School Bus Conversion Resources

School Bus Conversion Resources (https://www.skoolie.net/forums/)
-   Conversion General Discussions (https://www.skoolie.net/forums/f13/)
-   -   What kind of brakes does your bus have? (https://www.skoolie.net/forums/f13/what-kind-of-brakes-does-your-bus-have-63.html)

Will 06-19-2010 10:59 PM

Re: What kind of brakes does your bus have?
 
I drove 66,000# GVW trucks pulling howitzers in the marines. The old M813 5-ton 6x6 had air over hydraulics and the M923 6x6 5-ton had full air. The M198 howitzer had air/hydraulic. They both had the same 14-liter, nastily ass-pirated 250hp Cummins. The 813 was a 5-speed manual and the 923 was a 5-speed Allison auto. Driving it, the 813 had more power because the torque converter on the 923 was sucking it up. The 923 was better because the cab was a lot wider inside. In neither case did the brakes make a bit of difference. The hydraulics were just as good as the air.

The main issue that is being disregarded here is the benefit of a disc over a drum. A drum is an oven. A schoolbus doesn't have an exhaust brake, generally, and drum brakes are heat ovens. Once the brakes get hot, that's it. You can have lots of pedal pressure, but it isn't slowing you down.

I don't think drum brakes are allowed on heavy-duty trucks in Europe anymore because their stopping distance is much less than discs. Whatever applies pressure to the shoe or pad doesn't matter. It's a matter of convenience. A diesel makes no vacuum so you need a pump. A gasser makes vacuum and a resevoir is cheaper than a pump. The steering pump (hydra-boost) or an electric pump (my bus) can be used to boost hydraulic pressure. The real issue is disc or drum and disc is the clear winner.

XE1UFO 07-20-2010 09:25 PM

Re: What kind of brakes does your bus have?
 
Quote:

Originally Posted by CHEESE_WAGON
My personal observation has been that gas-powered buses typically will not have air brakes, and I have never seen a diesel model with hydraulic brakes.

Mine is a Ford B700, with a 28-passenger Thomas body, 5.9L Cummins diesel and 5-speed standard tranny. Yes, it has HYDRAULIC brakes.

npeace 12-14-2010 08:59 PM

Re: What kind of brakes does your bus have?
 
Air brakes. And I'm surprised no one has mentioned an obvious advantage to air brakes - no nasty brake fluid to deal with and no bleeding of the system. Most of the parts to the sysem are pretty much universal and widely available, and there are no steel lines to bend and rust out. I don't know why some people are scared of air brakes. That doesn't mean you should hop in a bus with air brakes and head across the mountains with no knowlege of the system at all. They are not quite as idiot-friendly as hydraulic brakes, but they are certainly safer and better.

gseufzer 02-18-2011 07:24 PM

Re: What kind of brakes does your bus have?
 
I have 4 wheel anti-lock Air brakes, and very glad to have them. Air brakes are a fail "safe" system, loose hydraulic pressure, no brakes, loose air pressure your going to stop like it or not. the down side would be the maintenance cost buit i think its a small price to pay to be that much safer. G

gseufzer 02-19-2011 06:56 AM

Re: What kind of brakes does your bus have?
 
a good place to look for that crash course is on you tube, look for school bus brakes, I found a bunch of training videos on there that were very good

syke 04-12-2011 01:37 PM

Re: What kind of brakes does your bus have?
 
Our bus is equipped with air brakes.

Kman 08-18-2011 08:37 PM

Re: What kind of brakes does your bus have?
 
We haven't bought our bus yet, but it will be an air brake bus. I have driven many trucks with both air and hydrualic brakes. I have driven cranes, log trucks, aerial lift trucks and fuel trucks with air brakes, I have also driven log trucks, aerial lift, and chip trucks with juice brakes and currently still own a Ford F600 with Lucas-Gerling brakes(I will NEVER buy another). I have no problem working on air brakes and we want the on board air to run air tools for working on the bus and our Jeeps while on the road.

