caliper issues 3gen 4runner help!! (1 Viewer)

[pillguy]

Hello all,
I have been fighting braking issues with my truck for a bit over a year. I can barely lock them up.
Went through a rear seal replacement at first and replaced shoes, they worked for a bit then the same thing.
Fast forward a few months...
Just a few days ago, I then replaced the shoes again with factory toyota shoes and new toyota wheel cylinder so the rears have been completely replaced, brand new everything, bleed everything and still I cannot stop.

I started to pull the fronts to replace the pads and think I may have found the issue. frozen or sticking pistons within my calipers.
waTCH the video and let me know what you think...

 

[Duane]

well off the top of my head as I watch this video(great idea to really show what it is doing)

To me if a piston is sticking or seized it does just that, it won't move or wont retract.
This to me looks like a volume problem or a system that needs a good bleeding to get rid of air.

You mentioned 5 pumps..can you keep pumping it to a point where the pedal will ever get hard? and then will it stay put with pressure applied or does it just keep dropping to the floor?

I would bleed the brakes..pump until hard maintaining pedal pressure..bleed a corner some and make sure to close it before the pedal hits bottom of the pedal stroke..release pedal and pump again..maintaining pedal pressure, crack open a bleed valve and close it before the pedal hits bottom of it's stroke again. repeat several times each corner and make sure to keep an eye on the fluid reservoir and top up brake fluid as required so as to not suck in more air as you keep bleeding the system.
If this gets you no where you might be in for a new master cylinder as it could be passing by the piston.

What does the brake fluid look like? clean or a sludge in the reservoir bottom?
Do you live in a high humidity area? sorry forgot to look.
Brake fluid collects water..I forget is it ab or adsorb?? oh well either way it can get too much water in it and then start buggering components. Thus a dealer recommends to replace it at certain intervals or can measure the water content and replace on that value.


A few years back the other half rear ended a Maxima in the winter. I took her 60 Landcruiser for a spin. It took me most of the way through the 3rd pump to get some brakes..the master cylinder was shot.(had 450,000 miles on it though..quality control hey..nothing lasts

 

[pillguy]

Duane
Thanks for response
I have bled the system multiple times and burned through several quarts of Val opine semisynthetic brake fluid. All the fluid I get is clear. Guess I could put a drop of food coloring in to see whether I bled it completely but I do not think air is the problem.

well off the top of my head as I watch this video(great idea to really show what it is doing)

To me if a piston is sticking or seized it does just that, it won't move or wont retract.
This to me looks like a volume problem or a system that needs a good bleeding to get rid of air.

You mentioned 5 pumps..can you keep pumping it to a point where the pedal will ever get hard? and then will it stay put with pressure applied or does it just keep dropping to the floor?
I have notice this slightly when driving in past, but it does not seem to go very far and I have no leaks anywhere.
My wife cannot remember if it continued to go to the floor or not.
One of the guys in the club thinks it may be the master cylinder that is bad. Truck has 166k miles so it's not that new. One thing that makes me suspicious is the first time I bled them when I swapped out the axle was that I did not put a block of wood under the pedal to prevent overextention when pumping the pedal during bleeding.
I hate just throwing money at it, but it is cheaper for me to replace some parts rather than giving up and carting it off to the dealer.
Is there a way to test

I would bleed the brakes..pump until hard maintaining pedal pressure..bleed a corner some and make sure to close it before the pedal hits bottom of the pedal stroke..release pedal and pump again..maintaining pedal pressure, crack open a bleed valve and close it before the pedal hits bottom of it's stroke again. repeat several times each corner and make sure to keep an eye on the fluid reservoir and top up brake fluid as required so as to not suck in more air as you keep bleeding the system.
If this gets you no where you might be in for a new master cylinder as it could be passing by the piston.

What does the brake fluid look like? clean or a sludge in the reservoir bottom?
Do you live in a high humidity area? sorry forgot to look.
Brake fluid collects water..I forget is it ab or adsorb?? oh well either way it can get too much water in it and then start buggering components. Thus a dealer recommends to replace it at certain intervals or can measure the water content and replace on that value.


A few years back the other half rear ended a Maxima in the winter. I took her 60 Landcruiser for a spin. It took me most of the way through the 3rd pump to get some brakes..the master cylinder was shot.(had 450,000 miles on it though..quality control hey..nothing lasts

 

[skeezix]

If it were me, I would rebuild (or buy reconditioned) both calipers. It's not hard for a DIYer to do. It's what I call a "thereputic" job and you can save some $$$ doing it yourself. Parts kits are available at the various auto parts stores. I think you'll find at least one tutorial on this forum or on the TTORA forum that shows what to do and from the looks of your video I don't think you'll have any problems.

