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RonF
Top Member

809 Posts

Posted - 01/17/2019 :  08:15:22 AM  Show Profile  Reply with Quote
I just finished working on a 2019 with a rear brake clunk, seems like it is fixed.

The rear shoes are 3/4". The temps are 340 on the left and 350 on the right. 1.25" on the stroke.

US Army retired CMBT
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RonF
Top Member

809 Posts

Posted - 01/17/2019 :  08:17:49 AM  Show Profile  Reply with Quote
I just finished working on a 2019 Blue Bird gas with 15475 miles on it for a rear brake clunk.

The shoes measured 3/4" the temps were 340 left 350 right. The stroke is 1.25".

US Army retired CMBT
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wwinters
Senior Member

USA
109 Posts

Posted - 01/17/2019 :  12:16:21 PM  Show Profile  Reply with Quote
did you check the front temp by any chance? the 340-350 is close to what my Internationals are on rear 190-220 on front, I see some hotter but the front also a little hotter. I am use to seeing 100*-150* difference at the most from front to rear. The biggest issue is no wear on front brakes. they are getting air(checked with inline gauge) the slack adjusters are working properly (engineers had us put new ones on also)
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wwinters
Senior Member

USA
109 Posts

Posted - 01/21/2019 :  08:19:57 AM  Show Profile  Reply with Quote
Finally got a Bendix trouble shooting tec that is VERY knowledgeably of their system. It is indeed a brake balance issue. I have hooked in psi gauges for a couple more reading which I had not done, we will see.
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wwinters
Senior Member

USA
109 Posts

Posted - 02/05/2019 :  05:31:32 AM  Show Profile  Reply with Quote
Still no answers to a almost 3 year ongoing question as to brake balance problem BUT a Bendix rep is supposed to be at my shop next week STAY TUNED....
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wwinters
Senior Member

USA
109 Posts

Posted - 03/08/2019 :  06:17:25 AM  Show Profile  Reply with Quote
Well after 3 years a Bendix rep came in and did a brake system check and agreed with what I had be saying for 3 years, there is a brake imbalance that the rear brakes are doing the work. I was allowed to add a QR valve for testing (with NO students onboard)which worked. still have buses down waiting on engineering for approval of adding QR valve...
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jeeptjken
Senior Member

147 Posts

Posted - 03/19/2019 :  12:16:06 PM  Show Profile  Reply with Quote
I sure hope they get this all set as 10 of mine are nearing the end of warranty all have had many many many rear brake jobs none had had a front brake job all are close to 50000 miles front look near new I have a 2019 with 13000 miles on it that needs rears aready bird wont cover that one because anything over 10000 miles is acceptable in there world my worst one will only go about 4500 miles on a set of rears

How did you get the gosinta in the whatchamacallit
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jeeptjken
Senior Member

147 Posts

Posted - 03/21/2019 :  09:24:28 AM  Show Profile  Reply with Quote
was told yesterday that bird is indeed in full knowlage and working on a solution (waiting very impaitintly) as I know they work at .0001 mph so fingers crossed

How did you get the gosinta in the whatchamacallit
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wwinters
Senior Member

USA
109 Posts

Posted - 03/27/2019 :  08:44:53 AM  Show Profile  Reply with Quote
Well still no word on Bluebird engineers allowing the QR valve that seems to get brake balance much closer on the drum brakes...
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Thomasbus24
Administrator

USA
4448 Posts

Posted - 03/28/2019 :  11:31:35 AM  Show Profile  Reply with Quote
QR as in Quick Release? So the brakes are dragging as the bus is taking off, and the valve remedies that, or am I misunderstanding this? I don't have any of these but my curiosity is up on it.
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wwinters
Senior Member

USA
109 Posts

Posted - 03/29/2019 :  04:31:42 AM  Show Profile  Reply with Quote
The problem I am having on the propane Bluebirds are a brake imbalance, the front brakes are not doing their part. I have questioned the crack valves for near 3 years and finally had a bendix rep come to my shop and verify the problem I am having. By installing the QR valve it increases the crack pressure allowing the front brakes to do more work. After installing one you can feel the difference in braking, the nose of the bus actually has a little set to it and brake temperatures have changed dramatically. I was getting 480-600 degrees on rear 120-180 degrees on front after installing the QR valve the rears are at 320-400 degrees and the front are at 230-280 degrees, the smell of brakes and smoking is gone. Now Bluebird engineers have to authorize the repairs.
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bwest
Administrator

United States
3783 Posts

Posted - 03/29/2019 :  05:28:01 AM  Show Profile  Reply with Quote
quote:
Originally posted by wwinters

The problem I am having on the propane Bluebirds are a brake imbalance, the front brakes are not doing their part. I have questioned the crack valves for near 3 years and finally had a bendix rep come to my shop and verify the problem I am having. By installing the QR valve it increases the crack pressure allowing the front brakes to do more work. After installing one you can feel the difference in braking, the nose of the bus actually has a little set to it and brake temperatures have changed dramatically. I was getting 480-600 degrees on rear 120-180 degrees on front after installing the QR valve the rears are at 320-400 degrees and the front are at 230-280 degrees, the smell of brakes and smoking is gone. Now Bluebird engineers have to authorize the repairs.



