Mushy Brakes = long stopping distance

[rockclmbr]

Let's rehash this just one more time. Searching did not give me the answer I wanted.

Let's assume my brakes don't stop worth a .

I have the SS brake lines installed.
I've flushed the system with Toyota DOT3 Brake Fluid. Followed by 2 rounds of bleeding in the correct order.
No leaks that can be determined, no loss of fluid.
Brake pads were changed around 10k miles ago along with new stock rotors in the front and DBA slotted rotors in the rear.

See signature for current set-up. I usually have 150+ lbs of weight from drawers and gear.
From day one the brakes just plain suck!

This weekend I plan to lower the LSPV as much as possible. This was only done after the first lift install (medium OME). Then i will check all pad thickness and rotor thickness. Then i will perform more bleeding.

I know I've got a lot of weight, but what else can I do to improve the braking? Am I missing something?

 

[FirstToy]

some more info-

does your brake pedal go to the floor or progressively softens... or no problem w/ the pedal feel, just poor braking distance?

Your setup doesn't sound heavy or overloaded...150lbs is like an extra person sitting in the back seat.

bump

 

[rockclmbr]

Pedal doesn't go completely to the floor, it progressively gets harder the more distance the pedal moves. I do know that it doesn't feel firm initially like good brakes should.

To clarify:

Additional weight (not that this isn't normal for this crowd)

- ARB Bumper - 100lbs
-Hanna Sliders - 120+ lbs
-Kaymar - 100lbs
- Drawer - 100lbs
- stuff in drawer - 50+ lbs
- Roofrack - 40 lbs
- Last night's meal - ??? 10lbs of porterhouse and a Guinness or two

 

[ShottsUZJ100]

Did you have your 100 first and then buy your 80? The 80's brakes stink. At times my butt is off the seat when going down hills. It takes a lot of pressure sometimes. Compare to your 100 that is 100 times better. Could this be what you're seeing?

 

[rockclmbr]

I've had the 80 for 3+ years before the 100. Comparing the 100 to the 80 when it comes to brakes is no contest. A fellow 80 series owner test drove my car the other day and almost left a present on the seat when trying to stop it felt so bad. I on the otherhand have gotten use to it and stop an extra 100 feet before I would if I were driving the 100.

 

[ShottsUZJ100]

I've had the 80 for 3+ years before the 100. Comparing the 100 to the 80 when it comes to brakes is no contest. A fellow 80 series owner test drove my car the other day and almost left a present on the seat when trying to stop it felt so bad. I on the otherhand have gotten use to it and stop an extra 100 feet before I would if I were driving the 100.

OK, my theory failed.

So your 80 isn't up to snuff. I'm not the expert there. Sorry.

 

[LX_TREME]

How about the MC?

 

[rockclmbr]

I was just reading on that. Aged / older Master Cylinders can have poor seals, which cause an internal leak and the brake fluid rushes past when braking. This in turn causes a mushy brake. You can do all the work in the world on rotors, pad, bleeding, but in the end if the MC is not up to snuff, then it will never improve.

Has anyone replaced the Mastery Cylinder in their 80 before???

Are these known to go bad or not be 100% effective after 9 years?

 

[LX_TREME]

Has anyone replaced the Mastery Cylinder in their 80 before???

Right here I had same problem, replaced with new MC (not rebuild) its all good now, by the way i also runnin' DBA, SS and Hawk metallic pads.

 

[FirstToy]

Ok so I guess this is as good a thread as any to ask something I was wondering-

can you put in a larger MC/resivoir from a newer Toyota suv and have it improve braking? I noticed the 4Runner's is about twice the size of the 80's.

 

[tiorio]

Sounds like classic MC problems to me. Also may be a problem with the booster hoses, had this happen as the booster wasn't doing as much as it should and so the brakes required a LOT of pressure, like it would if the car was OFF and you were trying to apply brakes...

 

[tiorio]

Ok so I guess this is as good a thread as any to ask something I was wondering-

can you put in a larger MC/resivoir from a newer Toyota suv and have it improve braking? I noticed the 4Runner's is about twice the size of the 80's.

Interesting idea but I don't think you'd see any improvement in stopping distance although you might get a better 'feel' or something...

Friction surface and pressure are the critical factors and the 80 MC provides enough pressure for the surface area...

 

[FirstToy]

(sorry for the hijack Jasper)
back to diagnosing the mushy brakes...

 

[Tools R Us]

How is the wheel bearing adjustment? If the wheel bearings have play it will push the caliper pistons back, so the first peddle movement has to take up that play, then the brakes will try to stand the wheel up, causing the peddle to feel soft and the brakes to be ineffective.

To test the master for internal leaks, have the motor off, pump the peddle a few times to deplete the booster, push the peddle hard like a panic stop and hold it. The peddle should stay there, if it leaks down you have a leak somewhere.

 

[rockclmbr]

"To test the master for internal leaks, have the motor off, pump the peddle a few times to deplete the booster, push the peddle hard like a panic stop and hold it. The peddle should stay there, if it leaks down you have a leak somewhere."

I think I've tried this before , but I'll try again tonight to confirm. After two brake presses, it is very firm with a short throw.

How much is a new MC anyways? CDan??

 

[rockclmbr]

can you put in a larger MC/resivoir from a newer Toyota suv and have it improve braking? I noticed the 4Runner's is about twice the size of the 80's.

FirstToy-

I was wondering the same thing. Although a coworker did that to his SAAB (I know, it's a Saab, who cares anyways) and he didn't get the improvement he was looking for.

 

[Tools R Us]

"To test the master for internal leaks, have the motor off, pump the peddle a few times to deplete the booster, push the peddle hard like a panic stop and hold it. The peddle should stay there, if it leaks down you have a leak somewhere."

I think I've tried this before , but I'll try again tonight to confirm. After two brake presses, it is very firm with a short throw.

How much is a new MC anyways? CDan??

The key is to hold it down, keeping the same pressure on it for a minute or so.

 

[cpg]

When you did your rotors did you use new pads? Did you burn the new rotors in? Since the 80 is so heavy it seems more picky than say a toy pu.

 

[rockclmbr]

I'm not aware of a burn in procedure. I used new rotors and new Toyota OEM pads.

I tried the brake stand with the vehicle off. On the second push, it firmed up. I held it for 30 seconds and it held. If I put all my wieght on it (which isn't a lot) I was able to get it to move another inch.

 

[Tools R Us]

If you could hold your weight on it and it didn't leak down, then the system isn't leaking. Any play in the wheel bearings, check all four.