buckz6319

95 4runner 3.0 SR5 4x4 auto
I have searched and didn't find a answer to my question
I would like to know why are my brakes so touchy in the mornings after sitting over night and after sitting in the parking lot at work all day.
The brakes will throw me through the windshield once I start up the 4runner and start rolling using my brakes.
Is there a reason why this happens?....and is this normal?...does anyone else have this same issue?
I do have a master cylinder leak at the mounting flange to the power booster, and my brake pedal is not as firm as it should be.The brake petal doesn't feel firm all the time like it use to so I think I will need a master cylinder soon.I have bled the brakes per the fsm but didn't really change the way the brake pedal feels
any advice will be appreciated
Dwayne

abecedarian

Check the pads & shoes for any contamination from grease, oil, brake fluid, etc.

PCE91V64x4

pedal not firm but the brakes will put you through the windshield? Do you have ABS?

Since the MC is (apparently) known to be bad I would change that and then see if your situation is same, worse or improved. And, as mentioned in the previous post, a good visual inspection before you start spending money.

MrPeepers

I have the same truck, I had similar issues, i tore apart the front calipers, and they are the 4 piston type, a couple pistons were stuck, and a couple seemed to be intermittently stuck, and the pads were wearing unevenly. I think on those sometimes a piston would be stcuk, and then break free suddenly and lock up under pressure. The reason I checked them is because at freeway speeds sometimes they would lock up the wheels, and at slower speeds, sometimes it did what you said , like it would almost buck me forwards. I replaced both calipers and front pads, total cost about $140 at Pep Boys for parts.

buckz6319

PCE91V64x4
thanks for the info and to answer your question....I do have ABS but just for the rear only on this 4runner 4x4.
I will also replace the master clyinder
it seams like they want more money for a master cylinder with ABS than a master cylinder without ABS but theY look the same I can't see any difference between the two.I would think the bore on both are 1" ?

buckz6319

MrPeepers
Thanks for your input also and I have changed the drivers side caliper with a rebuilt one but haven't changed the passenger side.
I also think I may have the same problem as you with the sticky caliper and it seams like it happens intermittently like you said.
I will try to check the passenger side this weekend and update this thread with my findings

desert-rat660

check the wheel cylinders for leaks

buckz6319

OK here is my dilemma with trying to purchase a brake master cylinder:...I have rear ABS only on this 4runner so when I'm trying to purchase a master cylinder with ABS it doesn't look like the one I have on my 4runner.
The one I have on my 4runner doesn't have a threaded port on the top, right in front of the brake fluid reservoir that another brake line threads into which the ABS MC have.I only have this one pictured below that only has 2 outlet ports and I think this master cylinder is for the non ABS is that correct? and is the rear ABS only considered "non ABS?" I have a 4x4 does that matter? ....and if that is correct then I can purchase a non ABS master cylinder?

buckz6319

Well I located the correct MC from Autozone $78.99 + tax for a new MC.I thought that was a vary good price
I removed the old MC and replaced it with the new one and followed all the instructions on bench bleeding ect.
I think I will have to bleed the wheel cylinders to get a firmer brake pedal.

I had some extra time today so I checked The rear brakes(which I replaced last summer) and star adjuster and the teeth are kinda ground down on the adjusters. I'm guessing that maybe my self adjusters are not working properly when I pull the emergency brake because I have to manually adjust the rear brakes once a month.
This may have something to do with not having a firm brake pedal?
If I purchase a set of the star wheel adjusters will my self adjusting brakes work like they should?

MrPeepers

Most self adjusting rear brakes adjust when you back up and apply the brakes. Sometimes when they are slightly worn, you can coerce them to self adjust by backing up rapidly a few feet and locking up the brakes, just do it a few times in a row, give it some gas and just exaggerate the stopping. See if that does the trick, if so you can just do that once or twice a month.

fthertime666

Is it humid/wet outside? Sometimes "flash" rust can build up pretty fast on drums and discs and cause the brakes to grab a little in the morning.

mcleranf1

it could possibly be the booster on its way out.

Fink

Mine are always ridiculously touchy after hitting the car wash - a few hard stops takes care of it though.

Fink

buckz6319

Thanks Yotatech members for the help!!....I will bring this thread to a close by saying "I haven't located the cause of my touchy brakes yet".... and when I do I will revisit this thread again

KVRunner

My brakes are touchy on my runner when it has been raining or humid. But this only lasts a couple of stops and then it goes away.