Williams Controls WM453109 Air Throttle Valve

Topic: Williams Controls WM453109 Air Throttle Valve (Read 2873 times) previous topic - next topic

Williams Controls WM453109 Air Throttle Valve

March 30, 2016, 09:52:42 am

While recently working on tightening up my air system, I have discovered that my throttle valve is leaking.

My main clue that something might be amiss with the throttle system was the white needle (rear tank) on my air gauge dropping more rapidly than the red needle when driving down the road. This is a recent change in behavior - in the past the two needles have always stayed pretty much in sync. Since the leak only occurs during "off-idle" conditions, I only noticed the gauge difference when moving. It was most noticeable during rapid changes in throttle position - with cruise control on it almost disappeared.

Investigation: Sitting in the driveway with the air pressure up, and engine off, I depressed the throttle pedal and heard air escaping from the rubber dust boot under the pedal. The leak varies with the pedal movement and position, and stops when I release all pressure on the pedal. That is why it has not been noticed up to now - it doesn't leak when the engine is idling, and when driving down the road I could not hear it.

I found some paperwork in my owner's manuals pertaining to the throttle valve. The condition is a little rough - it has some holes worn in it - but it is readable. Since I cannot find this info posted anywhere online, I thought it might be of interest to other members who have this same throttle system. The title of the document is:

Williams Controls Inc., Service Information Bulletin S-090, 117721, Rev. A, dated 3-79

I have ordered a repair kit for the air control valve, part #117103. I found it at Class 8 Truck Parts:

Williams Controls 117103 Repair Kit : Williams Controls

When I get the kit, I will do a little photo report on the installation, and add it to this thread.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #1 – March 30, 2016, 11:10:00 am

@Chuck,

You do realize that you've set yourself up as the goto guy for air problems. At least that's how I have your phone number in my contacts now.

see ya
ken

Re: Williams Controls WM453109 Air Throttle Valve

Reply #2 – March 30, 2016, 11:37:37 am

I assume that you will have to remove the throttle valve assembly to do the rebuild... looks like quite a job on the Unicoaches! Maybe you have easier access on the GV?
Don

Re: Williams Controls WM453109 Air Throttle Valve

Reply #3 – March 30, 2016, 12:21:19 pm

Quote from: Don & Tys (AKA acousticart) – March 30, 2016, 11:37:37 am

I assume that you will have to remove the throttle valve assembly to do the rebuild...

I THINK (won't know for sure until I try it) the rebuild can be done from above the floor. If you look on page 3, Sec.D of the tech bulletin, you find the disassembly instructions. It says to remove the pedal, and then "Pull the dust boot and actuating plunger out of the control valve". Sounds pretty simple! We'll see...

And Yes, if the whole valve had to be removed, it would be a LOT easier on the Unihome. I can kneel under the front of the coach and have pretty easy access to the valve body. However, I'm hoping total removal will not be necessary.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #4 – March 30, 2016, 12:36:40 pm

Chuck,

On our 240 after you pulled the pedal we had to take the body out the bottom to be able to get to the bolts that hold the valve body together. Seems like there were 6 bolts that had to be removed then you could get to the "cartridge" that the plunger sets on. Your rebuild kit may be different but we just put in the new cartridge and were good to go. I'm interested in how yours comes apart compared to what we had.

Pamela & Mike

Re: Williams Controls WM453109 Air Throttle Valve

Reply #5 – March 30, 2016, 01:27:02 pm

Quote from: kenhat – March 30, 2016, 11:10:00 am

@Chuck,

You do realize that you've set yourself up as the goto guy for air problems.

I HOPE nobody mistakes me for a "expert" on anything! That could be a costly error. I mostly learn by osmosis. If I hang around smart people long enough, some of their wisdom eventually soaks into my brain. That's what I'm doing on this Forum - learning from all the smart people. But I've only been here 3 years - not nearly long enough to be a "goto guy". I would rather think of myself as a "last resort" guy - if you just can't find the answer anywhere else, then ask me. I AM pretty good at doing Google searches!

