Spongy Brake Pedal

[crouse]

The brake pedal on my Marauder is really spongy. There is a lot of travel before the brakes begin to grab. And it seems like if I keep pushing, the pedal keeps moving towards the floor. I have the TCW SS brake lines, so I know it's not rubber hoses expanding. The brake fluid lever is fine. I also flush through new brake fluid each spring.

Is this a bad master cylinder or vacuum booster?

Thanks,
Curt

[Mr. Man]

Rotors and pads are in good shape?

[crouse]

Yes. New front rotors last spring and I run Carbotech AX-6 auto cross pads on all four corners.

[Comin' in Hot]

If it’s spongy, it could be your master cylinder. Typically when a booster fails, the pedal gets hard.

[TooManyFords]

Or you need to bleed the brakes again...

[BigCars4Ever]

I am having the same issue. I read that this could also be caused by the ABS system. My plan is to get a 10 and 12mm brass plug and plug the master cylinder and see if the pedal firms up and doesn't slowly go to the floor. I am afraid if it doesn't go to the floor I will be in real trouble because ABS parts are hard to come by for our cars.

[MyBlackBeasts]

Or you need to bleed the brakes again...


^^^^^
This, with ABS pump cycle.

[justbob]

ABS delete [emoji1303]

http://www.prbmachining-absdeletemanifolds.com/catalog/i43.html


Sent from my iPhone using Tapatalk Pro

[Gerry24]

Install SS brake lines, you will feel the difference.

[crouse]

Install SS brake lines, you will feel the difference.

Already have the TCE SS brake lines.

[crouse]

^^^^^
This, with ABS pump cycle.

I'm not familiar with this. Can you provide some additional information?

[MyBlackBeasts]

I'm not familiar with this. Can you provide some additional information?


Air gets trapped in the ABS pump/lines which makes pedal spongy even after bleading brakes many times.


Take to dealer for bleed with ABS pump cycle or get a scan tool that cycles pump and do yourself.

[Logan86]

I had a similar situation and it was a failed master cylinder. Bench bleed, go get the ABS bleed down at a dealer and then enjoy a nice firm pedal again.

[crouse]

Rock Auto lists a Raybestos, Cardone, Centric or AC Delco master cylinder. Anyone have any recommendations? Or how about NAPA?

[MTeoc]

I have the same problem now. My OEM brakes on the 2003 Marauder feel mushy and inadequate for a fast stop. Scared the hell out me a couple of times...almost had to take the ditch to avoid collision.

I was looking to upgrade brakes. Has anyone had any experience with the Power Stop® Z23 (or Z26) Evolution Drilled and Slotted Brake Kit with Calipers?
https://www.carid.com/2003-mercury-m...574631010.html

HL

[offroadkarter]

I have the same problem now. My OEM brakes on the 2003 Marauder feel mushy and inadequate for a fast stop. Scared the hell out me a couple of times...almost had to take the ditch to avoid collision.

I was looking to upgrade brakes. Has anyone had any experience with the Power Stop® Z23 (or Z26) Evolution Drilled and Slotted Brake Kit with Calipers?
https://www.carid.com/2003-mercury-m...574631010.html

HL

Drilled/slotted rotors are not going to fix the **** pedal feel these cars have.

If your pedal is going to the floor before barely anything happens, it's most likely a failed master cylinder. My parts car crown vic has this exact problem, I have to put the pedal on the floor to get any stopping action.


If your car however has the typical 300A *****y brake pedal feeling, where the pedal travels half way before it firms up, this is from the cars being equipped with crappy brake boosters. Marauders got 01/02 vic boosters while the 03+ panthers got a revised booster.

I swapped a brand new 03/04 vic booster into my 04 Marauder during the manual swap and I put the stock 04 booster in my 03 which had the 300A garbage brake feeling. Without changing anything else the pedal feel in both cars was immediately improved. I may throw the 04 sport booster and pedal box into the 03 Marauder just to see how much more it improves.

Honestly, what made the biggest impact in pedal feel was the TCE/Wilwood BBK. A fixed caliper does wonders for pedal feel.

[crouse]

I installed a new Napa brake master cylinder this weekend. Did a gravity bleed first then went to each corner and did 6-8 pump & hold then crack the bleeder method. Also bled the master cylinder. The pedal is firm, but still a lot of travel before it firms up. Any thoughts?

[RubberCtyRauder]

nevermind, you have TCE lines. Mine has travel before feeling anything, it's not like today's cars that is right there.

[crouse]

I was thinking about taking it to a dealer to have the brakes bled while cycling the ABS pump, but if that won't resolve the pedal travel, then it's a waste of money.

[blazen71]

Anyone with a good diagnostic tool can initiate the abs pump to bleed. Otherwise check this thread out to manually initiate the ABS pump.

https://www.crownvic.net/ubbthreads/...Number=2428904
.
.

[crouse]

The link didn't work for me, but I was able to find it on cv.net.

https://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2428904

[offroadkarter]

The link didn't work for me, but I was able to find it on cv.net.

https://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2428904

Instead of wedging wood in the calipers, here is an easier (yet less free) solution

get this

https://www.amazon.com/ScanTool-OBDLink-Bluetooth-Professional-Diagnostics/dp/B006NZTZLQ/ref=sr_1_3?crid=32H4QW7TQN5G1&keywords=obd+mx+bluetooth&qid=1559078149&s=gateway&sprefix=obdmx%2Caps%2C122&sr=8-3-spell

put this on whatever device you choose

https://forscan.org/home.html

connect to car

hit "run abs cycle"

boom, done

[EMAS]

Instead of wedging wood in the calipers, here is an easier (yet less free) solution

get this

https://www.amazon.com/ScanTool-OBDLink-Bluetooth-Professional-Diagnostics/dp/B006NZTZLQ/ref=sr_1_3?crid=32H4QW7TQN5G1&keywords=obd+mx+bluetooth&qid=1559078149&s=gateway&sprefix=obdmx%2Caps%2C122&sr=8-3-spell

put this on whatever device you choose

https://forscan.org/home.html

connect to car

hit "run abs cycle"

boom, done

So much this. I did it the first time just the other day. The DBP I recently picked up had a really low and soft pedal. The Master Cyl was leaking a bit so it needed to be replaced. Now I did immediately get a big shot of air out of the LF which helped enough. However did the service bleed, then when that was done did a couple more w/o the pump running and another good shot of air came out that was obviously stuck in the ABS pump. Also got some that had been trapped in the RR portion of the ABS pump.

While replacing the master cyl I also swapped in the newer larger booster and the pedal is now nice high and firm just like my 05 P71.

Plus there is oh so much else you can do with ForScan, though what it can do with a Panther is no where near what you can do on newer vehicles.