# New brakes pulsating



## DexterII

I do not recall anything that I would have described as pulsating on a drum brake, but I would check for a leaky wheel seal, the high spots on the backing plates that the shoes ride against, to see if they are gouged, the hardware, both for condition and proper orientation, the pins that the hardware attaches to for abnormal wear, the self adjuster, and if still no cure, would bleed them, just to be sure.


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## shanecurran

DexterII said:


> I do not recall anything that I would have described as pulsating on a drum brake, but I would check for a leaky wheel seal, the high spots on the backing plates that the shoes ride against, to see if they are gouged, the hardware, both for condition and proper orientation, the pins that the hardware attaches to for abnormal wear, the self adjuster, and if still no cure, would bleed them, just to be sure.


I have bled the brakes. One of the drums I replaced looked to be in good condition. I am thinking about putting it on one side and then the other (while also inspecting hardware as suggested) to see if I can pin point the problem. Is that a good idea?

Excuse my ignorance but why cant a drum cause pulsating? Can't it be slightly oblong (out of round) which would cause pulsating in the pedal?


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## shanecurran

Also, if brake fluid were the problem, then I would not be able to feel the pulsating when using the emergency brake as mentioned before.


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## oldrivers

even though you replaced the brakes in the front a few months ago doesnt mean that the rotors didnt warp in that time frame . if you hit the brakes fairly easy just starting to make contact does it pulsate? or do you have to press it pretty hard before it does it? usually the fronts make contact first and do 60 % of the breaking. im betting a rotor warped they replacements are usually alot cheaper than the oem ones . also they recomend retorqing your lugnuts after 500 miles or so .. im thinking all these factors are more critical on the smaller cars where metal is thin to start with.


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## shanecurran

oldrivers said:


> even though you replaced the brakes in the front a few months ago doesnt mean that the rotors didnt warp in that time frame . if you hit the brakes fairly easy just starting to make contact does it pulsate? or do you have to press it pretty hard before it does it? usually the fronts make contact first and do 60 % of the breaking. im betting a rotor warped they replacements are usually alot cheaper than the oem ones .


The rotors were and pads were replaced within the month (not a few months ago). As I said before there was no issue until I replaced the drums, shoes and cylinders in the rear. Also, the pulsating can be clearly felt when using the emergency brake only (another indication the problem is in the back)


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## oldrivers

when your emergency brake is engaged it pushed on the drum slightly offcentering it so that could possibly be causeing it to run out of centric . "SP" . but i dont understand why your using an emergency brake .


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## shanecurran

oldrivers said:


> when your emergency brake is engaged it pushed on the drum slightly offcentering it so that could possibly be causeing it to run out of centric . "SP" . but i dont understand why your using an emergency brake .


Just using the e brake to diagnose the problem. Also there is no pulsating in the steering wheel when I normally apply the brakes, another reason I don't think the issue is in the front of the car.


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## ukrkoz

you have ABS, right?

let me clarify my question. any "warpage" in rotors is felt in steering wheel. warped rear drums should be felt as "catch-let go" shake, which is longitudinal.back-for. 
you have pulse in the brake pedal. ABS comes to mind first. 

_
Do not confuse the ABS system’s check with pulsations
due to rotor runout or parallelism. And remember
the pulsation due to activation of the ABS
system, caused by moisture intrusion into a wheel
speed sensor. We covered this in “On the Line:
Brake Pulsation — Mechanical Problem? Electrical
Problem? Or Both?” Make certain you identify the
reason for the pulsation, or any brake problem,
prior to attempting to resolve the complaint. Failure
to do this may put the vehicle back in your shop
within a few days with the same complaint, along
with an angry customer.
MIGHTY DISTRIBUTING SYSTEM OF AMERICA, INC. ®
LARRY HAMMER
TECHNICAL SERVICES_

_Re: Pulsating brakes
__Rotors don't warp. It is the oldest and widest misconception in automotive history. They get depositions of abnormal material and the friction qualities are modified in certain parts of the rotor, but the runout you get is from load inconsistencies, not heat warping.

http://www.stoptech.com/whitepapers...rotors_myth.htm

You can temporarily solve the vibration by machining the rotors but if proper pad break in procedures aren't used it will come back very quickly, which is probably why SaturnSC2 had pulsating very soon.

Rust, pad material fusing, inconsistent pad application; all contribute to pulsating pedal, but make sure you attack the problem not the symptom.

Also, make sure you're diagnosing it right. In your post you say that the harder you press the pedal, the faster the pulsation. If that's the case, then it can't be a rotor issue since it would pulsate at the same speed the wheels turn regardless of how much you press the pedal._


of course, like you said - you might just have ****ty parts. "shady" it is. I had front rotors "bad" on a Civic in 2 weeks after replacement. You can easily check on drums. disassemble at least one of them, and look at mating surface. does it show uneven wear pattern, with "hills and valleys"? if it's out of round, it will touch pads in high areas and not touch them in low, resulting in less pad material deposit in low areas, or valleys.


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## shanecurran

ukrkoz said:


> you have ABS, right?
> 
> let me clarify my question. any "warpage" in rotors is felt in steering wheel. warped rear drums should be felt as "catch-let go" shake, which is longitudinal.back-for.
> you have pulse in the brake pedal. ABS comes to mind first.
> 
> of course, like you said - you might just have ****ty parts. "shady" it is. I had front rotors "bad" on a Civic in 2 weeks after replacement. You can easily check on drums. disassemble at least one of them, and look at mating surface. does it show uneven wear pattern, with "hills and valleys"? if it's out of round, it will touch pads in high areas and not touch them in low, resulting in less pad material deposit in low areas, or valleys.


