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[RESOLVED] probable bad power brake booster, need confirmation


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wsdmatty
Novice

Aug 5, 2019, 10:01 PM

Post #1 of 14 (1102 views)
post icon [RESOLVED] probable bad power brake booster, need confirmation Sign In

I have a 1998 Ford Contour that I am fairly certain needs a new power brake booster. But before I go out and waste time/money replacing it, I'd like confirmation that I'm properly diagnosing the issue.

Issue started with brake pedal requiring more force than normal. It occurred infrequently at first and I didn't really pay much attention. One night I came in too fast for a stop sign, slammed the brakes and the car stalled. Now I'm paying attention. The next week or two I noticed brake pedal becoming more difficult, sometimes nice and easy, sometimes hard as a rock.

In the past few weeks, the car has been stalling when I come to a stop. I hear air hissing under my dash when I press the brake pedal, which I never heard before. When I am parked, and press the brakes, the RPMs drop and the car idles real rough, occasionally struggling to stay running. CEL is on, I forget the code number but the description was "Lean conditions exist Bank 1/Bank 2".

Searched online, diagnosed it as a bad brake booster. Disconnected vacuum line from brake booster and plugged it, and the rough idle/stalling stopped. Had to reconnect the brake booster because the brakes were almost impossible to apply.

I'm fairly confident in my diagnosis of a failing brake booster. I believe the diaphragm in the brake booster has a hole/tore/cracked/whatever and that is the cause of the vacuum leak, lean engine condition, stalling and hissing while pressing brake pedal. I plan on going to a junkyard and finding a cheap-o replacement (or two..) but before I waste my only day off this week browsing a junkyard, I'd like to know that I'm not completely off base with my assessment.

Any feedback, alternatives, or pointing out errors in my thinking would be greatly appreciated. Thank you.


(This post was edited by wsdmatty on Aug 7, 2019, 12:44 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 6, 2019, 2:28 AM

Post #2 of 14 (1084 views)
Re: probable bad power brake booster, need confirmation Sign In

The hose connection could be bad and cause same issues just be sure.
The "boost" should hold overnight amount of time and give you a boost without running engine means the booster itself or check valve isn't holding. Start up feel fool sink a bit.
Option for repair may now include send that one out (wait time) and get it back or check on NEW or a swap job not thrilled with used this old just the diaphragm is that old too inside it.
Check, check on pricing for new I doubt now it's that much and a pest if you go get your own.
BTW for dirt cheap you can rig a vacuum pump that's hand held to make one work, off car or in junked car and know it works before wasting time. Used just may be fine if you find one just done on a fresh wreck or other reason car was junked.


Hey - it's important, everything is don't cheap out fixing that hose and valve new no used stuff plus a grommet alone could be the whole problem - another thing to check now but new if you keep messing with those,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 6, 2019, 4:21 AM

Post #3 of 14 (1081 views)
Re: probable bad power brake booster, need confirmation Sign In

Yes, it sounds like you are on the right track with a bad booster.

The hissing when stepping on the brake is pretty good confirmation and rules out a hose leak.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



wsdmatty
Novice

Aug 6, 2019, 7:18 AM

Post #4 of 14 (1069 views)
Re: probable bad power brake booster, need confirmation Sign In

I am doubtful that it is the vacuum hose. I disconnected the entire hose from the brake booster and capped the end, and it resolved the stalling / rough idle. The booster will hold a vacuum when the brake pedal isn't applied, but when the pedal is applied even slightly there's air hissing and the 'boost' is gone.

I'm not really thrilled about taking a used brake booster either. I understand the concerns, especially in a car that's 20 years old. The diaphragm in the one i get is probably as brittle and tired as the one I'm replacing. But the cheapest new replacement part I found was $80 and I just don't have that kind of money to spend on my car right now. I've already put close to $2k into a car that cost me $450 back in april and I'm not trying to put a single dollar more than I have to into the car.

