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Excalibrate 03-12-2007 10:04 AM

Air brakes here, had one with hydraulic and was barely adequate once I got it loaded and towed my jeep. Had to make a couple quick stops in the new bus, much better. Some people seem to want to justify their choices by telling everyone else he is right and we are wrong. A skoolie is a personal choice and can be configured in whatever way suites the owner and their needs. It's a freedom thing. Dont f#@k with my freedom man!

the_experience03 07-30-2007 08:53 PM

Re: What kind of brakes does your bus have?
250 hp Cummins? :shock: Do you have a 6CT or ISC (8.3 liter) in 30 passenger bus? Very cool if you do.

Abbott 08-19-2007 01:41 PM

Re: What kind of brakes does your bus have?
As a School Bus Conversion rookie I am finding this thread of great interest. Air-brakes verse hydraulic brakes is something I have been considering myself while researching this subject. I have worked on both types, hydraulics on cars and pick-up trucks, air-brakes on railroad cars. Both are easy to maintain. Hydraulics are well known, air-brakes (for the railroad) would require regularly scheduled COT&S (clean, oil, test and stencil) maintenance. Linkages and shoes would be visually inspected, bearing surfaces (fulcrums) would be cleaned and oiled. One end of the rail car (the B end) would have the airline plugged. The other end of the car (the A end) would be hooked up to an airline that ran through test gauges to bring the air-brake system up to the required specs. (pressure). The test would consist of testing if the cars air system would hold the required pressure (10 minute test). Then the brake system would be actuated and the shoes would be visually inspected for hitting the wheels properly. The linkages would or would not be adjusted and then the emergency system would be tested by simulating a complete air dump. When the car's air system received the proper inspection, maintenance and testing the test date was then painted (stenciled) on the car.

If something in the air brakes system didn't meet the Federal requirements then it would be adjusted or replaced to within tolerances for linkages and shoes. Air valves would require replacement of sections/parts of the valves and so forth. This consisted of loosening a few bolts and/or nuts, replacing a few O-rings and/or valve parts. The replaced valve parts would be sent back to the factory for rebuilding. The linkages and shoes would be replaced with new or used (again depending on Federal requirements) then be sent out for recycling. All in all the air-brakes were easy to maintain and repair once the system becomes well know by the mechanic, in the case of Skoolies, that mechanic may well be the owner/operator.

DizzyIzzy 10-12-2007 11:45 AM

Re: What kind of brakes does your bus have?
I have hydraulic brakes. I like them because I know how to work on them. I find it is best to know what your in for. Now by the time I replace this bus I might think of Air, But for now I like hydraulic. And I don't plan on a another bus for at least 5 years.

hoser 10-12-2007 09:09 PM

Re: What kind of brakes does your bus have?
Air Brakes

87 Bluebird Chevy C60 chassis

Jarlaxle 10-14-2007 01:08 PM

Re: What kind of brakes does your bus have?
Uh-oh. This is not good. I have bad news...I think you have the dreaded Lucas-Gierling brake system. Do you have a pull knob (like air brakes) for parking? Do you have a hydroboost or electric booter at the master cylinder?

Get a L-G brake manual, and MEMORIZE it. Any shop charges an arm, a leg, and your nuts to service these brakes.

the_experience03 10-16-2007 05:35 PM

Re: What kind of brakes does your bus have?
That sure sounds like every L-G brake system I've heard of. I don't know why Ford insisted on using it so much. In theory it's a great system, but in practice it proved to have its issues. Don't let that turn you off at all. Just be aware that the system is a little less common and make sure you understand how it works. Also, check that big main pipe that carried fluid back to the chambers to back off the parking brake and sure it isn't corroded. Everything I've read points to that as the most common failure point bringing you to a rather abrupt halt.

the_experience03 10-16-2007 11:27 PM

Re: What kind of brakes does your bus have?
The ones I have heard of having problems are the ones that actually use a large steel pipe to plumb the pressure back. I have never heard of a rubber version, but that most CERTAINLY doesn't mean it exists. If it is in fact a rubber line you might just be lucky enough not to have problems as I believe this is the retrofit most people go with....30 feet of hydraulic hose to replace the pipe.

BBTC2K 10-21-2007 09:22 PM

Re: What kind of brakes does your bus have?
Mine has good old air brakes...drum and "S" cams. Simple to change those out...The key is to REALLY lube up the rollers and the roll points. We use anti-sieze at the garage. works wonders. Changing out the rear air chambers can be deadly if you arent careful, but it is a relatively fast job. My bus uses nylon line just about everywhere. easy to repair those too. I may have learned a little too much about them... Mine has automaic slack adjusters on it so I don't have to crawl under it except to check the lining, and our company always removes the backing plates to allow for better cooling, so its a snap to check them


Caibel23 01-15-2008 08:32 PM

Re: What kind of brakes does your bus have?
Which pedal is the break?

My new bus is hydrolic, my old bus is air, I have hauled 1 ton of water with air breaks, is there anyone that thinks 1 ton of water would not be so wise with conventional hydrolc breaks?

the_experience03 01-15-2008 09:33 PM

Re: What kind of brakes does your bus have?
1 ton of water is nothing. You have a bigger hydraboost brake system than your everyday 1 ton truck and they can currently handle a payload in the neighborhood of well over 4000 lbs. As long as you aren't exceeding the GVWR of the bus I don't think it will be an issue safety-wise.

Now as far as legality I'm not sure. With water you're probably ok, but make sure there isn't a restriction on unbaffled tanks or on the total number of gallons you can haul without a CDL with tank endorsement. I think you should be just fine at about 250 gallons.

