Brake pedal feels soft (already bled the system)

[eldusto84]

Ok, so I recently bled my brakes because I had to disconnect the rear passenger line in order to replace the trailing arm bolt. I followed the correct procedure for bleeding, and there certainly was a lot of air in the lines, but I noticed that there wasn't much pressure coming out of the rear after pumping the brakes and opening the bleeder screws. The front brakes seemed normal though.

I put the tires back on and drove the car around, and while the car does brake, it doesn't brake quickly. I tried slamming the brakes while going 20-25 in a parking lot, and it didn't stop on a dime like it should have. Fluid reservoir/master cylinder is topped off, but the pedal seems mushy and I'm wondering what the deal is. It just feels like the rear brakes aren't doing much. Any ideas?

[DMCMW Dave]

Plugged hoses?

[eldusto84]

How would you unplug the hoses?

[82DMC12]

I also have a soft pedal after new master cylinder and calipers. Going to try to get a pump bleeder and do it that way.

You could find out if the line is plugged by disconnecting the rear metal line at the master and blowing shop air thru it. Obviously you will need to rebleed the brakes again but you will have to do that no matter what.

[DMCMW Dave]

How would you unplug the hoses?

You don't. You replace them.

[stevedmc]

I'm wondering if his brake booster might be leaking. Do you hear any hissing noises when your press the brake pedal?

[David T]

My guess is there is something wrong with your bleeding technique. First of all do NOT use DOT 5. You will never get a hard, firm pedal with it. Next, refill the reservoir and get a one-man bleeder. It is basically just two pieces of tubing and a check valve. Now, loosen the bleeder on one of the rear wheels and pump it for a while making sure you do NOT get the reservoir too low and suck in air. Close the bleeder and do the other rear wheel the same way. If you still can't get a good, hard pedal you probably have bad hoses. if you have any bad hoses just change them all. You should be using Castrol GTLMA DOT 4 brake fluid.
David Teitelbaum





I'm wondering if his brake booster might be leaking. Do you hear any hissing noises when your press the brake pedal?

[eldusto84]

Well before I opened the brake line, the pedal seemed firm like it normally should. I suppose I can try bleeding the lines again, but I'm just confused why after pumping the brake pedal 8-10 times and then opening the rear bleeder screws, there isn't more pressure shooting out like in the front brakes.

I bled them in the proper sequence, right rear/left rear and then right front/left front. And yes I am using DOT 4 fluid.

[LEVY]

If your rear brakes were working before you started messing with them, chances are that you have a lot of air inside your master. You have a double pump, the part that controls rear brakes might be full of air. Easy to fix.




Well before I opened the brake line, the pedal seemed firm like it normally should. I suppose I can try bleeding the lines again, but I'm just confused why after pumping the brake pedal 8-10 times and then opening the rear bleeder screws, there isn't more pressure shooting out like in the front brakes.

I bled them in the proper sequence, right rear/left rear and then right front/left front. And yes I am using DOT 4 fluid.

[Bitsyncmaster]

Well before I opened the brake line, the pedal seemed firm like it normally should. I suppose I can try bleeding the lines again, but I'm just confused why after pumping the brake pedal 8-10 times and then opening the rear bleeder screws, there isn't more pressure shooting out like in the front brakes.

I bled them in the proper sequence, right rear/left rear and then right front/left front. And yes I am using DOT 4 fluid.

How are you bleeding them?

[eldusto84]

If your rear brakes were working before you started messing with them, chances are that you have a lot of air inside your master. You have a double pump, the part that controls rear brakes might be full of air. Easy to fix.

Hmm, so how do I get air out of the master cylinder? The way I bled the brakes was to have my brother pump them 8-10 times, hold the pedal down, then I'd open the bleeder screw and let the air/fluid flow into a jar. After the flow stopped, I'd close the screw and we'd repeat the process as many times as necessary.

[David T]

Get a hose on the bleeder fitting. It should be long enough to go into a cup so it can't pull air in. Loosen the bleeder. Have your assistant pump the brakes till you see the the bubbles stop. After about 20 pumps you should stop and make sure the reservoir has plenty of brake fluid still in it and top it off and continue. Once you no longer see bubbles you close the bleeder and go to the next wheel. When you are all finished you top off the reservoir. Go around to all of the calipers at least twice. If you have a 5-speed you should also flush the clutch. You do this every other year. Eventually you will get good at it.
David Teitelbaum

[LEVY]

This technique is not going to work for the problem you have, I will send you instructions via PM. Ten if it works for you, post it for others to see.

The reason I don't post it now is due to the fact that someone will post negative coments before you even try.

LEVY

PM SENT!




