Disc Brake Pads, Part IV; A Happier Story

Grumpy's Garage; A Clammy, Dreary Armistice Day --

Well, as reported earlier, after much careful greasing of the metallic contact points in the front disc brake calipers, there remained a light moan or groan which the Grand Mother and Resident Grandson attributed to (variously) the left rear -- or the right rear. Grumpy vowed to tackle both of those two potential "complainers" as soon as possible -- or later.

However, much to Grumpy's delight, the noises have apparently gone completely away!!  It has been nearly a tank full of gas and several days since another peep has been heard from those pesky brakes. Perhaps there remained a dry spot between the metallic contacts in the front and the grease finally worked its way into these areas. Anyway, the "soon as possible" noted in an earlier BLOG and in the paragraph above, will now be postponed at least until fair weather sets in -- maybe as early as May 2011 -- if not later. [Heck, for all Grumpy knows, there might even be a Lemon Meringue Pie event before he gets around to working on the rear disc brakes!]

Reader may be assured that, fair weather or not, the task of lube-ing the rear brake calipers will not be long delayed if that annoying moan reappears.

Disc Brake Pads, Part II; A Sequel

Grumpy's Garage; A Sunny Thursday in November! --

In the last segment, I told the readers about the noise (let's call it a "groan" or a "moan") emanating obviously from one or both of the front disc brakes on Grumpy's Red Rocket. Today, the Grumpy One took matters into his own hand and decided (and acted!!) to do something about this annoying moan. Not because it portended anything catastrophic or potentially damaging, but simply because -- well, Grumpy just got tired hearing the noise everytime he touched the brakes, or made a slow turn to the left. 

Besides, it is embarassing that any "strange" noise should come from a car proudly maintained by the Eminent Engineer of Mechanical things. The noise must be eliminated or fully explained with something other than a bloviated theory.

Grumpy removed the wheels and found that the disc brakes on this Honda are the easiest of all to work on! Two bolts hold the caliper assembly (right) to the fixed part of the suspension. By loosening the top bolt a half turn and removing the bottom bolt, the caliper assembly can be swung upward and laid to rest on the top of the wheel suspension. The brake pads are now fully accessible to examine, replace, or, as Grumpy planned to do this time, to clean the non-braking contact surfaces (above, left and right) and apply some hi-temp grease to these contact areas so that these parts can be free to move relative to each other and thus not vibrate like a bass fiddle when light brake pressure is applied.

The picture at left shows the fine, thick condition of the left front brake pad, thus confirming what was reported in the previous post on disc brakes. Yes, after nearly 86,000 miles these original brake pads are showing very little wear -- perhaps the Grand Mother would prefer that they showed much more wear!!

But, I digress! The non-braking contact points on the brake pad backing are shown on the right with grease applied. Grumpy used a wheel bearing grease containing Molybdenum di-Sulfide. This grease is especially designed for use in high temperature applications, which is the case with disc brakes. The Molybdenum di-Sulfide is a solid lubricant (similar to Graphite) so that, even if the grease is disappated by the heat generated by the disc brakes, the coating of Molybdenum di-Sulfide will still function to prevent friction and/or binding between these contact points. It is when these parts stick together (held by friction) that the caliper unit vibrates to create the moan that has annoyed Grumpy and his passengers.

A critical caveat: Be careful to not get any grease on the brake pad friction surfaces or on the brake disc surface!!

Viva a Red Rocket!! Viva o mal-humorado Um!! Graças a Deus pelo silêncio!!