Thanks. I don't know if I have ABS. I am definitely feeling the catch let go on the rear rotor(s). It was raining today on the way to work and it almost sounded like it was the drivers side rear. 

What happened was my front rotors and pads were replaced. The mechanic who did the work claimed to have inspected the rear drums and said they were fine. Well I asked about the problem a second time because the rear brakes were making noise. He said it was probably dust. Last weekend I took the car ferry over to another island (St. John). I was driving down a hill and the brake pad went to the floor. Turns out one of the shoes came loose and the cylinder was fully extended causing the brake fluid to leak out. I found someone to do the work but I had to buy the parts. I wanted it done right, so I decided to replace everything on both sides and flush the fluid. I got the car back, but now this annoyance. 

I still have the old parts and as I said one of the drums is still in good shape, so I am going to put it on the drivers side to see if the pulsating stops. If not I will try the passenger side. If I still have the problem then I will have to take it to a shop. I will keep the forum updated to the progress.


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## ukrkoz

look at your dash when you turn the key to position 2. all lights should come up. does any of those lights say ABS? computer does routine ABS system check at every start up. if you have it - you have ABS, if you don't - you don't.
if you have ABS, due to hydraulic control system involved, special brake bleeding tool is required. or so they say. rumors are, you may bust your brakes if not done properly. might be just sellers bs.
"someone" to do the job? cost efficient guy? might as well have done it all yourself, it is not rocket science at all, especially on the front end. 

i am positive you did not do break in rotors and drums? 

like i said, before tearing and replacing it all, simply take the drum in question off, and check on mating surface. also, pads will show uneven contact, you will have shine/dull areas, sorta stripes pattern. keep in mind, pads may be uneven thickness. you can take a rough file and file down high (shiny) points on pads, making mating surface more even.


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## polarzak

ukrkoz said:


> l
> if you have ABS, due to hydraulic control system involved, special brake bleeding tool is required. or so they say. rumors are, you may bust your brakes if not done properly. might be just sellers bs.


It is BS if you are just bleeding brakes due to a caliper change, (just did one) hower if you do ABS module work, I believe you do either need a special tool or a special method to bleed the lines.


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## shanecurran

ukrkoz said:


> look at your dash when you turn the key to position 2. all lights should come up. does any of those lights say ABS? computer does routine ABS system check at every start up. if you have it - you have ABS, if you don't - you don't.
> 
> i am positive you did not do break in rotors and drums?


I looked at the dash and there are no ABS lights, so I don't have ABS. 

I did not break in the drums, which is impossible to do safely where I live. I live on St. Thomas in the VI. I would be hard pressed to find a place where I could get my car up to 60 mph, and in no way would it be safe to brake hard at that point. I think the highest speed limit is 35 mph.


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## ukrkoz

well, find a safe spot then and take drum off and check for wear pattern. best i can tell.


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## D-rock

If you have no steering wheel shake and only feel it in the pedal, it most likely is from the rear. Forget the entire ABS stuff, has nothing to do with pulsation. Did you use cheap drums? It sounds like just cheaply built drums to me. Sometimes its better to buy quality OE parts. Breaking in drums and what not is to create a good mating surface. Also check to make sure the shoes and drums did not get any grease or brake fluid on the inside area where the shoes sit. With the rear tires off and car in the air, rotate the drums in the direction of forward vehicle rotation, you should feel slight friction. If you can't turn them by hand then the shoes where installed too tight, this will cause excessive heat and can warp the drums. Regardless, shouldn't make a pulsation from the short time they have been installed. Help this helps


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## Marty1Mc

D-rock said:


> Did you use cheap drums? It sounds like just cheaply built drums to me. Sometimes its better to buy quality OE parts. Breaking in drums and what not is to create a good mating surface.


This would be my #1 suspect. I won't use any of the store brand components, they are just too cheaply made. I will use either OEM or a high quality manufacturer with a decent warranty. The constant drive to lower the price of parts has, in my opinion, crossed the line and resulted in much lower quality.


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## shanecurran

Update: I had the rotors turned in the front. I am still getting a pulsation. Now I am 100% sure that the drums in the rear are the culprit. I am going to get the rear drums turned this weekend.


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## shanecurran

@ D-rock, you had the most accurate advice of the group. I wish that there were more options for higher quality OM parts on island. In the struggle with parts so far I found one little shop with a stateside owner who can get OM parts, otherwise shipping is expensive and unreliable (I once had a package sit in the post office for 50 days AFTER being confirmed as arrived in ST. Thomas). 

Definitely going to invest in some more tools, the mechanic situation is ridiculous.

UPDATE: The front rotors were turned (even though I am 100% sure now that they were not the culprit). The pulsating persisted for a couple of weeks. In that time I was able to narrow it down to the rear driver side drum. The roads are very steep here and the pulsating was profound. Every once in a while I could hear a sound coming from the drivers side (at slow speeds it almost sounded like a soft clicking), and I had already narrowed the problem down to the rear of the car (see previous posts). I removed the rear drivers side drum and had it turned at western auto (who was the only game in town I found that turned drums), who ironically sold me the shoddy part to begin with. The pulsating is completely gone and the brakes work fine now.

FYI: I am proof that new drums can be out of round, or any drums for that matter. 

Moral of the story: Buy quality parts if you have the option.

Thank you everyone who responded for their input in the matter.


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