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D2 Governor

In reading the D2 Governor is tied to the front and rear air brakes, if I am reading things right.
There has been a lot of talk about PSI reading in the 130 range, and my front reading when
fully warmed up is about 100 in the front and with the rear reading around 110.  Is this normal or should i they be higher through adjustment?
It is my intention to purchase two of these, one to install immediately and one to keep as a spare.

Can anyone advise what the install procedure should be...ie: Do I dump all the pressure first before removing lines etc
If anyone here could provide me with a "coles notes" edition on how to go about he install it would appreciated
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: D2 Governor

Reply #1
The governor is tied to the wet tank and supplies whatever pressure it has been set for. 90/120 is usually default. It can be reset to 100/130 which helps when airing tires. The front tanks should read the same when the governor shuts off.
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: D2 Governor

Reply #2

As Chuck (craneman) said, when your air dryer purges (blows off) and your compressor cuts out (stops pumping) both of your dash air pressure gauges should read the same pressure.  Your gauges are reading different pressures.  This may indicate one (or both) of your pressure gauges not reading the correct pressure.  Your gauges are probably electronic (instead of mechanical).  There are informative threads on the Forum discussing this subject.  Search for the term "blue module" for more information.

If your system air pressure really does top out at 100-110 psi then this is lower than normal.  Normal is 120-130 psi.  It is possible that your D2 is plugged up with junk inside and not properly controlling the air compressor.  Installing a new D2 is a inexpensive way to eliminate this problem.

D2 installation is not complicated.  Before you do anything make careful note of any air lines connected to the D2.  Draw a diagram if necessary so that you are sure the lines will be reconnected properly to the new D2.  If you have any pressure in your wet tank release it by opening the water drain valve.  If the check valves on your front and rear brake tank inlets are holding your dash pressure gauges may still show pressure when your wet tank is empty...this is a good thing!  Don't worry about it.

Remove the old D2, clean any dirt and grease off so you can see all the ports on it.  The new D2 will come with some pipe plugs.  They should have thread sealant on them - DO NOT use teflon thread tape on the plugs.  Put the plugs in the new D2 in exactly the same place as where they are in the old D2.  Swap any air line connectors on the old D2 over to the new D2.  Use a little thread paste on the connectors.  (See links below)  When you get the new D2 ready to mount, it should look identical to the old one.

Permatex® High Temperature Thread Sealant – Permatex

Amazon.com: Loctite 483631 592 Thread Sealant, 6-Mililiter Tube: Automotive

Then all you have to do is bolt the new D2 in place and reconnect the air lines.  DONE!  ^.^d

https://www.youtube.com/watch?v=FHGcXvDmZ5E


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: D2 Governor

Reply #3
My brake performance had a notable improvement when I replaced my D2 and adjusted the pressure from previous 120# to 130#.
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
"The Pack"  Yogi and Diesel our Airedales -  Charlie our Boxer/Akita mix. Gone but NEVER forgotten Jake our yellow Lab.
NRA Law Enforcement Firearms instructor - Handgun/shotgun
Regional Firearms instructor for national Armored Transp. Co.

Re: D2 Governor

Reply #4
My front and rear air tanks had a 10 psi differential.  I replaced the check valves on inlet side of the air tanks and afterwards my pressure between the two tanks were the same.
2002 36' U270 Foretravel

Re: D2 Governor

Reply #5
It's easy to change I found if, I loosen the airlines before unbolting the D2 from the coach frame.  Then follow those instructions and plug the correct holes.  Then with the airlines at least finger tight I then remount the D2.  Then tighten the hose connections.
Dave Cobb
Buckhorn Lake Resort The Club, #6202, Kerrville TX
check the map.  I do rent it out when I am traveling!
2001, U320, 36' #5887, in Kerrville, FT Club #17006, (7/23 to present)
2015 Jeep Grand Cherokee, Overland, white
EX: 98 U295, 36' #5219, (mid door), (4/13-10/23)
EX: 93 U225, 36' (4/11 to 4/13)

Re: D2 Governor

Reply #6
Where is the D2 located on my coach. My brake gauges show 100# on dash. Just replaced 2 leaking tank drains, 2 safety valves and check valves.
2001 4010 U320
Build 5875

