Brakes? Pedal wiggles/pulsates advice

[De_Franza]

Does anyone here know cars?

I just had my rear brakes replaced (new drums, shoes and hardware) and now I find the brake pedal pulsates when I brake (the car seemed ok when I went in for oil change and some other work, but the rear brakes needed work, and checking my records it seems I've gone over 85,000 miles on the rear brakes the car came with when I got it at about 30k miles, so I believed them when they said the rear needed work).

Anyway, The mechanic says this pulsation is the front brakes, and that I only notice it now because they're doing a normal amount of braking after having done more of the work than they should have when teh rear brakes were bad before.

To me, this sounds like a snowjob... your thoughts?

Thanks much!

[Jonathan Randall]

Are you pumping the brakes? This can cause ABS to pulse. Also, did you change the tires? The wrong size can cause problems if the braking system is not adjusted to match. Also, are your brake lines in good order? How about your front bearings? The speed sensor on the ABS?

While I don't necessarily recommend this, you could try disengaging the fuse for the ABS (in a safe, isolated parking lot) temporarily and seeing if you still have this problem.

I wouldn't trust my life to the mechanic's explanation; although I am not saying he/she is wrong. A second opinion is required, imho, ASAP. I would have the whole front checked - lines, sensors, bearings, tires (correctly adjusted to match breaking system), brakes by a competent brake specialist.

[Abbax8]

If you have ABS on your car ,this sounds like it is activating when you brake. It should not do this during a normal braking operation. If the front brake sensor is bad it could cause this problem, along with other things. As an aside, my cars ABS has NOT worked for years.It is disconnected. The brakes work fine. I learned to drive without ABS and actually prefer not to have them,I'm a dinosaur,but I feel I am doing the driving not some computer module.

Ask your family or friends to recommend another mechanic and have them check out the braking system. It will cost $ but you will have peace of mind.

Dennis

[TonyU]

They're right that if it's not the ABS than it is the from break, but it should not be doing that.
It means that the rotors need to be cut because they're worn unevenly or replaced because they're warped.
As also been recommended, get a second opinion and/or new mechanic.

[De_Franza]

I never pump the brakes, and at 30 MPH on dry roads, I'm confortable assuming the ABS is not kicking in, unless it too, is very broken/sabotaged.

[Erik]

Wish you were out here, buddy. I have a very good, very honest mechanic who could help you out.

[jjaje]

You'd know if the ABS was cutting in, it is quite audible.

I don't know about a "snow job" - but I'd check the front rotors. If they were doing a lot more of the braking, they would generate more heat, and have a higher chance likelihood of warping. They should not be pulsating, but the fronts are likely worn unevenly or warped. With brakes, I almost always do all 4 corners at the same time. Just for balance.

[De_Franza]

But but but...
the car braked PERFECTLY on Saturday when I dropped it off... Sunday I pick it up and poof! new problem. WTH?

(I know from listening to Click and Clack that this can honestly happen to even the best mechanics, but STILL!)


How do we feel about the theory that the wiggle could be the rear pads "breaking in" ?
since the wiggle/pulsation does NOT occur when I pull the ebrake handle, I believe the pulsation is from the front brakes.
(I also have almost no idea what I'm talking about)

assuming it was the rear pads/shoes breaking in, how do we feel about several hard stops to clean the surface and make it smooth?

Thanksa gain everyone!!!!

[Tripitaka of AA]

Most of the answers seem to know what they are talknig about, but here are a couple of ideas from me (and I don't have a lot of driving experience at all).

New brake pads wearing in. Yes, I've been told that this takes a while and to expect some uneven braking until the initial period of wear has taken place.

Something else that I experienced in someone else's car; the wheels are not balanced correctly. There are small lead weights placed on the wheel rim, which have to be positioned and weighed individually. When the car slows down, at a certain speed the vibrations were alarming, but a visual inspection didn't reveal anything.

[Erik]

(I know from listening to Click and Clack that this can honestly happen to even the best mechanics, but STILL!)

Tony reminds me of these guys when he's on the phone...

[Jonathan Randall]

Most of the answers seem to know what they are talknig about, but here are a couple of ideas from me (and I don't have a lot of driving experience at all).

New brake pads wearing in. Yes, I've been told that this takes a while and to expect some uneven braking until the initial period of wear has taken place.

Something else that I experienced in someone else's car; the wheels are not balanced correctly. There are small lead weights placed on the wheel rim, which have to be positioned and weighed individually. When the car slows down, at a certain speed the vibrations were alarming, but a visual inspection didn't reveal anything.

You can easily check to see if it is the pads breaking in (or the rotors as Tony, etc. mentioned) by disconnecting the ABS system. Go somewhere isolated, though, to try.

