Squealing front brakes - 75 Mark 3

I bought my Commando in the spring of 07, and one of the many little maintenance items I did was to change the front and rear brake pads.

I put on the Lockheed AP pads. They were much pricier than regular old stock pads, but what the heck.

They worked fine on the back, but they screeched like a banshee on the front. I rode it for a week hoping they would "break in" or something, but finally gave up and put the old pads back on. (They have some wear life left in them). No screeching with the old pads back on.

A few weeks ago, I decided to try again, and bought the Ferodo Platinum pads. Damn - same screeching problem all over again. Tried riding around for a couple of weeks hoping it would go away, but no luck. Tried pushing the bike backwards with the brake on slightly, wiping off the disc frequently, etc. etc. Still screaming loudly - to the point I found myself flinching and backing off the brake - rather than using it to do what it's supposed to do.

Once again, I put the old pads back on and Voila - no more screeching.

Am I doomed never to enjoy the supposed superior quality of the AP or Ferodo pads?

Anybody had this happen to them? Solutions?

PS - I have no idea of whether the previous owner changed the stock front disc. It looks stock to me. (Though much more chrome looking than the rear disc, which is dark and even shows rust at the slightest opportunity.

Anybody have a suggestion?

Is it possible the DPO installed a stainless front disc, and you're using the wrong pads for stainless?

Otherwise, maybe try some anti-vibration lubricant on backs of pads - Permatex and others make some brake specific stuff for this.

Good luck

It does sound as if your front disc still has its original hard chrome. A cast iron disc should turn orange at the slightest hint of atmospheric moisture.

The platinum pads are certainly not recommended for chrome. Norton replacement discs haven't had chrome on for twenty years plus so most of those discs are now out of circulation.

As you're changing pads, presumably dust build-up isn't the problem ? Are they good and loose in the caliper ? A smear of copper grease on the back of the pads can help.

Commandos were of course made by Manganese Bronze who also built the London taxis. They always had the most ear-piercing brake squeal. I always assumed that it was some sort of audible warning of approach to stop pedestrians walking in front of them

When you are sure the pads are OK for the disc. Try making a couple of thin card or gasket shims to fit/glue behind the pads, that'll be sure to dampen out that squeal.

Cash

I have the exact same problem! Brand new brake pads. but the original chrome discs. Only the front brake squeels like a pig being castrated!
Took out the new disc pads and slightly sanded them to get the glaze off.. Put it back and ahhhhhhh..... no more squeels. That is, for about 20 stops and it started up again. Apparently those new brake pads are easily glazed over for some reason, which starts the squeeling process. Unfortunately I have no clue to offer for a solution as of yet. Do we have to remove the crome layer so the disc is more course??????

Very much audible braking In Canada

Josh

The original pads generally used to wear the chrome unevenly very quickly which then caused rapid pad wear. Most owners had them skimmed for better braking.

Modern pad compounds would not have been developed with chromed discs in mind so are certain to work better with a cast iron surface.

I think that Norton and Triumph were the only manufacturers who used hard chrome. The Japanese used stainless and the Italians plain iron. Their's always had the best reputation.

I see at least one person has the same problem as me. Frankly, if the stock discs were chrome, and modern pads (Ferodo, Lockheed AP) screech on these chrome discs - I am surprised this is not a more common problem.

As far as the recommendations to shim or put lubricant behind my two sets of screaming new pads (Ferodo and Lockheed), I don't see what this would do to resolve my problem. I get the screeching when I put these brand new pads on.

If I put my old pads (brand unknown and about 50% worn) back on - no screeching problem.

Seems to me the issue is the composition of the pads vs the chrome disc, n'est pas?

I see that OldBritts also has EBC and Emgo brand pads. I wish I knew the brand of my old pads (the quiet ones), so I could just order them with some level of confidence that they won't screech. Or I could order both and use the old trial and error method (which would mean I had order 4 different sets of pads to find one that doesn't screech).

Somebody out there must have quiet pads on a chrome front disc - and know which brand they are???

Keith Kelly

As I understand it, the screeching is the pad backing vibrating. The typical solution is to coat the back of the pad to dampen the vibration. This has been done with special anti-squeal coatings (available from most autoparts houses) and in some cases with a couple layers of standard spray paints.

I recently had a similar situation with Ferodo pads on my BMW. The previous BMW supplied pads were quiet. Wnen I changed out the Ferodos for another set of factory pads, I noticed that the factory pads had a heavy coat of black paint on the back of the pads where the Ferodos I was removiing had lost any kind of paint or coating on the back side of the pad.

I have used Ferodo, EBC, and NOS Norton pads on my Commandos and have never had a squeal problem. However, the rotors have either been OEM plated or had the plating removed. New Andover supplied rotors "hard" chromed look different from my OEM plated rotors, so the plating process may be different from that used in 1973-75.

You'll also find some pads come with a card or fibre type backing glued to the back. Some caliper systems have a metal anti squeal shim fitted between the pad and piston as standard.

I know the card works as I've used it many times on cars.

Give it a try it'll cost you nothing, cereal box card will do, worked on 2ton Landrover.

Cash