911...brake gurus needed!

To be honest you risk fucking up some abs systems doing that

 

Any way to trouble shoot or test this? Bleed the ABS etc?

 

Just an FYI for anyone doing their brakes, All the old Nasty degraded debris trash of the brake system finds it's way right behind the piston in a caliper over time. If you want to remove contaminates and water logged Brake fluid you need to locate the caliper in a position that will allow all the shit to settle nearest the bleeder and open the bleeder when you push the piston back in... I deal with high performance tighter tolerance shit on race bikes and see some pretty harsh shit behind calipers.

 

I'm not sure about the Tacoma but a lot of the newer vehicles require a scanner to bleed the abs modules. But you having to pump the brakes sounds like air in the lines or your tears aren't adjusted right. Clamp off the rear lines with a line lock and push the brake and see how the pedal feels. If it feels fine you will know your problem is in the rear.

 

Definitive way to determine whether the calipers are stuck is to remove the calipers, then remove the pistons, and check for corrosion/pitting on the piston sides and check the seal condition. Usually a signicantly more worn pad on one side (in the same caliper) is a hint that the other side's piston(s) may not have been moving as freely...

By the time the calipers are rebuilt, it may have already made more sense to replace the calipers. However, piston and seal kits arent terribly expensive, and may be an alternative. Cleaning up pistons is arduous and not worth your free time...not recommended.

If the Tacoma is the spare vehicle, then it makes sense to take the calipers off and fully refurb them your self including a prep/paint job.

 

As stated above use line lock or hose pinch off pliers and clamp Off flexible lines one by one until the pedal feels normal when applied. Start out front because that's where you worked before the problem started. If you clamp off all the lines and the pedal is still shit then go for the master. I have seen masters fail quite a few times from having fluid pushed back through them.

 

I've blown a master on a chevy bleeding brakes before!

 

Do you have a vacuum bleeder? With someone pouring fluid in the master while the other person is using a vacuum bleeder at the caliper you can move fluid continuously down the line and have a better chance at getting the air out vs pumping.

 

Some shops have a pressure bleeder. We have one at our shop and use the panties off it.

 

Maybe I am dense but I just did my front brake pads didn't open bleeder or master and everything is fine.

I observe two things about your situation vs my results. 1) I didn't open the bleeders or the master. After prying the pad just enough to remove them,I used a c-clamp and a very thin piece of wood to collapse each piston equally and just enough to get the new pads and shims in. After replacing the pads and greased shims but before putting the wheels back on I started the truck and had to push the brake about 5 times before the pistons snugged up. I then buttoned it all up, tested the e-brake and did a quick standing brake test before pulling out of driveway to test drive in a large empty football parking lot nearby. No extreme stops, just normal street stop sign type at first then about two or three hard stops. Worked like new! 2) My old pads were very worn but not enough to chirp.

If your pads were not worn and still had 3/8 or more left it would lead
me to believe it was your master to begin with. Could also be a number of possibilities... still have air, bad caliper(s), etc. I would exhaust all other possibilities before laying down 200$

 

Here's another thought. Maybe something with the calipers is not put together quite right, or something wrong with the rotors, so that when the brakes are released, the pads are cockeyed and the pistons are getting shoved too far back into the calipers. Then, the 1st pump has to take up the slack. Then the 2nd pump works. Maybe try pulling the front wheels off and watch the calipers while someone else pumps the brakes. If the 1st pump moves the pads a long ways, you may have found your problem. It's probably also possible that the new rotors have lots of runout, forcing the pistons back in. With the wheels off, screw the lugnuts back on and check the runout. If the lugnuts bottom out on the stud, stack some washers on the studs first.

 

I had this exact problem, reverse bled, tried the gravel road stops both with abs and with the relay pulled, even went so far as to change the master cylinder with OEM new no luck. The master cylinder resivoir is dual parted, so it can look like you have fluid when you are dry in the front reservoir. Ultimately I had to take it to a dealer to have the "ABS module solenoids actuated and ABS block bled" while the brake lines are being bled as normal. I put that in quotes becasue that is exactly what you need to ask for. The service writer will have no idea what techno jargon you're babbling at them so ask to speak to the tech who knows what's actually going on. He will know exactly what your asking for.

