Mushy brakes

[kenamond]

My brakes are mushy. I can pump them and they firm up. I just got done bleeding them...14 or so pumps per corner, and it didn't help. I just did some more searching (should've done that firs, huh?) and found a post by Defiant about he order. The 1g tech article is what I went from, and it went RR, LR, FR, LF. Defiant's order went RR, LF, LR, RF or something like that. He also said to do it with the reservoir cap off. I would keep topping off the level, but put the cap back on while bleeding.

So is the order that important? Could it be something other than air in the lines? It's a pain just jacking it up, pulling wheels off and putting them back on, so I'd rather only having to do this once more...

EDIT: Oh, and I didn't see any bubbles during bleeding.

 

[TwoLiterLaser]

I don't know about order, but is the master cylinder shot? Is there fluid leaking on the inside of the car under the dash rather than the outside? I had a friend with a bad master cylinder that did just that, no leaks visible on the outside.

 

[jrohner]

It could be that one of the calipers is not aligned quite right because something is bent. Take each wheel off and have someone pump the brakes fairly hard; look for a caliper that twists or moves a lot. Or the caliper is stuck to one side or the other (doesn't slide freely back and forth on the mounting bolts), so the pad on one side is not touching the rotor. It may also be that a caliper is bad. Also check to see that all of your wheels spin freely and you don't have a brake dragging.

If it just feels mushy when driving, it could just be really crappy brake pads.

 

[knochgoon24]

Time for SS brake lines?

 

[fhudsonjr]

Mack, according to my 1993 Chrysler Laser/Talon service manual, what Defiant said is correct. Chrysler must think it's important, but I don't know why.

Go's against everything I've heard about bleeding brakes in the past. It was always start w/the caliper farthest away from the MC and move sucessively to the next farthest and so on.

 

[Defiant]

The ABS system is what screws up the bleeding order. I didn't believe it the first time I read it, either.

Replace your brake booster line, making sure the internal check valve allows flow only toward the engine.

Also, check for any cracks in the firewall around the master cylinder that could be letting things flex.

 

[kenamond]

Thanks guys!

I have no fluid leaks. When bleeding each corner, there was no anomalous motion of the caliper while pumping the brakes, but I did notice a bit of flex in the FR caliper when we first started bleeding it. The stock lines are SS hard lines up to the wheel well, so I'm not sure what you mean by upgrading to SS lines. I can pump the brakes so that they firm up. I haven't noticed any dragging against the rotor.

I'll search to see about checking for a seized caliper.

So I guess I'll check the brake booster line and check valve and re-bleed in the correct order. Some say to have the car running, others say it doesn't matter. I'm wondering if there's any harm in doing it with the motor running. Maybe that helps with bleeding the ABS? Maybe having power brakes during bleeding helps somehow?

Can I use one of my USPlastics check valves (the one folks are using for PCV system) in-line for the brake booster check valve if that's the problem? The line might be too small for the barbs on the check valves I have, but I might be able to use some larger line. If that doesn't work out, I guess I'll see if Autozone has the line/valve.

 

[Defiant]

I'd stay with the factory part for the brake vac check valve.

 

[kenamond]

I'd stay with the factory part for the brake vac check valve.

Okay. I'm going to have to tear parts out to dig my way to the brake booster end of that line. The clip on the line has the tabs facing the firewall, so I can't get at it.

 

[TALONTRAX]

I kind of tripped over a method of isolating which corner of a brake system is causing the "mush". Take a pair of needle-nose style of vise grips, & clamp off 1 brake hose at a time (I would start at the right rear & work closer, despite what the literature says), and pump the pedal each time. When you get to the corner where when clamped off, the pedal feels more solid, you`ve isolated your problem . . .

 

[misterskeetz]

Exact same thing happened to me. A seal in the caliper had gone bad and was leaking brake fluid. If this is your case and the caliper isnt seized up, you can do a rebuild. If not, new calipers is the other option.

NOTE- If yer rich...go with a BBK...assuming you also have the money for new wheels to clear it

 

[kenamond]

I kind of tripped over a method of isolating which corner of a brake system is causing the "mush". Take a pair of needle-nose style of vise grips, & clamp off 1 brake hose at a time (I would start at the right rear & work closer, despite what the literature says), and pump the pedal each time. When you get to the corner where when clamped off, the pedal feels more solid, you`ve isolated your problem . . .

Should I worry about damaging the rubber part of the line doing this? I don't want to lose my brakes because the line ruptures later.

Exact same thing happened to me. A seal in the caliper had gone bad and was leaking brake fluid. If this is your case and the caliper isnt seized up, you can do a rebuild. If not, new calipers is the other option.

NOTE- If yer rich...go with a BBK...assuming you also have the money for new wheels to clear it

I'm not leaking any fluid. If I need new calipers, I may upgrade. I've been considering new rims/tires, but I'm also considering forged wheels ($$$), so I don't know if I could afford to do brakes, wheels, and tires all at once. I tend to upgrade when something breaks, but only if I can afford it.

 

[TALONTRAX]

No, I wouldn`t worry about collapsing the inner brake hose, as the clamp will only be on there for a minute or 2. Actualy, a bad brake hose (collapsed internally) may be your problem . . . Try the vise grip test 1 corner at a time, & let us know . . .

 

[VZRacing]

Don't forget to bleed the MC, that gave me the run around for a while. Also was it raining/ humid when you changed your fluid? If so moisture might have gotten into the fluid, it tends to happen with the high end fluid. If all else fails drain the system and start over with new fluid.

On a side note I have never worried about a specific order when bleeding and I haven't had any trouble.

 

[Defiant]

I'd not try crushing a brake line. Bad idea.

 

[TALONTRAX]

I know that clamping a brake hose sounds risky, but believe me I`ve done it many times with no damage to the hoses - And I would NEVER suggest that anyone do anything destructive to their car, nor would I recommend something unorthodox such as this unless I have done it myself sucessfully, or have seen it done, with no issues . . .

 

[Cs4g63]

I know this isnt the problem you are having but I wanted to add it to this thread because it is good for someone that doesnt know to understand the diference.

It was suggested in post #2 that your brake master cylinder could be leaking and you would see brake fluid inside of the car on the firewall. That is not the case with the brake master cylinder, but it is correct if it were for the clutch master cylinder. The clutch master cylinder is bolted directly to the firewall and goes through it into the passenger compartment and that is why when its seal leaks you will see brake fluid inside the car on the firewall. The brake master cylinder is bolted the to the brake booster and if it leaks it will leak into the booster and you wont see the fluid inside the car.

 

[TwoLiterLaser]

The brake master cylinder is bolted the to the brake booster and if it leaks it will leak into the booster and you wont see the fluid inside the car.

Woops. I underthought this one. The culprit car I reffered to happened to be a Mustang with manual brakes, no booster. My apologies.

 

[nlzn]

I'm dealing with brake problems myself.
I've got a constant mushy pedal feeling, and if i get on it the car still doesnt slow down like normal but I can feel the ABS acting via the pedal kick.

I think I've got a collapsed line somewhere, it's the only thing that makes sense. No caliper seize, replaced the MC, bled 2 pints of fluid, no fluid leaks. Wish there was an easy way to see which line was collapsed.

I'm also going to check into that brake booster check valve.