Get a hose on the bleeder fitting. It should be long enough to go into a cup so it can't pull air in. Loosen the bleeder. Have your assistant pump the brakes till you see the the bubbles stop. After about 20 pumps you should stop and make sure the reservoir has plenty of brake fluid still in it and top it off and continue. Once you no longer see bubbles you close the bleeder and go to the next wheel. When you are all finished you top off the reservoir. Go around to all of the calipers at least twice. If you have a 5-speed you should also flush the clutch. You do this every other year. Eventually you will get good at it.
David Teitelbaum

[82DMC12]

Levy, PM me too. I need to do something about the brakes on 11114 this weekend.

[LEVY]

.


PM Sent!

LEVY



Levy, PM me too. I need to do something about the brakes on 11114 this weekend.

[LEVY]

Word of caution:

Using a hose attached to the bleed screw and a little jar in theory should work.

You will not make a mess.
If the hose is immersed in fluid, air should not get back into the system.

Well, that is in the perfect world, if the bleed screw is a little bit loose, air will go into the system thru the bleed screw threads.

LEVY

[David T]

If you see a lot of air getting in that way you remove the bleeder and grease up the threads. I only see that much air when I use vacuum on the bleeder, pumping the pedal and pressurizing the system usually won't get you a lot of air through the bleeder screw threads.
David Teitelbaum




Word of caution:

Using a hose attached to the bleed screw and a little jar in theory should work.

You will not make a mess.
If the hose is immersed in fluid, air should not get back into the system.

Well, that is in the perfect world, if the bleed screw is a little bit loose, air will go into the system thru the bleed screw threads.

LEVY

[LEVY]

Not sure if I should answer but here it goes:

When you are using a vaccum pump, you see the air because air is going down the hose. You don't see the air when you are pumping the brake pedal because the air is going "UP INTO THE SYSTEM"!

Air is sucked into the system everytime you release the brake pedal and you don't see it because is not going thru the hose.

We are trying to help, please don't confuse those who ask for help.

LEVY





If you see a lot of air getting in that way you remove the bleeder and grease up the threads. I only see that much air when I use vacuum on the bleeder, pumping the pedal and pressurizing the system usually won't get you a lot of air through the bleeder screw threads.
David Teitelbaum

[Bitsyncmaster]

If you see a lot of air getting in that way you remove the bleeder and grease up the threads. I only see that much air when I use vacuum on the bleeder, pumping the pedal and pressurizing the system usually won't get you a lot of air through the bleeder screw threads.
David Teitelbaum

Don't use any grease on brake components.

I always see a little air bubbles using the bleeder and two man bleed. But I think its just sucking air around the threads on the bleeder. So keep working until large bubbles are gone but don't try to get those little bubbles to stop.

[LordeRyall]

Eldusto84: Did this ever get resolved? I have similar sounding symptoms on a car that I am thinking of buying and whilst we haven't even done a bleed yet it would be of interest to know if your problem was simply down to bleeding technique or it was a different issue.

Thanks.

[eldusto84]

Yes, the issue has been solved! So nice to have working brakes (a moderately important function for a car).

[lazabby]

Sometimes when I first start my car and my foot is on the brake it will feel mushy. If I pump the brake it firms up and I have no more issues with the brake feeling soft until the next time I start the car. What's causing this?

[Bitsyncmaster]

Sometimes when I first start my car and my foot is on the brake it will feel mushy. If I pump the brake it firms up and I have no more issues with the brake feeling soft until the next time I start the car. What's causing this?

Does the E brake on or off make any difference?

It's probably air in a line.

[Doogie]

Yes, the issue has been solved! So nice to have working brakes (a moderately important function for a car).

What may I ask solved it? I rebuilt my front calipers, and replaced all 4 hoses with stainless, and even replaced my master cylinder. I had hard brakes before all that, (but the front calipers were frozen so I had to rebuld them. My car sat for 25 years before I got it)

After a fluid flush, I have soft brakes. I mistakenly put DOT 3 in, and will replace with DOT 4 next Thursday. I use a power bleeder.

Curious what you did to fix yours...

Doogie

[lazabby]

Does the E brake on or off make any difference?

It's probably air in a line.

I don't know if the Emergency brake on or off would make a difference or not. It makes me think there is no pressure in the system until it gets started and then it's fine. But I've been wondering if there is air in the lines.

[dmc6960]

Ebrake has absolutely nothing to do with pedal pressure. It's a completely independent setup using dedicated cables, calipers, and pads. The only thing in common is the rear rotors.

[Bitsyncmaster]

Ebrake has absolutely nothing to do with pedal pressure. It's a completely independent setup using dedicated cables, calipers, and pads. The only thing in common is the rear rotors.

True. I just questioned that because that is a difference when you first start the car.