Accordion 01-17-2012 10:14 AM

Re: What kind of brakes does your bus have?
 
Air brakes on my bus. I had to do an emergency quick stop once and was impressed with the stopping ability of the air brakes. I also like the safety feature of the rear brakes locking on if you lose air pressure, although I would never want to be in that situation.

I was impressed that my bus stopped so quickly without screeching the tires.

PDBreske 01-19-2012 01:13 PM

Re: What kind of brakes does your bus have?
 
Four-wheel hydraulic disks with boost supplied by the power steering system on my bookmobile. It stops well.

As someone else mentioned, the main reason any truck that pulls a trailer with brakes and all trains have air brakes is because there is no other way to get the braking system connected from vehicle to vehicle. When a trucker backs up to a load, he just connects the air lines and the system fills the trailer brakes with pressurized air. Done. That would be ridiculously time consuming with hydraulic lines.

Looking at the poll results for this thread, it appears the air brakes reside in about fifteen percent more buses than do hydraulics. It's probably due more to the whims of school districts than the perceived benefits of one system over the other.

If air brakes were so vastly superior to hydraulic brakes, you know very well that someone would have sued all the major car manufacturers for subjecting millions of drivers to an unsafe and inferior system. And the government would have mandated their installation in all cars.

chev49 01-19-2012 02:06 PM

Re: What kind of brakes does your bus have?
 
there are other systems besides air and hydraulic with vacuum over. For example, i recently had one truck that had vacuum over hydraulic trailer. In the late 1930's magazine that i have, they used vacuum that pulled the mechanical rod for the mechanical brakes on a trailer.. and the article on how to build it.
Vacuum requires quick disconnects as well as air.

lornaschinske 01-19-2012 04:38 PM

Re: What kind of brakes does your bus have?
 
Air... and that very annoying buzzer. Back when David & I first met, I had an alarm clock with the same annoying buzzer, but slightly higher pitched. We woke up every day it went off with a headache. Took us a while to figure out it was the alarm clock. I bought a new clock. I really dislike that buzzer.

thommassey 01-22-2012 07:17 PM

Re: What kind of brakes does your bus have?
 
Quote:

Originally Posted by lornaschinske
Air... and that very annoying buzzer. Back when David & I first met, I had an alarm clock with the same annoying buzzer, but slightly higher pitched. We woke up every day it went off with a headache. Took us a while to figure out it was the alarm clock. I bought a new clock. I really dislike that buzzer.

Where was your buzzer located?

HolyBus 12-15-2014 04:14 PM

Re: What kind of brakes does your bus have?
 
Ours is a 12 row '88 International Blue Bird with steering assisted disc brakes. Smooth and firm.

AlleyCat67 10-02-2016 07:10 AM

Jasmine will have air brakes. I won't even consider a bus without them.

As a former long-haul truck driver I know the ins and outs of using air brakes, and in a pinch can get down there and work on them a little bit if needed.

cadillackid 10-02-2016 08:58 AM

I now have 1 of each,

my air brake bus is 4 drums, my hydraulic brake bus is disc front drum rear..

I feel like in a hard stop situation my air brakes react faster and i have more control over precise braking..

the hydraulic brakes hit hard, there is a definite time for the poedal to travel down before good engagement.. in hard braking even a 1/2 or 3/4 of a second can mean stopping soon enough vs not..

I believe air-brakes in a failure situation are much safer.. hydraulic if you lose pressure, pedal just goes to the floor and you have to manually react with emergency brake..

air brakes you get automatic spring brake engagement on brake failure of pressure...

-Christopher

Tango 10-02-2016 11:06 AM

Hydroboost with disks all around.

cadillackid 10-02-2016 11:39 AM

I noticed my hydraulic one is hydroboost with a little motor to run the hydrooost if the engine dies.
-Christopher

Rameses 10-04-2016 11:33 AM

Quote:

Originally Posted by cadillackid (Post 165218)

I believe air-brakes in a failure situation are much safer.. hydraulic if you lose pressure, pedal just goes to the floor and you have to manually react with emergency brake..

air brakes you get automatic spring brake engagement on brake failure of pressure...

