brakes work when they want too...

[T4Rex.]

i have recently completed the 231mm tundra brakes swap on my 99 t4r about a month and a half ago...about 2 days ago i started noticing my brakes were a lil squishy...so i looked around all 4 corners no visible leaks and then checked under then hood...not loosing any brake fluid...so i went on....then when coming to stop my brakes went st8 to the floor, NOT STOPPING!! i began to pump my brakes and i stopped...i put the 4runner in park and pumped on the brakes and they became really firm, still applying pressure my brake pedal slowly went further and further down to the floor eventually completely bottoming out like when you are bleeding ur brakes???

 

[4-Ripcord]

Refill and bleed it again.

 

[curtperry]

That's some scary **** man... most important system in any car.

check your fluid level again then bleed all four corners and find a safe place to test them.

 

[Singtoe]

If there are no leaks then the Master cylinder is going bad. You need to replace or rebuild.

 

[T4Rex.]

yeah it is most def scary as HELL!! i live on some curvy roads...Slingtoe i was thinking it was my master cylinder....just kinda wishin it wasnt!:happens: my T4R has been a money pit the past few months LOL....but its been a learning experience because this is first vehicle i have ever wrenched on...and so far i have accomplished all my mods/upgrades with my 2 hands and this BADA$$ website!

sitting in boxes: upper ball joints, steering rack bushings, 3 belts, & F&R sway bar bushing, factory fog lights, and some backup/fog lights. gotta long road ahead of me...i am gettin my 4runner ready for a move to Colorado. I have to find some good Docs out their for my fiancee/co-pilot! she has gastroparesis, and non of these DUMBA$$ docs here know how to help her condition...I believe in medical marijuana, i smoke because of PTSD and other things and it has changed my life, it is also the only way she has been able to eat/survive due to this CRAzY disease.

 

[BigFishAllDay]

THIS....

i have recently completed the 231mm tundra brakes swap on my 99 t4r about a month and a half ago...about 2 days ago i started noticing my brakes were a lil squishy...so i looked around all 4 corners no visible leaks and then checked under then hood...not loosing any brake fluid...so i went on....then when coming to stop my brakes went st8 to the floor, NOT STOPPING!! i began to pump my brakes and i stopped...i put the 4runner in park and pumped on the brakes and they became really firm, still applying pressure my brake pedal slowly went further and further down to the floor eventually completely bottoming out like when you are bleeding ur brakes???

Gives me the impression that your problem would be this.....

If there are no leaks then the Master cylinder is going bad. You need to replace or rebuild.

When you're bleeding the brakes, you should not be allowing the pedal to go all the way to the floor. The piston in the master cylinder has a "normal" range of travel during regular use. When you open the system and push that pedal all the way to the floor, you're pushing the piston beyond that range of travel, and you can damage it that way.

I always press the pedal down w/the system closed, see how far it normally goes down, then put a stack of books under it @ that height. Then I open the system and bleed it. That way when I press the pedal w/the lines open it doesn't travel beyond it's normal range.

Try bleeding again, then look @ the MC.

 

[T4Rex.]

THIS....



Gives me the impression that your problem would be this.....



When you're bleeding the brakes, you should not be allowing the pedal to go all the way to the floor. The piston in the master cylinder has a "normal" range of travel during regular use. When you open the system and push that pedal all the way to the floor, you're pushing the piston beyond that range of travel, and you can damage it that way.

I always press the pedal down w/the system closed, see how far it normally goes down, then put a stack of books under it @ that height. Then I open the system and bleed it. That way when I press the pedal w/the lines open it doesn't travel beyond it's normal range.

Try bleeding again, then look @ the MC.

thanks BigFishAllDay, i will go try this...i hope it works...really hoping its not the master cylinder..

 

[nissanh]

When you depress the brake padle to bleed the brakes, you supposed to keep the 10 mm bleed nipple closed.
Have you used DOT-4 oil? this will kill the brake washers.

 

[BigFishAllDay]

When you depress the brake padle to bleed the brakes, you supposed to keep the 10 mm bleed nipple closed.
Have you used DOT-4 oil? this will kill the brake washers.

DOT-5 is the one you have to watch out for. It's silicone based VS. Dot 3/4 which are glycol based. 3/4 mix just fine, but neither one will mix with 5.

RE this:

I always press the pedal down w/the system closed, see how far it normally goes down, then put a stack of books under it @ that height. Then I open the system and bleed it. That way when I press the pedal w/the lines open it doesn't travel beyond it's normal range.

