

 

Right?

I can't believe I missed that.

@sebnoob12 one of the biggest killers of brake systems is letting the brake fluid get old. Brake fluid is hygroscopic, or in plain English, "that shit likes to absorb water". When it does, guess what happens when that microscopic water interacts with your steel brake lines? Yup, you end up with all kinds of crap in the lines. Guess where all that crap settles? At the lowest point in the brake system, i.e. in your calipers (front) and wheel cylinders (rear), or in the case of our trucks, if you have the LSPV in the rear (load sensing proportioning valve), it'll gum that up, and your rear braking will be fucky, lethargic, anemic, and generally poor. Understand, the calipers specifically, there's not a lot of space between the piston walls and piston itself, so when you have little debris in the bottom end of the system, it doesn't take a lot getting jammed in the piston to kill the caliper's function.

There are cheap testers you can buy on scAmazon that you simply probe into the master cylinder reservoir to see how dirty your fluid is. Like this:

$13 ITEQ Brake Fluid Liquid Tester Pen with 5 LED Indicators, Calibrated For DOT3 DOT4 Brake Fluid

https://www.amazon.com/dp/B076SC377J/

Because it's hygroscopic fluid, you should (A) never run your truck with no cap on the brake fluid reservoir, else it'll soak up water out of the air and (B) try your best to always use fresh brake fluid, not stuff that you opened and left on a shelf for 1-2 years or more.

You should be fully flushing your brake fluid when a tester tells you it's done OR if you hold a flashlight up to the reservoir and it's any color between medium green to opaque. Brake fluid is typically clearish-golden straight out of the bottle, and will turn light green within a couple weeks of install.

It's critical whoever bleeds your brakes understands these trucks have the LSPV, because it MUST be bled, they can't just bleed the four wheels can call it a day. If you've never bled your brakes before, I'd actually start at the LSPV, bleed it until you get clear fluid, then bleed the passenger rear, then driver rear, then passenger front, then passenger rear. I've seen people on here say to do the passenger rear, then LSPV, then driver rear, but that makes less sense - if you get the fluid clear to the LSPV first, you'll clear any garbage that made it to the LSPV and have fresh fluid immediately to the rest of the back of the truck.

When bleeding your brakes, there's four methods, one is not advised:

• Pressure bleeding - A lot of people use the Motiv kit for this, you basically use a custom cap on the fluid reservoir, pump to pressurize it, then crack the bleeders downstream, being careful not to run out of fluid in the reservoir
• Reverse pressure bleeding - the inverse of the above, which is what I think dealerships do, you're basically forcing fresh fluid in from the caliper side first.
• Vacuum bleeding - The Motiv kit (MV8000?) is a popular choice.
• Old school stomp-on-pedal two-person method - DO NOT RECOMMEND. If you do it, put a block of wood under the pedal so you don't push the pedal so far you blow out a seal in the booster or MC.

 

Brake shoes can start delaminating. Moving in the direction of delaminated shoe may cause shoe biting sharply into drum with the end of pad, drum pries the pad away from shoe, then the shoe releases forcibly and starts biting into drum again. I had it happened in my car, it was making weird noises going in reverse. Turned out a delaminated parking brake shoe.

 

Wow holy shite there’s a lot of unpacking to do hahaha
Okay so @shifty` you mentioned having that god awful brake screech and that’s something I also randomly have. 20% brake input after first start while reversing, then never again. I looked at the threads and videos and it was the same sound. I guess I need to do something with the dust shield in the front brakes eventually.
In regards to my differential, I crawled back there and saw it does have the LSD sticker so it is that. When I got my oil done in October I believe, it was at a valvoline and they did replace my diff fluid also. Sooo maybe I’m okay on that end for now. Plus, whenever that shudder happens it’s only when I’m braking, and honestly my fluid is real dark and I just need to get that motiv kit and bleed starting with the LSPV valve.
Im just now learning about the abs sensors getting gunked up and it makes a lot of sense. Sometimes when im coming to stop at a light and i drive over a manhole cover/ small pothole while braking, my rpms rev up like abs is engaging but no light shows up on the dash and nothing really happens.. I’m assuming that’s not normal lol

 

Lots of people here want to help. Lots of people here beyond me know these trucks. And nobody here is going to feed you invalid or bullshit info like you'll find all over Facebook. It's up to you what you do with it.