My plan is to limp it along long enough to save up to buy another one. This car has some serious issues that will eventually render it inoperable. Engine wiring harness insulation is crumbling and in some places, bare wires are sticking out. Torque Converter slips and throws CEL codes on occasion.. So best case scenario I'm looking at a wire moving around and grounding out, worst case I'm looking at a trashed transmission. Wiring harness in the engine isn't expensive, but the labor to have it replaced is more than the car is worth. And I'm not replacing the transmission.

If swapping out one tired brake booster for another gets me another 2 months, I'd consider it a win.

Thank you both for the responses. I'll update after I do the repair, let you know how it went.

Wish me luck.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 6, 2019, 7:44 AM

Post #5 of 14 (1067 views)
Re: probable bad power brake booster, need confirmation Sign In

I don't need to read more than $80 you found new is trouble for you! That's the cost of shipping never mind the part. If that's too much for BRAKES begs the question should you be driving this at all?
You symptoms are almost without a mistake but re-assert just the rubber grommet on metal is both hard to find and barbed check valve there just removing it can wreck one. That 2 cent (more of course) item may hold vacuum or not intermittently with tears in it or hold full vacuum but not partial? It goes every time you mess with a booster or risking it.
Back to the bucks. $80 is dirt. Try an accident because you didn't fix this!!!!


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 6, 2019, 7:55 AM

Post #6 of 14 (1062 views)
Re: probable bad power brake booster, need confirmation Sign In

I understand your not wanting to or can't afford to put money into this car BUT we are talking about brakes here.

I agree with Tom here. You definitely should not be driving the car this way. If you cause an accident that severely injures or kills someone, your life will be over also.

Park this thing until you can fix the brakes right. $80 now or millions in a law suit or even jail time later.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



wsdmatty
Novice

Aug 6, 2019, 9:34 AM

Post #7 of 14 (1057 views)
Re: probable bad power brake booster, need confirmation Sign In

I definitely SHOULDN'T be driving this car. But I have no options.

I appreciate the concern, and the advice.

I'm doing the best that I can with what I have. Thank you very much for the advice and possible alternatives to my issue. I'll be hitching a ride with my cousin to the junkyard today to try to find replacement parts that look in good condition. Here's hoping I can get what I need and it fixes the problem.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 6, 2019, 9:54 AM

Post #8 of 14 (1052 views)
Re: probable bad power brake booster, need confirmation Sign In

I dare say we all understand $$ issues. If the junkyard is and I do suggest a pick your own type place with lots of these look at them all find one already new or newer perhaps some sticker on it?
I re-assert that rubber seal at a metal booster I call a grommet. That try to take a few used ones or you'll wait for one new unless super common. Check valve is plastic take those too used they bust just from being in heat under hoods.
Hose: New only marked for holding vacuum also PCV marked on it or ask that it is plus has to be oil tolerant is special hose. No room for mistakes.
Other - sorry to make a book it's worth it! If oil is getting into booster you have other engine problems it will just fail again if so, say so that could be a game changer for this car or another fix?


Tom



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 6, 2019, 10:53 AM

Post #9 of 14 (1050 views)
Re: probable bad power brake booster, need confirmation Sign In


Quote
I definitely SHOULDN'T be driving this car. But I have no options.


If you think a judge or a police officer is going to accept that answer after you cause someone harm, you are in for a rude awakening.

That's the sort of decision that can get you jail time.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 6, 2019, 12:30 PM

Post #10 of 14 (1046 views)
Re: probable bad power brake booster, need confirmation Sign In

Hope OP meant still getting rides from a cousin so said! This car is DOWN/GROUNDED over this problem. There are surprises nobody knows of, this isn't one of those it's KNOWN,


T


wsdmatty
Novice

Aug 6, 2019, 6:30 PM

Post #11 of 14 (1035 views)
Re: probable bad power brake booster, need confirmation Sign In

I came to this forum looking for advice and help, not a lecture.

I'm aware of the risks I was taking and I'm well aware of the consequences as only someone who's actually BEEN to prison can be. Which is why I came to this forum, trying to confirm my diagnosis, so I could try to fix the issue as quickly as possible.