I assume you're shooting the brake rotor itself with a temp gun to get the temps you are talking about? I had never thought of that but that's a great idea to see balance.

Bryan
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Thomasbus24
Administrator

USA
4448 Posts

Posted - 03/29/2019 :  05:45:39 AM  Show Profile  Reply with Quote
QR goes before for after the relay valve? Meaning does it "flood" the control port with sudden pressure or is it creating back pressure at the delivery ports?

I swear I'm not trying to discredit you! My inner engineering nerd personality is just wanting to know more!
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wwinters
Senior Member

USA
109 Posts

Posted - 03/29/2019 :  07:42:01 AM  Show Profile  Reply with Quote
The QR valve goes in the service delivery to rear brake valve causing a slight restriction which is enough to delay the rear brakes enough to allow the front brakes to work a little more. These are drum brakes. I am old school so was use to the proportioning valve in the old systems, it would usually see a 60/40 brake balance and with that when you change the 2nd set of rear shoes you could go ahead and change front ones. But with ABS the system changed to crack pressures to work brakes and the system will work with 15-30 PSI so 2-3 PSI differential in crack pressure can cause a pretty big difference in system operation.
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wwinters
Senior Member

USA
109 Posts

Posted - 03/29/2019 :  07:47:34 AM  Show Profile  Reply with Quote
Yes Bryan, I was temping the drums to check brake balance, from 35 years doing it 100-150 degree differential front to rear is not out of line after heavy braking. the rear should always have the higher heat readings.
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Thomasbus24
Administrator

USA
4448 Posts

Posted - 03/29/2019 :  08:25:25 AM  Show Profile  Reply with Quote
Oh now I understand. Very good idea!
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wwinters
Senior Member

USA
109 Posts

Posted - 04/12/2019 :  1:32:28 PM  Show Profile  Reply with Quote
Well it looks like they only want to approve the QR valve for 5 of the 12 buses that I am seeing the brake balance problem on, I sure thought there were several others seeing this issue with their propane visions?

Edited by - wwinters on 04/15/2019 08:22:38 AM
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jeeptjken
Senior Member

147 Posts

Posted - 04/19/2019 :  03:33:03 AM  Show Profile  Reply with Quote
update from my dealer
after I sent a letter to bird directly I got a response thru my dealer that a bird rep as well as a bendix rep will be on site in the near future ill let you know if its smoke and mirrors or real deal help

How did you get the gosinta in the whatchamacallit
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wwinters
Senior Member

USA
109 Posts

Posted - 04/26/2019 :  04:55:05 AM  Show Profile  Reply with Quote
Well, 3 years and 11 days later and still no answer, Bluebird says it is a Bendix problem Bendix says it is a Bluebird problem, NHTSA can sort it out.
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wwinters
Senior Member

USA
109 Posts

Posted - 07/26/2019 :  1:01:00 PM  Show Profile  Reply with Quote
Well Bluebird finally picked up one of my buses and took to Ft Valley GA for testing. The front brakes do not appear to be working. very little heat build up when using?? Maybe we will finally get answers
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bwest
Administrator

United States
3783 Posts

Posted - 07/29/2019 :  09:18:09 AM  Show Profile  Reply with Quote
quote:
Originally posted by wwinters

Well Bluebird finally picked up one of my buses and took to Ft Valley GA for testing. The front brakes do not appear to be working. very little heat build up when using?? Maybe we will finally get answers



Nothing like waiting until school is about to start!

