Bus Conversions dot Com Bulletin Board
September 02, 2014, 07:07:08 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an E-Mag Subscription: You can zoom in to make the text larger and easier to read.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 2 [All]   Go Down
  Print  
Author Topic: AIR BRAKE CHAMBER KNOWLEDGE  (Read 2998 times)
wayne
1990 Setra 215 HDH
Jr. Member
**
Offline Offline

Posts: 79


www.mybusgarage.com




Ignore
« on: October 18, 2011, 10:07:30 AM »

Does anyone have extreme knowledge of air brake systems from Bendix or MGM? I have a 1990 Setra 215. I matched up the tag axle brake chambers but the drive axle has a spring chamber with a crossover tube. Not sure what the tube is for, maybe a vent. The chamber is aluminum with Bendix & MGM cast in it. It looks like a type30/30. I talked with bendix and was told they never did anything with MGM. I talked with MGM and was told they never did anything with Bendix. After I sent a picture they said maybe they did but there is no info on it and it must be obselete. 
Logged

belfert
Hero Member
*****
Offline Offline

Posts: 5426




Ignore
« Reply #1 on: October 18, 2011, 10:47:59 AM »

Can't the service brake side be replaced separate from the spring brake side?  What are the chances someone replaced one side with a different brand name?
Logged

Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
bevans6
Hero Member
*****
Offline Offline

Posts: 4600


1980 MCI MC-5C




Ignore
« Reply #2 on: October 18, 2011, 11:29:57 AM »

Can you post the picture you took?  Where does the cross-over tube start and finish?

Brian
« Last Edit: October 18, 2011, 12:06:07 PM by bevans6 » Logged

1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Spicer 8844 4 speed Zen meditation device
Vintage race cars -
1978 Lola T440 Formula Ford
1972 NTM MK-4 B/SR
luvrbus
Hero Member
*****
Online Online

Posts: 12325




Ignore
« Reply #3 on: October 18, 2011, 12:04:37 PM »

Could be somebody replaced the chambers on a Bendix housing both the Haldex and MGM will work on a Bendix housing


good luck
Logged

Life is short drink the good wine first
Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #4 on: October 18, 2011, 12:38:38 PM »

I know what your talking about. You are referring to a crossover from the emergency chamber to the service chamber on the same maxi I think. Right Huh

Those 2 small holes that the tube connects are vent holes on the backside of  the diaphragms so that positive pressure is not created when the diaphragm is pressurized.

Not all maxis have this crossover because it is not really necessary. It is an afterthought in an attempt to keep out dirt and grime and limit corrosion.
Logged

Signing off from Cook County Ill. where the dead vote, frequently.
bevans6
Hero Member
*****
Offline Offline

Posts: 4600


1980 MCI MC-5C




Ignore
« Reply #5 on: October 18, 2011, 12:44:21 PM »

There was a long conversation recently about Maxi chambers, how expensive they are and how they can be replaced with normal spring brake chambers.  If that's what this turns out to be.

Brian
Logged

1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Spicer 8844 4 speed Zen meditation device
Vintage race cars -
1978 Lola T440 Formula Ford
1972 NTM MK-4 B/SR
wayne
1990 Setra 215 HDH
Jr. Member
**
Offline Offline

Posts: 79


www.mybusgarage.com




Ignore
« Reply #6 on: October 18, 2011, 12:48:35 PM »

The words "BENDIX" AND "MGM" are cast on the same housing. I think Joe is right about it being just a vent tube, so does that mean I can replace it with a type 30/30.
Logged

Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #7 on: October 18, 2011, 12:51:16 PM »

I can get 30/30s for 45 bucks a piece. prevo uses 16/24s on the tag those are pricey even more than 30/36s that are 175 a piece and you see on many bus drive axles.

Ususally I see folks with older stuff upgrading to maxis not the other way around.
Logged

Signing off from Cook County Ill. where the dead vote, frequently.
Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #8 on: October 18, 2011, 12:59:36 PM »

1 question is there a tag axle and if so are there maxis on that axle too?

