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 ;D but I don't what to look for and what may be the issue.
Any thoughts or advice for how to approach this issue?
Brake shoes wear going forward,lot of buses will chatter in reverse when you apply the brake just adjust the brakes to much slack
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).
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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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?
Quote from: Scott Bennett on March 16, 2016, 09:03:20 PM
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!
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.
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
Submit a picture of the slack first for identification.
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.
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
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.
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
Quote from: bevans6 on March 17, 2016, 03:41:33 AM
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.
Quote from: jav9956 on March 17, 2016, 08:29:45 AM
Well it is a 1985 102 A3 so it likely doesn't have automatic slack adjusters.
It can have either
I appreciate all the info and warning. I understand this is a critical part of the bus in order to function properly, thankfully that at least does not go over my head ;D.
At this point I do not drive the coach around, the most that I do is turn it on and pull it out and reverse it back in. Now that the build is starting to progress further I want to work this into my specific working knowledge of the maintenance and safety inspection of the bus. I do not just want to do one brake, I want to inspect them all, but I will be starting with the one that has made it evident that there is an issue.
I don't know of anyone in the area who would know how to do this; it would be great to get a walk through on it but this board may be the only option I have in terms of tapping into someone's expertise. I will try to take detailed enough pictures to post here so that you all can see the slack adjuster.
Maybe this is an easy point that just went over my head, but if you adjust one slack adjuster why would you have to adjust them all? As I said, I would like to for peace of mind. However, it seems they operate independently of each other so how would the amount of slack on one effect the amount of slack on another? I don't quite understand that.
Is there an easy way to determine between an automatic slack adjuster and a standard slack adjuster. I am assuming one would have an extra mechanism making it automatic, is that visible so that I can perform easy inspection to determine which one I have? As mentioned, I will also take pictures.
Auto slacks were an option for my 1975 MC8, Saab was the manufacturer, looked a lot like the Haldex of the mid 90's....
Saab? Those Swedes are into everything!
happy coaching!
buswarrior
well here you go Google is your friend... mine require a 9/16 box end wrench :)
https://www.youtube.com/results?search_query=slack+adjusters+air+brakes (https://www.youtube.com/results?search_query=slack+adjusters+air+brakes)
ps i would not own auto adjust slacks >:(
Of course youtube would have something! Thanks ;D
Saab... that is all my roommate drives, he has five of them! He cranks on them himself, all he likes ???
Almost sounds funny having to adjust automatic slack adjusters, not so automatic then are they ::)
Quote from: jav9956 on March 17, 2016, 08:48:21 AM
Maybe this is an easy point that just went over my head, but if you adjust one slack adjuster why would you have to adjust them all? As I said, I would like to for peace of mind. However, it seems they operate independently of each other so how would the amount of slack on one effect the amount of slack on another? I don't quite understand that.
Your brakes need to be adjusted equally on both sides, as well as front and rear, although that is not as critical as side to side. If you only adjust one side, then when you apply pressure to the
brakes, that one side will engage before the other, and can cause the vehicle to pull to that side more than the other. In a panic situation, it can be so bad that you actually lose control of
the vehicle. Equally adjusted brakes will apply pressure equally on all wheels, and will keep the vehicle in a straight line during a panic stop.
That make sense. So you basically want to tighten down and back off the same on both sides of the bus. I am guessing the only reliable way to know exactly what the slack adjuster is set to would be to set it yourself, there is not a way to visually inspect this? For instance, I can't simply go to the drivers side steer tire, measure the distance, and then set the same distance on the passenger side steer tire?
I think your problem is that a clown adjusted your brakes last time.
Quote from: jav9956 on March 17, 2016, 08:48:21 AM
I don't know of anyone in the area who would know how to do this; it would be great to get a walk through on it but this board may be the only option I have in terms of tapping into someone's expertise. I will try to take detailed enough pictures to post here so that you all can see the slack adjuster.
There's no substitute for having a buddy looking over your shoulder. Any truck driver SHOULD know how to adjust manual slacks but there's plenty of truck drivers who are just steering wheel holders. If you know someone who has gray hair and a CDL he should be able to show you what to do.
Auto slack adjusters work best when used every day. In the case of motorhomes where we replace tires based on age, not wear - the brakes aren't used enough to create the wear needed to keep the auto adjusters exercised. The lack of movement allows the grease to harden & that hardened grease prevents the mechanism from indexing.
That is why some prefer manual adjusters.