Bryan
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jeeptjken
Senior Member

147 Posts

Posted - 07/29/2019 :  10:56:59 AM  Show Profile  Reply with Quote
still no word at all I think bird is dragging there feet as 10 of mine will go off warranty in 3 months so were planning on 40 brake jobs this year for just those 10 units

How did you get the gosinta in the whatchamacallit
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wwinters
Senior Member

USA
109 Posts

Posted - 08/01/2019 :  10:06:55 AM  Show Profile  Reply with Quote
jeeptjken send me an email and I will have the engineers from Bluebird call you, they have been testing my bus for several weeks and were shocked to hear someone else was also having this problem.
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jeeptjken
Senior Member

147 Posts

Posted - 08/05/2019 :  05:02:53 AM  Show Profile  Reply with Quote
wwinters ill need your email please

How did you get the gosinta in the whatchamacallit
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wwinters
Senior Member

USA
109 Posts

Posted - 08/05/2019 :  11:49:23 AM  Show Profile  Reply with Quote
wayne.winters@crittenden.kyschools.us
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wwinters
Senior Member

USA
109 Posts

Posted - 08/21/2019 :  10:51:15 AM  Show Profile  Reply with Quote
Well after engineering found front brakes not working and 8 weeks testing the bus is on its way back for me to drive. I will give a AAA to Jeff Reitz CEO/President of Central States bus when he finally found out about the problem he was all over it sending someone to pick up the bus to take it to Ft Valley GA for engineers to test and find problem....
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jeeptjken
Senior Member

147 Posts

Posted - 08/21/2019 :  11:59:20 AM  Show Profile  Reply with Quote
I hope they fix yours I have heard nothing from bird at all and with just a little over a month of warranty remaining I have 9 units of the 17 model year that we cant keep rear brakes on to save or souls all have over 50000 mile all have had 7 to 10 rear brake changes and no front brake changes at all and all fronts look just about new heard from the road tech there next plan is to change the S cams in the front of one unit ????? but nothing from bird at all

How did you get the gosinta in the whatchamacallit
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wwinters
Senior Member

USA
109 Posts

Posted - 08/21/2019 :  1:08:25 PM  Show Profile  Reply with Quote
We are seeing that the fronts are around 30%-35% on the diesel buses and we replace them when doing the 2nd set of rears, seems a 60% rear 40% front is a good wear pattern with 100-150 degree temperature difference. After 6 weeks testing the engineers determined the front brakes were not working. They spent a few weeks testing different things to find out why. I fell it is a crack valve pressure problem due to the extra length on tubing the propane buses have, but the engineers think it is in the mechanical parts? We have seen this since the buses were new so I have a hard time finding mechanical parts on several buses bad from beginning? We will see I am just glad the President /CEO has took aggressive action to get the problem resolved. Jeff Reitz has certainly gain a great deal of my respect...
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Thomasbus24
Administrator

USA
4448 Posts

Posted - 08/22/2019 :  04:40:44 AM  Show Profile  Reply with Quote
Guys, would this be worthy of filing NHTSA complaints on each affected bus? I'm not seeing any for this issue posted publicly yet, but that doesn't mean they don't have them.

I think the argument could be made that excessive brake wear is a safety concern.
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jeeptjken
Senior Member

147 Posts

Posted - 08/22/2019 :  06:54:43 AM  Show Profile  Reply with Quote
That will be my next step

How did you get the gosinta in the whatchamacallit
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wwinters
Senior Member

USA
109 Posts

Posted - 08/26/2019 :  11:16:32 AM  Show Profile  Reply with Quote

Thank you for contacting the U.S. Department of Transportationís Vehicle Safety Hotline Information Center. We have received your email inquiry. It has been assigned to one of our analysts and you can expect a response by the close of the next business day.
Thank you,

NHTSA.dot.gov Response Team
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jeeptjken
Senior Member

147 Posts

Posted - 09/17/2019 :  04:49:29 AM  Show Profile  Reply with Quote
I have submitted mine to NHTSA I feel Blue Bird is stalling as they know these will drop out of warranty soon

How did you get the gosinta in the whatchamacallit
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jeeptjken
Senior Member

147 Posts

Posted - 10/01/2019 :  11:52:37 AM  Show Profile  Reply with Quote
Here we go again now they want to change every component except lines and tanks from the front to the back every single component s cams slacks backing plates shoes drums chambers when will the guessing end and the real fix begin survey says never

How did you get the gosinta in the whatchamacallit
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jeeptjken
Senior Member

147 Posts

Posted - 10/14/2019 :  04:04:27 AM  Show Profile  Reply with Quote
so I have a skid of parts to do the first one they are sending a road tech to change all the parts with same part numbers of the old parts this should be fun said no one ever

How did you get the gosinta in the whatchamacallit
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Thomasbus24
Administrator

USA
4448 Posts

Posted - 10/14/2019 :  06:48:30 AM  Show Profile  Reply with Quote
Is there anything that would indicate it's a revised part on anything? "Rev B" or any such markings?
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