User 051420

OK..here goes. For about 4 months/15k miles I've have an persistent brake issue. The truck DOES NOT like to stop, especially worse at low speeds like a red light. I know my stopping distance will be increased beacause of the bigger tires/heavier wheels and I compensate for that. The brake pedal seemingly disappears. I'll hit the brakes, the pedal goes down and reaches a point where it won't go any further and the truck SLOWLY comes to a stop.

What's been done:
Front Pads, Rotors & Calipers- 30k ago, still good.
Rear Shoes & Drums- 13k ago
Rear Wheel Cylinders- 13k ago
Master Cylinder- Few weeks ago.
Rear axle seal- This week.
Rear Wheel Cylinder (driver's side)-Again this week.
Rear Shoes- Again this week.
Bled NUMEROUS times.
Fluid Flushed 3x (Dot 3 & 4).

All of this stuff is fairly inexpensive, but I'm tired of throwing parts at the thing and having VERY temporary results (blocks, not miles). If I pull the e-brake up to the point that it heavily drags, the pedal is great and the truck stops perfectly. BUT, that's obviously not how it's supposed to work. I've adjusted the rear's several times, it helps but quickly goes back to the way it was (I now try to NOT use my e-brake in order to keep the adjustments I set).

The only think I can possibly think to do would be to replace the brake lines (mine still appeak OK), possibly do the brake booster (more likely useless parts), OR sell the crap and buy somehting that frikin works. This is the most frustrating thing with my truck. THE ONLY THINK I HATE ABOUT IT (besides the SAW's).

Sorry for the incredibly long post, but I need help! I've essentially replaced most of the brake system, and have done nearly everything mentioned in other threads. I drive 30k a year, and need this to work!


What next?

TACOMANATOR

My first guess would be your master brake cylinder. Since you have replaced that my second guess would be your booster. Had a buddy with a Tahoe that had simular problems and it turned out to be the booster. You've replaced everything else so why not the booster.

Marc

I recently changed my front calipers and could not get a good pedal.
I must have bled them 5 times.
I finally took it to a brake shop and had them bleed them.
Perfect brakes after that.
I have in the past bled many vehicles succesfully but just couldn't do it on my runner.

User 051420

I haven't been doing the bleeding for that exact reason. I want to know it's been done perfectly, and bleeding is free! The only actual work I've done drive it and biatch about it. I don't trust myself with something critical like brakes.

PirateFins

Have you checked the vacum hoses? It might be a small vacum leak not giving the extra boost.

User 051420

I really need to get a manual....But thanks, good idea! I'll look into that tomorrow.

Fahrenheit 451

>>I've adjusted the rear's several times, it helps but quickly goes back to the way it was (I now try to NOT use my e-brake in order to keep the adjustments I set).<<

Could it be that your adjusters are damaged somehow such that the lever that holds the adjuster wheel in place isn't latching properly. I don't know that it is even possible, but maybe they are on the wrong side or backwards(?)
I had a brake job done on my '85 4Runner a couple years ago that was problematic from the start. I took it back to mechanic 3 times and always got the same reply, "We can't find anything wrong with it." The last time I checked closely (I basically never wash my trucks so it is easy to tell what has or hasn't been touched) and it was plain to see that they hadn't even pulled the rear wheels off.
So, I pulled the rear wheels and drums and what did I find, but the adjusters not only hadn't been cleaned up, but the driver side one was installed with one end on the wrong part of the brake pad. The adjusters wouldn't self adjust and the driver side was dragging all the time
The thing about not trusting yourself to fix something is that it seems just as likely you wind up getting it "fixed" by some dips**t that doesn't know how to do it either and charges you $60+ an hour to boot.

User 051420

Good question....
I know..I need to learn how to do this. It shouldn't be too terribly difficult.
The shop in CA that installed the wheel cylinder that failed charged me $85/hour. Luckily, I only get charged $40 here, so I haven't spent THAT much.

AgRunner06

That was my first thought when you said they keep coming out of adjustment. My next thought would be the vacuum lines (already mentioned) and brake booster (also mentioned). Don't bother replacing your brake lines because it isn't going to do one bit of good.

If I was going to guess as to what the problem was, I would say it is the vacuum leak first then the brake booster. Even if your rear brakes come out of adjustment you should still be able to stop faster than that with the fronts. It sounds like you aren't getting enough pressure in your brake lines.

How many clicks are the rears coming out of adjustment and how long does it take for that to happen?

I've replace brakes plenty of times and I've always managed to get them working correctly unless there was something else wrong.

Good Luck

:bounce2:

Yoda

When they bled the brakes did they also bleed the height valve on the frame? (assuming yours has one). Son's truck had a bad master cyl. and even after change it wasn't great. Bleed all 4 wheels, still not great. Bleed the valve, BINGO....stops on a dime and gives change.

It does sound like there is an adjuster issue. Check to make sure they are on the correct side. I only do one side at a time, so parts don't get mixed up, but if they replaced the adjusters, they could have crossed it up.

MTL_4runner

I don't think there is such a valve...if there is one someone please correct me.

User 051420

I'm checking into the vacuum lines today. The rears are usually 6-10 clicks too loose. When I tighten them, it stops better but the pedal still isn't there like it used to be.

And no, I don't have a Load Sensing Proportioning (SP?) Valve (LSPV?) I have ABS instead.

User 051420

I'd be happy to stop on a Susan B!

EDIT:
Today I'm checking:
Vacuum Lines
Then getting a pic and checking the adjusters to the best of my ability.
If I find nothing wrong, it's going to the stealer.

Edit edit:
If I QUICKLY pump the brakes once and use the second pump to stop on, the brakes are amazing. BUT, if I let up on that second pump and try again normally, I don't have ˟˟˟˟e. Brake booster, huh?

MTL_4runner

Does flight time count?

User 051420

Lol no, and read above for double edit!

SloPoke

I have been experiencing this same problem. I too have bled many brake systems and can't seem to blled this one correctly. I've bled it till all the fluid is new and still have a squishy pedal. If and when you find the culprit, let us know. I'd love to not have to pump my brakes to stop like it should.

Good luck!!!

outdoorfever

A few yrs ago i spent about 1k on brake stuff in a 2month period. Final culprit was master cylinder and its all about adjusting the brake cables correctly. It still doesnt stop on a dime, but it stops.

User 051420

I checked all the vacuum hoses I could easily find under the hood. All of them passed "my" visual inspection. Haven't gotten a chance to look at the rear adjustment parts as of yet.

Out of curiousity, I looked up the cost for the Brake Booster. Conicelli wants $600 for that sucker. I'll pull my ebrake before I drop 600 on that!

Fahrenheit 451

I did a quick bit of not too in depth surfing on the net and came across a site where a mechanic replies to inquiries about people's problems with their vehicles.
One that caught my eye was his statement that a bad wheel cylinder will allow air to get into the system when the emergency brake is applied.
So, your solution of partially engaging the emergency brake may partially be the culprit.
I noticed on your list that you had only replaced the one rear wheel cylinder. Maybe it's time to check the other wheel cylinder and make sure it is in good working order.

User 051420

Thats really interesting, thanks for putting a bit of effort here! 13k miles ago (3.5 months), I replaced both rear wheel cylinders. One of those failed, and was recently replaced. I'm at a bit of a loss here, and I don't want to personally dig through it because I think my efforts would be aimless.

I'm taking it back to the mechanic and not picking it up until it stops perfectly. The dealer isn't getting a dime of my (mod) money.

One thing I should add, is that I'm not losing ANY brake fluid. Air in the line is likely possible, but where is it comin from?