CentralCoaster

I just bought a reman brake booster. The booster will hold a vacuum with no brake pedal, but as soon as I push the rod in, it looses vaccuum (measured at the check valve).

The worthless paperwork that came with it says:

"1. Vaccuum booster noise = improper push rod adjustment.
2. Excessive pedal effort = bad check valve, low vacuum, or bad booster."

I thought the vaccuum leak was from a bad diaphram or control valve. :confused: What does the push rod have to do with this noise?

Also, from the pic below, wouldn't a properly working booster still make a sucking sound, when the vaccuum behind the diaphram is filled to atmospheric pressure upon applying the brakes? This is normal operation I assume, but does this make a noise?



The booster that is on my car right now leaks when I first push on the pedal, or when I hold it very hard. Also with the car turned off, it does the same thing as the reman unit I just bought: it holds vaccuum (check valve works), but loses vaccuum when I touch the brake pedal.

Is this replacement unit working properly, or are both units bad?

Stupid Autozone. The people who 'inspect' these parts should stamp their home phone number on them.

Paul in Warren

I have to believe that the replacement unit you received does not have an adjustable brake pedal rod - so line 1 is a joke. :banghead:
The fact that you are reading a "loss of vacuum" at the check valve during testing is a bit lacking in info as this is how a good booster would respond. While hitting the brakes, engine vacuum would be demanded to continue the assist fuction and could cause a "loss of vacuum" as read by a gauge. Let's assume that you have installed a replacement vac booster and are still experiencing "the same problem". One of two things may be an issue here:
-vac supply to booster is suspect
-junk reman booster was built on a monday or a friday? :banghead:

This might sound ridiculous (?) but it really works to help rule out the issues (!); in a "driveway scenario" you could pull up a known "good vehicle", hook up to its power brake supply vac hose with a long length of vac hose (and vice versa) and see if your problems change in any way...

Keep us posted!

PeteL

I think you have a bad rebuilt booster.

I never buy rebuilt brake parts, my life is worth more then a couple of bucks.

But, for less than you might think your can:

Return the POS to Autozone as defective

Buy a brand new GM booster from Jeff Koop (18carfan)

Live a happy life with good parts.

The GM booster comes set, however you may need to adjust in or out a little - if you want the brake pedal just right. The adjustment is very simple.

Good Luck

Pete

gtsyellow

sounds like a bad rebuild, that rod is supose to slide back and forth.

CentralCoaster

I think I know what you're getting at, as the volume decreases, with a constant amount of air in there (with hand pump attached, not plenum), so the pressure increases, therefore less vaccuum. But as soon as I push the rod in a little, I lose all vacuum instantly. The booster on my car does the same thing.

Looking at the pic, there's no way to get from 'at rest' to 'applied' without both the vacuum control valve and air valve being open at the same time. It looks like it'd happen when the pedal is first applied, and cause a vacuum leak. Is this supposed to happen? If the valves overlapped, that is, they were both closed for an instant, the engine would never be able to pull a vacuum in the 'pedal side' of the booster.

Does this make sense? Still not sure if it's supposed to work this way or not, it doesn't seem right. Maybe I got screwed... maybe I didn't, but at the least, I learn something new. :thumbs:

gtsyellow

the big question...do your brakes work without pushing REALLY hard?

CentralCoaster

Yeah, to get to a full and complete stop, they take quite a bit of effort. The car will also stall if I slam on the brakes in cold weather. The booster is definitely bad.

Just wanna be sure I know how its supposed to work before I put another bad one on the car. :crazy:

I think I've got a rain cloud over my head.

new water pump = leaks
new master cylinder = leaks
new shifter boot = doesn't fit
new shifter links = don't fit
new hood emblem = defective paint
new mirror wind deflectors = don't fit
new stereo din adapter = fits wayy crooked
reman brakebooster = bad diaphram?
:cuss

This covers the past 6 months of purchases for my cars. I think there was one or two things that actually did work... like a thermostat :rolleyes: and a battery.

gtsyellow

sorry about your luck man, i posted in c4 parts forsale, hijack my post & buy one of the units guys replied to me about. a couple people mentioned working GM ones for $100 shipped

CentralCoaster

I wasn't gonna tell anyone, but this is for my Ford actually. :bb I already fixed the brakes on my vette. The basics are the same, and this is the best place for discussion IMO. I hope the mods don't get mad. :leaving: What if I said that the brakes on my Corvette Part Retriever were bad. Does that count? :p:

ittlfly

Parts are parts and brakes are brakes. Whether on GM or Blue Oval, the PRINCIPALS are the same. You got a bad booster...lesson learned...go buy the OEM replacment. :D

gtsyellow

true there, OEM ford is very high quality. a good deal of us run there injectors just for that reason. that's just sad a rebuilt booster leaked right out of the box. kinda funny though, around here i have noticed some parts stores sell pretty decent rebuilds and some are JUNK !!!!!!!!

Maxx

Other than the fact that the vehicle in question is a FORD and therefore suspect; I stopped going to Auotzone for ANYTHING years ago...I've bought alternators,starters, a waterpump and other small stuff from them. :banghead: The only thing I learned it that the term "Lifetime Warrantee" means you're gonna' spend you're lifetime replacing their parts! Heck...I even had a pair of AZ windshield wipers last all of 2 rainstorms... :mad . Life is short, time is money, buy good parts!

Chris

CentralCoaster

It doesn't matter where you shop, it's the brand name that's important. I've also gotten faulty parts from the catalog companies and Checker/Kragen, Napa, etc... Do you think the stores inspect and test each part? Hell no... and they don't manufacture them either. It's companies like GP Sorenson and A1 Cardone pumping out crappy parts by the minute. If it was more profitable to put some quality control to these parts, I'm sure they would do it. But, in my experience, paying some guy to place a little "inspected by #23" sticker is much cheaper.
:rant: