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Topic: Brake Air Cambers and Proportioning Values (Read 799 times) previous topic - next topic

Brake Air Cambers and Proportioning Values

Hi Group,
  I have been to a air brake mechanic.  I need help with part numbers for the brake air cambers at each wheel.  I would also need to replace the proportioning values.  The mechanic said that it was tied to the VIN Number.  FT will not give info to me or others about the parts.
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Brake Air Cambers and Proportioning Values

Reply #1 –
my brake rotors and pads were the cheapest at ft. they should give your mechanic the numbers, just not you. they did mine
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Brake Air Cambers and Proportioning Values

Reply #2 –
The U225 and U240 have air wedge drum brakes-- no resemblance to the air disk brakes on other models.  Work very well, but parts and and servicing are unrelated.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Brake Air Cambers and Proportioning Values

Reply #3 –
ForeTravel does not have any of my brake parts.  Just FYI

95 U240 36'
Meritor Rear Service Brake Air Chambers x673276L12  &  z333276L12  Type 12

        Front Service Brake Air Chamber v353276p16    Type 16

Hope to get some and get them changed out tomorrow.

Pat,
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Brake Air Cambers and Proportioning Values

Reply #4 –
WOW! They did for my 96. Guess you never know for sure. I've had good luck with them so I always promote them. Thanks for letting me know. I was told in 96, FT and fire trucks were the main users of our air-disc brake systems
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Brake Air Cambers and Proportioning Values

Reply #5 –
Quote from: wolfe10 –
The U225 and U240 have air wedge drum brakes-- no resemblance to the air disk brakes on other models.  Work very well, but parts and and servicing are unrelated.
And I would use caution when choosing a mechanic to service your wedge brakes.  It's not that they are overly complicated only that they are different.

FWIW, the braking force is determined by the taper on the wedge that applies the air chamber force to the shoes.
It may be that your brake mechanic doesn't want your work.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Brake Air Cambers and Proportioning Values

Reply #6 –
Yep. Same on the air-disc brakes. My shop didn't bleed the grease out of the calipers and one hung up in 200 miles. You all sent me the service bulletin and I hand carried to him and they fixed the problem at my expense!
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Brake Air Cambers and Proportioning Values

Reply #7 –
I asked some questions then started reading so that I'd understand the operation of the most important system on my RV.  No where did I see proportioning valves as are found on hydraulic systems.  I may be wrong but for the time being any mechanic that tells me that I have a problem with proportioning valves will cause me to take a step back.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Brake Air Cambers and Proportioning Values

Reply #8 –
I had a hydro brake proportioning valve on a piece of highway maintenance equipment, so I know they existed. It was on a chipper, as in seal and chip road repair, it had Rockwell axles all round and a 555 cumins motor.
88 Grand Villa 36' ORED 3208 (throwaway)Cat.
 Build # 3150
Happiness is the maximum agreement of reality and desire.

Re: Brake Air Cambers and Proportioning Values

Reply #9 –
as an Update:
  I now have new numbers from Meritor
Meritor Rear Brake Air X673276L12 Obsolete 
                                    Z333276L12 -> M243276L12  Type 12
                                    R63276T20 inActive                  Type 20

Meritor Front Brake Air V353276p16 inActive              Type 16

I am confused,  FT OEM #Z333276L12 updates to  M243276L12 , going by the axle tag the number should be R63276T20.  The first number is a type 12 chamber and the second is a type 20???  On top of that can't get the chambers due to lack of sales.  So I sent pics to a local truck repair place(they will not work on MH) and they said that the chamber is a common 30 30 with round connection ports. 
Why would FT have put a smaller chamber on rather than follow what Meritor recommends??  Why now does the MH have a 30 30 which is bigger than the OEM??  Only help FT gives is the old part numbers nothing else.

Pat,
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Brake Air Cambers and Proportioning Values

Reply #10 –
Be glad as the 30/30 can be found anywhere. I still have 4 new ones from the crane business I bought for spares.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Brake Air Cambers and Proportioning Values

Reply #11 –
Update:
  Some of the air leak issues was the air control valve (brake release knob).  I replaced all the brake air chambers, front new type 16 and type 24/20 on the rear.  On the way to Port Aransas, TX (Surfside RV Park), we noticed a thump under our feet when the MH hit large bumps.  Well when I checked this morning, guess what I found, the new brake air chambers on the front are hitting the frame/body of the MH.  Check out the pics.  The new ones are larger.

Holding 40 psi after 15 hrs.
Pat,
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Brake Air Cambers and Proportioning Values

Reply #12 –
Is it just the chamber clamp bolt hitting?  If so it can be indexed 45* from where it is now.  With this being the front you can swivel it around just don't do nothing but loosen just enough to move clamp..  The rear contain a wild cat and isn't a DIY.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Brake Air Cambers and Proportioning Values

Reply #13 –
Update:
  I did loosen the nuts on the band on the air chamber.  I moved the band around some.  It was not enought, on the way home I heard it hit the frame.  The other side was not hitting the bolt, it was the band.  I went back to the shop that did the work and got the old chambers.  After looking very close and finding on the rear, I found "midland t-16".  I looked this text up on inet and found the same chambers I have.  I bought 2 of the 6 on ebay site for $45.00 each plus $20.00 each shipping.  With this information I also now know that some FORD trucks use the same chambers, NaviStar trucks also use them.  I also now know that I do not understand why a type 16 chamber from one company/application is different from another???..?  In other words I have 2 type 16 chambers that are different from 2  MIDLAND T-16/N36216/NAVISTAR 593401C9 and FORD number.  I know they are different size and shape, bolt pattern and size are different.  Why?
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Brake Air Cambers and Proportioning Values

Reply #14 –
Here is another pic>
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Brake Air Cambers and Proportioning Values

Reply #15 –
There are standard stroke chambers and long stroke chambers. Looking at the Midland/Haldex specs the outside dimensions are about the same. The major difference is the long stroke chambers have a wider mounting stud spacing.
Steve & Sandy
2003 U320 4220 WCDS, build#6160
Motorcade #17794
USMC '67-'71