Today I will share with you what I know, what I did and what I do not know about brake squeal. First, I want to say that I have now driven 1,500 Miles (2,400 Kilometers) without out even one squeal from my front brakes (as I am pounding on my wooden desk lol).
This was not the case after I had replaced my calipers, rotors, and pads at the beginning of the season. In fact, the brakes started to squeal shortly after (300 kilometers) I had completed a new brake job. I then re-examined everything and thought I had solved the issue. In May of this year, I wrote an article titled MGB Brake Squeal Solved (boy was I wrong). At that time, I was certain that I had resolved the brake squeal issue by re-positioning the pistons correctly in the calipers and by using ceramic brake lubricant and doubling up on the clips. Well, 600 kilometers after that, I was proven wrong as the squeal crept back into my life.
Since then, it has been a constant battle, trying different suggestions from people on forums. In fact, I am almost certain that I could get into the Guinness Book of World Records for changing out pads the fastest. Here is what I do know:
- Squealing started when pads changed from asbestos to a variety of materials thought to replace asbestos by brake manufactures. There are many different materials out there.
- The dimensions of the pads differ between suppliers.
- The weight and feel of the original Lockheed Calipers are much different than the new ones manufactured in China. In fact, the original calipers have no markings or indents from the pads as do the new calipers used only a few hundred kilometers.
- The squeal comes from vibration of the metal tips of the pads on the top and bottom as they vibrate with the caliper surface.
I have now put on more than 1500 miles without a squeal and these are the steps I had taken. Honestly, I do not know if one particular step solved the squeal issue or if it were a combination of two or more. I suppose I could have implemented these fixes one at a time, but towards the end, I just went hellfire on the system with everyone’s suggestions hoping that I never hear a squeal again.
Below is a picture story of how I think I solved the issues:
Step One – Make certain the pistons are properly aligned in the caliper. I removed my calipers from the hub and placed them on a stool, still connected to the brake line. I blocked the middle of the calipers with a tool and pumped the brakes to have the calipers extend outwards without them falling out.
I then used a rubber bottle top opener to grab the pistons and turn them so that the recessed area is in accordance with the above sketch, facing to the back. Using the rubber ensured that I did not damage the surface of the pistons. Click here for a video on this step.
Step Two: After purchasing three different sets of pads, I decided on using the Wagner brand because the length was the least of the three. Note the NAPA and Moss Motors squealed in my car. I had purchased the Wagner last.
Step Three: I ground an angle on the top and bottom of the pads using my Dremel and a sanding paper roll. This eliminates such a sharp angle from the pad to the rotor. I then used a cutting wheel on the Dremel to grind in a groove in the center of the pad to help change the vibrating characteristics and to help eliminate brake dust.
Step Four: I used high temperature PTFE tape on the bottom and top sliding area of the caliper to reduce the contact between the metal pad and the caliper. This tape is very strong and withstands temperatures up to 250 – 300 degrees Celsius. Below you can see the groove marks on the caliper made from the vibration of the pads. Note: these were not on my old calipers by Lockheed and are probably the originals with 111,000 miles on them.
I decided that I would send the old Lockheed (original) calipers out to be completely restored. I found a great place in Stoney Creek, Ontario called John Stuart Power Brake Co. Ltd.. When they are returned, I will paint them.
Step Five: I put a thin metal backing plate on the back of the pads and covered it with a very thin layer of ceramic brake lubricant, again, trying to eliminate the piston-to-pad vibration contact area. Without this, you can see below the chips of paint off the previous calipers (NAPA and MOSS brands).
Step Six: When re-assembling the pads to the calipers, I doubled up on the clips to apply more pressure on the pads thereby reducing some vibration.
Will the squeal return? I certainly hope not. Which of the above fixed the issue? I have no idea. However, I suspect that on an original caliper, the cut groove in the middle of the pad and the ground angles on the edge may do it. The Teflon is an added feature that some swear by, and I think it is helpful on the new calipers made in China.
I hope this can or will help you eliminate your squeal if you have one.