Help with brake shudder

Missed the key phrase, and this does make ALL the difference with this issue: "OE TOYOTA PARTS." Seen it countless times.

 

You're guaranteed good results with genuine Toyota parts, that doesn't mean any bad symptoms can be attributed to aftermarket parts. The only thing left on my front end that is Toyota is my modified spindles, yet I have no brake shudder.

 

I totally agree with you. Half of my front end is also aftermarket.

My point is that, for whatever reason, some brands of aftermarket rotors (e.g., Centric) do not work with with the 1st Gen Tundras and create shudder that is otherwise unexplainable. Not sure why, but I have seen it many times.

 

...yeah, i've owned and worked on cars for 40 years and mixed/matched alot of stuff.( no expert obviously) ..but can't say i've had this much problem before
...

 

I had experienced very little shuddering on my new to me 2000.
But...I just replaced the rear brakes with Toyota shoes and Centric drums.

The shuddering is intense now. Next I will try the old (OEM) drums.

 

Replaced the New Centric Premium drums with the Original OEM drums (150,000 miles) and.......no shuddering.

 

Nice! I’ll keep this in mind when the time comes for new drums. Thanks for the feedback.

 

I am looking for help on this topic myself, I have an '03 Tundra TRD 4x4, and am getting pulsing/hopping at the initial brake application, the pulsing lessens during slowdown. Vehicle stats, stock ride characteristics (i.e. not raised), toyota pads and shoes (10k miles), slotted and drilled front rotors, std drums on the rear, both rotors and drums were turned today, still having the issue. Anti-lock brake device appears to be functioning properly, not sure? Is there anything else it could be, maybe the "load Sensing Proportioning Valve"? BTW, 288k vehicle miles.

 

Anti-lock sensors plugged in properly? When did your issue start?

 

You got me thinking about when the issue started, and then I remembered I changed my front struts to KYB's instead of the Bilsten's ( big mistake). The KYB's are mushier, more car like than truck like driving, not a good thing. Well with that being the case, I was able to determine that because the front end is diving a little more with the KYB's, it was unloading the rear of the truck and changing the proportional valve setting and causing the rear brakes to fluctuate.

So I went under the truck with my 12 mm wrench and adjusted the proportional valve to simulate the truck bed being more loaded (screwing the lever up the shaft about 7 mm). Results: problem solved! What I have effectively done is forced the rear brakes to maintain more braking power, not so much that they lock up, but enough to counteract the unloading from the front struts. I think this will also somewhat help reduce the over heating of the front brakes, which is very common on gen 1 tundra's.

 

Yeah bud. I just learned about this Proportioning Valve a few weeks ago. Mine was bottomed out at the lowest setting since new. I adjusted it up about 3/4” and the truck stops so much better. Glad you solved the problem.

 

How is your brake shudder problem now that we are a few months from resolution. I'm having a similar problem with my 4x4 and have been digging through threads trying to see what others have found.

 

Almost 5 months now since last adjustment of the load proportion valve, and my '03 is stopping smoothly 95% of the time. There is still some minor shudder as the brakes get up to temperature, then gets smooth again at temp.

I am a firm believer in toyota pads and shoes, but not of their rotors, the rotors need to be drilled and slotted, they get to hot without them.

 

Its pretty well known that drilled and slotted rotors are just a gimick and have no purpose but to look cool and actually decrease brake performance slightly.

I thought my front brakes where pretty badly warped...but I started on the rear brakes as one of them was seized and overheating. After replacing them the brake shudder that I attributed to the front rotors became worse.

BUT....after thoroughly bleeding the brakes and then properly adjusting the parking brake almost all that shudder is gone.

One thing I noticed is that the brakes are designed so that applying the parking brake automatically adjusts the rear brakes....but this only works properly if the parking brake is tight. I thought I had the rear brakes adjusted...but then after tightening the parking brake cable I was able to get a good dozen more clicks on the rear brake adjusters. (by repeatedly pulling on the rear brake cable by hand until it stopped clicking)

And once that was all done 90% of my brake shudder went away, to the point where I may not even do the front brakes for a while now.

Just saying...getting the rear brakes adjusted properly was more involved than I thought.

