Tag axle grease fitting

[Jim_Scoggins]

1995 Liberty:
Here is a picture of a grease fitting on the brake assembly on the tag axle.
The initial problem was the left tag axle brake would not release. This is a picture of the right side since it was easier to get at for the photo. While fooling around with that issue and doing the lubrication of every thing on the back end we started looking at things closely. There was a screw out plug that was obviously the place where a zerk fitting should be. Neither the left or right side had it while both steers did. This lubrication point has not been touched for 13 years or so. The hell of it is that it has had Prevost service, dealership service and who knows what all. Most of the existing documentation showing "professional" care.

Anyway, we installed the zerk fitting and gave it a shot of grease. Subsequent discussion with one of the board Gurus indicate that this fitting should only be given a very light shot of grease.

So, this leads me to one of my own favorite themes. There are many of us who do all our work on the coaches, many who do some of the work (me), and some who do none of the work. In any case, it still pays to be as knowledgable as one can be about the issue. Anyway, my premise is that "enlightened amateurs" generally do better work than professionals. A professional has as his primary concern the bottom line. Nothing wrong with that. The enlightened amateurs main concern is doing work of the best quality.

With that, my thanks to Jon for his help.

Yes, I will get under there this afternoon and polish the slack adjuster.

[rfoster]

A1 Jon: Jim Scoggins is posting dirty pictures on the board. He said you made him do it.

Good Job Jim, the difference between an owner operator and a service professional is that we drive these and they don't. We and our families are the ones that are in peril or sitting broken down on the side of the road. Makes a difference in how thorough you are vs the professional on issues regarding the bus.

[Just Plain Jeff]

[QUOTE=rfoster;12916]A1 Jon: Jim Scoggins is posting dirty pictures on the board. He said you made him do it.
QUOTE]

OK.

If this keeps up (tattle-tale included), everyone will have to turn off their computers and go to their own rooms.

Good grief.

[Joe Cannarozzi]

That fitting would be the S-Cam bushing for drum brakes. I'm no sure how that is refered to with disc. There is suppose to be a seal on the outer end of the S-Cam so when you grease it and its full the excess grease goes towards the slack adjuster and not the brake shoes. Too much grease and a failing seal will contaminate the brake shoes.


When you have your drum and shoes off that would be a good time to grease this so you can see if grease is getting past that seal or not. 3 or 4 squirts max at these grease points, unless you know that seal is good then grease it till you see grease pushing out at the slack adjuster.

Keeping the S-Cam bushings lubed will keep future brake jobs simple and less expensive. If kept sufficiantly lubed these bushings will last almost indeffinatly and future brake jobs will require simply replacing shoes, drums or rotors and spring kits.

It is important to clean the tips of the grease fittings off before you start to keep contaminants out and from ruining the fittings themselves. I have got in the habbit of power washing as much of the excess grease as possible away after greasing so that it is not allowed to become a dirt magnet. Things tend to stay much cleaner much longer when you do this.

[dalej]

When I adjusted my brakes, I tightend until they hit the drum and then backed off untill they didn't rub the drum. Is this correct?

I had read on Jon's info sharing to back off a 1/3 or 1/4th turn, but the shoes were rubbing the drum.

[Joe Cannarozzi]

Jon was correct. Of course too tight is no good but tighter is better.

After the adjustment is made grab the slack adjuster and pull it to CHECK SLACK. Sometimes its hard to grab and pull, mabye clamp a visegrip to it or something like that. It should travel 1 inch no more than 2. If the shoe is scraping the drum a little that is O/K. 1 inch of slack at the adjuster is what your shooting for.

[JIM CHALOUPKA]

Because the S-Cam grease fitting is associated with the brakes and probably gets hotter than other chassis points should a special purpose (hi-temp. / low creep grease ) be used on these fittings?
:confused: JIM

[dalej]

Joe, I will check the travel, thanks!

[Jon Wehrenberg]

Dale,

When I backed off the 1/3 or 1/4 turn I never heard any dragging. That was all it took to get them fully released. If you are getting some dragging see if you have an out of round condition. When the brakes are fully engaged the slack adjuster arm should be at a 90 degree angle to the brake push rod, or maybe just a little bit past 90 degrees. That last recommendation has less to do with the slack adjuster adjustment, but more with the adjustment on the clevis on the end of the rod, and that position is giving the brakes the greatest mechanical advantage.

Joe,

I agree that working alone you can check by moving the slack adjuster arm, but if you can get someone to apply the service brakes, and then check it with the emergency brake it gives a better idea of travel because you are trying to use your muscles to overcome the shoe return springs and the brake chamber return spring.

On disk brakes there is no "s" cam. Instead the slack adjuster is moving a screw to push the piston against the brake pads. If this area is overgreased the piston may not return and the pads will drag.

Jim,

It is highly doubtful the area of the "s" cam shaft or cliper piston shaft will get hot enough to require hi-temp grease. It is not even called for on the U-joints or driveshaft spline.

[Joe Cannarozzi]

Dale if your running manual adjusters and replaced all the shoes expect to have to do another adjustment very soon. As the shoes match themselves to the drums they will loosen up, sometimes quite significantly. Depending how you drive mabye go 100 miles or so and get under there again.

That innitial 1/4 turn from tight is the static adjustment. Checking actual slack at the adjuster is where you see exactly how loose or tight a perticular hub is, make them all equal. One hub may require 1/3 of a turn to achieve that same slack as another hub with only 1/4 turn on it.

Sometimes there is an extra hole at the pointy end of the slack adjuster and you can put a bolt with 2 nuts on it in that hole, long enough for you to grab and pull so you can check slack easier.