Pedal to the floor after brake job

[Falcon_LS]

Just did a front brake job on my Grand Marquis, which consisted of:

- 2 front rotors
- Cardone Select new master cylinder
- Dorman front brake hoses
- Dorman front caliper repair kits
- Carlson boot pin kit
- Speed Bleeders
- Raybestos PG Plus brake pads (old stock, made in Canada)
- Liqui-Moly Brake Cleaner
- Motorcraft dialectic grease
- Permetex Disc Brake Quiet
- Mercedes-Benz DOT 4+ brake fluid

Before installing the new master cylinder, I bench bled it and then bled it again when it was on the vehicle. I've got speed bleeders installed now, so I bled all the lines too. The pedal goes all the way to the floor, almost touching the it, but the brakes are pretty good.

I bled the master cylinder again, and it was the same thing. So I put the old factory MC back on, and it's still the same thing.

Any suggestions? Thanks!

 

[demarpaint]

Check for leaks, bleed again, you could also have a defective MC, it happens. There is a slim chance of this being the problem but, if you have rear drum brakes did you check the adjustment on them? If they are out of adjustment they can cause a low brake pedal.

 

[Eddie]

You didn't mention whether the fluid level in the MC reservoir was staying at the same level or going down.

 

[Falcon_LS]

Thanks for the input.

Just bled the system again, and still have the same issue. The fluid level in the reservoir stays at the same level, unless I'm bleeding the brakes. I'm not sure about the MC, considering it does the same thing with both the new and the old.

Forgot to mention, I've got drum in discs at the back. Could this be an issue with the booster?

 

[Trav]

It sounds like there is air in the ABS unit. You need a scan tool to activate it for bleeding, you will never get the air out otherwise.

 

[MichiganMadMan]

Originally Posted By: Falcon_LS
Thanks for the input.

Just bled the system again, and still have the same issue. The fluid level in the reservoir stays at the same level, unless I'm bleeding the brakes. I'm not sure about the MC, considering it does the same thing with both the new and the old.

Forgot to mention, I've got drum in discs at the back. Could this be an issue with the booster?


If you have ABS, you might have got air into the pump module when you swapped the master cylinder. It's next to impossible to get it out by convention bleeding. I was always lucky to get a MC swapped without getting air into mine.
I think you need a service tool that can activate the ABS pump and then you can bleed the air out.
Good luck.

 

[Bottom_Feeder]

You bled the fronts but did you bleed the rears?

 

[rshaw125]

Bleed it with the engine running.

 

[OVERKILL]

Why did you replace the master? Just curious.

 

[meangreen01]

Originally Posted By: Trav
It sounds like there is air in the ABS unit. You need a scan tool to activate it for bleeding, you will never get the air out otherwise.


I was under the impression that this was always the case. However, I needed to replace the ABS pump on my Durango. According to the FSM regarding bleeding after pump replacement, it basically instructed to bleed normally. So, who knows? It must vary by mfg and design.

OP- sounds like air must be in there somewhere.

 

[Bgallagher]

Originally Posted By: Trav
It sounds like there is air in the ABS unit. You need a scan tool to activate it for bleeding, you will never get the air out otherwise.


+1 Sounds like air in the system. Try bringing it to a shop and have them flush and bleed it. They can activate the bleed and flush it with clean fluid.

 

[Trav]

Manufacturers use different units from a host of suppliers.
The Marquis probably has a Teves unit while the Durango a Kelsey Hayes.

 

[Vikas]

Originally Posted By: demarpaint
Check for leaks, bleed again, you could also have a defective MC, it happens. There is a slim chance of this being the problem but, if you have rear drum brakes did you check the adjustment on them? If they are out of adjustment they can cause a low brake pedal.


Seconded; Please check the rear brake adjustment before doing anything else.

 

[homeyclaus]

You mentioning the rebuild kit for the calipers, and new hoses, leads me to believe you broke the seal in several places in the braking system at once.

What year vehicle is this? (ETA, sorry, read in the sig line it's an '01).

What others said is correct, different vendors' ABS units require different bleeding procedures, and there is a difference between the bleed for brake service and the 'bleed from factory empty'.

Some mfg's say bleed normally, whatever that means since there is more than one way to do that.

Some mfg's say bleed with the battery disconnected or the ABS fuse pulled.