-Christopher


^^^ THIS ^^^

I will never own anything larger than a pickup again with hydraulic brakes.

My first rollback truck was an old Ford F700 with a hydroboost setup. I bought it it put the body on a newer truck, but decided to run it for a little while until I had time to do the body swap.

I had just finished dropping off a 10,000 lb excavator at a demo job, so luckily the truck was empty when it happened, but a rusty brake line burst as I was pulling up to a stop sign at the top of a hill.

It was an old single chamber master cylinder, so I lost all brakes. I had engine braked down to almost stopped, hit the clutch and shifted into neutral, and then was hitting the brakes just to keep from rolling backwards at the stop sign. By the time I realized what had happened, I was traveling too fast backwards to get the transmission in gear. I grabbed the parking brake lever, but it was just that, a parking brake and not an emergency brake. It didn't have enough to even put up a semblance of a fight against the momentum that was quickly amassing.

Luckily there wasn't a car behind me when it happened, so I didn't run over anybody. I changed lanes while rolling backwards so I was at least travelling the correct direction for the lane I was in. It's a good thing I did, because I ended up doing about 35 backwards down that hill and had two cars pass me in the other lane before I rolled to a stop about half a mile later on an uphill slope. Dropped it back into third, drove back down that hill, down-shifted and turned back into the demo job I'd come from. Turned the key off with it in first gear and called my wife to bring me a clean pair of pants.

Air brakes. The only way to go.

Seabee890 11-03-2016 02:50 PM

Quote:

Originally Posted by lapeer20m (Post 1487)
I disagree with that post on so many levels! First of all, I actually drive my bus, it doesn't just sit on my property. Iv'e driven about 15 thousand miles in the past year and a half.

Hydrolic brakes are not actuated by atmospheric pressure, I believe almost all of them use vacuum from the intake manifold.

For must of us, if we had to get a brake job done once on our skoolie, those new brake shoes would last longer than our bus. Re-shoeing a bus with air brakes is actually quite simple.

You can't beat the stopping power of air brakes! They are far superior to hydrolic. If they we'ren't better, semi-trucks would all use hydrolic brakes. A kid can press the brake pedal hard enough to lock up all 6 wheels in a bus with air.

It's super easy to adjust air brakes, it takes about 10 minutes total to adjust all four. I do this once every couple months. (I plan to do it a few times on my 5k mile trip across the USA) IF part of your air brake system fails, parts are readily available at any truck repair shop. Air brake parts are nearly identicle for all big trucks/buses.

One huge safety factor with air brakes: If the system ever failes, your bus stops! If your hydrolic brakes fail, better hope you don't need to stop in a hurry.

Who says a skoolie shouldn't go over 45?? I do plan to get to my destination before I die! Most skoolies don't go much over 55 which is a perfectly acceptable speed.

An added bonus is the availability of compressed air for filling tires, or utilizing air tools, and of coarse using those new air horns.

I appologize for being so argumtative, I"m cranky today!

Enjoyed hearing your arguments, I am thinking that this will be the direction I go since I am needing to replace the system that sat for 15years with being maintained or even ran. The clutch pedal is a big ol floppy chunk o stwel at this point and the brake pedal has frozen solid. qould a junk yard be a place to look for parts if I know what I need to find and the condition that it "should" be in?

Tootalltechie 11-18-2016 09:40 PM

I have chevrolet Hydro-vac brakes. My brake lines need to be replaced. I have 2 frame mounted boosters and 2 vacuum tanks. My question is can my system be up graded to Hydro boost? I don't want air brakes because I would have to get a higher classification on my drivers license.
Thanks Gordon

Sent from my SM-G530W using Tapatalk


All times are GMT -5. The time now is 04:14 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.