Car dies when brake applied - the booster?

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  #1  
Old 01-02-06, 02:24 PM
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Car dies when brake applied - the booster?

I had my back brakes done and now my car runs horribly if at all and if you apply the brake, the engine dies. Friends doing this work. They bled the lines, front and back. No good. Changed out the master cylinder. Didn't help. They areundefined saying it has to be the booster since it has a connection to the engine. I am pretty irritated with this situation. Hope you can help me.

Thank you!
 
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  #2  
Old 01-02-06, 03:16 PM
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Try removeing the booster tube, and see if it does it, just dont drive to fast because its going to be really hard to push the brake.
 

Last edited by mattison; 01-15-06 at 02:57 AM. Reason: No need to quote entire post above.
  #3  
Old 01-02-06, 04:33 PM
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Hi!

This sounds like a temporary fix. What would be a permanent one?

Thank you!
 
  #4  
Old 01-02-06, 04:34 PM
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booster tube

Sounds like a booster to me you can take the tube off but make sure you plug the line or you will have a massive vacaccum leak.BE SAFE
 
  #5  
Old 01-02-06, 04:36 PM
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Thank you!

So, if we replace the booster, we should be okay? Would you mind explaining to me, yeah, I am a girl, what the booster is?

Thank you!
 
  #6  
Old 01-02-06, 04:40 PM
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not a fix

The removal of the tube is not a fix it is a troubleshooting trick.The booster is that black round thing the tube plugs into and your master cyliner sits on.
Do not drive around with the tube un hooked as you will have no power brakes.
 
  #7  
Old 01-02-06, 04:45 PM
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what is a booster you ask

The brake power booster is an aid that uses engine vacuumm so you do not have to push as hard to stop.It also uses a lot of air.It is a diaphram and it could get a hole in it I got this off the net read it you will understand better:

The power brake booster is mounted on the firewall directly behind the master cylinder and, along with the master cylinder, is directly connected with the brake pedal. Its purpose is to amplify the available foot pressure applied to the brake pedal so that the amount of foot pressure required to stop even the largest vehicle is minimal. Power for the booster comes from engine vacuum. The automobile engine produces vacuum as a by-product of normal operation and is freely available for use in powering accessories such as the power brake booster. Vacuum enters the booster through a check valve on the booster. The check valve is connected to the engine with a rubber hose and acts as a one-way valve that allows vacuum to enter the booster but does not let it escape. The booster is an empty shell that is divided into two chambers by a rubber diaphragm. There is a valve in the diaphragm that remains open while your foot is off the brake pedal so that vacuum is allowed to fill both chambers. When you step on the brake pedal, the valve in the diaphragm closes, separating the two chambers and another valve opens to allow air in the chamber on the brake pedal side. This is what provides the power assist. Power boosters are very reliable and cause few problems of their own, however, other things can contribute to a loss of power assist. In order to have power assist, the engine must be running. If the engine stalls or shuts off while you are driving, you will have a small reserve of power assist for two or three pedal applications but, after that, the brakes will be extremely hard to apply and you must put as much pressure as you can to bring the vehicle to a stop.
 

Last edited by michael van; 01-02-06 at 04:49 PM. Reason: add
  #8  
Old 01-02-06, 04:49 PM
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Thank you very much, Michael. It will be replaced in the next few days when it comes in.

Shannon
 
  #9  
Old 01-02-06, 04:51 PM
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OK good

OK good luck have fun
 
  #10  
Old 01-06-06, 01:26 PM
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Why the Booster failed

Hiya!

Would changing out the back brakes and bleeding the brake lines cause the booster to fail? I mean, I had no problem until they changed out my back brakes. Yes, they found leaking wheel cylinders and the back brakes had locked up, but I had no other problem other than my car breaking on its own. I think it is a very big coincidence that the booster failed during this brake job. What do you think? The repair folks are friends that are backyard mechanics and I do not think they deliberately did anything wrong.

(Did get the booster and master cylinder replaced and that fixed the problem.)

Thank you!
 
  #11  
Old 01-06-06, 02:09 PM
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no

I really dont think replacing the parts you said caused the booster to fail.However it is possible when the master cyl was replaced it could have been damaged but it is a remote possibility.
 
  #12  
Old 01-14-06, 03:56 PM
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adjust master cylinder rod

Hi!

What does "adjust master cylinder rod" mean to you?

Thank you!

Shannon
 
  #13  
Old 01-14-06, 04:49 PM
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this should answer your question

All internal push rods are pre-adjusted at the factory.

Due to some master cylinders having different piston depths, the following instructions should be used to make sure that all internal push rod adjustments are correct.

Install master cylinder on the booster mounting studs without the mounting nuts. If no resistance occurs, bolt the master cylinder to the booster. If the master cylinder cannot be placed flush against the booster without the internal push rod in the booster moving the master cylinder pistons, please proceed to step two.

If resistance occurs, remove the master cylinder from the booster. Hold the internal push rod at the knurled area (see diagram below) and turn the adjustment screw at the end of the rod clockwise (to lower the overall length of the rod) ONE COMPLETE TURN ONLY. Then repeat step 1. Continue this process until no resistance occurs.

Note - that some boosters do not have adjustment screws on the internal push rod. If the master cylinder will not fit flush against the booster, remove the internal push rod from the old unit and exchange it with the rod in the remanufactured unit. The master cylinder should then fit properly against the booster.

After completing step 1, and the proper bleeding procedures, your pedal should be at the top. If your pedal travels too far when applied, or feels spongy, it could be the result of the internal push rod being adjusted IN to far. This could also be caused by air in the hydraulic system, so the entire hydraulic system should be checked. At this time, go back to step two, but turn the screw at the end of the rod counterclockwise one complete turn, then repeat step one.
 
