Anyone ever have to replace the brake booster?

[Zack]

I can't get a good pedal to save my life. It's right at the top when the car is off.
While driving if I pump the pedal 3 times it stops awesome. Otherwise the pedal will be soft.

I've honestly never had a bad brake booster on any car I've ever owned.
New MC, IDS bled, no air in the lines.
SMH!


EDIT: Just ordered an ABS delete manifold.

[Shaijack]

The older you get the softer it is.

[martyo]

Did you make sure it is not losing vacuum?

[Zack]

Did you make sure it is not losing vacuum?

Don't cars usually run rough when that happens?
21in at idle, goes up to 25 when I let off the gas

[martyo]

Don't cars usually run rough when that happens?
21in at idle, goes up to 25 when I let off the gas

Not always if the vacuum is bleeding down after stopping.

I had a brand new bypass blow apart on a disc conversion I did a few weeks ago and had a lousy pedal. Strange things happen.

EDIT: As I am typing this I am rethinking here. You say that the pedal is fading? I am starting to lean on the idea that the master may be bad. I had this happen on the DPB car that I sold to Brad Wells.

[mrjones]

I've replaced several over the years. On most, it's caused the car to run bad at idle or at least when the brake was depressed. I have had one old Ford truck that did not run bad with a bad booster. My current 77 Ford pu has a bad booster and I'm about to replace it. It's idling funny and has a weak pedal too.

[Zack]

Not always if the vacuum is bleeding down after stopping.

I had a brand new bypass blow apart on a disc conversion I did a few weeks ago and had a lousy pedal. Strange things happen.

EDIT: As I am typing this I am rethinking here. You say that the pedal is fading? I am starting to lean on the idea that the master may be bad. I had this happen on the DPB car that I sold to Brad Wells.

Brand new MC

Pedal is not fading, it's just mushy until I pump it 3 times

[Zack]

It's holding vacuum. I just pulled the check valve out after the car was off for 30 minutes.
It belched a bunch of air out

[ChiTownMaraud3r]

Probably still has air in it. Same thing was happening to my motorcycle. Kept bleeding it and improved.

[martyo]

It's holding vacuum. I just pulled the check valve out after the car was off for 30 minutes.
It belched a bunch of air out

Then it does not sound like the booster.


Probably still has air in it. Same thing was happening to my motorcycle. Kept bleeding it and improved.

That is my guess.

I would rebelled it.

Did you carefully bench bleed the master?

[John Nero]

change the brake fluid - brake fluid attracts water - had a crapping brake peddle - my shop replaced the fluid in the system and everything was great

[Zack]

I bled the hell out of the MC and I just flushed a gallon of fluid through all lined. I'm deleting the ABS

[8UWITH6]

If he did calipers and a master Im sure its got 100% new fluid in the system.

[ctrlraven]

Im curious as well cause I've changed all my brake components besides the abs unit and brake booster and I still have a low pedal. I get a firm pedal after a few quick pumps.

Are the bleeders valves at the top or bottom of the caliper? There was a thread years ago about the stock calipers could be mounted on the wrong side which would leave the bleeder vavle sitting on the top side and could cause air in the line.

[Zack]

Im curious as well cause I've changed all my brake components besides the abs unit and brake booster and I still have a low pedal. I get a firm pedal after a few quick pumps.

Are the bleeders valves at the top or bottom of the caliper? There was a thread years ago about the stock calipers could be mounted on the wrong side which would leave the bleeder vavle sitting on the top side and could cause air in the line.

Wut

56789

[Mike M]

Bleeders have to be at the highest point.

[TooManyFords]

I replaced mine with a hydroboost out of a mustang. No vacuum lines. Best damn brakes ever. Almost a bolt-in.

[martyo]

I replaced mine with a hydroboost out of a mustang. No vacuum lines. Best damn brakes ever. Almost a bolt-in.

We do hydroboost conversions all the time. Great set up.

[ctrlraven]

Wut

56789
See below

Ok... problem with brakes FINALLY solved...
It had been to 3 different shops & finally a ford dealer found the problem after 2weeks of work...
They much much like myself & other bleed the brakes (properly) manually & via the ford system. Brakes worked fine till next morning then squishy pedal again... The ABS electronic were sent out & rebuilt & the master brake cylinder was changed 3 times...
Eventually we found that the brake caliper had been installed upside down & poss on wrong side(s)... this allowed air to either leak in or an air bubble to get trapped... the situation is now corrected...
FYI to others her. even the dealership mechanics didn't think it was possible to install the brake caliper in wrong location... but apparently it is... & u will never be able to get/keep air out of brake system...

