Spongy brake pedal after pad replacement...

[PPMotorsports]

Yesterday crept above 40 degrees, so I decided to install the slightly used Endless rear brakes pads that I got from Big Sky. I was running Endless NA-S in the front already. Prior to the brake installation, the rear brakes were almost to the wear indicator and the front pads are about half way cooked. I've got about 37,000 miles on the car.

I threw the rear brake pads on and bled the the rear brakes with my trusty vacuum pump. I re-installed the rear wheels and then pulled the fronts to do an inspection and bleed those.

Once I finished up, I pulled out for a lap around the block and...
The car still stops well, and maybe this is just because I'm used to driving my Neon, but the pedal feels very spongy.

Any tips on how to loose the spongy pedal feel? Bleed the lines again? Should I install some stainless steel lines?

-Jim

[Bask Oner]

Hahaha, I installed my stainless brake lines, etc myself, then bled the lines about 10 times. I still had to pump the pedal to stop. After taking it to Speedy Muffler King, I was good to go. Maybe you should take it to a mechanic?

Anyway, yes, the stainless lines help get rid of the spongy feel, but they don't reduce the pedal travel at all.

[PPMotorsports]

Apparently the brake bleeding procedure is very specific and I bled the brakes in the wrong order. After referencing my trusty service manual, I'll give it another go tomorrow.

15.Air Bleeding
A: PROCEDURE
CAUTION:
The FMVSS No. 116, fresh DOT3 or 4 brake fluid must be used.
Cover the bleeder with waste cloth when loosening it to prevent brake fluid from being splashed over surrounding parts.
Avoid mixing different brands of brake fluid to prevent degrading the quality of the fluid.
Be careful not to allow dirt or dust to get into the reservoir tank.

NOTE:
Start with the brakes (wheels) connected to the secondary chamber of the master cylinder.
The time interval between two brake pedal operations (from the time when the pedal is released to the time when it is depressed another time) shall be approximately 3 seconds.
The air bleeder on each brake shall be released for 1 to 2 seconds.

1. MASTER CYLINDER
NOTE:
If the master cylinder is disassembled or reservoir tank is empty, bleed the master cylinder.
During the bleeding operation, keep the brake reservoir tank filled with brake fluid to eliminate entry of air.
Brake pedal operating must be very slow.
For convenience and safety, two people should
do the work.
1) Disconnect the brake line at primary and sec-
ondary sides.
2) Cover the master cylinder with vinyl bag.
3) Carefully depress and hold the brake pedal.
S4M0.540
4) Close the outlet plug with your finger, and re-
lease the brake pedal.
I S4M0541
5) Repeat the above step3) and 4) until brake fluid
is completey bled from outlet plug.
6) Remove the vinyl bag, then connect the brake
pipe to master cylinder.
Tightening torque:
7) Using water, wash off the spilt brake fluid at the
master cylinder surrounding, then wipe up the wa-
ter.
8) Bleed air from the brake line. <Ref. to BR-46,
BRAKE LINE, PROCEDURE, Air Bleeding.>

2. BRAKE LINE
NOTE:
During the bleeding operation, keep the brake
reservoir tank filled with brake fluid to eliminate en-
try of air.
Brake pedal operating must be very slow.
For convenience and safety, two people should
do the work.
1) Make sure that there is no leak from joints and
connections of the brake system.
2) Fit one end of vinyl tube into the air bleeder and
put the other end into a brake fluid container.
8 N-m (0.8 kgf-m, 5.8 ff-lb)
S4M0246 W

CAUTION:
Brake fluid replacement sequence; (A) Front right (B) Rear left + (C) Front left + (D) Rear
I S4M0475A
(1) Master cylinder
(2) Hydraulic unit
(3) Proportioning valve
3) Slowly depress the brake pedal and keep it de-
pressed. Then, open the air bleeder to discharge
air together with the fluid.
Release the air bleeder for 1 to 2 seconds.
Next, with the bleeder closed, slowly release the
brake pedal.
Repeat these steps until there is no more air bub-
bles in the vinyl tube.
Allow 3 to 4 seconds between two brake pedal op-
erations.
CAUTION:
Cover the bleeder with waste cloth, when loos-
ening it, to prevent brake fluid from being
splashed over surrounding parts.
NOTE:
Brake pedal operating must be very slow.
4) Tighten the air bleeder securely when no air bub-
bles are visible.
Air bleeder tightening torque:
8 N.m (0.8 kgf-m, 5.8 ft-lb)
5 ) Perform these steps for the brakes connecting to
the secondary chamber of master cylinder, first,
and then for the ones connecting to primary cham-
ber. With all procedures completed, fully depress
the brake pedal and keep it in that position for ap-
proximately 20 seconds to make sure that there is
no leak evident in the entire system.
6) Check the pedal stroke.
While the engine is idling, depress the brake pedal
with a 490 N (50 kgf, 110 Ib) load and measure the
distance between the brake pedal and steering
wheel. With the brake pedal released, measure the
distance between the pedal and steering wheel
again. The difference between the two measure-
ments must be more than specified.

I'll edit this later to clean it up.

-Jim

[GV27]

You don't need to clean it up - it's all in the periodic maintenance sticky w/ diagrams, Jim.

It may also be a case of needing to bed the pads properly. Right now they're not making full contact with the rotor and that can cause a spongy feel. This is definitely the case when doing all four at once. I'm not sure I've ever encountered this with rears but it is possible. I've definitely experienced this when replacing fronts only.

I'd think this is a more likely case since you wouldn't have needed to bleed the brakes for a pad install.

The bleed order shouldn't have made a big deal because, like I said, you really didn't need to bleed them. I usually just bleed the calipers when doing pads.

UNLESS you let the reservoir run dry while bleeding. In that case you'll need to bleed the master cylinder which is a serious PITA. Take it to a REAL mechanic.

Stainless lines will help but I'd make sure I didn't have some other problem before throwing more variables in.

C

[Bask Oner]

Originally posted by GV27
UNLESS you let the reservoir run dry while bleeding. In that case you'll need to bleed the master cylinder which is a serious PITA. Take it to a REAL mechanic.

C

I was almost sure that I had done this to my car, and that's why I took it to a mechanic. They said that the master cylinder was fine, even though it was almost empty at one point.

[GV27]

Almost empty is OK. Empty empty is bad news.

[tan]

You can really tell the difference with SS lines when you're at the limit (around lockup). Still you have ABS, it is harder to tell the difference.

If the OEM rubber hoses have been subjected to a lot of hard braking, thus expanded already and worn....time for new lines.

I prefer a Pressure Bleeder myself