Master Cylinder failure(s)?

[Scotty_h]

Master Cylinder failure(s)?......................& 3" lift pics

Yo guys, I'm about to start a build thread, but wanted to float this out there ASAP.
-Story-
I pulled my truck into my garage on Friday with no problems braking. ever. (Always solid on the brakes. have been awaiting Tundra upgrade 'cause my brakes freakin rock. :guitar3: ) I put on my Toytec Ultimate lift over the course of a long day with new UCA's (sweet) Front end first, with two jacks and jackstands, then spun it around and did the rear. Upon completeing the job, I pulled the truck out with the brake pedal hitting the floor, pumping up and bleeding down. Not a lot of braking power, to tons of braking power, rears locking up only on gravel, the full gamut of symptoms. What i looked for was loss of fluid in the reservoir after many brake pumps and any sign of puncture in the lines themselves. No sign of any leaks. I will admit that I may have damaged the rear brake line when I dropped the rear axle without shocks.:nono: The line took the weight of the axle while installing my springs, but no damage is VISIBLE
I hopped onto the forum that night. Read up on master cylinder (MC) failures and decided that however unlikely, I may have had a failure and would need to start here for solutions
Following day was brake day. I bench bled a new reman'ed MC and installed it into the ride. My GF pumped the brakes for an hour as I moved from wheel to wheel systematically flushing 3X over with new fluid the lines that showed no signs of fatigue or leak. With no luck of improvement, I said "well, it's good that it's going to a shop tmrw for an alignment, I'll get them to look at it"

I took the truck into the Good Year (only name brand shop around) yesterday and the guy at the desk, not a mechanic, said that he had to put 4 new MC's on his t4r before he found one that worked for him. I dismissed it as messy shop talk and no bench bleed and let them look, without replacing anything, on ways to bleed improvement into the system.
-the reason this was an overnight visit is frustrating but irrelevant to the story-:AK47:
Today I picked it up and the guy had charged my $30 for bleeding the MC and lines that did not improve anything, but confirm that I might actually know how to bleed brakes.:redbrick:

-long story, sorry, but here is the meat and potatoes of the thread boys and girls- I put these questions to you for discussion,

1. The fact that I pulled it into the shop working, and pulled it out unworking says to me that I did something to it. This would knock out any wearing parts, like a MC seal?

2. Could tiliting of the vehicle at extreme angles for extended amounts of time cause air to enter into the system or goof anything else?

3. How much bullsh*t is it about MC's coming out of the box and not working? I've heard of that with starters and alternators but never something as simple and non electronic as a MC

4. Oh yeah, I talked to a buddy who said that the brake hoses are a double lined and that I may have snapped the inner liner of the rear hose and now it is filling the hose and flexing... T/F?

Thanks to all.
Here are some pics to coerce your assistance
stock
<a href="http://s1295.beta.photobucket.com/user/scott_hess1983/media/IMG_1720_zps71f28678.jpg.html" target="_blank"><img src="http://i1295.photobucket.com/albums/b629/scott_hess1983/IMG_1720_zps71f28678.jpg" border="0" alt=" photo IMG_1720_zps71f28678.jpg"/></a>
lift
<a href="http://s1295.beta.photobucket.com/user/scott_hess1983/media/IMG_1728_zps38484619.jpg.html" target="_blank"><img src="http://i1295.photobucket.com/albums/b629/scott_hess1983/IMG_1728_zps38484619.jpg" border="0" alt=" photo IMG_1728_zps38484619.jpg"/></a>
new shoes... Blicka, bow-wow...
<a href="http://s1295.beta.photobucket.com/user/scott_hess1983/media/IMG_1729_zps634fe839.jpg.html" target="_blank"><img src="http://i1295.photobucket.com/albums/b629/scott_hess1983/IMG_1729_zps634fe839.jpg" border="0" alt=" photo IMG_1729_zps634fe839.jpg"/></a>

 

[LittleCaesar]

I take it yours is not an 01-02 judging by the pics. 4wd?

In bleeding the brakes on your own with the GF's help, did you see a stream of bubbles in the fluid? Try finding out this first.
If there is firmness at any time during braking when driving your 4runner, I'd put some heavy money on it not being the MC.

Look closely at the rear brake line.It could have a partial tear but doubt it is collapsed since you did see fluid coming out of both rear cylinders correct?

Other culprits could be the brake booster (sounds like such) or possibly the ABS system, especially the ABS accumulator (valve not closing all the way).

 

[Scotty_h]

I take it yours is not an 01-02 judging by the pics. 4wd?

In bleeding the brakes on your own with the GF's help, did you see a stream of bubbles in the fluid? Try finding out this first.
If there is firmness at any time during braking when driving your 4runner, I'd put some heavy money on it not being the MC.