  #14  
Old 01-14-06, 05:27 PM
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Hi!

Thank you. They said they adjusted the pedal from under the dashboard. Was wondering if a throttle adjustment would be from under the dashboard or from under the hood? Know each car can be different. Throttle adjustment = pedal adjustment?

And, not to be rude, what is your experience level with car repair?

Thank you much!!!

Shannon
 
  #15  
Old 01-14-06, 06:07 PM
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Cars experience

I was the kid on the block that had to have a faster car then what the car people put out I would replace stock carbs with webber carbs and headers and remove emmision equipment before it became illegal to tamper with it.This was in the early 70s.
I did not go into the automotive field but have been a aircraft maintenance tech for 35 years.
Now days I am just getting to old to stand on my head under a dash so I try to avoid it as much as I can and besides I have a little more money then when I was 17.
I still like to tinker with cars but do not get involved with the actual work part just the advice part.(I leave that for the young kids).Cars these days are very complex as compared to early 60s cars but the basics are the same nothing but a air pump (engine).Brakes are the same except now they have speed sensors,computers, and wires for antilock.
 
  #16  
Old 01-14-06, 07:00 PM
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Gosh! I've never had the nerve to ask my physician to see his medical degree, lol ! And I'm from the Show Me state. For what it is worth, Shannon, Michael Van has been here on this forum for a long time, and has solid advice for all that listen. Good luck with your repair job and it's good to hear that friends still help friends with their car repair.
 
  #17  
Old 01-14-06, 10:18 PM
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Hiya, ya'll!

Guess I totally offended Lugnut, and yes, know where your Doctor came from and his credentials. This is the year 2006 where it is okay to ask questions and challenge folks. Do not follow blindly. Gee. Lugnut has a lot to learn about the real world. If it is important, wake up. Be proactive. Take charge and act. I do not trust anyone. No one should. We are human beings, the lowest level of life forms. Lugnut must be in his 20's.

Shannon
 
  #18  
Old 01-15-06, 02:10 AM
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thanks lug

Thanks Lug you try do do good as you can and help folks sometimes you have to mind read but it is all good We just keep on helping.
 
  #19  
Old 01-16-06, 06:01 AM
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We were all young once. Happy motoring IDDYMEANDMY.
 
  #20  
Old 12-05-07, 01:47 AM
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same problem (car stalls) :((

hi michael, lugnut and iddymeandmy.
im new to the forum and hoping to find a fix to my prob.

my car also dies when heavy brake applied suddenly.
i am also having problem with my carb.
my car stalls on idle and while driving.
does this have to do with each other?
maybe my car stalls because i have problem
with my brake system or my car dies when
brake applied because of my fuel system (carb) problem?

about my car stalling,
i think i've done everthing i know and every
suggestions from many forums to fix it but still no luck.

i observed my carb w/o the air cleaner and found out
that the car dies because the continuous flow of fuel
on the venturi will suddenly stop. so there will be no
air fuel mixture that would go to the engine.

what could be the problem?
i had my carb cleaned more than 3 times now.
cleaned it assembled and disassembled.
adjusted idle speed and idle mixture,
inspected all vacuum for any leaks but still no luck.

it runs fine with the a/c on since a/c is increasing idle speed.
but it would cost me a lot more fuel setting to to a high idle
and also stress to the engine.

please i badly need help.
I almost had accident because of these problems.

thanks in advance!
 
  #21  
Old 12-05-07, 02:12 AM
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more info please

More info like year and make of car engine size would be of great help. Cars of the past like late 70s used a lot of vacumm lines were as later model cars use electrical wires to operate valves etc.
 
  #22  
Old 12-05-07, 05:08 AM
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car info

i came back coz i forgot to include my car info
and i have a reply already.

thanks for the quick response michael...

these is what i know about my car.

Hyundai - Stellar Prima 2.0L year 1987, 4 cylinder
Rear wheel drive. Front disc brake and drum on the rear.
Change to manual trans. from original automatic.
I think the carb is also not original coz i've tried a repair kit
only to find out that it would not match.

I also forgot to ask if it could be the fuel pump that's
why my car stall? But the problem is I've been
observing my float bowl during idle and the float level
is correct and stable. So can i conclude that fuel pump
is not the problem or it could still be? btw, my fuel pump
is mechanical. not sure if it's the right term. it's attach to
the right side of the engine facing the car between
the intake manifold.

About my brake stalling prob..
I think I have a problem with my brake booster.
Is there other way to know if brake booster is really broke?
aside from driving w/o the vacuum. I've checked the "check valve" from booster hose to engine vacuum and i think it's ok. tried to blow on both side and the other didn't pass through.

As of now, I'm not changing anything yet coz i want to narrow things down to be sure that i will spend money on the real problem unlike some mechanics that even changing all parts to new, still the prob stays.

thanks again in advance!
 
  #23  
Old 12-05-07, 03:15 PM
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a booster check

To check the booster start the car and shut it off with foot off the brakes.
After shutdown apply the brakes you should get 3-4 good aplications of brake and after that pedal should get hard.
Also after all vacumm is bled off with foot on petal pushing start car pedal should go down.
 
  #24  
Old 12-06-07, 01:00 AM
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booster ok?

i've done what you told and it did exactly.
so is my booster ok?

does this mean that my real prob is the
fuel system? carb?

about my car stalling..
on my previous post about fuel pump,
does having stable fuel level in the
float bowl means fuel pump is good?

also, i've tested my fuel cut solenoid and
it's also working. is it possible that while
i'm driving or idle, that i may be having
power loss on the solenoid which may
cause to close the fuel flow?

thanks again!
 
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