My visit to the junkyard was fruitful. I found a power brake booster on a mercury cougar that was a comparable part and interchangeable. The cougar was a 01 or 02 ( i don't remember), the booster looked in good condition, no fluid leaking from the master cylinder. Booster holds a vacuum and doesn't leak. I also pulled the entire vacuum line with the check valve for good measure. I didn't test the check valve to see if it works properly.. I literally just thought of that... But I didn't pay any extra for it so it's a wash either way.

My car is currently sitting in my driveway with the repair half-finished. It got dark on me and I didn't think to park under the garage lights before I disconnected the brake pedal and lines. -.-

So I'm going to be getting up early tomorrow to finish the repair. This booster is a sonofabitch to get out.. There's no room to move around without removing half the engine compartment. But I got the old booster unbolted and disconnected.. tomorrows plan is to rip the bitch out and swap out the new one. Hopefully I'll be done before I have to go to work at 5...


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 6, 2019, 11:30 PM

Post #12 of 14 (1017 views)
Re: probable bad power brake booster, need confirmation Sign In

OK - Just good luck with the used part and understand the lack of light it's plain easier to do outside for lots of things and it runs out. Trust it will work as intended and be done with this,


Tom



wsdmatty
Novice

Aug 7, 2019, 12:44 PM

Post #13 of 14 (1001 views)
Re: probable bad power brake booster, need confirmation Sign In

Problem is resolved. Thank you both for your time and expertise in this matter.

Got the old booster out this morning, put the new one in. The new booster wasn't the exact same model, and I believe there may be a difference in the pedal rod length... Either that or I botched the installation. But the brake pedal does not return as far as it did before.. I know this because the brake light switch isn't being pressed and my brake lights were staying on.

I just found this video Link deleted ...........not allowed
I did not know the brake light switch self adjusted in such a way.. so i guess once it stops raining i'll fix that. (I currently have a washer taped to the brake pedal to bridge the gap that was there... Not a ideal fix xD)

AAANNNDDD to add icing to the Sh!t sandwich that was my day, While returning the air intake hose and air filter, i apparently ripped the rubber hose running from the Mass Airflow Sensor to the throttle. So I had to patch that. That part, I could not find ANYWHERE online. None of the stores or parts places I usually shop had anything like it listed online. I had to go to Advance Autoparts and show the guy the part and part number, and finally got an OEM part number to reference.. Apparently the only way to get this specific part is direct from Ford.

Anyway, just wanted to give you guys an update. Car is fixed, brakes are bled and working beautifully. New booster makes braking sssooo smooth. 100% night-and-day difference. The old booster must have been failing for some time because the car didn't brake this smoothly even when I bought it.

Took the old booster apart and confirmed the diaphragm was cracked in numerous places. Adding to that, as I think Tom may've pointed out.. the check valve was ALSO bad. Both the booster and the check valve were failing, so it's a good thing I grabbed the new check valve too.

I apologize for the longwinded post, but I'm finally sitting down after spending... about 6 hours outside, working on this. I'm just.. relieved.


(This post was edited by Hammer Time on Aug 7, 2019, 1:07 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 7, 2019, 1:08 PM

Post #14 of 14 (989 views)
Re: probable bad power brake booster, need confirmation Sign In

It's not over yet! That part has to be exact fit and pedal where it belongs - any model of anything. Why?
It's a master cylinder it's ultimately pushing harder for you thru boost of any kind. If it doesn't return fully the pressure is trapped in lines will burn up brakes, drag and worse as it warms up and brake fluid expands till you get zero brakes at all if you kept going. That's a risk not definite.


You have to take that one back out hope you have the old one bring it, paint on it showing it's yours and match it up exactly. There was a day of adjusting pushrods long gone like when most cars/trucks didn't have power assisted brakes at all and yes I was alive then too still kicking.


Be warned even if it feels fine it's not right if it did what you said. Take the time and now be ready for brakes to heat up and fail as a maybe over this. Can you drive it? C'mon sport we would have to say NO it's the open web.
Wheel or all wheels would be getting hot you might feel that in no time without hard use. Yes means test drive but only in the right places off and out of harm's way.


Not done yet sorry. It has to be the right one or some screwed up thing is lurking I just mentioned the one I'm used to,
Tom







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