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drums/pads in disk hub can this be

chevy6673

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ok weekend warroir here.. just took off back DISKS on my 75vette off ... to my surpise it looks like theres a set of drum like pads there also .. should i replace them also have never seen this. first brake job on a vette;shrug
 

bossvette

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thats the parking brakes. Personal choice if you want to replace or not many go to stainless replacement parts
 

zachh

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They are your parking brake shoes. Most new cars use the rear caliper as the parking brake, the pistons screw out to engage the parking brake. Back when our cars where rollin off the line, they didn't have the technology to do it, so thats why we got mini drums in the rotor. I would replace the shoes, clean, and lubricate everything before you put everything back together.

zachh
 

chevy6673

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thanks zachh and bossvette after finding out i had to drill out rivets then the mini drums ..hope theres no more surprise thanks
 

bossvette

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just be sure you have all the rivets in your hand before you close it up :L
 

GTR1999

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Be sure you check the rotor runout now that you removed the rivets. You may be in for a big surprise in the brake department if the runout is now over .005"
 

chevy6673

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Be sure you check the rotor runout now that you removed the rivets. You may be in for a big surprise in the brake department if the runout is now over .005"
WHAT IS ROTOR RUNOUT AND HOW DO I CHECK IT
 
Joined
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1978 L-82 4 speed Pace Car
Rotor runout is the amount of wobble in the rotor as it spins. You check it with a dial gauge.

Unlike modern cars, the C-3's brake calipers are mounted solidly to the car - they do not slide left and right. Consequently they have pistons on both sides of the calipers - most modern cars have pistons (or just one piston) on one side of the caliper. As that piston squeezes, the whole caliper moves to apply equal pressure to both sides of the rotor. C-3 calipers stay in one place and squeeze from both sides to get equal pressure on each side of the rotor.

If there is runout in your rotors - if they are not close to perfectly perpendicular from the axis of wheel rotation - then they will vibrate your brake pads and pistons in and out with every wheel rotation. This can cause air to be sucked into the caliper past the piston seals. Air mixing with the brake fluid is bad. This is why many people can't seem to get and keep a firm, high, solid brake pedal.
 
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WHAT IS ROTOR RUNOUT AND HOW DO I CHECK IT

You check rotor lateral runout with a dial indicator setup - if it's more than .003"-.004", you have to correct it. Did you mark your rotors and lug studs so you know exactly how they were indexed to each other before you removed them?

:beer
 

chevy6673

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You check rotor lateral runout with a dial indicator setup - if it's more than .003"-.004", you have to correct it. Did you mark your rotors and lug studs so you know exactly how they were indexed to each other before you removed them?

:beer
i only have the back ones off at this time but did not mark them,did not no i should .. what does this mean ,,,,going to see if they can be cut or if i have to buy new ..
 

Vettehead Mikey

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The rears will only fit in two positions and still line up the holes for the parking brake. Choose the position with the least run out.

DO NOT take your rotors to a shop and have them resurfaced!
 

chevy6673

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1973 Corvette ,1966 ss impala
The rears will only fit in two positions and still line up the holes for the parking brake. Choose the position with the least run out.

DO NOT take your rotors to a shop and have them resurfaced!
looks like am going to order some new rotors from muskegon
 

muddywaters

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GTR1999, Hi , That ring gear on your avatar, the contact pattern is not correct, should be centered both ways, just an observation............
 

Koop

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looks like am going to order some new rotors from muskegon


You're still going to need to have the new rotors turned attached, they will have run out. If you don't you'll be sorry.
 

chevy6673

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1973 Corvette ,1966 ss impala
You're still going to need to have the new rotors turned attached, they will have run out. If you don't you'll be sorry.
what do you mean turned attached .????
 
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From the factory, the surfaces of the brake rotors were turned while the rotors were attached to the car in order to create a plane that is perpendicular to the rotational axis of the wheel. That is why the rotors were riveted on.

If you have the rotors turned on a machine off the car, or if you buy new ones, the most correct proceedure is to turn them on the car. Many people don't have access to the equipment that does this and they end up shimming the rotors to get the runout within limits. One guy here on CAC goes so far as to tap the rivet holes and bolt the rotors back on - but I can't find that thread by searching for it.
 
B

bmotojoe

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In my opinion the rivets were installed for production assembly reasons only.
If rivets need to be drilled out and re-installing same rotor, I would mark one stud and one hole of the rotor so it can be re-installed at the same position. In the Chevrolet Service Manual in the brakes section under Rear Hub (“Y” Models) Disassembly it states “When reassembling the disk to the hub, it is not necessary to rivet the two assemblies. The lug nuts will supply ample retention.”
Clean the surface of the hub and the inside mating surfaces of the rotor for rust etc.
It is recommended that after rivets are removed that you do check rotor run out using a dial indicator if your re-installing the rotors that were riveted on. This is done by applying parking brake, installing the lug nuts on the studs and torque to specks disengaging parking brake and setting up the dial indicator and rotating the rotor completely.
Even NEW replacement rotors should be turned! Depending on how long they had been on the shelf stacked on top of each other there is always a chance they have become untrue. Also make sure that when re-installing the rear rotors to line up the parking brake adjusting access hole with the one in the hub.
I really don’t think there is clearance between rotor and brake backing plate to machine rotors on the car, this I also believe is a snake oil trick to save labor time and charge the customer more.
Brian
 

chevy6673

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1973 Corvette ,1966 ss impala
You're still going to need to have the new rotors turned attached, they will have run out. If you don't you'll be sorry.
TURNED ATTACHED TO CAR I GOT IT,, IT WAS A LONG DAY
 
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'67 Marina Blue Convertible
I really don’t think there is clearance between rotor and brake backing plate to machine rotors on the car, this I also believe is a snake oil trick to save labor time and charge the customer more.
Brian

Nope, it's not a snake-oil trick - it's essential with a fixed-caliper system when installing new rotors, and is preferred even with floating caliper rotor replacements. Any brake shop worth their salt (and many dealers) have on-car rotor turning equipment. The discount brake shops in abandoned gas stations won't know what they are. :boogie
 

chevy6673

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illinois,crete
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1973 Corvette ,1966 ss impala
OK LETS RECAP new rotors will be here this weekend ,and i need to cut all 4 or just the back ..and check runout on back do i need to check runout in front also ...THANKS AGAIN TO ALL
 

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