Brake Adjustments

[Dave5Cs]

Agree with Tom C. My 5C though has manuals on both front and rear. To do the rears I have to be up on my ramps to get to them or take off back tires.

[luvrbus]

Old school guys would insert a business card tighten till you could not pull the card out, back off till the card came out easy lol that is high tech stuff there

[eagle19952]

Auto slacks and auto drains....
There are at least 11 other things one should be looking at while under the rig.
Never been there and you'll never know.
I would not have auto slacks.

[buswarrior]

Auto slacks doesn't mean you ignore them.

On the same interval that you feel the need to adjust, you measure the stroke, or look at your installed stroke indicators to confirm they are in adjustment.

With this hobby going the same way as the professional drivers, might be a good idea for 'em all to have auto slacks? Nothing getting checked anyway...?

I am no fan of auto drains either...

Happy coaching!
Buswarrior

[Fred Mc]

What is involved in installing stroke indicators.

[GnarlyBus]

After my recent air dryer purge valve experience, I've been studying the air and brake system of my bus. I have a way better understanding of the brake system now.

I actually think it wouldn't be a bad idea to make people get air brake certified to drive one (even for personal use). Kinda freaks me out how little I understood before! If you don't know much about your air brake system and how it functions, go on YouTube. There are lots of great videos.

When I bought the bus almost 5 years ago the guy showed me how to add diesel, how to start the engine and how to open the door.

"Ok, need anything else?!" he says to me.

"uhhh... Yah. How do I drive it?!"

After my brief lesson where I learned not to tap the brakes constantly when making a 10 point turn out of his compound, we were on our way and bus life had begun.

After stopping at a Walmart in Oklahoma to get sweatpants to put over our jeans as winter greeted us on our way back to Minnesota, the bus wouldn't start! I started getting worried and frustrated. I hit the switch to start it up in the rear and nothing! The two switches up front were on so why wasn't the engine turning over?!

My wife walked away and asked a trucker if he knew why our bus wouldn't start. "uh, is it in neutral?". My eyes got real wide and I knew instantly he had nailed it.

I walked back to the bus and put it into neutral then it fired right up.

My point in this story is just that this has been a learning experience from me for years now. I started from knowing nothing and without a teacher. I've learned some good stuff on this forum and YouTube.

The more I've learned the more I take safety very seriously. Many systems on the bus need to be inspected and maintained regularly. This is especially true of the brakes. I don't have much extra money and I prefer doing things myself so here I am. Good mechanics are hard to find and no one cares more about my bus than me.

Thanks to all the knowledgeable people who post on this forum. I appreciate it. I don't know a ton so I can't always post on other people's threads and I have a slow time accessing the site without Tapatalk but I try to make up for less knowledge with adding more photos of my little projects for the people who come after me!

[buswarrior]

Brake stroke indicators can be as simple as attaching a zip tie to the pushrod against the face of the chamber and observing the distance it stands off when brakes applied, attached goal posts with a pointer pin replacing the clevis pin for rubber boot equipped pushrods, all the way to an in-cab indicator that shows in the moment stroke.

That one is neat, you'll see a slight lngthening of the stroke if you put some serious heat to the drums.

Google "brake stroke indicators" and click on images to see a forest of them.

Spectraproducts.ca is where Big Transit here got theirs for their extensive support truck fleet.

Happy coaching!
Buswarrior

[bevans6]

What is involved in installing stroke indicators.

Put a tie wrap around the push rod at the face of the chamber with the brakes off, apply the brakes (parking brake is fine for the rears, stick on the pedal for the fronts), measure how far the tie wrap is from the front of the chamber.  Chock at least two tires front and rear if you crawl under to look at the rears.  When I took my air brake course it was pointed out that if I was ever stopped by DOT for a roadside check (quite common in certain places and times in Ontario) I would be in some trouble if I didn't have a push stick for the pedal because checking the brake stroke is part of the mandatory daily inspection on trucks (less so on buses, which in Ontario get mandatory inspections every month/10,000 KM, from memory).  I bought a brake pedal push stick (hook for around the steering wheel, adjustable length, I use it to hold the door open mostly) at my local truck parts store.

[luvrbus]

LOL there is a lot more to a air brake system than adjusting the brakes ,someone told me Bendix had a on-line course now it's probably cheaper than 400 bucks for the hands on course and cold sandwich some Utube stuff I ?

