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Brake horror the second !!!


FSchuett

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Hello,

after brake-master-cylinder change (´95 Eldorado), the problem is the same !!!

After rotor and pad change, the brakes are very bad.

If I drive I can "normal" brake, but If I press with power (emergency brake) the brake pedal go

to the floor and the ABS are not go on because the brakes/wheels are not blocking.

It´s a feeling how is air in the system. Nothing air in the brakefluid because it is new and bleeded,

any brake hoses (rear steel), a proportioner valve and today the master cylinder are also new.

All brake cylinder and lines are not leaking. No error codes.

ABS goes at sandy street without any error codes.

Today we are bleeding the system after the master cylinder change

and the fluid are grey not light yellow (after one week and 100 mls).

We think its dirt in the system but from where ?

The following think are not change:

- Power Booster

- Front lining

- Front hose

- Rear hose

- ABS hydraulic modulator

I don´t now what it is... why is the fluid grey ?

Please help me...

Frank

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Frank, unless someone posts it first, Ill post info from the 95 manual on bleeding the brake system, changing the master cylinder, etc. I just stopped home and saw this, I post info later unless someone else has it

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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For a pedal to be spongy, something must be giving way. The stainless steel brake lines will burst before they give enough for the pedal to go to the floor. If you have the air out of the system, the most likley thing left is the flexible brake lines to the wheels. Be very careful if someone looks at them while someone else is pressing the brake pedal because if one of them bursts in someone's face it could cause eye injury.

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Frank, unless someone posts it first, Ill post info from the 95 manual on bleeding the brake system, changing the master cylinder, etc. I just stopped home and saw this, I post info later unless someone else has it

Hello Mike,

We (2 mechnic man and I) bleed exact with bleeding instruction.

The master cylinder are brand new not remanufactured.

The bleeding procedure are correct.

Why is the fluid grey after one week (100 mls) ?

Frank

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For a pedal to be spongy, something must be giving way. The stainless steel brake lines will burst before they give enough for the pedal to go to the floor. If you have the air out of the system, the most likley thing left is the flexible brake lines to the wheels. Be very careful if someone looks at them while someone else is pressing the brake pedal because if one of them bursts in someone's face it could cause eye injury.

You mean it´s the flexible brake lines ? Not the power booster or the ABS modulator ?

Why are the fluid grey after one week and 100 mls ?

If I drive I can "normal" brake, but If I press with power (emergency brake) the brake pedal go

to the floor and the ABS are not go on because the brakes/wheels are not blocking.

Why is it so ???

Frank

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Where did you get the bleeding procedure? ABS can be tricky to bleed

Not sure why it is grey, it is typically the color of cooking oil no?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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We´ve bleed with the instructions from the master cylinder and the ´92 service manual.

For 2 minutes I drive the Eldo in the garage and found this:

Motor in idle speed...

I press the brake pedal with the same pressure and it goes very slowly to the floor.

Motor off...

I press the brake pedal with the same pressure and the pedal stay.

No leaking fluid !

The last parts where I can change are ABS module, power booster and brake hose.

Frank

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Did you bench bleed the master cylinder before installing it? If you didn't, it will be very difficult to purge all the air from the lines.

There are either plastic plugs that seal off the ports where the brake lines attach to the master cylinder or there will be hose fittings that direct the fluid back into the master cylinder. With the cylinder clamped by the mounting flange in a vise, the piston is stroked slowly, released, and a waiting period of 15-20 seconds. Repeat the sequence until no bubbles are present in the rservoir. Then connect the brake lines and bleed the air from all four calipers.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Did you bench bleed the master cylinder before installing it? If you didn't, it will be very difficult to purge all the air from the lines.

There are either plastic plugs that seal off the ports where the brake lines attach to the master cylinder or there will be hose fittings that direct the fluid back into the master cylinder. With the cylinder clamped by the mounting flange in a vise, the piston is stroked slowly, released, and a waiting period of 15-20 seconds. Repeat the sequence until no bubbles are present in the rservoir. Then connect the brake lines and bleed the air from all four calipers.

Yes we did it so...

Frank

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I don´t know why the fluid is grey !

A friend tell me it is the ABS module and another say its the power booster, or new master cylinder or brake hose...

I don´t know what we make at next !

Power Booster: I think a damage power booster make the pedal hard to press and the brake have a normal function (also more pedal pressing)...

ABS module: Absolute no error code, I think it´s OK...

Master Cylinder: Is new, why should it damage...

Brake hose: Can the flexible brake hose pumping off (ballon) ? Than it is...

Any idea ?

Frank

PS: Cadillac write I must put DOT 3 in the brake system.

I think DOT 4 is newer and only the same...

Also DOT 5 ist nocht correct !

Is it so ?

A friend tell me that DOT 4 damage all seals !

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