Poor brake pedal feel

[7Mboost]

Posted this problem a while back, the brakes worked decently and I've avoided the problem since. Anyways my brakes still have no resistance in the pedal. I have bled them several times, adjusted the MC rod, brand new brake master cylinder from Toyota and bench bled that. What is left? My pedal has really never felt right.

 

[gaboonviper85]

How old and what condition are the brakes in? How about brakelines

 

[radiod]

Any visual leaks? Are you losing fluid at all? If the system can't build pressure or is losing it, the pedal will feel really soft.

 

[Black Cat]

I don't mean to make it sound like you don't know what your doing, but did you bleed the brakes in the right order?
Starting with the wheel the farthest from the master cylinder (Passenger Rear)
and working your way towards the wheel closest to the master cylinder.

 

[mkIIIman089]

So, you push down, the car stops as it should but you don't feel any feedback in the pedal; is this correct? Is the pedal travel normal?

 

[ValgeKotkas]

I don't mean to make it sound like you don't know what your doing, but did you bleed the brakes in the right order?
Starting with the wheel the farthest from the master cylinder (Passenger Rear)
and working your way towards the wheel closest to the master cylinder.

For a car with ABS - start furthest from the ABS unit

 

[7Mboost]

I don't mean to make it sound like you don't know what your doing, but did you bleed the brakes in the right order?
Starting with the wheel the farthest from the master cylinder (Passenger Rear)
and working your way towards the wheel closest to the master cylinder.

Yes, and I've tried it fursthest from ABS block as well.

So, you push down, the car stops as it should but you don't feel any feedback in the pedal; is this correct? Is the pedal travel normal?

Yes. With the car off I have good feedback but when it's running the pedal works but has no feedback.

Also my brakes are the Doward's 13" with stainless lines, but the brakes still felt this way before I put these brakes on as well.

 

[Black Cat]

Did you check the vacuum hose to the power booster?
I know in cars that don't have a power booster the brake pedal can be really hard to press in order to stop the car.
I know on my moms Chevy 2500 that the brake pedal has no resistance to it but once you start the truck and it builds vacuum the brake pedal will kickback your foot.
I'm not sure how a bad booster of one that's disconnected from vac will affect the feel of the pedal, but its worth a shot to check it out.

 

[7Mboost]

My dad thinks the brake booster may be bad. He said its a dual diaphragm booster and he thinks one of the diaphragms may have a hole or rip in it, does this sound logical?

 

[Chira]

I just ran into this problem on my 88 and it ended up being a combo of the brake booster and a clogged line. However replacing the booster helped push some of the junk out of the line. Look into finding a brake booster and see if that will help, they tend to be costly. If you plan on finding one used make sure its from a reliable source. I got panhandled on two before just buying a newer one. I believe it was a remanned unit.

 

[mkIIIman089]

My dad thinks the brake booster may be bad. He said its a dual diaphragm booster and he thinks one of the diaphragms may have a hole or rip in it, does this sound logical?

I'd have to look that up to be sure... but it does sound logical if memory serves right.

The good is you may now know the problem... wait till you see the price on a new booster though.:aigo:

 

[7Mboost]

Yeah it's like $900+ new, my parts car out back has a good one though

 

[Hmong_1G]

CHeck the Banjo and bolt for the booster line. Check the check valve inline there too. Over time the passage way can be clogged with oil and carbon.

 

[Poodles]

When you pulled the MC off the booster was there rusting or brake fluid there? Did air leak?

 

[7Mboost]

When you pulled the MC off the booster was there rusting or brake fluid there? Did air leak?

No rust or fluid. Did air leak as in a leakdown test off the brake booster? I'm checking that later today, my car wouldn't start when I wanted to test it.

 

[anonymic]

So your brakes work fine? Your stopping distance isn't affected? Kind of a mushy feeling under your foot, with no idea what's really happening at the wheels? Sounds like you're driving a Ford. I'd say it's your booster but I'd expect the opposite effect, unless your foot is going to the floor when you start it with your foot on the brake. Just did a master cylinder and booster on a Honda, MC was leaking into the booster & shit was all rusty so we did them both instead of just the MC. The pedal was gradually going down at lights, felt a bit light on pressure going down but the brakes worked great. The pedal pumped up hard with the car off but got really soft as soon as the car started. Your problem is in either the MC or booster. I'm leaning towards your booster as that MC had been leaking VERY slowly for several years and this came on pretty fast.

I know it's a different car, but the parts are the same fundamentally.

 

[mkIIIman089]

Assuming it was installed properly... he did say he got a new MC already from Toyota (VERY unlikely to be bad DOA) so it takes that out of the equation.

With brakes that big you could likely drive around without the booster working and the system would still be somewhat effective; if you wanted to take the booster completely out of the equation. (Just unhook and cap the engine side of the vacuum line.)

 

[Asterix]

I've been chasing much the same problem for a while now. Nothing seems wrong and I've tried new parts, yet there's still too much pedal travel.

Next I need to get an assistant to watch things move as I push the pedal so I can find out where it's sloppy.

I'm just afraid there's something in the ABS unit that needs some pumping up. It is 22 years old, after all.

Asterix

 

[Chira]

Assuming it was installed properly... he did say he got a new MC already from Toyota (VERY unlikely to be bad DOA) so it takes that out of the equation.

With brakes that big you could likely drive around without the booster working and the system would still be somewhat effective; if you wanted to take the booster completely out of the equation. (Just unhook and cap the engine side of the vacuum line.)

Granted the very first part of this statement is true. However when you replace the master cylinder or the brake booster, it is usually best to replace both as they tend to fail out at about the same time. I do agree with checking by unhooking that vacuum line.

 

[Poodles]

Nope, as long as the booster isn't damaged they usually don't fail (hence their cost). Damage from a leaking MC is usually why they fail, hence why I asked if there was rust or brake fluid in the bore.

The adjusting rod may be the issue, but I can't say for sure.