If so 30/30s are good. If however you have a 3 axle bus with only 1 axle with maxis you should use the 30/36.

I can tell you from personal experience owning a bus with only 1 axle with maxis (parking brakes) I have encountered this.

.... if you are not right on top of the brake adjustments you will know it because when they get out of adjustment a bit too much and you are on unlevel pavement the buss will still roll after the parking brake is set. And that's with 30/36s so you can assume the situation would be even worse with the 30/30s.
Logged

Signing off from Cook County Ill. where the dead vote, frequently.
wayne
1990 Setra 215 HDH
Jr. Member
**
Offline Offline

Posts: 79


www.mybusgarage.com




Ignore
« Reply #9 on: October 18, 2011, 02:02:00 PM »

I'm getting a little confused, I thought 30/30's were a maxi. I better read up a little more before I continue.
Logged

prevosman
Full Member
***
Offline Offline

Posts: 185





Ignore
« Reply #10 on: October 18, 2011, 02:37:25 PM »

Does anyone have extreme knowledge of air brake systems from Bendix or MGM? I have a 1990 Setra 215. I matched up the tag axle brake chambers but the drive axle has a spring chamber with a crossover tube. Not sure what the tube is for, maybe a vent. The chamber is aluminum with Bendix & MGM cast in it. It looks like a type30/30. I talked with bendix and was told they never did anything with MGM. I talked with MGM and was told they never did anything with Bendix. After I sent a picture they said maybe they did but there is no info on it and it must be obselete. 

The crossover tube is not important because it does not impact how the brake chamber functions. I think you are describing a spring brake parking or emergency brake coupled with a service brake. Let's presume it is a 30/30 which is common. If you get one with the same stroke you should be good to go.

I cannot explain why you see Bendix and MGM cast on the unit. Just take your old one to your local purveyor of brake chambers and they likely can sell you a new one, matching the stroke you have. 30/30 mis not an oddball. If you had an oddball such as the 16/24 mentioned previously it might have been built from a piggyback which might have used the spring brake section from one manufacturer, and the service brake section from another.
Logged

Jon Wehrenberg
Knoxville TN
1997 Prevost Liberty
Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #11 on: October 18, 2011, 05:05:44 PM »

Sorry to confuse you. Yes 30/30 are maxis.
Logged

Signing off from Cook County Ill. where the dead vote, frequently.
thunderstruck
Newbie
*
Offline Offline

Posts: 42





Ignore
« Reply #12 on: October 18, 2011, 05:17:09 PM »

30/30's are the most common and should run about $100 each. probably the reason you see two brand names is the outter parking brake chambers were replaced at some point. I just replaced two 30/36's and they cost me $130 each...
Logged

PREVOST H3-45 Featherlite Vantare
Ft.Lauderdale, Florida.
Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #13 on: October 19, 2011, 03:18:47 AM »

Where did you get 30/36s for 130 bucks that is a good price on those Huh

Or possibly that was for a "piggyback" and not the entire thing.

« Last Edit: October 19, 2011, 03:23:12 AM by Joe Camper » Logged

Signing off from Cook County Ill. where the dead vote, frequently.
buswarrior
Hero Member
*****
Offline Offline

Posts: 3571


'75 MC8 8V71 HT740




Ignore
« Reply #14 on: October 19, 2011, 05:32:23 AM »

Hello Wayne.

The discussion so far is pretty good.

Sounds like you may go shopping for a relatively inexpensive replacement.

Do be sure that you have no space issues with the shape of your current chamber and the replacement. Some coaches (besides the MCI and DD3) have clearance issues, and chose the particular, and often rare, chamber to solve a packaging problem.

Joe Camper's suggestion to upgrade to a bigger parking portion if you only have spring brakes on the drive is worthy of consideration. The newer coaches are coming from the factory with a lot more parking/emergency braking strength than your 1990 has.

And, if space permits, consider an upgrade to long stroke chambers. That will give a busnut more stroke to defend against the loose brake adjustment creep as described above by Joe Camper.

happy coaching!
buswarrior







Logged

Frozen North, Greater Toronto Area
akbusguy2000
Full Member
***
Offline Offline

Posts: 172





Ignore
« Reply #15 on: October 19, 2011, 09:58:58 AM »

Pictures would help a lot.

