Brake Pads Dragging Rotors. Normal?
Thread Starter
Instructor
Joined: Jun 2001
Posts: 131
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Brake Pads Dragging Rotors. Normal?
I had the front my '78 up on stands last week and noticed that neither of the front wheels turned freely.
When I spin the tire there is a noticeable drag and the faint "shhhhh" noise of the pads dragging the rotors, but no screeches. So, I pulled the wheels off and check the pads, calipers and rotors.
Both calipers seem fine with no noticeable leaks although they could stand to be rebuilt. The pads seems fine with plenty of pad left (I forgot to measure the thickness.:rolleyes: ) The rotors were smooth with no scoring and no obvious run-out. The left front rotor was apx. 1.8 in thick and the right front was just over 2.1 in thick. Both rotors are technically out of spec.
The brake fluid was changed last year when I bought the car and the two front rubber brake hoses are new last April.
Is this dragging normal? Shouldn't the wheels spin freely? :confused: I don't expect them to spin like a bicycle tire, but they shouldn't be dragging. Talk about a lose of horsepower! :eek:
Would the fact that the front is elevated about 2.3 inches above normal be a contributing factor?
Thanks (ia)
Rexx
-save the wave
When I spin the tire there is a noticeable drag and the faint "shhhhh" noise of the pads dragging the rotors, but no screeches. So, I pulled the wheels off and check the pads, calipers and rotors.
Both calipers seem fine with no noticeable leaks although they could stand to be rebuilt. The pads seems fine with plenty of pad left (I forgot to measure the thickness.:rolleyes: ) The rotors were smooth with no scoring and no obvious run-out. The left front rotor was apx. 1.8 in thick and the right front was just over 2.1 in thick. Both rotors are technically out of spec.
The brake fluid was changed last year when I bought the car and the two front rubber brake hoses are new last April.
Is this dragging normal? Shouldn't the wheels spin freely? :confused: I don't expect them to spin like a bicycle tire, but they shouldn't be dragging. Talk about a lose of horsepower! :eek:
Would the fact that the front is elevated about 2.3 inches above normal be a contributing factor?
Thanks (ia)
Rexx
-save the wave
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
Re: Brake Pads Dragging Rotors. Normal? (Rexx)
yes this is very normal. there are springs pushing the pistons and pads against the disc at all times. however, there is some debate over if they are really required or not. but i say leave them in; drag is minimal.
minimum rotor thickness is 1.215". better get a set of calipers...
runout should be less than .005", need dial gauge. make sure bearing endplay is not excessive.
[Modified by Turbo-Jet, 10:00 PM 2/3/2002]
minimum rotor thickness is 1.215". better get a set of calipers...
runout should be less than .005", need dial gauge. make sure bearing endplay is not excessive.
[Modified by Turbo-Jet, 10:00 PM 2/3/2002]
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Re: Brake Pads Dragging Rotors. Normal? (Rexx)
The drag keeps the pads hot. Which is what they need to operate properly. They will squeak if run too cold. This seems to defy logic but that is how it was explained to me a couple of years ago. I had a bad squeak in city traffic but not on the highway with semi-metallic pads. My thinking was that stop and go traffic in town was heating up the brakes and at speed they were cool: from not being used. The opposite was true; stopping at red lights left them too cool. And on the highway they were at the proper temperature. As most of my driving is in town, I changed to Muskegon Brake organic pads. Problem went away.