I called several mom and pop shops only one even knew wtf I was asking for and told me they did not own the scantool to do the job and recommended I take it to the dealer, so reluctantly and one hour of dealer labor later my truck stopped better than it ever had, actually slammed into the steering wheel when I tested the brakes in the parking lot at 10mph, don't usually put my setbelt on until I'm going down the road. My horns scared the hell out of a poor salesman.

Recommendations for next time,

DO NOT REVERSE BLEED AN ABS SYSTEM, it will force air into the actuator block.

NEVER LET YOUR RESERVOIR GO BELOW HALF WAY. You will intoduce air into the system.

DO NOT PUMP THE PEDAL TO THE FLOOR, you can hyper extend the gasket inside the master and cause an internal leak or tear.

PRESSURE BLEED THE SYSTEM, you can make a pressure bleeder from $10 in plumbing parts from home depot, can't tell you how many times I have used it, about time to buy a new boot as it's worm out from so much use.

SPEEDBLEEDERS not the dorman parts but legitimate speedbleeder branded ones ordered directly from their webpage, expensive yes, but well worth it. I have them on all corners and clutches of everything I own. Worth the investment if you're a DIY'er like me.

 

thanks everyone. Gonna try the dealer route today to get the abs bled. I have pulled apart all my work, checked, rechecked and reassembled. Everything brake wise looks correct and works correct. The only variable I can't do in the garage is the abs. So it's next on the checklist. I really appreciate all the replies and possible solutions.

 

I'll be interested in the outcome. Mine behaves exactly how you describe: first press is spongy, second press feels perfect. Bled everything a couple times and never come across air. Both front calipers are new-ish because the seals were going on the last ones. Everyone tells me master cylinder, but I'm hesitant to jump to that.

It was much worse a few thousand miles ago, some of it worked itself out and it doesn't bother me as much anymore, but I still don't think it's right. Honestly, the brakes on this truck have always been a little funny.

 

Yeah I was super bummed when I realized I fubar'ed myself with introducing air into the abs block, I knew exactly what I had done when I did it too. Super face palm moment. Basically you can't bleed the block without the sytem firing and you can't make the system fire becasue with the air in the block there isn't enough pressure to make the computer actuate the solenoids.

Bummer, but it is what it is. Hopefully the stealership is reasonable with you price wise. It SHOULD NOT be more than an hour of labor. If they want to charge you more I can PM you my labor ticket from when I had to have the service done. It's hard for a service writer to BS a mechanic such as myself. Good news is I thought my brakes were pretty darn good before but hot dam I had to relearn how to use the middle pedal when driving the first week!

By the way last I checked the ABS scantool was like 5k. Only reason I don't have one. Can't justify the cost!

 

When bleeding it by hand (pressure, gravity, mighty-vac etc) the fluid bypasses the ABS block for the most part. You can put air into the block and it collects in the high points of the system against the closed pistons of the actuators, this displaces the fluid but as the air is higher and less dense than the fluid it will not bleed out of the lines so your collection will be solid but air is in the system, trapped in a dead end, then when you drive you can feel it as you describe. This is why you never let your master get below 1/2 way. Ever.

Easist way to rule out the mastercyl/booster.

Put the truck in 4L or lowest gear you have and put your foot on the brake pedal, pump it till it is hard if need be, if your truck creeps it could be the booster, if your pedal sinks it is your master bypassing internally.

But if you stay put (or can stall the engine in the case of a manual trans) and the pedal stays solid and doesn't creep toward the floor then the problem is outside the booster/master.

 

I'm almost positive the latter scenario is what would happen, but I'll double check. Thanks!

 

Ok, dealer can't get med in until tomorrow morning. In doing the 4 lo test it stays put. Pedal stays steady. I am pretty confident at this point it should just be air in the abs system. Going to call a few local shops today and see if anyone has the means on hand to bleed it. Small town blues.

 

Yeap. Sucks, make sure you talk to the tech doing the work not just the service writer or desk guy at a mom and pop, and ask specifically for "ABS modulator solenoids to be actuated and bled"

If the "techno-babel" confuses them then the don't know how to do it right if at all.

 

The snap on solus and modus scanner have this option. Just looked in mine.