Brakes Act Funny in Reverse

[jav9956]

The front right wheel has an issue with breaking in reverse. It makes quite the noise and rattles the bus. Everything seems to work fine when in drive, it is only in reverse. I want to start investigating this issue but don't know where to start. Of course, starting with the brake itself would be great  but I don't what to look for and what may be the issue.

Any thoughts or advice for how to approach this issue?

[luvrbus]

Brake shoes wear going forward,lot of buses will chatter in reverse when you apply the brake just adjust the brakes to much slack

[jav9956]

There is too much slack causing the chatter?

Just adjusting them sounds easy enough if I knew what I were doing! I will take a look in my manual to see what that involves, any pointers are appreciated (keep in mind that I am very new to this, so even the most basic information helps).

[Scott & Heather]

Bjorn, your slack adjusters are easy to adjust. If you look at your brake can (turn the tires if you need to it will help with access). There's a rod that goes to an arm that you can adjust. Here's a pic. Basically you want to use a socket and Rachet to tighten the nut until the brake shoe hits the drum. Then back off the bolt one quarter of a turn (or at most a half turn) and you should be all set. Fronts are easy. Rears are a pain to get to.



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[jav9956]

I believe I found how to do it in the manual.

By the look of it I am supposed to jack the tire up and disengage the locking sleeve, turn the adjusting screw till brake shoe is tight against the brake drum and the brake chamber push rod is in the released position, and finally back off the adjusting screw two notches for the front units.

Does this sound like the correct line of action?

I am assuming the wrench for the locking sleeve and adjusting screw are all standard sizes and I will not encounter for any unique tools?

[jav9956]

Bjorn, your slack adjusters are easy to adjust. If you look at your brake can (turn the tires if you need to it will help with access). There's a rod that goes to an arm that you can adjust. Here's a pic. Basically you want to use a socket and Rachet to tighten the nut until the brake shoe hits the drum. Then back off the bolt one quarter of a turn (or at most a half turn) and you should be all set. Fronts are easy. Rears are a pain to get to.



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Thanks for the picture and description Scott, you replied while I was also replying. Impeccable timing!

[jav9956]

I suppose I am lucky it is only my front right tire than. Should be easy enough. I will try to tackle the issue this weekend.

[bevans6]

I would find it odd if a 102D3  still had manual slack adjusters on the front wheels, I would have expected that it would have automatics by then.  I would not personally start randomly adjusting an automatic slack adjuster.

Brian

[chessie4905]

Submit a picture of the slack first for identification.

[gumpy]

It can be caused by rust buildup from lack of use. My bus chatters like hell when I back out of the driveway after not having used it for a few months. Stops this after
I have driven a few blocks and the drums get cleaned up.

Brakes are kind of critical, and you should be adjusting all of them on a regular basis. Don't just adjust the one you think is chattering.

If you are not familiar with this procedure, which it sounds like you are not, you really should find someone to walk you through it. Especially on the drive axle as you
will need to block the bus and release the parking brake to adjust them, putting you in potential harms way.

Be safe.

[buswarrior]

Please understand that if you get this procedure wrong, the brake will not work, and the bus will not stop properly.

Yes, believe it or not, busnuts have been known to back it off instead of tighten it...

There are brake defects that disguise themselves as "simple" brake adjustment.

The manufacturers of brake components have detailed materials to inform you in this regard, and many have excellent videos.

It is especially important that you have the specific instructions for your brand of slack adjusters, if they are automatic. Between manufacturers, the procedures can be completely opposite. Doing the wrong thing can break the automatic adjuster mechanism.

Measuring what you start with and measuring what you end up with so you can determine what you accomplished, or not, is instructive.

Throwing a wrench on it, and not measuring the results, is reckless, with all that has been learned up to 2016.

Here in the province of Ontario, there is a nice course and a qualification in brake adjustment from the same smart people who license the technicians.

happy coaching!
buswarrior

[eagle19952]

 IF you adjust one, you MUST adjust them all, .... easy to get to or not. 
BW is right, odds are if you adjust one wrong, they will all be wrong. This would certainly ruin your day.

The most common error is while adjustig it seems "easy" and you continue. If it feels easy... you are doing it wrong.
Next there is a procedure for adjusting manually the auto slacks.
It is always employed when replacing new.
Otherwise you spend a bit of time wondering when they will work... possibly as you are headed into a multi car pile up....

Find a mentor nearby.

[luvrbus]

Any one that has done a major brake job on a bus most of the time and they should be the drums are turned with a pattern to make the shoes run inwards and when you back up the pattern changes then they chatter with to much slack he does need to adjust all 4 but it's not a rocket science if he follows his manual   

[jav9956]

I would find it odd if a 102D3  still had manual slack adjusters on the front wheels, I would have expected that it would have automatics by then.  I would not personally start randomly adjusting an automatic slack adjuster.

Brian

Well it is a 1985 102 A3 so it likely doesn't have automatic slack adjusters.

[luvrbus]

Well it is a 1985 102 A3 so it likely doesn't have automatic slack adjusters.

It can have either