Got A Work Van On GovDeals Today!

[Brewerbob]

The annual maintenance cost thread I think? Not looking it up on my phone.

 

[EastCoastCB]

That's what I was thinking. Bus is going to do the same. Rear engine less so. The engine weight would be transferred to the rear axle since the engine is behind the axle instead of mid engine.

Front engine bus especially a shorty is going to nose dive like a car.

None of mine had had any nosedive like a car at all.

 

[EastCoastCB]

You guys are forgetting why brakes work. There's twice the rubber back there too.

Charlie, for a long bus yes. Wranglers have no towing capacity when they have the same engine as the Cherokee; short wheel base. It's going sideways.

For a shorty, single rear I bet the bias is that of a car.

Shorty's brake systems work just like any bigger bus, man.

 

[Brewerbob]

Shorty's brake systems work just like any bigger bus, man.

4 or 6 tires?

 

[EastCoastCB]

4 or 6 tires?

I missed that part about SINGLE rear wheels. My bad.

 

[Robin97396]

These TC1000s tend to dip a little when they get locked up even at low speeds. At first I was pretty sure I needed some kind of rollers under the front bumper. Haven't tipped over frontwards yet.

 

[Tango-SKO]

Since I am having to build my Shorty's entire brake system from scratch, the bias issue is of interest to me. My system is hydraulic and the Corvette hydroboost should be more than adequate to feed the four wheel disks but I will definitely be adding an adjustable proportioning valve so I can tune the front/rear balance. I've been told on of the best ways to "feel" the balance is to progressively apply the brakes on a flat, straight gravel road to see which set locks up first and by how much. Also been told that the rears should lock first so that you maintain rolling control over the steers. Just a matter of dialing in how much and when.

Sounds like fun, but...I am open to any suggestions.

 

[cadillackid]

in my opinion I would want the drives to lock JUST before the steers.. I agree that you always want the front wheels in some state of spin vs stopped.. reality is that no matter how straight you are driving, locking the rears almost always ends up in the rear end swinging one direction or the other.. if you are in a right lane and it swings right, great you hace some room to play with... but if you are in the middle lane of a bunch of traffic and the only option is an all out straight stop then any swing is bad. and causes the driver to partially lift on the pedal. which reduces the front braking as well..

myu experiences in the DEV bus with rear lock have been in the rain.. so I need to learn about how air brakes apply proportioning..

of course an empty school bus has a little bit of the empty pickup-truck syndrome where theres not alot of rear weight.. so im guessing the mechanical air brakes are proportioned assuming a certain amount of load in the bus? that bus has the single 3-partition tank.. so it doesnrt take long to run out of air if I pump to maintain real wheel rotation.. lower air pressure of course means my fronts are starting to lose effectiveness... a bigger air tank would allow me to pump a little if I need to.
-Christopher

 

[EastCoastCB]

in my opinion I would want the drives to lock JUST before the steers.. I agree that you always want the front wheels in some state of spin vs stopped.. reality is that no matter how straight you are driving, locking the rears almost always ends up in the rear end swinging one direction or the other.. if you are in a right lane and it swings right, great you hace some room to play with... but if you are in the middle lane of a bunch of traffic and the only option is an all out straight stop then any swing is bad. and causes the driver to partially lift on the pedal. which reduces the front braking as well..

myu experiences in the DEV bus with rear lock have been in the rain.. so I need to learn about how air brakes apply proportioning..

of course an empty school bus has a little bit of the empty pickup-truck syndrome where theres not alot of rear weight.. so im guessing the mechanical air brakes are proportioned assuming a certain amount of load in the bus? that bus has the single 3-partition tank.. so it doesnrt take long to run out of air if I pump to maintain real wheel rotation.. lower air pressure of course means my fronts are starting to lose effectiveness... a bigger air tank would allow me to pump a little if I need to.
-Christopher

You don't really want the steer to lock is the thing.

 

[cadillackid]

I dont want any wheels to lock unless its nearly together.. i dont like my drives locking up whileI can still stomp down and get a LOT more braking from my steers
-Christopher

 

[Brewerbob]

I don't want any wheels to lock unless its nearly together.. i don't like my drives locking up while I can still stomp down and get a LOT more braking from my steers
-Christopher

I've done done any hard brake stomping in my bus but you've got something wrong for sure. The rears should lock JUST before the fronts. I dunno how smart bus ABS systems are but it should know the difference between locked and unlocked and self proportion. Being that you aren't scared by technology you should go find a fancy Porsche, Volvo, whatever system that is 4 channel instead of 2.