Super easy to check. Jack truck. Take off front wheel. See if the dust shield is touching the rotor (shiny brake disc part) on its backside. Just don't get oil or grease or other bullshit on the rotor by touching it.

RE: Valvoline, they may list on the receipt (hopefully you keep your service records) what they used. If not, you could call and ask.

If it's "conventional" gear oil, you're likely fine.
If it's "synthetic" gear oil, if Valvoline brand, you should be fine.

Just because the name on the shop says "Valvoline" doesn't mean that's what they used. but shops like that will often go cheapest-possible which means using conventional, not synthetic. They'll know. And you can call them and ask, they should have your service record in their system too.

Tell us this: Is your truck lifted, or still stock height?

ABS shouldn't make RPMs increase, I don't think, unless I'm misunderstanding. Typically ABS engagement will cause the brakes to pulsate, essentially to prevent the brakes from locking up. By jackhammering the brakes (onOFFonOFFonOFFonOFF) rapidly, you still stop in a reasonable distance, but you avoid the caliper grabbing the rotor disc so hard the wheel stops spinning, and your truck then skids/slides into something.

If you have ABS (there'll be a big octopus-like square box with hard lines coming out of it between the passenger fender and firewall, in the engine bay), each wheel has a sensor installed, held in with a 10mm/12mm/14mm bolt (I forget).

That sensor reads a ribbed metal ring on the axle or in the hub, called the "tone ring". The sensor has a magnet, and it reads each rib on that ring to know how fast each wheel is going.

If you get shit built up on the magnet, it can't read the ring. Likewise, if someone ever replaces your wheel bearings, they can press that tone ring incorrectly into place, and the sensor can't read it.

Sometimes simply not having the sensor seated in its hole correctly will cause ABS pulsing!! Or if the O-ring on the sensor gets mangled from uninstall/reinstall. We've seen it. A LOT!

 

Wow. Yeah, I would not let that guy within 100 yards of your vehicle.

 

Another thing.

if your dad's friend didn't know that Hydraulic brake systems NEED to be bled. It's highly, HIGHLY likely he doesn't torque things to spec and goes with the German metric of "gut ehn tite"

Just putting it out there.

you wheels are probably over torqued along with your calipers.

 

Thanks, it means a lot to have genuine conversations on the internet these days lol. I’m learning a lot more on here than FB and everyone is very helpful on here so I’ll definitely be sticking around.
So I couldn’t for the life of me find my receipt- I usually keep them in a little booklet in my glovebox but I guess I didn’t do it that time..oops. I called the people up and the guy told me they used synthetic valvoline brand on the truck.
My truck is a 2wd TRD- meaning I guess that I have the belsteins, but it’s stock. Guy before me was older and didn’t do anything to it but did most of his service at a Toyota dealership thankfully.
Hmm.. yeah that rpm thing that happens I guess is from something else. It’s a little jarring when it happens but it doesn't do anything to try and kill me luckily. It just feels like something trying to engage and my revs go up a little, almost as if my truck lost traction and is trying to regain it. and I asked a friend of mine that’s got a couple of old Toyota trucks and he told me it’s something to do with the ABS, but I’m not feeling any kind of rapid pulsing or anything so I guess not.

 

Uh oh. Good point. All the more reason for me to just start doing all this shit myself lol, at least then If something goes wrong it’s on me

 

Since you have 2WD, be aware there is a known problem with the bolts that hold your transmission to its crossmember falling out.

More info in the community megathread, which you should probably read the 1st two replies of before you write another reply