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Discussion Starter #1
Hey guys... last night I parked the car in the driveway and all was right with the world. Went to go out this morning and all of a sudden I have no brake pedal... it goes to the floor. Thank goodness the car will still be able to stop or I would have ended up rolling out into main st. traffic (would not be a good thing). Anyway... I digress.... the fluid level is at max.. no evidence of it leaking anywhere. I figured it must be the master cylinder... does that sound about right to y'all? Any advice will be greatly appreciated...... Peace

As long as I am looking for advice I changed the spark plugs a few weeks ago and now my gas mileage seems to be worse than before the change??? Any clue what might have caused that to happen?
 

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Better rectify that brake situation before u worry about mileage. Does the auto have ABS? If so there could b air in that ABS system....expensive to deal with. However, if u have any brake pressure after repeated pumping there is an old shade tree mechanic trick that has saved me many dollars. Find an isolated dirt road. Drive the auto on that road about 20 miles an hour. With no one following you hit your brakes hard. Hard enough that the brake pedal shudders back and forth which is exactly what ABS brakes do to counter a skid. Doing this a couple r three times will "purge" the air from the ABS module and restore ur pedal pressure....if of course the problem is in the ABS module and not the master brake cylinder. Worked for me ...twice!
 

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Could be the brake booster.

Remember the brake booster has to transfer your pedal effort to the master cylinder. The internals of the booster can fail and cause an issue similar to this.

I would take the screws loose holding the master cylinder to the brake booster, separate them gently. And peek inside the booster. Helps to have someone push on the pedal while u do this. Careful, dont over extend the booster.
Basically, you push against the rod inside the booster while someone else pushes on the pedal. There should be no deviation in travel....if the pedal goes to the floor while your pushing into the booster, then for sure the booster is defective.
If it seems ok, then it could be the master cylinder especially if you werent leaking fluid and all the caliper seals and rear wheel cylinder seals are ok

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Discussion Starter #4
[/QUOTE]
Better rectify that brake situation before u worry about mileage. Does the auto have ABS? If so there could b air in that ABS system....expensive to deal with. However, if u have any brake pressure after repeated pumping there is an old shade tree mechanic trick that has saved me many dollars. Find an isolated dirt road. Drive the auto on that road about 20 miles an hour. With no one following you hit your brakes hard. Hard enough that the brake pedal shudders back and forth which is exactly what ABS brakes do to counter a skid. Doing this a couple r three times will "purge" the air from the ABS module and restore ur pedal pressure....if of course the problem is in the ABS module and not the master brake cylinder. Worked for me ...twice!
Could be the brake booster.

Remember the brake booster has to transfer your pedal effort to the master cylinder. The internals of the booster can fail and cause an issue similar to this.

I would take the screws loose holding the master cylinder to the brake booster, separate them gently. And peek inside the booster. Helps to have someone push on the pedal while u do this. Careful, dont over extend the booster.
Basically, you push against the rod inside the booster while someone else pushes on the pedal. There should be no deviation in travel....if the pedal goes to the floor while your pushing into the booster, then for sure the booster is defective.
If it seems ok, then it could be the master cylinder especially if you werent leaking fluid and all the caliper seals and rear wheel cylinder seals are ok

Sent from my SM-G975U using Tapatalk
Could either of these issues happen overnight.... all of a sudden.... seems like there should have been some type of sign that they were in the process of crapping out. As far as I remember the brakes were working just fine when I parked the car last night... anyway, I'll check the booster first cuz I can do that in my driveway..... then if needed I'll go find a dirt road somewhere. Thanks for the info guys.. it is appreciated........ Peace
 

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The fact that u noticed a sudden falling of the brake pedal pressure quite possibly could b a seal in the master brake booster failed....while air getting in the ABS would happen if u let the brake fluid get too low. The bad master brake seal would account for the no loss of fluid because the fluid is going back and forth around the bad part of the seal. If this is the case, there's still the majority of the seal doing it's thing so u should b able to pump up the brake pedal pressure.....but if the seal is bad the brake pedal pressure will quickly go down after pumping....go out to ur car and start pumping and report back.
 

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The brake pedal is mechanically linked to the master cylinder even if the booster fails. It'll make braking effort considerably greater, but the brakes will still work with a failed booster.

Have you pumped the brake pedal to see if you get a solid pedal? If so, then check the bleeder screws and rubber hoses for leaks or weeping, also on the ground for signs of brake fluid dripping.