Look closely at the rear brake line.It could have a partial tear but doubt it is collapsed since you did see fluid coming out of both rear cylinders correct?

Other culprits could be the brake booster (sounds like such) or possibly the ABS system, especially the ABS accumulator (valve not closing all the way).

Yeah sorry, some info would be a good idea.
99' SR5, Auto, 4WD, 273K
ABS light has been on since my purchase of the vehicle in June 2011 ~20K ago.

Fluid flowed clean from all 4 calipers of the color of the new addition, 2 shops bled them, (really 1) besides my efforts.

Yes. I can hold pressure now. Low to the floor, but it can hold.

Yeah man, lines look good. They are all muddy so you could see leaks VERY easy and dry rot style splits in the line were it would expand.

As far as ABS or booster is concerned, It seems like either could be a culprit at this age and mileage. I would be interested in bi-passing the ABS system all together and maybe having room for a second battery.

:thanks:[

 

[Scotty_h]

Bump

So today, I put almost 400 miles :scaredn the truck which gave me a chance to really get aquainted with the symptom. First pedal pump grabs the brake without a lot of power before it hits the floor, second pump getsstiff half way down enough to stop the vehicle on a dime.
I can hold it down with almost no bleed off.

-Anyone?

-Bueller?

 

[LittleCaesar]

Scotty,

I'd find out the source for the reason of the ABS code first before jumping to any assumptions.

Most basic code readers do not read Toyota ABS codes so you will have to go to an indy shop or a Toy dealer.

 

[audiness]

I would start by replacing the rear flexible line... since you suspect that you damaged it. Although the symptoms do not sound like that could be the problem. What steps did you take to bench bleed the new master cylinder?

 

[the great him]

on the side of the MC there is a small plug in, did you plug that in, that can cause the ABS light to come on, its a fluid level sensor... sounds to me like you have a bad MC... ive never been a fan of remans., ive had a few that were crap out of the box, never one for a toyota but still... its not the booster, if it was the booster your peddle would be rock hard and youd have little stopping power, i know cause i have had a bad booster a time or two before -its not fun when the diaphragm tears while driving... scary chit. anyhow yeah id just do yourself a favor and buy new lines. get an extended brake line for the rear, and then buy two new flex lines for the front... its not gonna hurt anything, you will know they are new and not 12 years old, and you can rule that out as a part of the problem or fix the problem.

 

[nissanh]

Where did you buy the master cylinder? If it is not OEM.... I seriously doubt about it. It is extremely easy to bleed toyota cars and trucks. I spend about 20 minutes to bleed all around.

This is why I buy parts OEM and if it is expensive... less miles used toyota parts from a yard. Never had a problem. Did this for the past 22 years!!!

 

[So Many Roads]

long shot but...

If your rear brakes are out of adjustment it can lead to long brake pedal travel. Easiest way to adjust the rears is to go in reverse at 10 mph or so, then apply the brakes hard. Do this a few times.

I may be way off, but its worth a shot. If it works let us know.

 

[Buckaroo]

What did you do/replace just before brakes failed? I am having a hard time figuring it out. I do agree with the comment about figuring out what is causing the ABS light to come on - need to get to ground zero on that. But, it sounds like it was working OK otherwise and you did something - changed the front pads or rear shoes? I do agree that miss-adjusted drum brakes can cause low pedal height but why would it change all of a sudden? Because you adjusted them out to get the drum off when you changed the shoes? Then you changed the master cylinder and bench bled it first (good). Then you bled the brakes at each wheel?

So, when you changed the master cylinder, could the push rod length have been different on the old cylinder....I would think that would have been set the same as the old one but should always be checked. If it was shorter, I think you would increase the pedal free-play which seems to be your issue. Is the peddle engaging lower or is it mushy? I am so confused......

 

[Scotty_h]

ALL : Thank you for the responses. This is something that needs to be fixed ASAP and I will answer all questions and try some of these suggestions tmrw to get it fixed...

Scotty,

I'd find out the source for the reason of the ABS code first before jumping to any assumptions.

Most basic code readers do not read Toyota ABS codes so you will have to go to an indy shop or a Toy dealer.

I agree that this could be the issue, but I don't care to have ABS and it has not worked since I've owned the truck... no trouble with the brakes, ever...

I would start by replacing the rear flexible line... since you suspect that you damaged it. Although the symptoms do not sound like that could be the problem. What steps did you take to bench bleed the new master cylinder?