Re: D2 Governor

Reply #7
So funny.  I recently replaced the tires on my 2004 36U295 and the front tires spec out to require 115psi given my weight.  Now my air pressure only went to 112psi so I was always dreading that last 3lbs.  Played games with my wife stomping on the brake to engage the compressor and trying to time it just right.  Then I got into this thread and decided I would locate and adjust my air governor.  Now where to find it?  Tried multiple compartments only to see the air lines dive into a giant bundle of black wires and tubes.  Finally opened the engine bay and low and behold mounted on the block of my ISL400 just to the right and in plain view was my D2 air governor.  "Oh, so that's what that is!"  Off came the cap, loosened the 7/16 jam nut, turned it 1/4 turn counter clockwise and checked the dash.  Perfect 125-130psi.  Thank you all for the information and motivation.  Now instead of dreading checking my front tires I'm looking forward to it!
Mark, Monique & Steven Hachigian
2004 36U295  Build No. 6239
2019 Ford Ranger Lariat 4x4

Re: D2 Governor

Reply #8

It will be close to the air compressor or even on the compressor in some cases. Some are mounted on the frame rail around the area of the A/C compressor.  I know this isn't an exact location but just where you need to look. It seems like depending on what shift installed the D2 would dictate the location.

Mike
Pamela & Mike 97 U 320

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

Re: D2 Governor

Reply #9
When you get your spare D2, also get the fittings and pre assemble. That way if you ever need to change the D2 on the road you just have attach the air lines and not mess with fittings.
Alan Fink
Waupun, WI
2000 Blue Bird Wanderlodge  LX40
2018 F150 4x4
2020 Jeep Wrangler Unlimited  Rubicon JL

Re: D2 Governor

Reply #10
On my 2014 IH45 it is mounted to the side of the engine block.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: D2 Governor

Reply #11
Found it. I will try to adjust air pressure up tomorrow. Will get spare for parts bin.
2001 4010 U320
Build 5875

Re: D2 Governor

Reply #12
I will try to adjust air pressure up tomorrow.
Turn adjusting screw counter clockwise to raise pressure.

http://www.plazafleetparts.com/uploads/2/1/9/0/2190100/d-2_governor_maintenance.pdf
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: D2 Governor

Reply #13
This thread reminded that the guy who does our chassis/engine maintenance told me it's a good
idea to "swap out that D2 at next service, keep the old one in the spares bin onboard".
Also a new drier is also in order since we can't read the date of the last upgrade, could be 2014 or 2016, just not sure.
I agreed with him and he'll have the parts on hand, ready to install.
A lesson learned from Bill Chaplin when I asked what tools he carried, "never the right one".
Bookmarked this thread just in case!

One more thing not to worry about while "sailing the asphalt highways".

Frank & Connie Williams
1999 U320 '36
Build: 5466
MC: 18335

Re: D2 Governor

Reply #14
...the guy who does our chassis/engine maintenance told me it's a good idea to "swap out that D2 at next service, keep the old one in the spares bin onboard".
Sorry, I can't agree with this advice.  If you remove a D2, for whatever reason, then I suggest consigning it to the dumpster.  New D2 governors only cost $20-30, or less, depending on where you buy them.  I can see no good reason to keep a "used" D2 for a spare, when brand new fresh ones are so inexpensive.  Seems like false economy to me, that might just come back to bite you on the A$$.  Just my O-pinion.

https://www.napaonline.com/en/p/TWRBENOR275491X?partTypeName=Brake+Governor&impressionRank=4&keywordInput=governors


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: D2 Governor

Reply #15
After reading the D2 Governor post, thought I would take the Forum advice and purchase a spare.
But I see all different Part Numbers ? Is a D2 Governor the same, regardless of the Part Number ?
Thanks as always for the Forum and your kind advice.
Charles
W5CRY
1997 Dynasty - Sold

Re: D2 Governor

Reply #16
Is a D2 Governor the same, regardless of the Part Number ?
If you go shopping for a spare D2 keep two things in mind.