With it happening overnight, you may have parked it at home just in time to avoid a deadly issue, or there could have been some kind of critter chewing on things.

Have you had any brake work or inspections done lately? If so, what was done and how long ago?
 

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The rod in the booster can break or get damaged. Seen that happen especially on older cars

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Discussion Starter #8
The fact that u noticed a sudden falling of the brake pedal pressure quite possibly could b a seal in the master brake booster failed....while air getting in the ABS would happen if u let the brake fluid get too low. The bad master brake seal would account for the no loss of fluid because the fluid is going back and forth around the bad part of the seal. If this is the case, there's still the majority of the seal doing it's thing so u should b able to pump up the brake pedal pressure.....but if the seal is bad the brake pedal pressure will quickly go down after pumping....go out to ur car and start pumping and report back.
Ok.... I went out and started the car backed all the way to the end of my driveway put 'er in drive went as fast as possible (twice) and slammed on the brakes. The anti lock system worked fine but the pedal still went to floor. So I got under the hood and now the fluid reservoir was empty. Did a walk around and noticed fluid on the ground next to the right rear tire so at least I know it isn't the booster or master cylinder. The car has drum brakes on the rear so I guess I have to pull off the tire and pull apart the brake drum to see where the leak is. I crawled under the car and I just can't see exactly what is leaking. I appreciate all you guys help. Thanks a million....

Peace
 

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Well I'll B DD was right by suspecting a leak somewhere...he's a smart man. Replacing the drum brake cylinder will b a mess. The reason is because the fluid mixing with the brake dust will make a dirty soup. So don't forget a can of brake cleaner and a couple of rags and check the runout on the brake drum also...a new one is fairly cheap. A new brake cylinder is cheap ....don't go for the cheaper rebuild kit .....you'll regret it! Also, I can't reiterate this enough.....do not let the fluid reservoir run out of fluid r you'll b dealing with air in the ABS for sure this time! Have fun on this nice Sunday.
 

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Well I'll B DD was right by suspecting a leak somewhere...he's a smart man. Replacing the drum brake cylinder will b a mess. The reason is because the fluid mixing with the brake dust will make a dirty soup. So don't forget a can of brake cleaner and a couple of rags and check the runout on the brake drum also...a new one is fairly cheap. A new brake cylinder is cheap ....don't go for the cheaper rebuild kit .....you'll regret it! Also, I can't reiterate this enough.....do not let the fluid reservoir run out of fluid r you'll b dealing with air in the ABS for sure this time! Have fun on this nice Sunday.
Thanks again and thanks to DD also.... you all enjoy today as well. I ended up taking the car to a repair shop I trust so I won't have to deal with the issue. I guess it is tough getting older. At 67 I just don't want to deal with this stuff anymore, 20 years ago it would be done already but hey.... it is what it is.... enjoy the holiday Dallam1.....Peace
 

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Bought all five of r kids a car but because funds r tight had to b old cars. Worked on them by myself and often. U haven't experienced purgatory till you've installed a clutch in a front wheel drive auto. At 70 years old that ain't fun! Glad we could help!
 

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Discussion Starter #12 (Edited)
Bought all five of r kids a car but because funds r tight had to b old cars. Worked on them by myself and often. U haven't experienced purgatory till you've installed a clutch in a front wheel drive auto. At 70 years old that ain't fun! Glad we could help!
so..... nothing can go smoothly... ended up replacing the master cylinder due to it going dry the seals were shot... not only that but the bleeder fitting on the right front caliper is rusted shut and can't be loosened and so is the right rear wheel cylinder bleeder so they both need to be replaced as well.... so what started as what I thought would be a section of brake line turns out to be a $300.00 fix.... go figure.... sometimes it just doesn't pay to get up in the morning......oh well.... spit happens....now to figure out why my mileage went from about 26 down to about 18 after replacing the "original" spark plugs that were really toasted after 98k miles (actually pretty low miles for a 17 year old car). So if anyone has a clue to problem #2 I'd be all ears.....Thanks in advance...

Peace
 

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Sounds like ur brake situation was a mess but to have it fixed for 300 bucks was not that bad. It would have cost me at least $150 and I would have had to go to the salvage yard and look for and pull parts then take several days installing them....and b tired and dirty afterwards. As for ur significantly lower mileage after installing new plugs. That's unusual because u could put nails in these modern engines and they still would get ok mileage....the ignitions r that powerful. Did u unplug a coolant sensor by mistake.....is the engine smooth....can u go to a parts store and ask them to run a code reader to check for "pending codes"? This is something that should b fairly easy to sort out.....more homework.
 