Re: Williams Controls WM453109 Air Throttle Valve

Reply #6 – March 30, 2016, 01:28:54 pm

Quote from: Pamela & Mike – March 30, 2016, 12:36:40 pm

I'm interested in how yours comes apart compared to what we had.

Me too! I'm not pulling stuff apart until I get the kit - then I'll let you know what I find out.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #7 – March 30, 2016, 01:57:26 pm

A note of possible future interest to owner's of older coaches (myself included).

The Williams Controls Inc. company was purchased from the original owners by the Curtiss-Wright Industrial Group in 2012.

http://www.cw-industrialgroup.com/About/Williams-Controls.aspx

More recently, the manufacture of Williams Controls products has apparently been taken over by Brake Systems Inc.

Brake Systems Inc. - Williams Controls

At least SOMEBODY is still building the parts we may require in the future, if we want to keep our old coaches running.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #8 – March 30, 2016, 08:23:48 pm

Better diagrams of the pedal and the valve. I'm afraid the whole valve assembly will have to come out of the coach, as Mike surmised (above). The repair kit is supposed to include the "barrier plate assembly" and there's no way that is getting replaced without taking the two halves of the valve body apart. I'll see when the kit arrives, but that's what I get from the diagram.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #9 – March 30, 2016, 08:39:30 pm

Is there a chance that the mounting plate bolts in from the top side and the whole assembly can be brought up through the floor?
That is providing the air lines are long enough.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #10 – March 30, 2016, 08:50:21 pm

Quote from: FourTravelers – March 30, 2016, 08:39:30 pm

Is there a chance that the mounting plate bolts in from the top side and the whole assembly can be brought up through the floor?
That is providing the air lines are long enough.

Possible...I haven't pulled the carpet back yet to look at how the pedal assembly is secured to the floor. I have been up under the coach recently looking at the bottom view of the valve body. I don't think there is much, if any, slack in the air hoses. It's most likely gonna be the way Mike said - unhook the hoses and pull the whole thing out from the bottom. I have learned that Mike is VERY savvy about this mechanical stuff, and he didn't just fall off the turnip truck.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #11 – March 30, 2016, 09:36:17 pm

Chuck,

The "barrier plate assembly" is the same thing I was calling the "cartridge" (it's been a while & that info went with the '92) that came in the repair kit. The last prints show what seems to be the same throttle valve we had. When we pulled up the carpet there was a hole about 1" that was just big enough for the dust cover to slip through.

No, the dust has at least settled since I bailed off.

Pamela & Mike

Re: Williams Controls WM453109 Air Throttle Valve

Reply #12 – April 06, 2016, 07:28:18 pm

Update. I ordered the rebuild kit for my throttle valve - it should arrive tomorrow. I decided to go ahead and investigate the valve mounting.

First step: remove throttle pedal. The pedal is held in place by a chrome pin secured at each end by a "E" clip (retaining ring). I removed both clips, and pushed the pin out with a long drift pin. It is a snug fit due to the tension spring under the pedal, but slides out with gentle persuasion. Lift the pedal out of the way, then lift the tension spring out of the retaining holes and remove it. The brass top of the pin which activates the throttle valve is now visible, surrounded by the rubber dust boot.

Gently pull up on the pin and the dust boot comes free. Pull the pin and boot away from the valve. The 1.50" mounting nut is now visible. I just happen to have a 1.50" open-end wrench which worked well to remove the nut - a similarly sized socket would also work. After you have removed the nut, just push the threaded valve neck down and out of the mounting hole.

Going under the coach, you will find the valve is attached to 2 air hoses. There is just enough slack in the hoses to pull the valve down from the recess to where you can get a 5/8" open-end wrench on the compression nuts. Remove the hoses, and the valve comes free.

Take the valve in to your work bench and clean it up. I could not find ANY identification of any kind on the valve. I don't know if it is OEM or was replaced at some time in the past. Kinda weird there isn't SOME kind of marking on it...