 

Drilled and slotted rotors are not gimmicks, they have been used for years by the best racers in the world to reduce brake temperatures. Only carbon rotors are more resistant to heat issues, and I don't know anyone using carbon rotors on the gen 1 Tundra's.

I also would not recommend using the parking brake to adjust your rear braking, by over tightening the parking brake it only causes the shoes to continually drag against the drums, causing brake wear and reduced gas mileage due to added brake drag.

 

I don't know what to say, except both parts of this are entirely wrong but I doubt you will just take my word for it so you can do your own research if your inclined. You can just take off your rear drums and look at the mechanism and see that its impossible to over adjust your rear brakes by using the parking brake..or you could read the service manual which tells you that the parking brake is what you use to adjust them in the first place (but only if the parking brake is actually properly adjusted)

As for drilled and slotted....just use da google.

 

If you look back through this thread, no one ever said anything about brake pressure at all, let alone about what type of rotors may or may not increase the brake pressure. Especially since the rotors only receive the pressure that is supplied through the brake pads, they don't create it. The use of the d&s rotors is simply to dissipate heat to minimize rotor warpage, which happens frequently on gen 1 tundra's if you drive in traffic, or tow anything, or drive mountainous areas.

As for the parking brake, yes it is adjusted by backing up and applying the brakes! This is the proper way to adjust the parking brake. There is no valid reason to ever have to adjust the cabling to that system, because Toyota does a good job of it at the factory, where it is done with all components in the braking system correctly adjusted. If the parking brake is improperly adjusted it is because of worn brake shoes, and adjusting the cabling to fix this is just wrong. And saying the parking brake cable can't be over adjusted is false.

But, I do have a question for you Aerindel, if you have adjusted the cabling on your parking brake and it isn't over adjusted and isn't causing your brake shoes to prematurely touch the drums, how to you account for that adjustment to have corrected the brake shudder? The parking brake doesn't apply brake pressure any different than the operational system.

 

The parking brake shares the same shoes as the hydraulic system but it does work very differently. I account for the decreased brake shudder by the rear brakes actually working properly now and removing some of the work from the front brakes.

Let's break this down into parts to make sure everyone understands how this works as the rear drum brakes and parking brake system are rather complicated compared to disc brakes.

Inside your drums is a double ended hydraulic cylinder that pushes your brake shoes apart and applies pressure to the brake drums. This cylinder shares brake fluid with the opposite front disc brake. So if we are talking about the right rear brake, that is part of the same hydraulic system as your left front, this is a safety system so that if you loose pressure in one brake you don't loose all your brakes but keep braking to opposite corners so in theory you don't loose control.

Okay...so what this means is when you push the pedal it has to push fluid to six pairs of cylinders in total. To make it so a short pedal press can move this many cylinders you want each cylinder to move the smallest amount possible as any extra travel of the cylinder uses up fluid (and thus pedal movement) without actually causing braking force and reduces the ability of the other brakes to function properly.

So this is the 'why' of why you want your brake shoes as close as possible to the brake disc or rotors.

Looking into the how is where it gets relevant. In the front brakes there are no return springs so once you take your foot off the pedal the brake pressure ceases and the pads just float barely in contact with the discs, the ideal position so that no real free movement is needed for them to start applying pressure again. Because every time you press your brakes the pads press against the rotors they are always right up against them, even as the rotors and pads wear away they stay in adjustment.

In the rear brakes there are a set of springs that pull the shoes away from the drums when the pressure is released. Now, if they pulled the shoes all the way back that would mean a great deal of cylinder movement with every pedal press...which would not be ideal since your front brakes do not need this movement.

So for the rear brakes there is a nut and bolt arrangement that sets the maximum distance away from the drums the brake shoes can move. The nut of this system looks like a little sprocket and has a tooth in it that prevents the sprocket from turning in one direction so your brakes will not self loosen over time.

That tooth is attached to a lever that is moved by the parking brakes. Everytime the parking brake is pulled that little tooth moves back, and if it moves far enough, indicating there is freeplay in the system, it catches the next tooth and tightens the brake by one tooth. This is a great system as it automatically keeps adjusting the brake freeplay shoes as they wear so that there is never excess freeplay.

The parking brake, rather than pushing out hydraulic cylinders, uses a cam level mechanism to force the brake shoes against the drum.

It CANNOT over tighten the automatic adjuster as if there is not enough travel in the system that tooth cannot move far enough to ratchet the brake adjustment sprocket.