I tried to order one of these from a couple shops. I have a two day wait for it, but am going tomorrow to order it as it will be my first,"next" step in solving this.

on the side of the MC there is a small plug in, did you plug that in?
sounds to me like you have a bad MC... ive never been a fan of remans., ive had a few that were crap out of the box, never one for a toyota but still... its not the booster, if it was the booster your peddle would be rock hard and youd have little stopping power, i know cause i have had a bad booster a time or two before -its not fun when the diaphragm tears while driving... scary chit. anyhow yeah id just do yourself a favor and buy new lines. get an extended brake line for the rear, and then buy two new flex lines for the front... its not gonna hurt anything, you will know they are new and not 12 years old, and you can rule that out as a part of the problem or fix the problem.

Sensor is plugged into the reservoir,
Hmmm... so that wanker at the shop may be right... Dang, I thought I had him pegged, but It's counterintuitive to replace brand new parts. This will be fix #2 I do. Glad to hear it prlly isn't the booster. Those are $$$
Yeah new lines are a great idea. I keep looking at that dusty old rubber thinkin "one of these days" Good call

Where did you buy the master cylinder? If it is not OEM.... I seriously doubt about it. It is extremely easy to bleed toyota cars and trucks. I spend about 20 minutes to bleed all around.

This is why I buy parts OEM and if it is expensive... less miles used toyota parts from a yard. Never had a problem. Did this for the past 22 years!!!

Master Cylinder purchased from Advanced. (Central KY 'sigh') Ok then. This could be tomorrow's fix.

If your rear brakes are out of adjustment it can lead to long brake pedal travel. Easiest way to adjust the rears is to go in reverse at 10 mph or so, then apply the brakes hard. Do this a few times.

I may be way off, but its worth a shot. If it works let us know.

My braked have all been replaced last year (spring-summer). No issues since. Like I said, they kicked *ss before I pulled it into my garage. No adjustments were made/lines opened during the lift install. E-brake still works and feels the same.

What did you do/replace just before brakes failed? I am having a hard time figuring it out. I do agree with the comment about figuring out what is causing the ABS light to come on - need to get to ground zero on that. But, it sounds like it was working OK otherwise and you did something - changed the front pads or rear shoes? I do agree that miss-adjusted drum brakes can cause low pedal height but why would it change all of a sudden? Because you adjusted them out to get the drum off when you changed the shoes? Then you changed the master cylinder and bench bled it first (good). Then you bled the brakes at each wheel?

So, when you changed the master cylinder, could the push rod length have been different on the old cylinder....I would think that would have been set the same as the old one but should always be checked. If it was shorter, I think you would increase the pedal free-play which seems to be your issue. Is the peddle engaging lower or is it mushy? I am so confused......

Hah, join the club buddy on the confusion. I put on a lift and UCA's. this is all that was done to the truck, no opened brake lines of any sort.
ABS is not important to me, since my ABS light has been on for a LONG time pre-lift, I'm having a hard time pointing to it as my issue, thought I may be wrong.
I changed out the MC ONLY to attempt to solve this problem. The brakes feel the same after new MC. Mushy, but can be pumped up.

 

[nissanh]

We had several members with new starter and no start (or no clicks even), new Master pump and mushy brakes..... All from auto parts stores. I buy low miles OEM parts from junk yards and work it right in the first attempt.

By the way how is your rear brake shoes? Toyota has auto adjusting brakes in the rear. With the parks brakes it will automatically adjust the rear brake shoes.

How about the brake hoses? Do you see they expand with the pressing of brake paddle?

If your ABS light is on, it says ABS function is not working, but your brakes should work 100%.

 

[Scotty_h]

-Update-

Bought a new MC from same autoparts store and bolted it on, bench bled, bled MC in the truck, then bled to all brakes. Same muchy feel. I'm starting to think that the MC has been fine all along. Brake hose was inspected again and it still appears to be intact with no swelling, though I am ordering one tonight just to check.

My last thought is to put in a new booster anyhow. I know that this had been previously thought not to be the problem, but I'm out of things to replace. I will likely order some new front lines as well.

I dunno, this seems to be a problem that I can't solve...

 

[Buckaroo]

Scotty - I have lost track of where you are. I would propose that if your brakes are mushy - you most likely have air in the lines. This may be a result of not bench bleeding the master cylinder correctly or perhaps air has been introduced elsewhere. The process to make sure this is not the case is to bleed the master cylinder and then bleed at each wheel following the correct sequence. If you have questions about how to bleed the master cylinder or do not know the correct sequence, yell out and we can talk further.
No need to keep replacing things.....

 

[Scotty_h]

Scotty - I have lost track of where you are. I would propose that if your brakes are mushy - you most likely have air in the lines. This may be a result of not bench bleeding the master cylinder correctly or perhaps air has been introduced elsewhere. The process to make sure this is not the case is to bleed the master cylinder and then bleed at each wheel following the correct sequence. If you have questions about how to bleed the master cylinder or do not know the correct sequence, yell out and we can talk further.
No need to keep replacing things.....

