| Best way for bedding brakes? [message #281460] |
Sat, 04 July 2015 18:26  |
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thainglo
Messages: 132
Registered: March 2015
Location: Iowa
Karma: 2
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Senior Member |
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Hi gang! Just finished rebuilding my rear drum brakes with OEM shoes and hardware from NAPA, plus a couple new wheel cylinders. Upgraded fronts to 80mm using thePerformance Friction Pads (52.20). One rear drum had to be very lightly machines, the rest of the drums just scuffed with emery cloth. Didn't do anything to discs as the PF site said not to withthe ceramic metallic pads
What steps would you guys that have replaced these items recommend for bedding in the pads and shoes? The PF site recommended some increasingly aggressive stops from 50-30, 70-30 then 100-30 (which I immediaey scratched off the list).
Appreciate any thoughts. Thanks!
Matt Sladek
1976 Eleganza II
Coralville, IA
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| Re: [GMCnet] Best way for bedding brakes? [message #281462 is a reply to message #281460] |
Sat, 04 July 2015 19:24  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Matt,
When I installed the PF Carbon Metallic pads in Double Trouble Dave Lenzi told me to sand the surface of the disk to open up the
pores in the cast iron. He noted that material from the carbon metallic pads will transfer to the disks and reduce the wear on the
disks to virtually nil. He noted that he installed new disks when he installed carbon metallic pads and has 80,000 miles on them and
they have not worn any appreciable amount. He checks them with a micrometer regularly.
IIRC the OEM disks are 1.200 inches thick, and MM X-7525 / Section 5 - Brakes / Page 5-38 states; "DO NOT reduce total thickness of
the braking surface any more than the turning dimension of 1.185". Also Figure 54 - Discard Dimension (Disc) shows that "MIN.
THICKNESS 1.170" is cast into the inside surface of the disc.
As far as bedding the pads and shoes in I did a number of aggressive stops but I don't remember the speeds or the number of times I
made them.
No need to scratch 100 - 30 off the list, you'd NEVER get there! ;-)
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Matt Sladek
Hi gang! Just finished rebuilding my rear drum brakes with OEM shoes and hardware from NAPA, plus a couple new wheel cylinders.
Upgraded fronts to 80mm using thePerformance Friction Pads (52.20). One rear drum had to be very lightly machines, the rest of the
drums just scuffed with emery cloth. Didn't do anything to discs as the PF site said not to with the ceramic metallic pads
What steps would you guys that have replaced these items recommend for bedding in the pads and shoes? The PF site recommended some
increasingly aggressive stops from 50-30, 70-30 then 100-30 (which I immediaey scratched off the list).
Appreciate any thoughts. Thanks!
--
Matt
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Best way for bedding brakes? [message #281466 is a reply to message #281464] |
Sat, 04 July 2015 20:08 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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YEs, I agree with the PF bedding procedure, except the 100 mph part !
Then park the coach as soon as you can and let the brakes cool overnight..
This does assume fresh rotors, a light sanding or turning is good if you have been using a different pad type caus elike dave said, there is material transfer to the rotor / drum
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Best way for bedding brakes? [message #281498 is a reply to message #281497] |
Sun, 05 July 2015 11:36 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Not necessary in 95% of brake jobs. Why grind away good brake lining? Just
scuff the drums and degrease them with brake kleen. Adjust the shoes by
tightening the starwheels as tight as they will turn, then back them off 5
clicks at a time until there is a light drag. ( remember, drums expand when
warmed to operating temperature) Make sure there are no fluid leaks, bleed
ALL THE AIR from the system. Then drive them, gradually applying slightly
more pedal pressure for the first 100 miles or so, then drive like a normal
person would. Avoid sudden panic stops for the first couple hundred miles;
then drive like YOU normally do. If you were normal, you wouldn't be
driving a GMC motor home. (Grin)
Jim Hupy
On Jul 5, 2015 8:50 AM, "David H. Jarvis" wrote:
> Does anyone arc the brake shoes to match the drums?
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