Re: Williams Controls WM453109 Air Throttle Valve

Reply #13 – April 06, 2016, 07:31:59 pm

Next I disassembled the valve, to see what it looks like inside. In the last 3 photos, the piece in the lower right corner is called the "barrier plate assembly" (what Mike called the "cartridge" in his comment above). This is the heart of the valve, and a brand new one is supposedly included in the rebuild kit, along with some O-rings and seals. We shall see...

Now I just wait for the rebuild kit! More to follow...

Re: Williams Controls WM453109 Air Throttle Valve

Reply #14 – April 06, 2016, 08:25:39 pm

Chuck, nice pics etc again. My foot valve has 4 or more lines coming to it. I took the pedal off when I was putting the new maple flooring in and had a bi--- of a job to get that spring aligned to push pin thru. Hope you have an easier time. I think mine is designed a bit different.
John H

Re: Williams Controls WM453109 Air Throttle Valve

Reply #15 – April 06, 2016, 09:24:47 pm

Chuck, could it be a WABCO product?

Re: Williams Controls WM453109 Air Throttle Valve

Reply #16 – April 06, 2016, 09:34:16 pm

WABCO? I don't know...like I said, not a single mark of any kind, inside or out, to indicate origin. It could have been made in Bangladesh out of melted down beer cans, for all I know.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #17 – April 08, 2016, 06:07:27 pm

Got my repair kit. Here are the contents. You get pretty much everything needed to make the valve "like new", except for the outer housing. The "barrier plate assembly" has some differences in construction, but looks like it should be functionally identical. (Old one on the left - new one on the right) Also included with the kit is a copy of Williams Controls Service Bulletin S-044, which is nice to have because I haven't been able to find a copy of it anywhere online.

I will close out this thread with a final operational report, after I get the valve reinstalled and take the coach for a test drive.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #18 – April 10, 2016, 10:33:01 pm

Well, I got the valve rebuilt - all the parts fit perfect. Replacing the valve in the coach was a mixed bag. The valve itself was easy - I hooked up the two air lines, pushed the valve back up through the hole in the floor, and tightened down the big mounting nut.

Then came the fun part: reinstalling the pedal. John H. mentioned in his post (above) that he had a hard time getting the chrome pivot pin back in position. I would say he GROSSLY understated the difficulty of that procedure! I would second his "Bi---" word, and add quite a few more of my own, were this not a family-rated Forum. The engineer that designed that pedal must have had a diabolical sense of humor.

I worked over 2 hours getting that pin in place. It is the *#&$^%*$)@($*%& SPRING that makes the whole thing so hard. There is no room to get hold of it, and no way to keep it in place while you TRY to slide the pin through the SIX different very snug holes. I finally resorted to removing the steel wheel that pushes down the activating pin in the valve. That helped, but still no go. Then I removed the "stop bolt" at the base of the pedal, which gave me a little more room to work. I was then able to get a smaller diameter drift pin through all the holes, which helped line them up. Then I pushed the pivot pin through from the other side, and FINALLY got it in place. After that I replaced the "stop bolt" and lastly the steel wheel. I guarantee I will not remove that throttle pedal again...EVER!

The good news is...THE LEAK IS FIXED! Tight as a drum, throttle works perfectly again. PLUS, as a added benefit, I discovered another problem I didn't even know I had: my Bendix air throttle cable was not moving the "fuel" lever on the engine to "Full Throttle". The instructions included with the repair kit say to check this after installing the valve, and I'm glad I did. I haven't gotten out for a test drive yet, but I'm hoping I may have a bit more power at full throttle after making this adjustment. We'll see...

Re: Williams Controls WM453109 Air Throttle Valve

Reply #19 – April 11, 2016, 12:10:16 am

Glad you got it Chuck and funnily enough using a tapered drift pin was what I did to align the parts making it a lot easier to push that pin thru.
On the Bendix cruise system I will note that should you (or anyone else) have a problem with it not working to take the cylinder assy apart and make sure there is a good coating of grease on the walls then rebuild. The valves also should be r&rd. I had the one on the 240 not working and found this to be my answer. It was not working when I picked it up from PO ( along with many other things!!!!!
JohnH

