Brake issues

[durrell]

My pedal is completely gone. I can push it to about an inch from the floor and then it finally pressurizes enough to stop. Once it does, it stops just fine.

I've searched and figured out that I should definitely bleed my brakes, but I'm worried something else may be wrong. Does it sound like a master cylinder problem or could it be completely related to air in the lines/old fluid? I've dealt with air in the lines before, and it felt nothing like this. This is borderline scary to drive.

Thanks.

Edit: I apologize if this is in the wrong section. I have a 98 SR5 4x4, so I figured it should be in the third gen forum. Might be better in Maintenance, though. Mods, feel free to move it if necessary.

 

[Fireball]

It could be due to air in the lines. Lots of air.

Did the change in breaking pressure occur all of a sudden? Have you checked the fluid? Is it low? Any leaking?

 

[notrayray]

Did the change in breaking pressure occur all of a sudden?

x2 when did it start? other work performed on the brake system?

 

[durrell]

Thanks for the replies guys.

It has been like this since I got it on Tuesday. I'm a newbie.

The fluid level looks exactly like it should. There doesn't appear to have been any brake work done recently, but I haven't gotten a chance to look at them yet because I can't get my tires off. The lug nut lock key is broken and I've got to find a way to get the locks off.

 

[Mr. Leary]

Bleed the brakes twice and call us in the morning.

(You can bleed the brakes without removing the wheels. Bleeder valve is on the back side of the brakes)

 

[durrell]

I don't have a power bleeder. Will pumping the pedal suffice? How exactly should I go about it?

 

[PTY507]

Mines are also kinda messy now. When i push the pedal, it sounds like there is air in the line. Tomorrow i'll take my 4R to the dealer to get them check.

 

[Mr. Leary]

Bleeding works best if you can get a volunteer to pump the brakes for you. Have them pump five times and hold. Then you open the valve and bleed until you get a solid stream of fluid, and close it again. Repeat this about half a dozen times for each brake, while checking the fluid level in the master cylinder each time, add fluid as necessary, a little at a time. There are lines on the little tank indicating proper fluid fill levels for brake fluid. Once you have done each front brake, take it for a test drive. IMO, people get bubbles in the front more often than in the rear.

Poor braking has few causes.

1. Improperly bled or unmaintained brakes.
2. Pinched or leaking brake lines.
3. Faulty master cylinder.

Check the easiest thing first. Make sure the brakes are bled. Then you can continue in to visually inspect for leaks or pinches in the lines. If all these look good, check them again, THEN start worrying about the master cylinder or the proportioning valve.

 

[GoFaSSter]

Any tire shop will be able to remove those locks almost as fast as regular lugs. Just take it in and have them removed or get a new key before it becomes an emergency.

 

[durrell]

Cool. I plan to take care of the lugs on Monday. I already purchased new ones.

I'll try to bleed them tomorrow hopefully. I'll let you all know of the outcome. Thanks a lot for the help.

 

[durrell]

Bleeding didn't go so well. The passenger rear bleeder nut wouldn't budge, so I just didn't bother rounding any of the others off.

I did replace the rotors because the pads actually looked brand new. I can already tell a huge difference in braking. The vibration and noise they were making is gone.

The pedal is of course still pretty soft, though. I need to figure out how to get those nuts off. Is there some sort of lubricant I should buy? I'm finding that most of my nuts and bolts are seized on, which worries me because that leads me to believe maintenance wasn't performed as often as I'd hoped.

 

[BTO]

It's probably that the seals in the master cylinder have had it. Our's is a little spongy too. I used a power bleeder and flushed the lines but it did not help much.

Did you try soaking the bleeder screws in something like PB Blaster?

 

[durrell]

I just bought some PB Blaster so I'm going to try that.

I guess I will plan to buy a new master cylinder in the near future. That's kind of what I suspected, anyway. It is the original master cylinder from what I can tell.

 

[GoFaSSter]

Use a wrench made for tube fittings. This type of wrench grabs more surfaces and helps to remove fittings without crushing and stripping them.

 

[BTO]

Not sure what a tube fitting wrench is but I always use a 6 point box wrench.

 

[GoFaSSter]

Not sure what a tube fitting wrench is but I always use a 6 point box wrench.

Same same.

 

[durrell]

Yep. Gonna try that today.

As far as bleeding the brakes..does the cap need to be on or off after sucking out old fluid and adding new fluid? I assumed off, but I dunno. I don't have the power bleeder like the write-up has on 4runners.org, so I guess I'm doing it the old fashioned way.

 

[BTO]

Doesn't really matter. I'd leave it off so you can add more as you go without having to mess with it. Just go slow with the pedal making sure you get coordinated with your helper. Make sure you don't push the pedal further than normal and you don't lift up with a bleeder open.