I guess I should clarify. I currently use a Motive power bleeder, so I pressurize the system, then go to each corner and open the bleeder valves. I don't even touch the pedal.

Before I got the Motive bleeder, I'd have my Wife help me, using the stack of books to prevent her from pressing the pedal too far/low. Pump pedal softly 2-3 times > press pedal down > open bleeder valve > close bleeder valve > release pedal. Repeat until no more bubbles come out of the line. Never let off the pedal w/the bleeder valve open, it will suck air back into the sytem.

 

[nevada]

If there are no leaks then the Master cylinder is going bad. You need to replace or rebuild.

yup. mc is bad.

all the bleeding in the world wont change that.

dont take any chances, the next time the pedal drops, you might not get it pumped back up.
replace the mc, and move on.

 

[T4Rex.]

I have the worst luck!! While bleeding my brakes, somehow my bleeder valve broke off!! These are brand new 231mm calipers....

 

[T4Rex.]

Just had to order a new caliper and mc .

 

[nevada]

you cant easy out the bleeder?
it shouldnt be too bad to drill, and extract it.

 

[theizzardking]

you cant easy out the bleeder?
it shouldnt be too bad to drill, and extract it.

if it's a new caliper just warranty it back and get a new one, no since in marring up a brand new caliper. if you bought used, well that sucks and do what NV said. no way though should a bleeder break on a new piece...stupid Chinese made fittings and the rest of their crap....

 

[T4Rex.]

if it's a new caliper just warranty it back and get a new one, no since in marring up a brand new caliper. if you bought used, well that sucks and do what NV said. no way though should a bleeder break on a new piece...stupid Chinese made fittings and the rest of their crap....

yeah i was pretty pissed off because these calipers are brand new...so that is what i was able to do warranty it out...i will be picking up new caliper in morning and also grabbing a Master Cylinder since i think that is what my problem is....but since my Runner has been giving me such a hard time over the past few days, I gave her some love and threw some TRD Offroad Decals on today!! had them sitting in my cup holder for a few days now...since it gives ya "15 extra horses under the hood" i figured why not? LoL!


I really dont know if i am diggin them that much though :shrug:!!! hopefully i get come around....

 

[T4Rex.]

you cant easy out the bleeder?
it shouldnt be too bad to drill, and extract it.

I just bought them about a 1 1/2 months ago...so, warranty, thank goodness!!

 

[Nelsonmd]

Is it possible you could have some air in the ABS system as well? Did the pedal maybe go to the floor when the ABS kicked in?

The pedal travel issue is another reason I like speed bleeders because you can, by yourself, loosen the bleeder valve, then depress the pedal yourself only as far as you want (not have someone who isn't experienced with it press the pedal), then walk back to the caliper and close it. Not saying this is better than something like the motive power bleeder, it's just another good way to do it.

 

[Singtoe]

This issue is a no brainer. Master cylinder. I had my body off my chassis and every line open and exposed for at least a month.

When I reinstalled everything, I had my wife pump the brakes and i bled them out. Starting with the closest first. My brakes work great. My abs works great. This is not relavent but my emergency brake works great too.

Too much thought going on here.

To the Op. Remember to prime your new master cylinder before installing .

 

[nevada]

I just bought them about a 1 1/2 months ago...so, warranty, thank goodness!!

if they warranty it out, then good for you.

but, it wasnt a manufacture defect, unless it was broke when you got it.
you broke it, *I* personally would not warranty it.

 

[T4Rex.]

if they warranty it out, then good for you.

but, it wasnt a manufacture defect, unless it was broke when you got it.
you broke it, *I* personally would not warranty it.

WELL...they gave me the warranty...*I* personally didnt break it myself because *I* was barely turning the bleeder valve and *I* wasn't applying much pressure at all to it...besides that they were only a month old!!!

BUUUTTTTTT....anyway glad you were NOT checking me out....*I* mean is the partstore's money!!! do you think its yours TOO??? I guess that's why they have warranties HUH?? who are you the warrany olice:!! :flipoff:

While i was there though i went ahead and bought the Master Cylinder, some brake fluid and found some new Polyperformance swaybar bushing w/ brackets for my frt sway bar.....got it all fixed now and everything is working SMOOOOTHlY i got BrAKES YAY!!! gotta start working on putting on my steering rack bushing, FRT sway bar, UBJs, and a buncha other stuff i have sitting in the back of my runner....