When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
About six weeks ago I went through the brakes of my 96. I replaced the pads with Porterfield street compound. On the rear pad sets there was one pad with an integral metal shim. The pad material was thinner to make up for this shim. The other pad was just the metal backing plate. I had always thought the pad with the shim went on the outside (non caliper piston side). Since Porterfield did not include any directions I called them. I was told it did not matter but they suggested the piston caliper side. I did that. Then I got to thinking and searching the internet. I then sent an email to the Porterfield tech department. I got the cut and pasted response. Now I know. Maybe everyone here already knew this but I did not. Dan
On a single-piston caliper, the brake pad with the shim (or layered shims) goes against the caliper piston, with the shim acting as a buffer to reduce noise (squealing/rattling) and heat transfer, while the other pad (without the shim, often the inner pad) pushes against the caliper bracket or guide. The shims are designed to float or be applied with special lube to absorb vibrations, preventing metal-on-metal contact noise.
How it works:
Inner Pad (Piston Side): The pad with the shim (or shims) is the inner pad, facing the caliper piston.
Outer Pad: The pad without the shim (or sometimes with just a wear indicator) is the outer pad, facing the caliper bracket/guide.
Function of Shim: The shim's job is to sit between the piston and the pad's metal backing plate, controlling vibration and heat.
I had bookmarked the Porterfield web site when you initially mentioned about them on another thread for whenever I need to replace pads and rotors.
So that's good information to have. Thanks for posting!
Thing is that I hardly drive the car so may end up just replacing the pads arbitrarily. I drive it so infrequently that it'd likely take several years for the pads to wear down to actually neededing replacement.
Is this "shim thing" specific to Porterfield pads only? I bought some EBC RedStuff pads this winter and don't recall seeing any shims in the box.
The shim appeared to be attached to the metal backing plate. It could have been some soft glue like grease. Nothing appeared to be welded or riveted. It was not loose in the box. Dan
The shim appeared to be attached to the metal backing plate. It could have been some soft glue like grease. Nothing appeared to be welded or riveted. It was not loose in the box. Dan
Well damn, I just learned something new too!
I looked in the EBC rear pad box again and sure enough, at the bottom are four 3M stick on anti-squeal shims. Not sure if they are needed. Won't know until I actually do the work this spring. I've had Chevrolet trucks my whole life, never had to use shims before.
Instruction sheet says:
Insert the pads and anti-squeal shims, if fitted, into the caliper and secure in position ideally using new split pins/retaining pins and spring clips. Reconnect any electrical connections (wear indicators) as applicable. Repeat the whole procedure on the opposite break assembly.
When I did mine I took the recommendation of IHBD and used this on the back of all pads. Two good coats. It dries tough and sticky. Dan
I reached out to EBC to find out what "if fitted" means in their instructions. My guess is I would use the stick-on shims on all four pads. Waiting to hear back from EBC. I might try that Permatex on another vehicle I have with noisy brakes.
I reached out to EBC to find out what "if fitted" means in their instructions. My guess is I would use the stick-on shims on all four pads. Waiting to hear back from EBC. I might try that Permatex on another vehicle I have with noisy brakes.
Just taking a wild guess but if you were road racing your brake pads could get hotter than the rubber backing could take. Dan
Just taking a wild guess but if you were road racing your brake pads could get hotter than the rubber backing could take. Dan
I don't do any type of racing.
EBC replied with, "If you do want to use the shims we recommend using them on all pads. But they are not something that has to be used."
I don't do any type of racing.
EBC replied with, "If you do want to use the shims we recommend using them on all pads. But they are not something that has to be used."
Well, that makes it clear. I personally would use them. Dan
I learned something new