Re: Williams Controls WM453109 Air Throttle Valve

Reply #20 – April 11, 2016, 08:59:32 am

John,

Thanks for the tips - I think all the bits on the Bendix throttle/cruise control panel are working properly (for the moment). My major concern is my throttle cable, which is disintegrating from a combination of (engine compartment) heat and age. The outer plastic covering on the metal sheath is totally gone in several places, and the metal reinforcement is coming apart into individual wire strands. The cable itself is still contained within a thin inner plastic tube, but much of the necessary rigidity of the assembly is now missing. I think this is why the fuel lever was not being pulled fully open. I was able to adjust the cable end mounting position to restore full fuel lever movement, but I fear total failure of the cable is imminent.

The answer is to fit a new cable...which is, of course, proving to be very elusive. Using some identifying part numbers from my cable, I tracked down a discussion of this same problem on a Blue Bird Forum, where they listed some more complete numbers:

Morse D-303192-000-0047.8

Bendix 102735 (supplied in Bendix Cruise Control "engine kit" for Cummins applications)

Bendix 102298 (supplied in Bendix Cruise Control "engine kit" for DD and CAT applications)

Unfortunately, my Ninja Google search skills have turned up zero sources for any of these parts. I have a photo of the Bendix cable 102735 from a Bendix Cruise Control Parts Manual, and it does not look like the cable on my engine, leading me to believe that Foretravel may have had these cables custom made for our coaches (why would that not surprise me?). In that case, I may only have two choices. One would be to have my old cable repaired. One member on the Blue Bird tried this approach on a broken cable, with only temporary success before it again failed. The other option is to have a reproduction fabricated by a custom cable shop. Morse throttle cables are commonly found in boating applications, although they are usually much longer. I'm still researching this option.

Re: Williams Controls WM453109 Air Throttle Valve

Reply #21 – April 12, 2016, 10:06:36 am

Continuing my discussion about my disintegrating throttle cable.

I called FOT parts dept. and asked about a replacement. Parts guy said the cable is, as far as he knew, no longer available. He said he would "check around" and call me back (which he never did). He also suggested I might consider replacing the whole Bendix air throttle/cruise control setup with some aftermarket device (probably one of the King Control kits). I didn't request any further details, because I'm not interested in that (expensive, difficult, time-consuming) option...at this time.

I did locate a source for one of the cables I listed in the previous post, the Bendix #102298. FinditParts has it listed for $258.

Since this is not the correct cable for my application, it would require some serious modification to work. I decided to pass on that offer, but will file it away for future reference.

102298 by BENDIX - CABLE COURSE LAID

So that left me with the "repair" option. I removed the cable and took it to my bench for inspection. Sorry, I was lazy and didn't take any photos, but the first 2 photos (below) will give you a good idea of the condition. The operating cable itself was fine - both ends looked good, no kinks or frayed spots in the wire. The thin inner sheath was still intact, but was at dire risk due to being exposed to the elements. All the real damage was confined to the exterior parts of the housing. The plastic was rotting, the wire reinforcement was coming apart, and the structural integrity was badly compromised. I decided I could fix that!

First I cleaned all the dirt off the outside. Then I got out my handy roll of aluminum (metal) duct tape. I use this stuff all the time for various jobs - it is super sticky, UV resistant, heat resistant, water proof, etc. I cut the tape into .5" wide strips, and started wrapping the outside of the cable housing. As I went along, I manipulated the reinforcing wires back into place best I could. I applied one full layer of tape the whole length, and several additional layers in the really bad spot near the "engine" end. When I finished, the cable had much of it's strength restored, and is also protected from further degradation.

Next, because I believe "overkill" is just another word for "barely sufficient", I decided to add some additional strength/rigidity to the housing. I found a couple pieces of 3/8" i.d. fuel hose in my "scrap box". I cut the hose length-wise, wrapped it around the outside of the cable housing, and secured it with nylon zip ties. For a final touch, I worked some Super Lube into both ends of the housing while moving the cable in and out, until it felt virtually frictionless. The finished result is a almost-like-new control cable that is probably even stronger than it was originally.