"Crossover?" - Think anti-compounding setup.

maybe.

tg
Logged
Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #16 on: October 19, 2011, 10:06:17 AM »

I think our bus at 41000lb and only having parking brakes on the drives is just flat dangerous. I have a set of 16/24 I pulled off of the tag on a 95 XLV and the next time I get under it for anything requiring the same tools for any other reason I will be installing those maxis on the tag on ours. It is a pretty easy upgrade.

That also carries another benefit being. With another axle with parking brakes I can go down to the way more common and less expensive 30/30s on the drive axle if I so choose.

I have pulled 30/30s off of buses that originally came with 30/36s a handfull of times at minimum and when Wayne first started this thread the first thing that came to mind was I wonder if those are original equipment for that chassis or were they also downsized by a previous owner. You should check to see what the book says.

This can happen in 2 ways, 1 out of cost savings 45 bucks vs 175 and the other is ignorance cause to the untrained eye they do look similar

Can anyone say for sure that they know of ANY 3 axle bus chassis with maxis on the drives only came with 30/30s in that location from the factory?
« Last Edit: October 19, 2011, 10:15:59 AM by Joe Camper » Logged

Signing off from Cook County Ill. where the dead vote, frequently.
bevans6
Hero Member
*****
Offline Offline

Posts: 4600


1980 MCI MC-5C




Ignore
« Reply #17 on: October 19, 2011, 11:18:34 AM »

For people like me who are a little slow to pick up things, on spring brakes the rear section of the canister holds a big ornery spring which is held back by the spring diaphragm.  In a 30/36 chamber, the spring diaphragm is 36 square inches.  That means that it can hold back a stiffer spring than a 30 square inch diaphragm can, so it can generate more emergency/parking brake force.  A normal 30/30 canister has a spring that can generate around 60% of a full service brake application, so a 30/36 would be closer to maybe 80%.  These things have to be carefully judged - one thing you don't want is the spring brakes coming on while you are on a slippery road and locking your rear wheels.  It's not just a "more is better, Tim the Toolman Taylor" kind of deal.  But I do think Joe's point is very valid - 30/30's are pretty ubiquitous on a lot of things, and therefore cheaper and easier to get than 30/36's or 36/36's, and may be on there by mistake.

The other thing is that spring brakes often have a vent hose or tube for the spring brake chamber, since it it open to atmosphere you want to keep as much moisture out as you can.

Brian
Logged

1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Spicer 8844 4 speed Zen meditation device
Vintage race cars -
1978 Lola T440 Formula Ford
1972 NTM MK-4 B/SR
belfert
Hero Member
*****
Offline Offline

Posts: 5426




Ignore
« Reply #18 on: October 19, 2011, 11:22:05 AM »

Dina uses 36/36 chambers on the drive axle.  They cost about $150 each to replace which is a lot cheaper than the rotochambers on the tag and steer axles.
Logged

Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
dickegler
Full Member
***
Offline Offline

Posts: 110





Ignore
« Reply #19 on: October 19, 2011, 06:00:18 PM »

Hi All, please remember SAFETY FIRST!

when I bought my bus, it just never stopped well.  it's heavy, about 40k, but I always had an uneasy feeling about braking force.

while replacing linings and drums, I discovered a previous unknowling mechanic has replaced the slack adjusters with wrong type, and replaced cans, but did not cut the rod to the proper length,  the geometry was completely wrong and DANGEROUS

after correcting the deficiencies it stopped much better, but still not up to  my standards,  I then replaced the 30/36 cans with the 36/36 cans on the drive axle.  now I'm very happy with the brake performance.

Long story short, there is lots of information on the web about getting the proper set-up on the cans and slacks.  remember at full brake application the push rod/slack adjuster should approach 90 degrees.  anything else degrades performance.