Welcome to the madness.
With some safe clearance underneath the bus, like on ramps and blocked for sure.
Its possible to take a look at the slack adjusters, and the automatic types will have a small bracket attached to it in some way, many are L shaped with a slot with a bolt fastening it and also to something else stationary like a pipe/tube.
This bolt is also used in initial setup adjustment.
All that aside when the air is built up to governed cut out setting, and several wheels blocked. If checking the rear have many wheels blocked to secure bus movement and adjustment should be checked with park brake "not applied"
You can have someone apply the brakes and watch the chamber rod move through its travel, this part is a measured area of DOT inspection.
If you can put a piece of tape around it for temporary measure or install some orange plastic things designed for the purpose, anyway mounted against or taped next to chamber housing.
So when the brake is applied or manually applied carefully with pry bar the distance can be measured between chamber housing and previous applied tape, giving a figure for record and or adjustment.
my best 2 cents, probably to download a manual for it.
good day there
Floyd
Man I wish I were closer to you. If you can take some pics of your adjusters and post them here it would be awesome. You're really good at posting pics here...curious now whether you Haw autos or manual
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Quote from: jav9956 on March 17, 2016, 11:46:08 AM
Of course youtube would have something! Thanks ;D
Saab... that is all my roommate drives, he has five of them! He cranks on them himself, all he likes ???
Almost sounds funny having to adjust automatic slack adjusters, not so automatic then are they ::)
two reasons...no one greases them as thy should with the right stuff, and kinda like a Harley Davidson...if you want to be one with your machine you gotta roll in the mud..the blood and the beer :)
it sucks to find out the auto slacks failed when you are running into the @$# end of a school bus full of 1st graders... just sayin, i don't trust them...
Quote from: jav9956 on March 17, 2016, 01:28:41 PM
That make sense. So you basically want to tighten down and back off the same on both sides of the bus. I am guessing the only reliable way to know exactly what the slack adjuster is set to would be to set it yourself, there is not a way to visually inspect this? For instance, I can't simply go to the drivers side steer tire, measure the distance, and then set the same distance on the passenger side steer tire?
simply put no... but there is a maximum travel measurement, there is no minimum i run mine tight as tight and back off 4-5 clics and go by drum ring...but i bet i've adjusted 5000 rigs... not wheels. and 80% of those while dump truck drivers were eating lunch... in the mud.. on Sunday's, uphill both ways during grade school :)
PS you can replicate the slack travel by using a crescent wrench as a fulcrum prying the direction of application..
You can also buy a little tool called a brake buddy, it is the adjusting wrench and safe pry bar for manually stroking the chamber all in one tool. Cheap and helpful.
Ryan.
Quote from: MB LeMirage on March 17, 2016, 08:43:59 PM
You can also buy a little tool called a brake buddy, it is the adjusting wrench and safe pry bar for manually stroking the chamber all in one tool. Cheap and helpful.
Ryan.
never seen one... got a picture :)
http://flxibleowners.org/article-the-brake-system-an-airbrake-primer/ (http://flxibleowners.org/article-the-brake-system-an-airbrake-primer/)
Quote from: eagle19952 on March 18, 2016, 08:30:31 AM
never seen one... got a picture :) I have a OTC brake buddy never use it takes to much room to work
http://flxibleowners.org/article-the-brake-system-an-airbrake-primer/ (http://flxibleowners.org/article-the-brake-system-an-airbrake-primer/)
If your brakes are out of adjustment, (you have to measure the amount of slack), with automatic slack adjusters, then the adjusters are faulty and should be replaced. Taking up the slack with a wrench is just masking the problem and is dangerous. I would replace with manual slacks if you don't already have them.
JC
Brake stroke needs to be measured, in order to decide whether to adjust.
Installing a set of brake stroke indicators is a great way to accomplish this.
After a manual adjuster has been adjusted, measure the applied stroke to confirm everything is right.
An automatic adjuster that is found over-stroking is broken, or there are other brake related problems, all of which needs a technician level knowledge to diagnose and repair. (worn bushings, cracked drum, cracked/bending mount, broken bits)
If all this brake stuff was simple, you have to ask yourself why brakes continue to be the number 1 defect when the authorities inspect commercial vehicles?
If the people who get paid, and know they are exposed to regular roadside inspections, can't get it right....?