I really dont want to keep throwing new parts at it. The whole deal is that I didn't even replace anything when I got the issues. Truck went into my shop, new lift was put on, no cracking of the brake system, then brakes came out mushy. I have bench bled, then bled at the MC, the bled at the wheels. I have had a couple of shops re-bleed with no improvement. Had heard that some MC's are bad out of the box and threw a new one on again just to limit that factor. New lines coming soon, just ordered some SS from Toytec, but Bleeding is not that hard. I bleed brakes on mtn. bikes for all my buddies, those are difficult.

I have my GF sit and pressure up the brakes while I move from wheel to wheel, furthest first, and crack them open and have her pump them up, catching the fluid and taking it back to the reservoir without it ever going below the Minimum FL. I feel like I've got that covered.

-however- I am always open to new suggestions...

 

[nissanh]

Still you didn't get your brakes to work? If there are no leaks from the wheels, you'll probably have a bad (refurbished... NO!) master cylinder. Without getting it fixed, I don't think you'll get the brakes to work. IF you need, let me know I'll find a used TOYOTA master cylinder. You pay shipping. This is what I can do from my side.

 

[Scotty_h]

-Update-

Bought a new MC from same autoparts store and bolted it on, bench bled, bled MC in the truck, then bled to all brakes. Same muchy feel. I'm starting to think that the MC has been fine all along. Brake hose was inspected again and it still appears to be intact with no swelling, though I am ordering one tonight just to check.

My last thought is to put in a new booster anyhow. I know that this had been previously thought not to be the problem, but I'm out of things to replace. I will likely order some new front lines as well.

I dunno, this seems to be a problem that I can't solve...

Check this Previous post out Nissanh,

Still you didn't get your brakes to work? If there are no leaks from the wheels, you'll probably have a bad (refurbished... NO!) master cylinder. Without getting it fixed, I don't think you'll get the brakes to work. IF you need, let me know I'll find a used TOYOTA master cylinder. You pay shipping. This is what I can do from my side.

This second one was not OEM, but not a reman'ed either and I still had the exact same pedal feel as I've had for the past week. Makes me think it's not the MC. Especially with the original cause still out... Into the shop; worked great, a lift later; no brakes. It seems like I broke something or don't have a vaccuum hose on (checked for that). The change was so abrupt.

 

[nissanh]

This is your master pump. It's been a while since we talked about this. Have you inspected all 4 wheels for any leaking cylinder, caliper?

If the pedal gets soft with time, there is air going in.

We had several members buying starters from auto parts store and had failures one after another.

Your servo (brake booster) has nothing to do with the soft brakes.

After pumping multiple times, do you get a hard brake pedal?

 

[Scotty_h]

This is your master pump. It's been a while since we talked about this. Have you inspected all 4 wheels for any leaking cylinder, caliper?

If the pedal gets soft with time, there is air going in.

We had several members buying starters from auto parts store and had failures one after another.

Your servo (brake booster) has nothing to do with the soft brakes.

After pumping multiple times, do you get a hard brake pedal?

I have no fluid loss in the system. I've searched up and down and drove the crap out of it lately with reservoir levels staying consistant.

I do get a hard pedal, this is why I'm able to drive it. I pump it up each time I use the brakes... In town( used often) I pump less, coming off of the parkways, i have to pump it up more.

I get what you're saying, i promise I do, how did I get this air in there if it's just air? I have had 3 MC's feel the same with the rest of the brakes. I'm not trying to argue with you, especially since everyone is being so helpful, just trying to make sense of it.

Thanks

 

[nissanh]

Trust me your problem is nothing when it comes to the hilux pickup my dad still ownes. Long story... problem was a lose front axle bolt. When making turns the pedal is soft. Replaced a Toyota Master cylinder but same problem.

Anyway... I think the rubber seals in your master pump some how become soft. What kind of OIL do you use? did you mix DOT3 and DOT 4? I will never mix these two. Some may argue with me now. TOYOTA cap says DOT 3.

This got to work. Remove the dust covers in the rear wheel cylinders and see any oil accumulated there. Oh.. you said you are not losing oil... So my only guess is bad washers in the master cylinder.

My 4runner had cracked flexible brake hoses and it still worked fine.

IS this how you bleed the system?...

While the valve is closed, some one press the padel all the way to the end and release ... repeat 3-4 times and hold it pressed and you open the valve (10 mm bolt).... air bubbles come out... STILL your helper is keeping the pedal pressed, correct?

Then you close the valve and now your helper takes the foot off the pedal. Repeat until no air comes out. Do it for all 4 wheels.