[sledhead]

I took the air brake coarse  ( weekend coarse cost $ 350 and inc. the licence )   and this is the type of clamp I use . you reverse the end of the clamp so it push's the brake peddle and the other end push's under the steering wheel . I think mine is 30 " long . it works great for other things and as of yet have never been asked to use it when on the road

https://www.amazon.com/dp/B07K9ZV8MZ/ref=sspa_dk_detail_2?pd_rd_i=B01H63VLPG&pd_rd_w=qO5yE&pf_rd_p=8a8f3917-7900-4ce8-ad90-adf0d53c0985&pd_rd_wg=5oWn9&pf_rd_r=7T73EH1M2HBRMW9M30S8&pd_rd_r=efd9594b-6518-11e9-9f49-5707d913d0fd&th=1

dave 

[Jim Blackwood]

Thanks for the pic. I probably have a couple of those.

Jim

[buswarrior]

Don't mind the water... we're under flood conditions...

Here's the zip ties used on a truck. With brakes released, the zip tie would be against the chamber, so a quick glance, and all is fine.

Happy coaching!
Buswarrior

[GnarlyBus]

Update:

Pasted from my thread on greasing in case someone needs it here in the future:

We got the jacks, ramps and stands out to grease up the rear end of the bus yesterday. This was our first time lifting the back of the bus up and it went very well. I flipped the dash switch to drain the tag axle air then flipped the valves in the engine compartment to finish draining the tag airbags. Then I backed over two 2x12s and chained up the tag axles. I don't think the chains I've put together were the right size (none came with the bus) as they weren't tight when the bus was up.

We ran up on 2x12 treated ramps. Those were made from an 8' on each side. We normally a board of two for leveling when we're parked. Then we used two 20-ton HF air jacks to lift the bus using the jacking points. We placed the jacks on 12"x12" squares of 1/4" steel channel we'd painted blue with tractor paint to keep them from rusting. (they have 1" lips on two sides and are often used for stair tread in industrial applications but we found them in the steel yard scrap bin. These steel squares were on top of 16x24ish 3/4" plywood to help spread the weight because we were on asphalt. Once we got it up high enough we let the axle down on the ramps and the body rested on the 22-ton jack stands (I love those things). We kept most of the axle weight on the jacks. So we had a some redundancy in case one should fail.

Adjusting the Drive Axle Brakes:

We adjusted the rear brakes yesterday. After greasing the rear end, we double checked the front wheel chocks and got to work. The wheel chocks are absolutely necessary because you need to release the parking brakes to adjust them. I found out I have manual slack adjusters on steer, drive and tag axles. I expected to find autos on the drive but nope.

We lifted the axle off the ramps and started by measuring the brake chamber stroke lengths. The DD3 chambers were adjusted first. The lock sleeve that needs to be pushed down to adjust the slacks were all stuck but freed up easy with a lil' PB Blaster, a wrench and a some light hammering. The drive axle slack adjusters we kind of a pain to reach as the bus wasn't high enough to sit up under it so I had to do some gymnastics to reach them. I tightened them down tight and then backs off 3 notches (per the manual) aka 1/2 turn. I did it multiple times to "practice" and make sure I did it correctly. Then I measured the stroke length. They were good. The angle formed by the slack adjusters and chamber push rods were all over 90 degs when applied which is what you want. I tested my work by spinning the wheels and having my wife hit the brakes (this job is a lot easier with a partner).

Adjusting the Tag Axle Brakes:

Compared to the drive axle, the tags and front axle are super easy to access. When I got to adjusting the tag axle slacks, I noticed an obvious air leak out of the passenger side brake chamber when the brakes are applied. I sprayed lots of soapy water then realized it was coming out of a hole on the side of the chamber. From what I've read this is likely to be a leaking diaphragm. The brakes still applied forcefully. I ordered new diaphragms for both sides. I might just replace the chamber as they are super cheap.

We're gonna do the steer axle brakes today.

[windtrader]

Nice post. I'm needing to do the same soon and just got some inspiration. Like the safety consciousness and measures to make the repair goes as safely as possible.


When you test the brakes, you do this without air I assume? Doesn't seem right to have to run the bus or get the air tanks full but maybe so.

[GnarlyBus]

Glad I could be an inspiration!

The bus does need to be aired up to adjust the brakes. I used a few alt 200 psi, 5 cfm @ 90 psi compressor which works pretty well. See attached photo. I believe it should be kept at above 100 psi. This is so the parking brakes release ( don't forget to chock the front tires!) and so that when you press the brake pedal the brakes activate. It is possible to adjust them by pulling the brake chamber push rod out with a pry screwdriver and measure, but it doesnt seem to be as accurate. The pulling force you can make manually doesn't come close to the pushing force the brake chamber would make. People do it both ways, though.

Hope that helps!