Read a lot, publications from reputable sources, take a course, pay attention to the consequences of glossing over the irregularities or jumping to conclusions as to the defect that it looks like.
happy coaching!
buswarrior
Quote from: buswarrior on March 18, 2016, 09:13:14 AM
Brake stroke needs to be measured, in order to decide whether to adjust.
If all this brake stuff was simple, you have to ask yourself why brakes continue to be the number 1 defect when the authorities inspect commercial vehicles?
If the people who get paid, and know they are exposed to regular roadside inspections, can't get it right....?
happy coaching!
buswarrior
Seriously...adjusting the brakes/slacks has got to be the simplest maintenance that can be done with a tool..on a vehicle/rig so equiped.
Heck it is easier than greasing...easier than an oil change...
The reason it isn't done are lazy complacent drivers who think it beneath their status and dignity...steering wheel holders. :(
I recall the argument as to who is ultimately responsible to adjust the frictions on 100T cranes. It is virtually impossible to satisfy a crane operator. As a master mechanic, I would not allow any operator/driver on my job that wouldn't or couldn't adjust their own.
Yup.
Here is the break in question. Interestingly enough I did not hear any issues when reversing this weekend. That is either very good or very bad. I have not played around with any adjustments as of yet. To my untrained eye these are not automatic slack adjusters but perhaps someone who knows what they are talking about can fill me in!
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That is a manual adjuster. The spring loaded lock ring around the adjusting bolt should be out farther and almost even with the outside edge of the nut. When you are done adjusting, you turn the bolt a little one way or the other so the ring springs up to lock the bolt in position.
JC
Needs some grease via the zerk, and some penetrating oil around the collar to free it up.
This whole area would benefit from the pressure washer.
A caution, all that crud ends up on the ground. Don't wash it off someplace that will get mad at you for the mess.
happy coaching!
buswarrior
And, don't underestimate the importance of that lock ring that should pop out to secure the adjusting bolt. Many years ago, when I had the department heads of both Transit Operations and Maintenance reporting to me, I'd walk through the shop a few times every day. I recall seeing one fishbowl in every other day for a while, and asked what was going on. Turns out, I was the only one that noticed that it was the same bus in for a brake adjustment every two days. Made them dig deeper, and the lock ring wasn't popping out to do its job.
Arthur
Jav, its a standard time for the putty knife and a pan. I'm passing on that scraping party.
Only in an emergency would I adjust without a bit of scraping. I tell you I still to this day haven't got a "shorty spray wand" but musta swore a hundred times I would!
Nothing like all hid up in an undercarriage with a three foot pressure wand.
Uvex makes some nice clear goggles, I need another pair to think about it.
Good day there
Floyd
it is clearly evident that those have been neglected... but... they are in the wide open, easy access (many are not)... I would remove them and scrape clean and soak in diesel then re grease...pull the pin and a snap ring... easy peasy... ;D
and heck the clevis for wear too they are cheap...
I see there is agreement that the brakes need to be cleaned... I will add this to the list of things to do ;D.
I will report back with pictures once finished with cleaning and adjustment in the upcoming month or so...
Yes, It is spring brake come to think about it ;D
Have a good week there, then a dissertation
cheers
Floyd
Accumulated dirt like that is evidence that nobody has touched that adjuster in some time.
That suggests to the experienced eye careless preventive maintenance.
In a commercial enforcement situation, it would attract unwanted attention, like waving a flag in front of a bull.
And excess grease hanging around helps start those wheel end failure fires.
Clean equipment is easier to maintain, and sends the message you want: Somebody cares about this vehicle.
Nobody wants to unwittingly attract the attention of an enforcement officer, and getting full body dirty every time you go near the coach gets old fast.
happy coaching!
buswarrior
I don't know if this has been mentioned before, but S-cam brakes are single leading shoe design. They have a leading shoe and a trailing shoe, and the leading shoe has a "self-servo" effect. Basically the geometry of the shoe install mechanically drags in into the drum surface, so there is a mechanical boosting effect and it does far more of the braking work than the trailing shoe, which mechanically is thrown away from the drum surface as the drum rotates. This means that the shoes wear differently, and with different patters, yet the adjustment is equal for both. Which shoe is leading and which is trailing is completely dependent on what direction the drum is rotating so when you drive backwards the normal trailing shoe is leading and grabs unusually hard for it, and the normally leading shoe has almost nothing to do. This is a big cause of odd noises and grabbing brakes when driving a vehicle with single leading shoe brakes in reverse.
Brian