Bleeders have to be at the highest point.
The only reason why I even brought it up is the fact when I had my front calipers replaced the mechanic put them on the wrong sides (driver is on passenger and vice versa) and the bleeder is at the bottom now. I plan on correcting this in a few weeks.

[yjmud]

^^^^^huh the bleeder is on the top

[ctrlraven]

^^^^^huh the bleeder is on the top
It's been a long morning already, I was thinking of something else. lol

[Zack]

Just ordered the ABS delete manifold.

I'm tired of complicated stuff....going back to old school on as many things possible. :beer: :banana2:

[martyo]

Just ordered the ABS delete manifold.

I'm tired of complicated stuff....going back to old school on as many things possible. :beer: :banana2:

Does that mean you will be logging off the internet? :flamer:

The internet is newer school than ABS.

[ChiTownMaraud3r]

Does that mean you will be logging off the internet? :flamer:

The internet is newer school than ABS.

The old school way would be Zack unwillingly logging off mm.net. :flamer:

[Zack]

The old school way would be Zack unwillingly logging off mm.net. :flamer:

THIS.


LMAO!!!1

[tbone]

My problem with soft pedal went away when I snipped an inch of the vacuum line off at the black plastic box near the cruise control servo.

When I reconditioned my brakes I did the all the calipers, lines, master, booster, rotors and pads. Had the anti lock module opened and bled too. The brakes could still be more powerful as we all know.

[Logizyme]

While driving if I pump the pedal 3 times it stops awesome. Otherwise the pedal will be soft.

This is telling you that the booster is working exactly as it should. This is exactly the kind of test I do to make sure vacuum boosters are working properly, if this is the result, then the booster is working.

Agian, how many miles have you put on the car? What kind of pads did you put on?

Friction on metal brake systems do not operate on the friction actually grabbing the metal rotor, they operate from the friction material imprinting itself on the iron rotor, then using friction on friction to slow the car, you can't really see it but a fresh rotor/pad will give a low-somewhat spongy pedal until the friction is imprited on the rotor.

When replacing or machining rotors the friction material that was previously imprinted on the rotors is gone, or when switching pad material formulas, the imprited friction on the rotor will need to be broken in. The vast majority of break in(90% ish) will take place in the first 10 miles and should be done by the technician replacing the brakes. The addtional 10% of break in will occur during the next 500-1000 miles. Getting the brakes nice and hot by doing long consistant stops will promote proper pad/rotor break in(lol brake in). Avoiding panic stops and avoiding coming to a complete stop will help to prevent uneven break in that could cause premature warping/pulseation. Generally 10-20 cycles of 50mph to 20mph and back to 50mph will complete this initial break in.

Also certain formulas of brake pad can give a lower brake pedal feel than others, particularly premium ceramics. They give a more luxurious pedal feel, than can be mistaken for air in the hydraulic system. They can give a much longer pedal travel with less initial "bite", but as the pedal travel increases they tend to have very good braking upon the far pedal travel. Also ceramic pads tend to have less grab when their cold. So especially in the morning or if you've been crusing without the brakes for a while, the first few pedal applications may feel even lower than normal until the friction and rotor warm up.

So before you go messing with the hydraulic or booster systems, give the car a good proper break in, and if the pedal is still not to your satisfaction try a semi-metallic brake pad, which will give a more consistant, high pedal feel, but agian, dont forget to break in your new brake pads.

Also in the installation pictures your calipers appear to be right side up, and if you didnt catch an upside down caliper yourself, pretty sure the dealer tech doing the IDS bleed would have caught it.

[Zack]

This is telling you that the booster is working exactly as it should. This is exactly the kind of test I do to make sure vacuum boosters are working properly, if this is the result, then the booster is working.

Agian, how many miles have you put on the car? What kind of pads did you put on?

Friction on metal brake systems do not operate on the friction actually grabbing the metal rotor, they operate from the friction material imprinting itself on the iron rotor, then using friction on friction to slow the car, you can't really see it but a fresh rotor/pad will give a low-somewhat spongy pedal until the friction is imprited on the rotor.