You can also google on "rebuild toyota brake calipers" and find a ton of information.

Figure an hour per wheel to get everything clean and reassembled. Maybe two hours on the first wheel if you've never done it before. You'll have to of course bleed the brakes afterwards but something tells me you are an old hand at that

 

[Duane]

Duane
Thanks for response
I have bled the system multiple times and burned through several quarts of Val opine semisynthetic brake fluid. All the fluid I get is clear. Guess I could put a drop of food coloring in to see whether I bled it completely but I do not think air is the problem.

Here is a copy & pasted wording on how to test your master cylinder. it references just testing the master cylinder but if you have no leaks in your system the same should apply. In my words I would say push the pedal firmly and hold it, if it hits bottom keep pushing it all the way down as many times until you get resistance and hold it there... if it feels squishy it is likely air in the system, if it slowly drops then you have a leak. If it isn't leaking externally it is then leaking internally which is most likely around the master cylinder piston.
In my opinion you rebuild or replace calipers when the pistons won't move or when they leak.
Good luck

1. Apply constant pressure to the pedal, the pedal should be firm, hard and should not drop over time.
2. If the pedal is squishy there may be air in the system. Bleed the system and test again.
3. If the pedal is firm and then drops over time under constant pressure, the master cylinder should be replaced.

The other thing watching your video again is that normally the 4 pistons would not be retracted that far requiring that much volume to take up the clearances between the pistons, the pads and the rotor. I assume you had to compress the pistons some to be able to remove the caliper assembly. Normally the small amount of run out,side to side movement of the rotor as it turns, is what returns the pistons just enough to allow the rotor to turn. In your video that is typical if you have forced all the pistons way back and then installed a new set of pads. The first time taking up the excessive clearance will take more volume to move all the pistons outward.
Why don't you extend your video to show us the release of the brake pedal, rotating the rotor a turn or two and then apply the brakes again. I would think that 1 stroke/push on the brake pedal will get you to place where the 5th pump got you to in the video.

 

[97kurt]

I'd re-build the calipers or upgrade to the tundra ones. A rebuild kit should cost you about $11 per caliper and takes maybe an hour to do both. Once you rebuild a caliper you start to realize how simple these systems are in our trucks.

I wrote a guide a long time ago on rebuilding them, if you search the wiki on ultimateyota.com I think they still have it posted.

Also to double check, you removed the guide pins from the calipers before filming that correct? If not then you are missing some parts.

 

[chitown40]

I just did the 231mm Tundra brake upgrade on my 2002 4Runner. All I can say is, wow, night and day difference.

I used lifetime warranty Cardone reman calipers from O-Reallys and BrakeBest brand rotors. The rotors were about $20 more than the 4runner rotors and the calipers were only about $2 more than the 4runner spec'd ones. Check on the 4runner boards or yotatech.com before you buy any parts to make sure your wheels will clear the calipers.

 

[pillguy]

The guys in my club think its either a bad master cylinder or air in the master. I ordered a rebuild kit for both the master and the calipers.
Figured I might as well go ahead and get this done.
Just sucks it so dang hot outside....

 

[Duane]

The guys in my club think its either a bad master cylinder or air in the master. I ordered a rebuild kit for both the master and the calipers.
Figured I might as well go ahead and get this done.
Just sucks it so dang hot outside....

you are an ambitious guy.. I would be nailing down the problem and only fixing what I needed to.

Can you pump the brakes to a point where they will offer resistance and then at that point by maintaining pressure on the pedal do they feel spongy, hold in one place or keep slowly dropping to the floor?

 

[flyfishexpert]

Is it all four, or just a single wheel? Does the other caliper act the same way?

Have you replaced the rubber brake lines? I experienced the oposite problem a couple of years ago with my 98. I would barely step on the break and the passenger front rotor would completely lock up and the ABS would throw a code. It turned out I had a bad brake line and, I believe, had a flap of rubber that was acting like a check valve. After replacing the caliper and ABS controler, I narrowed it down to the rubber line. Replaced the lines and now everything works.

 

[pillguy]

They are just weak as they just won't stop the truck. I was too dumb to think about pumping them while I was test driving them. . At this point, everything will be new on the brakes, shoes, drums, rotors, rebuilds, etc. over the past 12 months. I feel like it has been a bit of a black hole, but I would rather be able to stop vs. rear ending a vehicle.
I was reading somewhere that you should rebuild calipers every 150K Km. Who knows, but given all the mud we run in, it might be a safe bet.
I will keep you posted.

you are an ambitious guy.. I would be nailing down the problem and only fixing what I needed to.