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When replacing spark plugs and certain other parts (VVT solenoids come to mind), the newer cars seem to be pretty finicky. Your 2002 might be throwing a tantrum until it gets what it wants.
 

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so..... nothing can go smoothly... ended up replacing the master cylinder due to it going dry the seals were shot... not only that but the bleeder fitting on the right front caliper is rusted shut and can't be loosened and so is the right rear wheel cylinder bleeder so they both need to be replaced as well.... so what started as what I thought would be a section of brake line turns out to be a $300.00 fix.... go figure.... sometimes it just doesn't pay to get up in the morning......oh well.... spit happens....now to figure out why my mileage went from about 26 down to about 18 after replacing the "original" spark plugs that were really toasted after 98k miles (actually pretty low miles for a 17 year old car). So if anyone has a clue to problem #2 I'd be all ears.....Thanks in advance...

Peace
1st plug replacement with 17 yr old wires....need I say more?

There is some gap sensitivity on GMs, though mostly on the later years. It likely that the wires need replaced, or that you ripped a wire removing the boot.

Did you do an OEM plug replacement or try something different?
 

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Discussion Starter #16
When replacing spark plugs and certain other parts (VVT solenoids come to mind), the newer cars seem to be pretty finicky. Your 2002 might be throwing a tantrum until it gets what it wants.
I used Champion plugs... not OE but it still runs super smooth, no hiccups, spits or misfires. I went to auto zone and had them run a code reader on it for shits and giggles and it threw a PO442 code (I think it was) which turns out is a purge valve (vapor can vent valve). They said this could be the issue but it seems to run fine. I bit the bullet and spent the 40 bucks but haven't had the chance to put it in yet. Maybe just coincidence but it seems to get worse the colder the weather is??? Could be my imagination too I guess.
 

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New vaper purge valve won't do much if anything to improve mileage. If a plug r wire was not right, the engine would not run smooth. I keep going back to a temp sensor issue....r maybe a bad O2 sensor. The point I'm getting at is a rich running engine might run fine (and not throw a code....unless it was way too rich) but the mileage would suffer. Pull a plug, if it's sooty it's rich but with these modern computer controlled engines the plug might not show sooty but still run a bit rich. The car needs to go back on a good (Snap-On comes to mind) scanner. A half way decent mechanic will pinpoint the problem in a hurry....if he has a good scanner. Unless u want to live with the reduced mileage you'll have to spend more money...sorry couldn't b more help.
 

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Smooth idle eliminates most plug related issues. Any chance you accidentally disrupted vacuum or other (PVC) lines?

Gasoline typically switches to a winter blend at this time of year which affects mileage, but not the amount you have.

Safe to assume that you put the correct heat range plug in?
 

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And that they are correctly gapped? It is possible that you could have a smooth idle and the plug would still blow out under load (though this should throw misfire codes, though I am not sure if they would on the earlier models).

You can always put the old plugs back in.....
 

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New vaper purge valve won't do much if anything to improve mileage. If a plug r wire was not right, the engine would not run smooth. I keep going back to a temp sensor issue....r maybe a bad O2 sensor. The point I'm getting at is a rich running engine might run fine (and not throw a code....unless it was way too rich) but the mileage would suffer. Pull a plug, if it's sooty it's rich but with these modern computer controlled engines the plug might not show sooty but still run a bit rich. The car needs to go back on a good (Snap-On comes to mind) scanner. A half way decent mechanic will pinpoint the problem in a hurry....if he has a good scanner. Unless u want to live with the reduced mileage you'll have to spend more money...sorry couldn't b more help.
I'll check the plugs Sunday (supposed to be in mid 40's) tomorrow is only to be 28* so that's not conducive to working outside on a car..If it had a bad temp or O2 sensor wouldn't that cause the ck engine light to come on? Something just entered my drain bamaged mind.... I had a new fuel pump put in a while ago (couple of months ago I think) and I did the plugs shortly after that. I wonder if something was moved or jiggled loose when they had the tank out??? Not sure what they could have disturbed. I know I didn't mess up any sensors or vacuum lines when doing the plugs. Can't use old plugs either, threw them away. Trust me they were toast.... the center electrode was burned to a point like it was put in a pencil sharpener..LOL ... Worst case scenario I have to get to my mechanic and have them go through it.... spending $90 an hour kills me cuz when younger I could do all this crap myself.... anyway... I'll stop rambling now... thanks to all of you that helped.....

Peace
 
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