Both rear calipers siezed

[Slowgoat]

I suspected the calipers were stuck on the rear for a while. They are trashed.

I finally caught the left rotor getting hot by using an IR thermometer on the rotors the other day.

I have some questions, and would appreciate any feedback.

The two rear rotors measured 18.7 mm and 18.9 mm with the digital calipers. What is minimum?

The rotors are scored and trashed, so I am going to replace them with new ones.

When I pulled the pads, the inboard passenger pad had lines in the pad like a potato chip. I am assuming the previous owner put the pad back on a scored rotor? Or is this possible with a stuck caliper? Scary if he did that.

Here's the rough plan:

I'm going akebono for pads (ceramic or semi metallic? I hate brake dust), Centric for rotors, and lifetime Autozone calipers.

I'm going DOT 4 synthetic. Is DOT 3 ok?

How much fluid do I need to flush the system?

Any feedback on my setup is welcome.

I've read half of the brake threads on toyota120.com and t4r.org getting ready for this project. So my head is spinning.

Oh, and some yokel today at the parts store informed me that I should use tundra calipers because they don't have stuck calipers. Had to post that "tidbit". Is he right? :thumb3:

I thought we upgraded to tundra brakes because of the bigger size?

Another winner at another store gave my fiancée a 12 oz bottle of fluid and told her that would be enough for a brake fluid flush. :bash:

Man add me to the list of the stuck caliper club!

 

[tranmd]

I'm in the process of replacing my front caliper too. When you jacked up the rear axle , did you try rotating the rear wheels? Were they difficult to rotate? I'm just trying to see if my rear are seized too.

 

[Slowgoat]

Yes. Very hard to move the wheel.

Drove 15 min on the interstate before I got home tonight. While I was removing the lugs, I could feel the heat from the whole wheel radiating on my face and hands. It puts off a lot of heat.

 

[fourwd1]

The minimum allowable thickness is stamped on the rotor, but since you're replacing them does it matter?
Two, maybe three quarts of fluid should be enough.
You should bleed the entire system in the proper order.
Because of the ABS system you should do it first with the engine off, then with the engine running, and again with engine off

 

[blackoutt]

Did you try to compress the pistons back into the calipers to see if they could be saved? Lot's of questions there and I don't have all the answers but I use almost an entire 32oz bottle of fluid (changed 2 front calipers, lines on all 4 corners, and wanted to replace all old fluid) You could get away with less if you're okay with leaving some of the old fluid in there.

 

[Slowgoat]

The minimum allowable thickness is stamped on the rotor, but since you're replacing them does it matter?
Two, maybe three quarts of fluid should be enough.
You should bleed the entire system in the proper order.
Because of the ABS system you should do it first with the engine off, then with the engine running, and again with engine off

I wanted to know if the rotors are well below the recommendation, which would show that the previous owner (or their mechanic) was reckless, so I can be on the lookout for other crazy stuff. Honestly, I've gone over this vehicle a good bit and it is clean as hell, and seems to be well taken care of. The fluids looked fresh, etc., when I got it.

I saw on a couple of older posts you had put in that this had to be done (off/on/off), but I was confused by "with the engine running". Do you mean with the key off, then on, then off?

I know you can bleed the rear brakes by just holding the pedal down and opening the caliper with the ignition "on", that the ABS system will pump fluid through for you. Then the fronts need to be bled manually (old school style).

Also, there seems to be confusion about which order. Some say front, then rear, but I've read many say rear passenger first, then rear driver, then front passenger, then front driver.

What is the "right" way?

 

[Slowgoat]

Did you try to compress the pistons back into the calipers to see if they could be saved? Lot's of questions there and I don't have all the answers but I use almost an entire 32oz bottle of fluid (changed 2 front calipers, lines on all 4 corners, and wanted to replace all old fluid) You could get away with less if you're okay with leaving some of the old fluid in there.

No, I definitely want all the old fluid gone. I just thought it was funny that that knucklehead said 12 oz would do a bleed. ound:

I'm going with 48 oz. Thank you!

I tried pusing them back in. I bent the handle of the C clamp, I pushed so hard. They are both definitely stuck (I tried everything I could think of). 1 pad (the inboard one) on both sides was down almost to metal.

 

[nevada]

I wanted to know if the rotors are well below the recommendation, which would show that the previous owner (or their mechanic) was reckless, so I can be on the lookout for other crazy stuff. Honestly, I've gone over this vehicle a good bit and it is clean as hell, and seems to be well taken care of. The fluids looked fresh, etc., when I got it.

I saw on a couple of older posts you had put in that this had to be done (off/on/off), but I was confused by "with the engine running". Do you mean with the key off, then on, then off?

I know you can bleed the rear brakes by just holding the pedal down and opening the caliper with the ignition "on", that the ABS system will pump fluid through for you. Then the fronts need to be bled manually (old school style).

Also, there seems to be confusion about which order. Some say front, then rear, but I've read many say rear passenger first, then rear driver, then front passenger, then front driver.

What is the "right" way?

if you are just flushing the old fluid out, it doesn't really matter which order. also, you should be able to bleed it manually for all positions.