When replacing or machining rotors the friction material that was previously imprinted on the rotors is gone, or when switching pad material formulas, the imprited friction on the rotor will need to be broken in. The vast majority of break in(90% ish) will take place in the first 10 miles and should be done by the technician replacing the brakes. The addtional 10% of break in will occur during the next 500-1000 miles. Getting the brakes nice and hot by doing long consistant stops will promote proper pad/rotor break in(lol brake in). Avoiding panic stops and avoiding coming to a complete stop will help to prevent uneven break in that could cause premature warping/pulseation. Generally 10-20 cycles of 50mph to 20mph and back to 50mph will complete this initial break in.

Also certain formulas of brake pad can give a lower brake pedal feel than others, particularly premium ceramics. They give a more luxurious pedal feel, than can be mistaken for air in the hydraulic system. They can give a much longer pedal travel with less initial "bite", but as the pedal travel increases they tend to have very good braking upon the far pedal travel. Also ceramic pads tend to have less grab when their cold. So especially in the morning or if you've been crusing without the brakes for a while, the first few pedal applications may feel even lower than normal until the friction and rotor warm up.

So before you go messing with the hydraulic or booster systems, give the car a good proper break in, and if the pedal is still not to your satisfaction try a semi-metallic brake pad, which will give a more consistant, high pedal feel, but agian, dont forget to break in your new brake pads.

Also in the installation pictures your calipers appear to be right side up, and if you didnt catch an upside down caliper yourself, pretty sure the dealer tech doing the IDS bleed would have caught it.

I bought the car 45k miles ago and have 3 different brake setups installed. The pedal has never been right.

[Marauderjack]

Just ordered the ABS delete manifold.

I'm tired of complicated stuff....going back to old school on as many things possible. :beer: :banana2:

ABS pulsing can get you into a crash test demo too......extended stopping distance straight into a car in front of ya!!:mad2:

I'll be interested in the details of the ABS delete and how you get the PCM to cooperate!!:D

[Zack]

ABS pulsing can get you into a crash test demo too......extended stopping distance straight into a car in front of ya!!:mad2:

I'll be interested in the details of the ABS delete and how you get the PCM to cooperate!!:D

The PCM will send a signal to something that isn't there....and nothing will happen.

[Logizyme]

Sounds like you want a brake booster delete.

[Zack]

Sounds like you want a brake booster delete.

Lol wut????

[lji372]

Man up, go manual :banana2:

[martyo]

Man up, go manual :banana2:

You think he can push manual brakes with those skinny chicken legs??? :confused:

[lji372]

You think he can push manual brakes with those skinny chicken legs??? :confused:

He ben workin out, u diint c him climb dat wall in loosville :lol:

[martyo]

He been workin out, u diint c him climb dat wall in loosville :lol:

Spiderman sheet right there!

[J-MAN]

He ben workin out, u diint c him climb dat wall in loosville :lol:

Just trying to get to room 412!

[vegasmarauder]

When the 300A was new and at 8K miles it started getting a low pedal that had to be pumped up or you had to stop hard and activate the ABS system. They had to replace the ABS valve and that cured the problem.

The post about the new pads not conforming to the rotor until broken in is correct. Especially if the rotors are not turned but are just sanded down or new pads put on un-turned rotors. Since the pad is held further out from the surface of the rotor it takes more fluid (and pedal movement) to push them firm aganist the rotor surface, hence the low pedal.

[massacre]

I'll be interested in the details of the ABS delete and how you get the PCM to cooperate!!:D

The ABS runs off a completely different computer system than the PCM.
Just FYI.

[ChiTownMaraud3r]

Delete the brakes.

Real men don't use brakes anyways. Just drift around stuff.

[Marauder_Santa]

I replaced master cylinder a few years ago.

[Logizyme]

Lol wut????

Well you say that when the car is off or when you pump the brakes several times you get a pedal you like. Otherwise its soft. Well that's what a brake booster does, when the pedal is pumped three times the booster exhausts its vacuum and looses boost. When the car is not running the booster is not boosting. So it sounds like you like the pedal when the booster is not boosting. Also your getting rid of ABS, a system which does nothing but improve braking performance, so it seemed reasonable to suggest a booster delete since you like the pedal better.