I wouldnt dream of hiring maintenance labor, but am fanatical about learning the proper procedures to remain safe.

dick egler
Logged

dick egler  atlanta, in  92 prevost/beaver conversion
Joe Camper
Hero Member
*****
Offline Offline

Posts: 666



WWW

Ignore
« Reply #20 on: October 20, 2011, 03:53:31 AM »

Hello Dick.When are you going to come over to Georges and labor on my bus with him for nothing like he likes to do? He makes some very cool tools too. Its a blast.  Grin  Hope Fla was good this year. We need to get togeather again soon.

Yes safety first. Let me make a safe guess.

I will say that on Waydes 90 Setra either it DOES also have maxis(parking brakes) on the tag axle making the 30/30s the right parts OR someone has replaced the correct ones for the drive axle with a set of less expensive smaller and IMO inadequate 30/30 or its only a 2 axle bus sorry for not knowing that LOL

switch gears a bit........

Here is a small piece of something a fellow was asking me to help him with. Shocked

This is dangerous. Very dangerous. Dick combine the prior performance of your bus with something like this and then try to imagine a panic stop or cross town traffic.

IMO the air compressor on this bus is damaged goods now and possibly prone to failure too. Who knows how long this situation took to progress.

 and it is out there more than you would ever guess.

" When I got to the RV resort (Aztec RV Resort in Margate,FL) to check in at the office, I let the coach idle and when I came out the right rear was listing (10 minutes). I got in the coach to go to my lot and the air was just above 50psi and when I accelerated it came up. By the time I got backed in to my lot, the entire coach laid down on all sides evenly."

Poor old bus. Id a laid down too if Id been huffin and puffin trying to stay up like that.

 Anything under about 70 or 80 psi and those maxis were talkin about are no longer sufficiantly released and the brakes begin to drag.


« Last Edit: October 20, 2011, 05:52:44 AM by Joe Camper » Logged

Signing off from Cook County Ill. where the dead vote, frequently.
luvrbus
Hero Member
*****
Online Online

Posts: 12325




Ignore
« Reply #21 on: October 20, 2011, 05:55:43 AM »

You should never replace a smaller size chamber like a 30/30 with 30/36 without doing reinforcements to the brackets you can get away with it for a while but it will catch up with you some day

good luck
Logged

Life is short drink the good wine first
edroelle
Sr. Member
****
Offline Offline

Posts: 351


1998 Royale Prevost




Ignore
« Reply #22 on: October 20, 2011, 09:28:16 AM »

Vehicle brake systems are designed with various considerations.   High on the list, is front to rear balance.   A perfect design would have all wheels start to skid at exactly the same time, under all loads, temperatures, and surfaces.   

Exaggerating, consider a massive rear brake, and a wimpy front brake.   The rears would skid and the front brakes would provide very little braking.   The vehicle deceleration rate would suffer and stopping distances would be much longer.

Be cautious before increasing a brake size, because it may negatively effect the balance and overall performance.

Ed Roelle
Flint, MI

Logged
robertglines1
steam nut
Hero Member
*****
Offline Offline

Posts: 3994





Ignore
« Reply #23 on: October 20, 2011, 09:48:04 AM »

Some responding have factory converted coaches designed for a certain gvw and braking to match. most of our coaches were seated and designed for a differant gvw. I myself have never reached that original gvw after conversion of the 89 seated coach.  Food for thought.  If you have passed that original designed brake. Then you might need to adjust .  Bob     
Logged

Bob@Judy  98 XLE prevost with 3 slides --Home done---last one! SW INdiana
thunderstruck
Newbie
*
Offline Offline

Posts: 42





Ignore
« Reply #24 on: October 20, 2011, 07:10:39 PM »

Where did you get 30/36s for 130 bucks that is a good price on those Huh

Or possibly that was for a "piggyback" and not the entire thing.



L&L Distributors Inc. in Pompano Bch,Fl. compleat unit. I think it was actually $137...
« Last Edit: October 20, 2011, 07:17:49 PM by thunderstruck » Logged

PREVOST H3-45 Featherlite Vantare
Ft.Lauderdale, Florida.
Pages: 1 2 [All]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!