Replaced the cable, and had DW press the gas pedal while I observed the "reaction". I now have perfectly smooth movement of the "fuel" lever between the idle stop screw and fully open position, with no loss of travel due to cable flex. This repair should extend the cable life many years.
Mission accomplished!

Re: Williams Controls WM453109 Air Throttle Valve

Reply #22 – April 12, 2016, 03:44:59 pm

I got a call back this morning from Brad at the FOT parts counter. He said their parts book shows the throttle cable used on the Bendix system to be "obsolete" and "unavailable", but one of the guys remembered seeing some on a shelf in the warehouse. They scrounged around yesterday and came up with 2 Morse cables - one was marked "GV" so he called to see if I wanted it. I asked for more details, and had him measure it. Both of the cables he found are about 38" long...the one on our coach is 51" long, so obviously something doesn't compute. Also, the connector on the "engine" end of his cable is different from mine, but with the length being so far off it doesn't really matter.

I asked him if the fuel control lever on a DD or CAT engine would be in a different spot than on our Cummins. I thought that might account for the shorter cable, but he didn't know without having a coach to look at. Anyway, I give him credit for trying to help me, and I appreciate the time he spent looking. In this case, the factory simply didn't have any way to meet my needs.

But No Worries! I have made my repairs in the best Shade Tree Mechanic tradition, and my coach lives on to fight another day!

Re: Williams Controls WM453109 Air Throttle Valve

Reply #23 – April 13, 2016, 10:01:00 pm

I'm gonna wrap up this thread with my final Road Test report. Beautiful day today in West TX, so we went out for a nice cruise/exercise/test run. It was ALL good news! At the top of the list: my pesky air leak is totally gone (see my original complaint in my first post). Both pressure needles are now moving in sync again, and there is no unusual loss of air while driving. So rebuilding the throttle valve achieved the primary objective.

The big surprise to me was the ADDITIONAL benefits resulting from the rebuild project. I was not expecting so much goodness. Here are the other (surprise) improvements:

1. Reduced physical effort pushing the gas pedal. I don't know how to account for this one. My pedal has always (since we bought the coach) been very hard to push. It actually made my foot and leg tired to drive "manually" for very long, so I quickly got into the habit of getting on the cruise control ASAP. I even asked on the Forum if this was "normal" - got several vague answers from others who had the same gripe - so I assumed it was just me being not used to driving a RV (or being a wimp). Well, I now know it was NOT normal, because it has suddenly gotten much easier since the rebuild. I didn't change anything on the pedal...same return spring as before. The big heavy spring inside the valve was also reused, so no change there. All I can think is there was some kind of friction in the old valve that was eliminated by installing the rebuild kit. Whatever the reason, it is a BIG improvement, and makes driving much more pleasurable.

2. Improved throttle response. My throttle pedal used to feel very "vague", like there was a time delay between pushing the pedal and feeling the engine respond. I think this was caused by the air leakage inside the throttle valve, and by the throttle cable coming apart. A lot of the input from the pedal was being lost before it ever reached the fuel lever on the engine. Now, the instant my foot moves the pedal I see the tach jump and the engine responds. I had no idea a diesel engine could feel so "lively" - it's like having a super light flywheel in a hotrod racing engine.

3. Increased horsepower. This is a direct result of my repairing the throttle cable. Before the repair, I was not getting full movement of the fuel lever. With my gas pedal flat on the floor, the fuel lever was a good 1/4" short of being full open. I have always cruised at 65 mph, which felt fine, but when I had to pull out and pass a truck I could only accelerate to about 70 mph and that was it...there was nothing left. Today, I got out on a straight stretch of highway, cruising at 65, and gave it full throttle. My speed immediately climbed past 70 and went to 80 mph before it leveled off! The extra movement of the fuel lever to full open was good for at least 10 more MPH at the top end! It feels like a brand new engine to me.
I am so glad I followed the installation instructions that said to check for full travel at the fuel lever.

This has been one of the more rewarding projects that I have completed. For very little money, it made a tremendous improvement in our coach, and you can't beat a deal like that.

Affiliate Notice