Any competent auto shop can quickly check the balance on your tires -- as well as the rotors.

[Jonathan Randall]

You can easily check to see if it is the pads breaking in (or the rotors as Tony, etc. mentioned) by disconnecting the ABS system. Go somewhere isolated, though, to try.

Any competent auto shop can quickly check the balance on your tires -- as well as the rotors.

I should have added -- the absolute best thing to do, imho, is to bring it to a brake shop or a second, competent, mechanic and have them take a quick look. Avoid those large chain shops where the help is, for the most part, young, inexperienced, low paid workers. I stopped going to the one near where I used to work when I realized I knew more than their "master mechanic". Now that's scary, given my own lack of expertise. Also, OEM parts are far superior to the cheap stuff these mass, commercial shops use.

[rainesr]

Ask around and find a reputable mechanic to tale a look, an assessment like that shouldn't be too expensive.

I don't mind ABS except in snow and ice, I learned without it and feel like I am out of control when it kicks in.

~Rob

[De_Franza]

Thanks everyone!
I believe the wheels are balanced because part of the work I had done was to patch two slow leaks, and they balanced the tires afterward. (also, there was no shimmy before and no reason to suspect unbalance before... and teh car rides smooth UNTIL i brake; my understanding is it would shimmy the whole time with unbalanced tires).

SO I took it back to the shop to be quietly assertive and the manager took it for a spin and immediately noticed the pulsation. he was like , woah. He opened up the brakes and the current idea is that the new drums are defective or out of round. Not visibly, but enough. So they're replacing those (free, of course) and we'll see. This is Thursday when I already have a busy "day off" (i have like, a dozen appointments even though I'm not at work... alas). FWIW, the manager wasn't there Sunday when i picked it up and he was pissed they let me leave with a car in this condition, so he seems to genuinely want to make it right. Even he was like, it shouldn't be the fronts since we didn't touch those.
Maybe it's placebo effect, but I can feel it a little when I pull the e-brake handle, so that indicates a rear issue.

Aside: is the e-brake supposed to make teh car actually stop? it slows it a little, a very little, but I've always read to keep the button depressed so it doesn't lock and make the car spin out... to spin out I'd have to halt the rear wheels and that just doesn't happen. i think the rear brakes / e-brake is more for keeping it stationary when parked, right?

[Abbax8]

Your e-brake is for parking. In an emergancy you could engage it to try to slow you down but it will fail quickly. I've made the mistake of driving with it on a few blocks until I remembered (DUH!). When your driving it should not be engaged.

Dennis

[Jonathan Randall]

Your e-brake is for parking. In an emergancy you could engage it to try to slow you down but it will fail quickly. I've made the mistake of driving with it on a few blocks until I remembered (DUH!). When your driving it should not be engaged.

Dennis

Same here!

As a new driver, years ago, somehow I engaged it, either by forgetting to take it off or by bumping it (it was an old, first car, with loose stuff). Thought something was wrong with my automatic transmission, lol, or fuel system, because the car was so sluggish as I drove out of the parking lot of the Sears where I then worked.

Also, as others have noted, Mr. De Franza, even the best of mechanics make big mistakes from time to time. It is their willingness to identify and correct them that is the measure of their quality. Wouldn't automatically dump this place/mechanic -- unless, of course, such mistakes become a habit.

[De_Franza]

Ok I thought so. From a parked stop it will often prevent the car from going (not if I really punch the gas) but no appreciable slowing at driving speed. So it's really a parking brake to keep the car still on hills if the tranny totally fails.

Post script: after replacing everything Last thrusday, the car rode and braked like butter (everything being the new drums, and they resurfaced the front rotors). Sunday... (fathers day, on the way home from a nice breakfast) BOINK the rear passenger side wheel locks. Doh! I managed to pull over safely and AAA towed me to the shop where we found the self-adjusting ratchet had flown apart and wedged between teh drum and shoe, locking the wheel. more parts, another new pair or rear rotors and set of shoes and 3 hours later it's good again. I'm like... whatever at this point. but it brakes safely and feels good and was all free after the first work, and they gave me three certificates for free oil changes. I'm not sure I'm gong to use them, but then again, free oil changes. (then a new shop!)
on teh other hand, as a long time listener to click and clack, they always say other things breaking (no pun intended) isn't really the mechanic's fault, and they are really stupid to sabotage things because that prevents return business. on the third hand, it's gotta be their fault because who else was poking around in the brake system? or if not their fault fault, opening up the brakes probably speed up the failure of the ratchet thing (of course, i can't really know that).

So I'm going in circles over this, as you can see.

But the point I started out trying to make is THANK YOU ALL for the advice!