First, you should try to find a genuine Bendix brand unit if possible.  You will see a lot of generic knock-off reproductions, especially if you shop online at Amazon or eBay.  The ad will say their product "...replaces Bendix D2..." or "Bendix style".  These look-alike brands will probably work fine and do the job, but the genuine Bendix brand usually doesn't cost much more.

https://www.napaonline.com/en/p/TWRBENOR275491X?partTypeName=Brake+Governor&impressionRank=4&keywordInput=governors

Second, you will see different D2 governor part numbers with different pressure ratings.  Some say "100-120", others say "105-125".  Don't worry about the advertised pressure - they are usually adjustable after you get them installed.  If the pressure is not what you want, you can change it.

Note:  When you adjust the "set" pressure on the D2 you are raising or lowering both the cut-in and cut-out pressure.  The range between the two pressures is supposed to remain constant at about 20 psi (although I have had some where it seems to be more like 30 psi).

NAPA stores are pretty easy to find, and a good place to get the genuine Bendix D2.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: D2 Governor

Reply #17
Thank you, Chuck !
The Forum is the GREATEST.
Have a great day.
Charles
W5CRY
1997 Dynasty - Sold

Re: D2 Governor

Reply #18
I can see no good reason to keep a "used" D2 for a spare, when brand new fresh ones are so inexpensive. 



[/quote]

After thinking about it, I agree.
I carry 2 new ones (came with the coach), so why carry around a used one.
DUH!
Frank & Connie Williams
1999 U320 '36
Build: 5466
MC: 18335

Re: D2 Governor

Reply #19
I'm a life long gear-head, but am embarrassed to admit that I don't know where the air compressor or D2 is on my coach, since my Foretravel Owners Manual is severely lacking in the gear-head department and this thread assumes a lot.  I've been unable to glean said detail from the forum or interwebs. 

Could someone pleeze crawl under their ISM450 powered rig and take a picture of the D2 on their engine and post it here???...one that shows exactly where the D2 is, and what it looks like mounted on the ISM450?  Thanks in advance.  Woody.



Where is the D2 located on my coach. My brake gauges show 100# on dash. Just replaced 2 leaking tank drains, 2 safety valves and check valves.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: D2 Governor

Reply #20
I don't know where the air compressor or D2 is on my coach...
Sadly, I do not have a 450 HP engine.    :'(

BUT, I do have Google search!  Google knows all.

There is a good chance that the D2 on your ISM450 is bolted directly to the engine air compressor.  The photos below are of a ISM500 but should be the same general configuration as your engine.  You can clearly see the D2 bolted to the air compressor, which is bolted to the engine, down low on the passenger side of the block.

If your D2 is not bolted directly to the air compressor, then it is probably close to this same location, perhaps bolted to the frame and connected to the air compressor with a short air hose.  There will also be two additional air hoses connected to the D2 - one going to the wet tank. and the other going to the air dryer.


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: D2 Governor

Reply #21
I'm on the other side of the coin on new or used (working) spare.
If I need it it will get me home. If I install a new spare that should work but if it doesn't then what?
I have been burned by new stuff that didn't work in the past.
John Duld
1995 U320C SE 40'

Re: D2 Governor

Reply #22


Could someone pleeze crawl under their ISM450 powered rig and take a picture of the D2 on their engine and post it here???...one that shows exactly where the D2 is, and what it looks like mounted on the ISM450?  Thanks in advance.  Woody.



No problem. I do need to order new plugs and fitting to pre build up new one. Mounted on top of compressor passenger side
Scott
Scott and Kim Davidson
If you're going to be dumb, you got to be tough.
DEGOIWKY
Don't ever get old, it will kill you
June 30, 2020
2001 U320 3610 Barn find
Build 5834

Re: D2 Governor

Reply #23
Scott,

Hard to tell from your photo.  Is your D2 mounted on the frame or directly on the engine air compressor?
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."

Re: D2 Governor

Reply #24
I'm on the other side of the coin on new or used (working) spare.
That is fine - every owner should do whatever makes them happy.

My reasoning is that if you remove a D2 because it is not working, then why would you assume it would work if it was later reinstalled?

Of course, I generally carry 2 or 3 brand new D2s in my parts drawer.  If the first one don't work, I'll pull out another one.

In past years I've also given a couple of them away to other coach owners who were in a bind.  Kinda like a party favor.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"It goes without saying..."