My rear drums were vibrating a little when braking, so I bought a new set of drums and changed them. Now when I brake, the vibration is MUCH stronger than before! What could be causing this?

Thanks for any help. I searched but could not find an answer....

 

Anybody can help?

 

did you change the shoes along with the drums? what about the front brakes?

 

you most likely got a bad set of drums, they sit on the shelf for years and CAN actually develop runout just sitting there stacked on pallets and during shipping.

get them machined for about $15/both, and then redrive it to make sure the front isnt warped as well.

 

my guess its the brake shoes are worn uneven due to the old drums. change those out and im sure itll be fine.

 

Supposed to change shoes when you change or refinish drums.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Malakai &raquo;</TD></TR><TR><TD CLASS="quote">my guess its the brake shoes are worn uneven due to the old drums. change those out and im sure itll be fine.</TD></TR></TABLE>

nope, shoes do not move, therefore they do not cause runout, and will not be felt.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blu99teg &raquo;</TD></TR><TR><TD CLASS="quote">Supposed to change shoes when you change or refinish drums. </TD></TR></TABLE>

and who told you this??? wrong, no point, if you are changing an alternator belt should you change the alternator too???

NEW drums and rotors CAN and usually DO have some runout, its not like they machine them, send them to a parts store the next day and you get em the day after, they are usually on a pallet (with many other parts on top of them) for YEARS. most of the 8-10 i do in a given day where machined in 2004.

 

I &lt;/3 drums

 

[QUOTE=schardbody]

nope, shoes do not move, therefore they do not cause runout, and will not be felt.

^^Shoes DO move, I dont know where you were going with that one.


and who told you this??? wrong, no point, if you are changing an alternator belt should you change the alternator too???

Would you change your front rotors without changing the pads? Granted, different design of braking system..same concept. Also, if you change your front pads and dont break them in properly they can cause the rotor to warp correct? You should always change the shoes when you change out drums.. If shoes did not cause runout, how do you explain runout in the first place? Please dont say heat, and age.. shoes play a part also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schardbody &raquo;</TD></TR><TR><TD CLASS="quote">


and who told you this??? wrong, no point, if you are changing an alternator belt should you change the alternator too???

</TD></TR></TABLE>

Your analogy makes no sense. 2 moving parts against each other? The alternator wheel uses grooves to line up with the ribbed belt.
2 totaly different things here.
If a shoe has worn down grooves or something, that would create less frictional area to use for stopping. Basically, your analogy sucked and you should turn your rotors when you get new shoes.

 

Thanks for all the input guys.

I had a new set of shoes, so I put them on today and went for a test drive. There seems to be less vibration, but I can still feel some in the brake pedal, although not as much in the hand brake handle.

My front brakes are less than a few months old. Disks and pads. I do not feel any vibration in the steering wheel either, so I don't think it's the front brakes.

I'll try to get the drums exchanged. I bought them only a few weeks ago.

 

i will put it to both of you this way, seeing as how I DO ABOUT $1200 per day in brake jobs i would feel very inclined to say i know this subject very well.

brake shoes do not move with the wheel, THEREFORE, no lateral movement, or runout, which is what causes a brake pulsation.

and when changing drums or rotors the only time the friction material should be changed is IF there is uneven wear, scoring of the material, or any other defect. but none of the above will cause a brake pulsation, FRICTION MATERIAL WILL NOT CAUSE A BRAKE PULSATION PERIOD.

of coarse you should always resurface the drums/rotors when changing friction material to give the new pads/shoes fresh smooth clean surface to bed into, but when talking about runout in a rotor or drum you are talking thousandths of an inch. less than a fingernail thick amount of lateral runout will cause a pulsation.

i guess a better example would be, if you wanted to plant new grass would you replace the dirt as well????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schardbody &raquo;</TD></TR><TR><TD CLASS="quote">i will put it to both of you this way, seeing as how I DO ABOUT $1200 per day in brake jobs i would feel very inclined to say i know this subject very well.

Just because you do multiple brake jobs in one day does not mean you are an expert, and know everything about how the system works. Perfect example, i work with a middle aged man that has been a mechanic for years, he does about 5 brake jobs a day and about 50 percent come back. When they do, he asks for help. Point proven.

brake shoes do not move with the wheel, THEREFORE, no lateral movement, or runout, which is what causes a brake pulsation.

...you have no idea what your talking about. just stop.

and when changing drums or rotors the only time the friction material should be changed is IF there is uneven wear, scoring of the material, or any other defect. but none of the above will cause a brake pulsation, FRICTION MATERIAL WILL NOT CAUSE A BRAKE PULSATION PERIOD.

"friction material" can wear unevenly, which can lead to warped mating surfaces. therefor, creating a pulsation. so again, your wrong. scoring is a whole diff issue.

of coarse you should always resurface the drums/rotors when changing friction material to give the new pads/shoes fresh smooth clean surface to bed into, but when talking about runout in a rotor or drum you are talking thousandths of an inch. less than a fingernail thick amount of lateral runout will cause a pulsation.

this is the only true statement you've made in this post.

i guess a better example would be, if you wanted to plant new grass would you replace the dirt as well???? </TD></TR></TABLE>

Though i do agree, when rotors or drums have been sitting a while on the shelves they tend to warp.. get them resurfaced you should have no problems (now that you have your new shoes )