Terrible Awful No Good Squishy Brake Pedal

Picked up a 2000 SR5 4runner in great shape. Has 300k miles. Seller said it “has no brakes”, sure enough the MC reservoir was dry and pedal went all the way to the floor. It would still stop, but only at the last 1/2” of pedal movement.

I have since replaced both rear drum cylinders, both front calipers, tried to bench bleed the original MC (same squishy symptoms), bought a reman MC (same symptoms), and finally ended with a junkyard MC (unknown mileage, still kinda squishy - better, but squishy).

SURELY not all three of these MC’s are bad, and surely my brake bleeding skills don’t suck that much - I’ve bled many systems before. When bench bleeding each MC, I pushed the piston on level ground until no more air came out (using the clear tubes and fittings to direct fluid back into the reservoir).

The brake pedal is still squishy. Better than before, but still squishy. It’s also erratic - sometimes the pedal feels pretty good, then nothing until the last 1/2” or so. Whats up? What am I missing? Do I need a power bleeder to do a “better” job at bleeding?

EDIT - believe me I’ve googled the heck out of this. I keep getting road-blocked! Brake systems are so rudimentary, especially since my MC doesn’t have all that ABS nonsense. Figured I’d reach out to the enthusiasts for help because I’m baffled.

 

Replace the rubber brake lines.

I say this because rubber brake lines can separate inside and cause squishiness.

At 300k miles they should be changed anyways.

 

I’ll definitely check them out and replace if necessary.

Upon more research, I learned that it’s quite common for air to get trapped in the ABS pump itself. Remember - this is a 2000 4Runner, the MC and ABS unit/pump are completely separate. To remedy this issue, people have had good luck triggering the ABS system a number of times and then bleeding the brakes again.

My only problem is the ABS light is on! Codes 31, 33, and 41. Already ordered front right and front rear speed sensors from RockAuto. Code 41 has to do with low voltage, and yes the car dies if it sits too long - battery is probably old.

If it’s not one thing, it’s another. I’ll keep you guys updated once my new sensors come in and can get my light to go away so I can try and burp the ABS system!

 

Don't chase codes until your battery/charging system is up to snuff. Those codes may go away. I've seen cars go crazy with codes due to a bad battery cables.

 

On it! Parts arrive this Thursday, battery should be more than charged after 48 hours or so.

 

Not sure how you did it, but I thought you just use the tubes on the fitting at the caliper, then run the tube into a bottle of fluid, make sure the reseivor is full then pump several times and this pushes the air out and doesn't allow it to get sucked back in. Then you can just keep pumping it flushing it through until its clear, and no air.

I wouldn't expect the brakes to work like "rental car" brakes. We all know getting into a rental car and the brakes are so touchy. I think brakes just get worn out and if every part is not new, then it will be somewhat squishy

 

Once I get the ABS light to go away, I’ll activate the ABS system to try and burp it. I’ll bleed the way you recommended! Cross your fingers I want my 4Runner normal again.

 

ABS light gone! Both passenger side sensors are OUT and MAN were they a pain. Took two afternoons to get out the rear. Charged the battery 100% and voila good to go.

Now I need to find a public gravel road to actuate the ABS system!! Hopefully this weekend.

 

Locked up the brakes a couple times this past weekend. Re-bled the brakes, got some air out of the rear passenger drum cylinder (not really from any others, much to my dismay).

Pedal is still squishy, but the pedal feels solid about 2/3 down and the brakes bite well. I’m going to try and lock up the brakes again/re-bleed in the future. For now I’m going to attack the rear drums and adjust the shoes so they’re tighter against the drum. Who knows their alignment after 300k miles! That’ll be this weekend when I have the time. Thank you all! Stay tuned!

 

I still have stock drums and over 300k. My SUV runs, brakes, 4WD’s flawlessly!!

 

But I don’t have anti-lock...

 

Still don’t know the story with this 4Runner but we’re trying to bring her back to her old glory, slowly but surely!!!

good to hear yours is still purring!

 

To adjust the shoes closer to the drums, all you have to do is hold button on parking brake and lift and lower brake a few times. That's it!

 

You’re assuming my e-brake even works

But yes that’ll be part of my sleuthing this weekend!!

 

So 2/3s down before it engages? I'm thinking you have a bulging rubber brakeline still.

 

Short of inspecting the line as the pedal is pushed, is there a more “scientific” way of diagnosing rubber lines as the issue?

 

How old are those rubber brake lines?

Aren't cheap ones $14 a corner? Still gotta be better than 300k milers.

You've had everything apart already...replaced everything, why not just replace them?

I mean, if your main goal in life is to see just exactly how long an original TOYOTA rubber brake line can last...go nuts.

 

https://my.cardone.com/techdocs/PT 10-0005.pdf

Found this for you. It might get you to at least the correct corner of the car.

 

It’s the ever classic, do I get the cheaper RockAuto special for $6? Or go to the pull a part and get an older unknown original Toyota line. Not sure which would be better.

and YES! I wanted to start by plugging the ports in the MC to isolate it and get pedal feel, but I couldn’t fine m10x1 block off nubs!

 

I looked up those things and I see they look mostly like a bolt.

Can't you get a bolt that size at Home Depot/Lowes?

 

HA. Okay. Brakes are fixed.

Took off driver side drum only to find the star wheel adjuster piece was NOT attached to the adjoining shoe. Literally just rattling around. Reattached the star wheel adjuster, adjusted BOTH driver and passenger sides. I started the 4Runner and immediately felt rock solid brakes. Engage hard 1/4 of the way down.

This truck still needs more work, and WILL get it, but I’m grateful the brakes are at least adequate for casual driving. Thank you all for the help - I feel so foolish not noticing anything awry while replacing the drum cylinders. Live and learn!

 

Nice! I have to remember that we have rear drums and those pesky drum cylinders. Those should have been higher on the list!

Thanks for reporting back. You actually inspired me to start planning my brake rejuvenation. I have the original factory vintage brake fluid. Never been changed. I think I'll drain it and sell it on ebay.

I think I'll pull the calipers, rebuild them. Replace the rubber brake lines and may as well replace the rear cylinders now that you mention them. I think I'll do it when I need new front rotors though.

 

Forum etiquette requires the solution to be posted! Too many threads are started and never buttoned up.

Do it! I plan on replacing the drums in the near future - just grateful the current ones are still up to the task. Ive never rebuilt calipers, though. Honestly never even thought about it. Let me know how that goes!

When I purchased this 4Runner there were four things that NEEDED to get done to get it up to snuff. 1) it was leaking fuel at the fuel filter. Replaced the filter and a foot or so of seized fittings and fuel line. 2) no brakes. Fixed that. 3) leaking oil like crazy out of the valve cover gasket. This engine is getting a top end rebuild, short of the head gasket. 4) Transmission cooler. Hoping to do that this weekend, we’ll see when it arrives. 5) crusty sections of frame. I’m a good welder and have no problem patching and reinforcing. I find it fun actually!

Anyways. Very grateful to all. Another 4Runner was saved from the crusher. So happy!

 

Rebuilding calipers is mostly just a couple of inner seals and the dust boots I think. From what I see, it's a dirt simple job.

 

Get it done! Let me know how it goes.

 

You all will be happy to know we thoroughly revived this old beast.

- Replaced master cylinder, rotors, pads, calipers, drums, shoes and cylinders
- Replaced ALL bushings with Poly, lowers with whiteline
- Refreshed the engine (valve cover gasket, intake gaskets, full timing belt kit, etc)
- Patched and painted frame

and a whole bunch of other Knick knacks like door lock motors, brake lines, lubing hinges and whatnot. Truly a different truck!