Can you pump the brakes to a point where they will offer resistance and then at that point by maintaining pressure on the pedal do they feel spongy, hold in one place or keep slowly dropping to the floor?

 

[pillguy]

Not sure about the other caliper, no pulling in one direction when I brake.
Yes, I replaced the rubber lines a while back. There was a crack in one, but they seem I hate to say have a braided liner. Hopefully, I did not waste my money.

Is it all four, or just a single wheel? Does the other caliper act the same way?

Have you replaced the rubber brake lines? I experienced the oposite problem a couple of years ago with my 98. I would barely step on the break and the passenger front rotor would completely lock up and the ABS would throw a code. It turned out I had a bad brake line and, I believe, had a flap of rubber that was acting like a check valve. After replacing the caliper and ABS controler, I narrowed it down to the rubber line. Replaced the lines and now everything works.

 

[pillguy]

Still more brake problems

Hi guys
Well I am back to same issue, weak brakes.
The only thing I have not done is rebuild the front calipers.
I adjusted the rears again and I can barely stop, only seem to engage the abs is when I really. Stand on the brakes and pull parking brake.
Even with this I do not think they are that great.

So two options
1. Rebuild existing calipers and hope
2. Go with tundra 231s. I have 16" wheels

Thoughts?

 

[Hanz]

I'd rebuild the calipers and if you haven't already, change out the front brake hoses. At this point, it just doesn't sound safe for anyone.

 

[Jeremy9A]

You said you replaced the brake fluid, which is good to do anyways. Have you left the cap off the master cylinder or bottles of brake fluid for a while? The fluid is hydroscopic and will absorb moisture out of the air, lowering the boiling point of your brake fluid under pressure.

I have experienced similar problems with my 98 4runner when either- The rears have a bit of air in them, or they are out of adjustment. I also had a clogged breather on the rear axle which was pushing the gear oil out the axle seals and contaminating my shoes at one point.

I see that you have 33's. I went to 33's and swapped to steel rims, which is a lot of extra rolling mass to stop. I would consider the tundra brake upgrade a must if you want it to stop like it originally did.


To sum it up, I would re check the rears, and do the brake upgrade to account for the extra rolling mass- as long as the pedal feels normal.

 

[pillguy]

I have been reading a lot about the tundra upgrade and looks like I will reluctantly go for it.
Just not sure why some of my friends who run 37s on a mini truck do not seem to have a problem

You said you replaced the brake fluid, which is good to do anyways. Have you left the cap off the master cylinder or bottles of brake fluid for a while? The fluid is hydroscopic and will absorb moisture out of the air, lowering the boiling point of your brake fluid under pressure.

I have experienced similar problems with my 98 4runner when either- The rears have a bit of air in them, or they are out of adjustment. I also had a clogged breather on the rear axle which was pushing the gear oil out the axle seals and contaminating my shoes at one point.

I see that you have 33's. I went to 33's and swapped to steel rims, which is a lot of extra rolling mass to stop. I would consider the tundra brake upgrade a must if you want it to stop like it originally did.


To sum it up, I would re check the rears, and do the brake upgrade to account for the extra rolling mass- as long as the pedal feels normal.

 

[Duane]

well the upgrade sounds cool, it also makes me uneasy to think that will resolve it either.
Wondering about the ABS or proportioning valves...

 

[Jeremy9A]

Did you rebuild the master cylinder with that kit yet?

Is the pedal height good? Can you mash down on the brakes and still fit a foot under the pedal? I can on mine when the rear brakes are in adjustment. But if they get the slightest bit out of adjustment, like a few months of driving or a few days of wheelin, my pedal gets low and I have the same brake feel as you describe

 

[pillguy]

I rebuilt the master a few months ago, very easy to do with the rebild kit.
I did finda lit of mud in one of my drums and scored shoes because of the grit. I had to have the drum resurfaced last week and ordered some parts for my tundra calipers.
As much as I have read, I am going to bit the bullet on the front rotors
It's sucks as it cost about $350 for all the parts, but it's better to know I can stop if I need to stop.

I her you on the adjustment of the shoes though

 

[pillguy]

good thoughts, but nom proportioning valve and I do get the abs to kick in a bit if I really tighten the back up

well the upgrade sounds cool, it also makes me uneasy to think that will resolve it either.
Wondering about the ABS or proportioning valves...