IsolationRide 03-17-2008 05:11 AM

Re: What kind of brakes does your bus have?
Hydraulics. And after reading someones post in this thread. New parts and brake lines for my baby ! WHOAAA BUS !!!! Good Girl.

lapeer20m 06-24-2008 09:53 AM

Re: What kind of brakes does your bus have?
I had 2 buses in my driveway that had diesel engines, gvw over 28K, and hydraulic brakes. Phill's bus also is diesel, big, perhaps 81 passenger, and has hydraulic brakes.

There is a good backup braking system on these buses. it's a 12 volt hydraulic assist mechanism.

I've also had a couple of buses that have air brakes and have similiar gvw's to the other buses.

so weight doesn't seem to play much of a's more a matter of what the school district prefers when they order their buses.

the_experience03 06-24-2008 10:07 AM

Re: What kind of brakes does your bus have?
Here in the north country buses operate almost exclusively with hydraulic brakes. Replacing rusted out hydraulic lines seems to be preferable to dealing with frozen brake components. -20 F is not an uncommonly low temperature in this neck of the woods during morning pickups and the buses need to be reliable at that temperature.

Anyone have any idea what the cost difference is between the two systems?

Navistate 12-01-2008 11:25 PM

Re: What kind of brakes does your bus have?
My 1959 Superior with International chassis has Hydrovac brakes. I feel I should upgrade but they can sit for years and always work.

lapeer20m 12-02-2008 10:24 AM

Re: What kind of brakes does your bus have?
only slightly off topic.....

i just started a new job as a professional firefighter/paramedic. I was very intrigued by the braking systems on our ambulances. They are similiar to this one here:

basically a bus chassis, just a little shorter and for a different purpose.

anyhow, the brake system is new to me. It has air ride suspension, and a regular engine driven compressor, and you set the parking brake with the familiar air brake knob you hear "whoosh* when you set the parking brake. Now for the strange part......When you turn the key on and the engine is off, i can hear the familiar sound of an electric over hydraulic backup brake booster. hmmmmm. After researching, i found that the ambulance has hydraulic disk brakes.

so, it has

air ride suspension

air parking brakes

hydraulic primary brakes, with abs


i'd love to buy one when they are taken out of service. These cummins 5.9 engines and 6 speed electronic transmissions rock! They do 85 or 90 mph right now!

the_experience03 12-02-2008 08:33 PM

Re: What kind of brakes does your bus have?
Does it have air over hydraulic? That's actually a fairly common setup. I suppose they could be air screw style discs, but you wouldn't have a master cylinder then so you would know. Neither option really explains the backup motor noise though I don't think.

Jarlaxle 12-04-2008 06:47 PM

Re: What kind of brakes does your bus have?
They're a common MDT and shuttle bus setup, air-assist hydraulic. The shuttle company I worked for had five buses (three IH 3800's with T444E/AT545's, one Freightliner FB65 with 5.9 Cummins/Allison 1000, one GMC C5500 with 6.6 Duramax/A1000) with that setup.

dieselman69 01-21-2009 06:55 PM

Re: What kind of brakes does your bus have?
air brakes on mine like them very much so far :lol: :lol: :lol: :lol: :lol:

busdriver_phil 01-13-2010 07:11 PM

Re: What kind of brakes does your bus have?
I'm jealous of your Jake. I briefly owned a 72 Crown tandem-axle, Detroit 671/5sp stick, for historic preservation purposes. Sold it to a friend who was in a better position to restore it. I'd love to get one for the Skoolie project but my bus nut friends would kill me if I ever chopped up a Crown to make an RV. They're a page out of history, and I think us bus nuts should preserve as many as possible. On the other hand, they're lots of fun to drive, and I'd rather see one enjoyed in its second life as a nice camper than go to the scrapyard.

As for brakes, I think any bus longer than 6 rows should have air. Air brakes are more powerful, and have the spring-applied failsafe that will stop the bus in most brake failure situations. Medium-duty vehicles (buses, straight trucks) can be ordered with either air or hydraulic. Heavy-duty vehicles (tractor trailers, larger straight trucks, and don't forget trains) always have air - that tells me something.

I had a brake line blow out on a hydraulic school bus - I was able to stop using the other half of the dual system, but it was pretty scary feeling the pedal go to the floor. The parking brake is designed to stop the bus in an emergency, but I've seen those cables snap when applied for normal parking and let go while buses were parked. In normal use, the adjustable handle (twist the knob at the end of the lever to increase or decrease pressure) tends to loosen up, and some brakes may be "applied" with less than enough force. Most parking brakes are mounted on the driveshaft, and any driveshaft or rear axle failure could render the parking brake useless.

If you blow an air line, you can pull the park knob for a full rear brake application. It won't be the smoothest stop, but unless you're on snow or ice it won't lock the wheels. If anything breaks on the system, aside from a failure of the rear brake components, the parking brake will keep the bus from moving until you get enough air in the system.

For the record, school buses are offered in nearly every size with either hydraulic or air brakes. Gas engines usually had hydrovac. Air was an option on gas buses, but rare. Ford buses ordered with hydraulic from the 80s-90s nearly always had the Lucas-Girling system. Some heavy-duty transit-type buses are only available with air, but I've seen models up to 40 ft (84 capacity) with hydraulic. Internationals from the late 90s and early 2000s could be ordered with hydraulic service brakes but an air parking brake - this was driveshaft-mounted but spring-applied and air-released (other manufacturers also offer this system in buses and trucks). Since 05, International has used a power hydraulic brake system (in lieu of the optional air brakes) which includes a spring-applied electric-hydraulic driveshaft parking brake, and gives the pedal more of an air brake type feel.

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