Some mfg's say start the engine, and when you pop a brake line the system starts pumping fluid on its own, you just have to keep the reservoir topped up. From factory empty these systems usually require the mfg diagnostic computer hookup (Techstream, Consult-II etc) and not a standard OBDII device.

The point is, check the factory service manual.

If you have to, try vacuum bleeding with the battery disconnected, and see how much vaccum you get at the caliper. If it pulls fluid, you can do a bleed that way. If the vacuum goes up, the ABS/brake assist has closed the line and probably needs power and something set in a computer somewhere.

 

[mechtech2]

A low but hard pedal?
Pump the pedal with the car off to eliminate any vacuum in the booster. Then wait and step on the pedal. Is it low and hard? will it pump up higher and hard?
See what you have . Low and hard is probably rear brake drum adjustment.
Also, the front pads/rotors may need to seat in, if they are really fresh.
ABS systems can be finicky about bleeding.

BTW, there is no use or need for dielectric grease on any brake system. It is for electrical connection use only. Get the right brake lube on the parts.

 

[oldmaninsc]

Originally Posted By: mechtech2
A low but hard pedal?
Pump the pedal with the car off to eliminate any vacuum in the booster. Then wait and step on the pedal. Is it low and hard? will it pump up higher and hard?
See what you have . Low and hard is probably rear brake drum adjustment.
Also, the front pads/rotors may need to seat in, if they are really fresh.
ABS systems can be finicky about bleeding.

BTW, there is no use or need for dielectric grease on any brake system. It is for electrical connection use only. Get the right brake lube on the parts.


I've never seen any 2001 Grand Marquis that had rear drum brakes. The parking park yes but the "main" brakes are disc.
Also you guys are assuming he has ABS. According to his post over at another forum, he does NOT!

Checking at Rock Auto - there are different part numbers for master cylinders with ABS vs. NON ABS.

 

[Trav]

Quote:
According to his post over at another forum, he does NOT!


Why the bold letters and exclamation point?
Maybe you follow people around all over the internet and know what they drive but most of us dont.
Lighten up!

 

[oldmaninsc]

Originally Posted By: Trav
Quote:
According to his post over at another forum, he does NOT!


Why the bold letters and exclamation point?
Maybe you follow people around all over the internet and know what they drive but most of us dont.
Lighten up!
You lighten up dude! I'm only trying to help and point out the wrong assumptions people were making. The bold part was indicate the part of his post that I was referring to. I didn't see anything wrong with that.

Did you get up on the wrong side of the bed or something? Please! People like you are why some people leave this forum and are reluctant to help! Maybe you should take a chill pill!

BTW - so sorry for using the exclamation point - next time (if there is one) I'll use the period - just for you.

 

[demarpaint]

Originally Posted By: oldmaninsc
Originally Posted By: Trav
Quote:
According to his post over at another forum, he does NOT!


Why the bold letters and exclamation point?
Maybe you follow people around all over the internet and know what they drive but most of us dont.
Lighten up!
You lighten up dude! I'm only trying to help and point out the wrong assumptions people were making. The bold part was indicate the part of his post that I was referring to. I didn't see anything wrong with that.

Did you get up on the wrong side of the bed or something? Please! People like you are why some people leave this forum and are reluctant to help! Maybe you should take a chill pill!

BTW - so sorry for using the exclamation point - next time (if there is one) I'll use the period - just for you.


Wow, if anything members like Trav are why people come to this board. When it comes to mechanical knowledge and ability there are few if any members here that can top him.

 

[OVERKILL]

Originally Posted By: demarpaint
Originally Posted By: oldmaninsc
Originally Posted By: Trav
Quote:
According to his post over at another forum, he does NOT!


Why the bold letters and exclamation point?
Maybe you follow people around all over the internet and know what they drive but most of us dont.
Lighten up!
You lighten up dude! I'm only trying to help and point out the wrong assumptions people were making. The bold part was indicate the part of his post that I was referring to. I didn't see anything wrong with that.

Did you get up on the wrong side of the bed or something? Please! People like you are why some people leave this forum and are reluctant to help! Maybe you should take a chill pill!

BTW - so sorry for using the exclamation point - next time (if there is one) I'll use the period - just for you.


Wow, if anything members like Trav are why people come to this board. When it comes to mechanical knowledge and ability there are few if any members here that can top him.


Agreed

Trav knows his stuff.