I will usually start at the furthest position, and work towards the front. but again, as long as the system isn't full of air, it doesn't matter where the order.
there will of course be air AT the calipers, but that is after the MC, and still doesn't require a special order.

 

[Slowgoat]

Well, I got a bigger C clamp and just for the hell of it right before swapping the calipers, I pushed the hell out of them and they retracted. So I worked them in and out a bunch, and put it all back together.

If they still drag, I'll replace them.

Wonder what my odds they'll just stick again?

 

[nevada]

Well, I got a bigger C clamp and just for the hell of it right before swapping the calipers, I pushed the hell out of them and they retracted. So I worked them in and out a bunch, and put it all back together.

If they still drag, I'll replace them.

Wonder what my odds they'll just stick again?

pretty high. but it probably wont happen until the pads wear down, and the pistons are out to the same position.

 

[Slowgoat]

pretty high. but it probably wont happen until the pads wear down, and the pistons are out to the same position.

When I got it all back together, took it for a test drive and the rear driver side caliper was stuck down heating that side up way hotter than the other side.

I just swapped them both. Only took a minute and bled it. Now I'm good to go. Fronts look like the previous owner swapped them lately, so good news there.

 

[M1911]

I feel your pain. I've lost track of how many times I have the calipers replaced.

 

[fdbyrne]

I think that the problem isn't with the caliper, per se. I could be wrong but I think the problem is actually with the pistons. I've read other posts and seen writeups of caliper rebuilds and it seems like the cause is the sides of the pistons rusting. Since they are rusty and no longer smooth or lubricated, they won't retract.

It seems like there would be money to be made by somebody making up some dimentionally correct pistons that are hard chromed, coated with nickle boron, or maybe even melanited (nitrided) to prevent corrosion and can be retrofitted into the calipers.

 

[Slowgoat]

I think that the problem isn't with the caliper, per se. I could be wrong but I think the problem is actually with the pistons. I've read other posts and seen writeups of caliper rebuilds and it seems like the cause is the sides of the pistons rusting. Since they are rusty and no longer smooth or lubricated, they won't retract.

It seems like there would be money to be made by somebody making up some dimentionally correct pistons that are hard chromed, coated with nickle boron, or maybe even melanited (nitrided) to prevent corrosion and can be retrofitted into the calipers.

Yes. It would make sense for that to work.


What is weird about the rear pistons, is that they are covered by a boot, and they STILL rust.

It obviously is a piston design flaw IMHO.

Lots of posts claim they know which piston is sticking before they even pull the brake apart in the front, the inboard lower piston, I believe? Why is this just a problem with the 4runners, or is it common in Tundras, etc.?


Long before I bought my 4runner, 2 years ago +, I had been reading about this issue, and had been waiting to catch it ( I have an IR thermometer, which I bought just to shoot the rotors). Finally caught one, and they were both sticking!

 

[jonesmw10]

How hard was it to actually spin the real wheels with both off the ground and in neutral? I've been suspecting that mine may be frozen too but haven't had a chance to take it apart.

I did jack it up and they move, bit it takes quite a bit of force.

 

[Slowgoat]

The rotors were heating up the whole wheel area, so one of mine was really stuck. The other rotor was just dragging, not retracting.

You can see rotor burn marks (where it heats the rotor up, then when you stop, it puts a lot of pad material down, like an imprint of the pad on the rotor), scores, cracks or just heating up (like mine) are signs of this.

Rotating the wheel was more difficult than it should have been.

Here is some further reading (scroll down to "how to diagnose a bad brake caliper"):

Solving Brake Problems - Eric The Car Guy- Stay Dirty!

 

[nevada]

Yes. It would make sense for that to work.


What is weird about the rear pistons, is that they are covered by a boot, and they STILL rust.

It obviously is a piston design flaw IMHO.

Lots of posts claim they know which piston is sticking before they even pull the brake apart in the front, the inboard lower piston, I believe? Why is this just a problem with the 4runners, or is it common in Tundras, etc.?


Long before I bought my 4runner, 2 years ago +, I had been reading about this issue, and had been waiting to catch it ( I have an IR thermometer, which I bought just to shoot the rotors). Finally caught one, and they were both sticking!

brake fluid is hygroscopic. it absorbs moisture straight out of the air.
so even tho the piston is sealed, moisture can still gain access through the MC....


to the best of my knowledge my 4runner still has the original calipers and brakes from 06. that was 110,000 miles ago. they are still just fine....

 

[Slowgoat]

brake fluid is hygroscopic. it absorbs moisture straight out of the air.
so even tho the piston is sealed, moisture can still gain access through the MC....


to the best of my knowledge my 4runner still has the original calipers and brakes from 06. that was 110,000 miles ago. they are still just fine....

I'd bet it's the road salt.

We have some here but we have a kind of short winter.

Do you have a lot of road salt there, Nevada?

 

[nevada]

I'd bet it's the road salt.

We have some here but we have a kind of short winter.

Do you have a lot of road salt there, Nevada?

well, my 4runner originally came from NJ. I imagine its seen its fair share of salt.
the last few years, they have been spraying the road with that nasty crap. rust isn't too big of a problem where im at though. so im not sure if its that or not.