Rear Rotor Removal?
To my fellow C3 panel of experts...
I am considering removing the rear rotors on my 78 Vert. Initial inspection with the wheels removed show that the rivets were drilled out by the PO.... My question is: I am assuming that the caliper(s) have to be moved out of the way and would appreciate it if the experts could tell me how they are removed and can they be reinstalled without the calipers trying to close the brake pads. Any and all help, tips & guidance etc. as always is greatly appreciated... mk's78 Mike:flag::flag: |
There should be two bolts on the back of the calipers that are holding them in place. Once the bolts are removed you should be able to pull the caliper off the rotor. The rotor shouldnt close the pads unless you press the brake pedal. I have had them close a little bit but you can usually open them back up easily enough with a c-clamp or a caliper compression tool.
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Two bolts hold rear caliper on, make sure you remove the larger bolts, as the smaller ones hold the two caliper halves together.
If concerned about the reassembly, place a piece of wood between the pistons to keep them stable. The rear caliper has the hard line attaching it to the rear brake hose, be careful not to bend this once the caliper is off. If you're going to be reinstalling the rotor, make sure it's indexed to the hub before removal. A dial indicator gauge would be useful to verify run out when you reinstall the rotor. I replaced calipers at the start of this season, along with the rubber lines and the two rear hard lines and master cylinder. My rotors were fine, as were the pads.....so a brass wheel on my cordless drill cleaned all the mating surfaces. I bought a clamp on dial gauge and was able to get run out down to .002 and .003 respectively on the rear rotors. The tricky part will be keeping the lines attached (if indeed this is your goal) and not bending/twisting the hard lines. Good luck. |
Why are you considering removing the rotors? Do you need to remove the rotors?
:thumbs: |
???
Originally Posted by jdunfee
(Post 1587851697)
There should be two bolts on the back of the calipers that are holding them in place. Once the bolts are removed you should be able to pull the caliper off the rotor. The rotor shouldnt close the pads unless you press the brake pedal. I have had them close a little bit but you can usually open them back up easily enough with a c-clamp or a caliper compression tool.
mk's 78 Mike |
Where did you find a 78 vert? :leaving:
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I found it..........
Originally Posted by Kevin68
(Post 1587854042)
Where did you find a 78 vert? :leaving:
mk's78 Mike:flag: |
Brian.........Pls check my..........
Originally Posted by briankeery
(Post 1587851700)
Two bolts hold rear caliper on, make sure you remove the larger bolts, as the smaller ones hold the two caliper halves together.
If concerned about the reassembly, place a piece of wood between the pistons to keep them stable. The rear caliper has the hard line attaching it to the rear brake hose, be careful not to bend this once the caliper is off. If you're going to be reinstalling the rotor, make sure it's indexed to the hub before removal. A dial indicator gauge would be useful to verify run out when you reinstall the rotor. I replaced calipers at the start of this season, along with the rubber lines and the two rear hard lines and master cylinder. My rotors were fine, as were the pads.....so a brass wheel on my cordless drill cleaned all the mating surfaces. I bought a clamp on dial gauge and was able to get run out down to .002 and .003 respectively on the rear rotors. The tricky part will be keeping the lines attached (if indeed this is your goal) and not bending/twisting the hard lines. Good luck. mk's78 Mike:flag: |
Originally Posted by Easy Mike
(Post 1587851717)
Why are you considering removing the rotors? Do you need to remove the rotors?
:thumbs: |
Originally Posted by mk's78
(Post 1587858480)
online 5 yrs ago, went to look at with my wife and had it shipped a week later............
mk's78 Mike:flag: The photo in your profile is a 78 Coupe.... |
Had all of that work..
Originally Posted by Mike Ward
(Post 1587858863)
:iagree: No reason to remove them unless you're servicing the parking brake ass'y.
And yes he did a complete parking brake installation and adjusted it three times and it just barely holds....Of course his response was that it was a poor GM design.....The PO had the whole PB assy removed for some reason I just don't understand to this day.. mk's78 Mike............:flag: |
You're correct....
Originally Posted by Ontario73
(Post 1587859110)
Ummmmmmm, they never produced a convertible in 78! Records show the last C3 vert was 75?
The photo in your profile is a 78 Coupe.... mk's78 Mike:flag: |
Originally Posted by mk's78
(Post 1587859271)
done by my NCRS specialist..
No need to disassemble the rotor ass'y to isolate a rubbing noise. It's probably rotor runout causing the surface to rub on a pad. Does it go away when you touch the brake pedal? |
A little trick on removing the calipers. Go through your sockets and as you take the caliper off slip a socket the same size as the rotor in. Makes it easy to re install.
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You don't have to remove the hard brake line going to the caliper to remove the caliper from the rotor for the purpose of removing the rotor. Just be careful and rest the caliper, with the line attached, somewhere close to it's normal position on the car (I rest them on the rear sway bar attaching point - your car may not have one of these though). The hard line will have some give. That is less likely to be true if they are stainless lines, however, because that is a much more rigid metal.
The sound you are hearing is very likely rotor runout or related to it. Once the rotor rivets have been drilled out, the rotor is usually just held in place by the caliper and the wheel lug nuts. This can cause the rotor to not sit properly on the hub to the tune of a very few thousands - enough to cause runout sounds. If you have runout, you can shim the rotor on the hub to lessen it (some disparage this, but I've had good luck in the past, just takes patience). |
Yes...........
Originally Posted by Mike Ward
(Post 1587859329)
WTF is that? :eek: :rofl:
No need to disassemble the rotor ass'y to isolate a rubbing noise. It's probably rotor runout causing the surface to rub on a pad. Does it go away when you touch the brake pedal? |
You can buy shims through Rock Auto, I believe in .003 and .006 thicknesses. They have a 'wedge-like' cross section; actually pretty cool idea. My advice would be to verify with a dial gauge what your best runout measurement is through indexing the rotor, before worrying about any sort of shims.
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Originally Posted by mk's78
(Post 1587859652)
One reply suggested shimming....what's your take......mike:flag:
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You really should get a dial indicator on the rotor to determine if runout exists. In the US, they can be had from Harbor Freight for relatively cheap.
With runout commonly the squeak or rubbing sound will go away when the brakes are applied. If the runout is bad enough, the sound may just change in pitch rather than disappear on light braking. You might have a look to see if the "NCRS expert" installed the rotor indexed away from having the parking brake adjustment hole lined up. The rotor and spindle were installed as a unit (hence the rivets), so if it is in the wrong position it might be creating a high spot that otherwise wouldn't exist. |
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