 

[cadillackid]

I've done done any hard brake stomping in my bus but you've got something wrong for sure. The rears should lock JUST before the fronts. I dunno how smart bus ABS systems are but it should know the difference between locked and unlocked and self proportion. Being that you aren't scared by technology you should go find a fancy Porsche, Volvo, whatever system that is 4 channel instead of 2.

we are mixing up 2 busses here.. my DEV bus is the one with proportioning issue.. it is air brakes No ABS.. the redbyrd is hydraulic with ABS (and it workds perfectly).. I believe my bus is 4 channel from the ABS controller on.. i'll have to look again but im pretty sure it is..

DEV is just plain mechanical no-electronic air brakes.. I need to learn more abiout how air brakes are proportioned.. if its done in the treadle valve or in another device.. that bus is 27 years old its surelty possible that something is worn or not working correct..
-Christopher

 

[dan-fox]

What's the percentage in trying to backfit ABS onto a bus that doesn't have it, perhaps using donor parts from a corpse? Are you going to die trying to get the wheel position sensors mated up to a used ABS computer, or ???? Are those ever found in the absence of a larger managing-systems module like an ECM or similar?

And harking back to an earlier point on the thread, 1st gen Econolines (61-66) also had a 200+ lb slab-o-iron mounted underbody behind the rear axle. One of those unicorn spare parts; hard to find 'em.

 

[Tango-SKO]

Personally, I hate ABS. Having road raced for many years, there are times I may want to lock my tires. I can understand that most drivers probably need it, just don't like it myself.

 

[cadillackid]

Personally, I hate ABS. Having road raced for many years, there are times I may want to lock my tires. I can understand that most drivers probably need it, just don't like it myself.

racing is different. just like traction control... ever watch a NooB with a hellcat try to launch at the track and doesnt FULLY turn off the traction? funny to say the least..

retrofitting air brakes with ABS.. now lets talk dangerous.. if you could even actuate it then. youd run out of air real fast and then would have full rear wheel lock with no control..

hydraulic ABS is a pretty simplistic system.. 4 channel means when a wheel slows down below what any of the others do then it momentarily lowers pressure to that wheel.. the system assumes the driver is still rolling by monitoring how quickly a reduced pressure wheel resumes speed. (or multiple wheels).. detecting wheel lock is fairly easy to do by rate of decel.. and also figuring out that the vehicle has slowed below a set threshold when its allowed to lock the wheels..

im not sure what it takes to retro fit.. other than the proper encoders and speed sensors, computer for a vehicle your weight class and length and tire size... the program is specific... some of them pull in info from the ECM as to throttle, brake pedal input, driveline speed, engine RPM.

the newest automobile systems even read steering wheel and steering rack position.

some vehicles even immitate Limited slip differential by using the brakes.. if wheel spin is excessive on one wheel it will brake that wheel slightly to push a little more torque to the wheel on a less slick surface. I havent seen anything that elaborate on a bus.. but my Jeep wranglers had it. my new dodge pickup has a real locker so its not needed though the description in its computer shows how aggressively to activate the BLSD in the custom tunes.

ultimately in my case on the DEV bus it comes down to making sure all parts are working as they are supposed to .. and yes I do have control over when the rear wheels are locked, but my stopping distance is increased by having to lift off the brake pedal. I tend to drive my busses real conservatively anyway.. but as anyone who drives in cities know, other drivers dont give a crap.. if there is 6 inches to spare to slide in between you and the car in front of you they will do it.. and hit the brakes doing it..
-Christopher

 

[Brewerbob]

Personally, I hate ABS. Having road raced for many years, there are times I may want to lock my tires. I can understand that most drivers probably need it, just don't like it myself.

Long reply disappeared.

ABS> any human in the wet or dry for stopping distance

Trail braking.

Trail braking in a 40 foot bus =

 

[Rusty-SKO]

Personally, I hate ABS.

You can skip ABS day now.

 

[EastCoastCB]

My govDeals work van has abs

 

[Twigg-SKO]

Long reply disappeared.

ABS> any human in the wet or dry for stopping distance

Trail braking.

Trail braking in a 40 foot bus =

ABS may have improved to the point that it is > any driver, but that wasn't the case just a few years ago when tests demonstrated that racing drivers could beat ABS handily. Of course, most drivers couldn't.

Slipper clutches have also appeared on road bikes. They started as a way to get around corners faster, but have other advantages. One of which is a 50% reduction in clutch lever pressure. Very nice in cities, or when you are spending 18 hours on a motorcycle.

 

[cadillackid]

ABS isnt for the highly skilled driver its foe the person who just stabs the brake pedal and still wants to escape when they realize they wont stop..

automatically actuated braking ios incredible. as the computer's reaction time is better than 99% of humans.. my chevy malibu saved me from plowing someone in the driver door (in florida) this past spring... it was on the brakes and slowing the car down before i even had my foot on the pedal...

i wont buy another car without it.. not to mention the auto-distance keeper cruise control is beautiful in mountain-road trips where traffic ebbs and flows alot.
-Christopher