Brakes effecting MPG?
 

Judging from the position of my gas guage needle to where it normally would be about this time, my FE has taken a big blow. As to why, I'm not too sure, but I think my rear brakes might be doing it. This is in the Metro..

Whenever I release the e-brake in the mornings and go, the rear brakes feel like they are stuck. They break free soon as I move, but I'm worried they might be "dragging". The car has never did this before even if I didnt move it for a week or 2. This morning was its first time moved in 3 days and it was worst than normal. About 7 hours later at school, they did the same thing but not as hard, so I dunno if they are rusting up or what. My rear drums were inspected about 1000miles ago and they had plenty of pad left. Any thoughts?

Nic

They might just need the adjusters backed off a bit

Hmm, its never done it before though. Adjusters wouldnt move on their own would they?

Easy way to tell if they're dragging: just jack up a rear wheel and give it a spin. Rears should turn very easily and spin for a long time after you give a good shove. You'll probably be able to hear if the shoes are dragging.

On the drum brakes I've seen, the adjusters do move on their own to account for shoe wear. There's a spring loaded clip that rests on a gear. If they are dragging, you'll have to lift this clip while you turn the gear to release the e brake a little.

Isn't there just a nut to loosen/tighten the e-bake cable's tension? I thought most drum adjusters were automagic these days.

Easiest way to find a dragging brake is after a 15-20 min drive with decent speeds see if one of the rims is warmer than the others around the lug nuts. Fronts will be warmer than the back generally but none of them should be hot to the touch. Also try rocking the back wheels side to side and up and down while it is sitting on the ground it could be a wheel bearing getting ready to die. Usually you get some slack in them right before they go and you can feel it when you shake them hard. The metro has pretty crappy bushings so if you shake hard enough you can feel those so don't get carried away with shaking it. :)

The link below shows how to adjust different parking brakes. The photo on the bottom of page 3 is similar to the drum brakes on my CRX and the Nissan I owned a few years ago.

https://www.autoshop101.com/forms/brake06.pdf

E-brake cables are probably sticking.

May also be the springs holding the shoes in place. They need to be replaced any time the shoes are replaced, as they lose strength over time due to the heat applied to the springs through normal use. When the springs are weak, the shoes will hang. Sometimes the springs break, parts go flying around inside the drum, and by the time you can get to a repair shop most of the innards are metal dust and other bits. Had this happen once, when I was 16. Brakes were the first vehicular system I ever learned to repair.

I've had the friction material come loose from their metal backers on the drums and discs of my metro, then it moves around and hangs up alote. The most recent was during my current tank and I could tell something was off. My coasts were terrible and like coyote X said, the wheel was warm that was causing the trouble. These were old rusty brake parts though. All mine are new now and once in a while I'll jack up each end and make sure none of them are dragging.

Thanks for all the responses guys. Tomorrow Im going to swing by the shop and have my mechanic friend look into the issue.

Yes there is a nut to tighten/loosen the ebrake lines. I dont have my console in right now and I can see it. There is slack in the line. As to the automatic adjusters these days, I have no clue, the car is 13 years old.

And here's something I forgot to mention. Lately I noticed my "brake" light on my dash was coming on every so often. This is the light that tells you the brake is still drawn. Well, I would be driving down the road and it obviously not drawn. Now it is doing it all the time, esp. in turns. Another reason why I think they may be dragging...

back up
 

How often do you use reverse? I know on some cars (maybe most cars), automatic brake adjustment only happens when you back the car.

MOST cars self adjust when you back up and hit the brakes (its how you get your rear brakes aligned after you bled them or put new shoes on. gotta drive forward and stomp on the brake and reverse stomp on the brake.)

but SOME cars require you pull up and down on the parking brake handle a bunch of times. usually asian import cars...but not all.

but all cars about 30-40 years ago to present are self adjusting

Not much, its screws up my FE. My odometer rolls backwards..

Nope - check your brake fluid reservoir. The other thing that light tells you is when your fluid is low. The float is dropping when cornering. (Which is likely just a sign the brake surfaces are worn out, but it could be something else.)

Haha, your right, its low. Ill fill it tomorrow.

Im just trying to find a reason for my sudden drop in mpg. I might be able to scrape 50mpg this tank.

Hey, seeing as though you are taking it by a mechanic, might have him do a full brake fluid flush. That stuff does go bad, just like motor oil. If you are running DOT3, you can go to DOT4 and get a higher fade temp out of it.

English MF'er, do you speak it?:D

I've steadily increased my FE and now generally get mid to high 50's. So, scraping 50mpg is terrible for me...

don't forget your front brakes, i had my right side caliper hanging up so hard that I could barley spin it when it was on the lift. cleaned out the slide pins and lubed them up, and took the pads off and lubed where they contact. much better mpg now ;) . tho it does seem like your rear could be the culprit

lol sound slike my car when i first got it:D rebuilt calipers for me and problem partially gone! my fronts arent low drag calipers ...kinda weird design:p

Finally got to my half tank mark and at 47mpg w/ EOC. this sucks!

lol sheesh how far do you think you have to go backwards?!?!? you have to get up to like 5 mph in reverse(takes like 1 sec then stomp, forward then stomp.) id rather have a car that stops quickly than a car that can get 50 mpg and cant stop...

I used to back down my driveway which is 1/20th mile. So, backing down it compensated going up the driveway, so my odo never moved but i still wasted the fuel.

...so you would rather save a penny than be able to stop safely...ok i will mail you a nickel if you will adjust your brakes before you hurt someone to cover your "fuel expenses". btw most newer odometers have a mechanism in them to "disenguage" while going backwards so its harder to prevent odometer fraud.(still can do it if you know what your doing)
you dont need to go super far or fast... i find an empty parking lot and do this, sometimes being able to slam on the brakes several times before i come to a complete backwards stop.

this is when i think saving gas has gone to much overboard when your willing to have an unsafely operating car to save a penny.

I think you need to go back and re-read the entire thread, you seem to be very confused?

When did I say my car can't stop normally?
When did I say I'm participating in odo fraud?
When did I say I was saving a penny by driving an unsafe car in this entire topic?
When did I say I was going super fast or far in reverse?

Perhaps your reading some other conversation and posting all your thoughts in this one, becuase I see no correlation between your responses and what I have written.

Nic

i might be on one or 2 but,
this thread is about your cars brakes which might be dragging.

just thought of something else, since you say your fluid is low, it means theres a leak or a very very slow one (depending on how often you check it) the brake light will come on. in all cars nowadays theres a proportioning valve when it senses one half of the brakes pressure drop(a leak) theres a metal piston that will go to the end of that valve and set the warning light off telling you that theres a major problem with your brakes.

i never said you or anyone was committing odometer fraud, i was just saying since when you said your odometer goes back wards then forwards so you go nowhere at all i just generally said there is a mechanism that prevents that so no one on here freaks out and tries not to back up ever again cuz it may take off some fraction of a mile.

lol when you said stuff like "but i still wasted the fuel" and saying I'm barely scraping mpg made it seem to me that you were penny pinching a bit to hard. (my mistake sorry about that)

lol and again my bad, when i said you dont need to go super fast i didn't mean you personally i meant it as kinda general info chunk for people who haven't done brakes and wanna know how to correctly get them adjusted. i gotta say that separately next time...

so all in all sorry as if it seemed like i was attacking ya, its just a misunderstanding on my part/me not telling when i switch from a personal quote to a general thing.;)