You can think of this just like you're the ratchet tool on your socket set. It has to move a certain amount to catch the next tooth. If it only moves a very small amount it doesn't catch a tooth and doesn't ratchet.

But in order for this to work properly your parking brake has to bee tight enough that it can pull the internal lever in your brake drum enough to take up all the freeplay. You can think of a loose parking brake as a ratchet that never moves far enough to catch the next tooth and so just moves back and forth in place without tightening.

Where it gets tricky is that there are four sections to the path between your brake lever and your actual brakes! You have the cable in that starts in your cab and runs underneath your truck, this cable is attached to a second cable by an adjustable turnbuckle...and this cable runs to your rear axle where it is attached to lever, which is attached to yet ANOTHER cable....which runs to a small lever on the back of your brake cover....which is attached to YET ANOTHER cable. Ever place where there is another connection is another place where there is a small amount of slack in the system.

If any one of these cables has too much slack in it you will bottom out your parking brake before it can apply maximum force to your rear drums...which gives poor parking brake performance but ALSO prevents the automatic adjustment mechanism from doing its job...which in turn prevents your entire braking system from working properly as now your front brakes are applying pressure instantly but your rear brakes have to first take up the freeplay...resulting in more pedal travel and less ultimate braking force on the rear wheels. It undoes the instant, incompressible nature of your brake system and causes symptoms similar to a brake system that has not been properly bled as it is just another way to introduce 'slack' in the hydraulic system.

Starting at the brake drums you first adjust the set screws on those small levers you see on the backside of your brakes until all slack is out of the short cables inside your drums. Then you adjust the turnbuckle until all slack is out of the main brake cable...and then adjust the pedal travel on the parking brake pedal itself.

If you make this too tight you can indeed cause parking brake drag....but that has nothing to do with the automatic brake adjustment system. That system will not over tighten....but also not properly work without a properly adjusted parking brake. (You can adjust this manual by using a screwdriver through the access port in your brake backing plate or by repeatedly backing up and applying your brakes but this is very tedious)

As for why you have to readjust this system from time to time...thats simple. Cables stretch, rust, get replaced, etc. (The brake cable on my truck was so loose when I bought it someone had looped it over the proportioning valve bracket to keep it out of the way) Virtually every component of your vehicle is designed to be adjusted as it ages and wears. The brake freeplay mechanism is automatic...but only if everything else is also properly adjusted.

Thats what I meant when I said the system is more complicated than I thought (I never had to work on drum brakes before)

You can't just throw a new set of shoes and drums on and call it good. Without properly adjusting the entire rear system your will get both poor parking brake and poor hydraulic brake performance in all four wheels.


As for drilled and slotted....

Drilled does nothing...it was just an idea someone had once to lighten brake rotors....but its the mass of the brakes themselves that determine how much heat they can absorb so drilled brakes are slightly WORSE than solid discs when it comes to heat as they have less mass to soak up heat.

Slotting was an idea to make a sharp edge that would cut a fresh surface on the brake pads during use so they would be self-deglazing. This is not an issue with modern brake pad material but does cause greatly increased pad wear. Neither improve performance but customers like the look of 'fancy' brakes and so people keep buying them and expecting to see them on new cars even though in the best case they cause no improvement in braking, and at the worst actually decrease it.

If you think about it for a minute you can see its just common sense. Removing surface area from the brake discs means the brakes have to work harder to cause the same amount of friction. It's no different than decreasing the size of the discs themselves...with predictable results.

Another automotive gimick in a long line of them. Add it to the list with K&N style filters and 'cold air' intakes. (That usually are in fact replacing the OEM cold air intake with a short ram hot air intake and thus more than canceling out any benefits.)

 

I just went to school! This makes me want to finally fix the crapola parking brake I’ve had for years that even the mechanics seem to not be able to fix.

Two things helped my street braking.

1) The Load Sensing Proportioning Valve Adjustment (shifting more power to the rear drums) resulting in WAY better braking (shorter distance braking). Safe feeling.

2) Adjusting the Rear Brake Star Adjuster through the peek-a-boo holes (3 clicks per side in my case) which firmed up my pedal action to the point I feel like I’m stepping on a potatoe compared to the old mushy feeling. Braking distance didn’t change, but the ‘pedal action’ is WAY better. A better driving experience.

I feel like I’m on the edge of Parking Brake Adjustment success now. Its all those cables that cause the problem. Its like 1 step forward and two steps back with the cables.

 

Damn. Props on that one. I can attest that the rears dont adjust by themselves and if left all the way out after a brake job, they'll freak the abs system out. Now to fix my sloppy parking brake cable and truly adjust them...

Also, I dont believe in drilled rotors. Seen too many crack. Slotted is ok. No science, just opinion.

 

Indeed. That was what threw me at first. It's not just one cable. It's three to four cables depending on drivers side or passenger side plus three levers with four points of adjustment. It sounds ridiculous on paper but it really just comes down to taking all the slack out of each system without actually putting enough tension on it to drag the brakes. Its just the mechanical version of systematically bleeding your brakes so that when you step on the pedal all that force is going into applying pressure rather than moving parts into contact.

If you could just keep pulling your parking brake cable forever it wouldn't matter but you you look at the total distance the cable pulls is actually something like an an inch and half and that movement has to be leveraged into enough force to hold thousands of pounds of truck still so there isn't a lot of extra slack to work with. Again, its the same principle as your hydraulics, if you've ever bled your own brakes you can see the actual amount of fluid pushed through the system with a brake pedal press is tiny, just a couple of tablespoons, and yet that is what will bring your truck to a screeching halt, but only if there isn't any slack in the system.

Now, most people don't care enough about their parking brakes to go through the effort of keeping them perfectly adjusted BUT the original point I was trying to make is that if your parking brake is working then it will automatically keep your rear hydraulic brakes working properly which IS something worth caring about.

 

Sorry to ask but can you post the pics again about adjusting the rear? I know you did it recently. There are so many posts happening in the "what have you done" thread I cannot keep up. Really think that one is growing so fast we need a 2nd thread for all the other stuff.

 

This is good info. My parking brake actually holds like a champ. Pretty sure the previous owner must have redone the rears. I do have a spongy feel though which I'd like to improve. I noticed something when swapping out the power steering and brake fluid.

The PS has to be done gradually over the course of a week or two. It's like the system is continously pushing out dirty fluid and replacing with new.Eventually it is clean and no more is needed. On the other hand, the brake fluid I only sucked out twice and the 2nd time the fluid was very clean. It's like the reservoir is just for overflow and doesn't really feed in and out. Maybe a true bleeding of the system yields different results.

 

This. It's impossible to find anything in there. I'd like to see separate threads made like how I did on my "repairs".

 

Its impossible to find anything anywhere on this site regarless of how its ‘threaded’. I say keep it like it is.

 

Just as a note, adjusting the brakes through the backing plate works fine but need to be careful as unlike the automatic system, you can over adjust them that way to the point where they are not releasing. If you do it that way its a good idea to have both rear wheels up on jack stands (and in 2WD) so that you can turn them by hand and feel for brake drag.

"The PS has to be done gradually over the course of a week or two. It's like the system is continously pushing out dirty fluid and replacing with new.Eventually it is clean and no more is needed. On the other hand, the brake fluid I only sucked out twice and the 2nd time the fluid was very clean. It's like the reservoir is just for overflow and doesn't really feed in and out. Maybe a true bleeding of the system yields different results."

You are correct on both counts. The power steering system uses a hydraulic pump that cycles the fluid through the system (and will self bleed)

Brakes do not. The master cylinder only pushes a very small amount of fluid a very short distance back and forth. When you open a bleed valve is the only time you get any fluid actually moving through the system.

Anyway, anyone curious about the parking brake and the auto adjuster, look at hand models photo, you see how very small the teeth are? You can see how having just a small amount of slack in the system could prevent that little tooth from ever reaching up high enough to move the adjuster the last few clicks that actually get it in adjustment.

 

Did a few clicks on each side. Can't say I notice any difference in braking but I don't want to go too far. Could I jack up the rear and spin the tires to make sure the brakes aren't dragging or is there a better test?

 

I just put the truck in ‘N’ on a very slight decline and see if it rolls forward on its own. Or, drive down the street and coast (not use brakes) to a stop and feel if the drum gets hot (drag equals heat).

Or, take tires off and spin drums by hand and listen/feel.