Valve Stem Extensions

[Jon Wehrenberg]

I have always advised against valve stem extensions. Unfortunately because I kept procrastinating I never got around to pulling them off my bus when I got it.

Today I pulled the drive axle outer wheels so I could access the forward air bags. I'm glad I did. The attached photos are of my drive axle, inner wheel valve stem extensions, and one of the wheels showing the hole the extensions go through.

Michelin at one time spoke against extensions because of the fact that eventually the valve stem would fail at the bend due to fatigue from centrifugal force. What they failed to stress was if the valve stem does not fail due to fatigue, the extension would eventually wear a hole in itself and the inner tire would lose its air.

[Coloradobus]

Oooh Ouch, Jon.
I use them but replace them annually. The mag-chloride for snow removal on the roads here degrades them fast. I also use a rubber grommet that fits into the wheel slot. Seems to help with "extension wobble" you appear to have.

[Jon Wehrenberg]

I should have added that I have the grommets on both wheels. At the end of a trip, invariably I have to push the grommet back into the hole.

I got along quite well without extensions on my other coach.

I use hex shaped valve stem caps. I used a 3/8 deep well socket and extension and I could reach in the appropriate hole (always 180 degrees from the outside wheel stem) to remove the cap. I checked pressure or filled the tire with straight foot tire gauges or fill valves.

A second reason I don't want to use extensions is it is just another joint with the potential to leak, and if you ever get a blowout because of the slow leak the worst wheel for that to happen is the inner drive. It is the hardest to check, replace, and tears up more when it fails.

[win42]

Jon: This is another one of those reasons for us all to be here sharing. The smallest thing can cause major problems. I felt bad because they only put one extension on after polishing the wheels. Now I'll remove that one. The hex stem caps sound like the way to go, are they readily available. It may be a good post to display the air filling and checking devices you use Jon and others. Those inside duals are always a worry.

[Jon Wehrenberg]

Now that I am finally following my own advice I'm going to be checking and filling tires as I have for years on the last coach.

In the attached pictures I have shown the tools that I use or have used.

Since the tags, outer drive and steers all have the valves easily accessible almost any straight or angle chuck works. But rather than using different tools I have used a Milton valve with a straight chuck that reaches through a hole on the outer drive wheel and with a little practice easily finds and slips on the valve stem for the inner drive wheel. The Milton fills the tire when you squeeze the trigger, and when you let up, lets you see tire pressure in the little window.

I ran across the one with the round gauge at Walmart for about $15, and replaced the angle chuck on it with a straight foot chuck and this one is my favorite. It also reads lower than the others so when I fill it to my desired pressures I am either right on the pressure or a little high which is OK.

I replaced all valve caps with the hex type. I install and remove all caps, including the inner drive with the 3/8 deep well socket and handle. I only put them on hand tight. I will throw out the caps at the first sign the seal is not functioning. The valve stem is the first seal against a leak but the cap is the final seal. I have loosened a cap in the past and heard a baerly detectible hiss when I did that, indicating a slight leak in the Schrader valve core.

I show in the photo a pair of valve stem extensions screwed together. If you have them and remove them, they work (as a pair) very well for also filling the inner drive wheel. Just remove the valve strem cap, screw the extensions on hand tight, and fill away. When the pressure is good, unscrew the extensions and replace the cap.

FWIW, I have had my share of leaks in tires. No blowouts, but just leaks and in order of frequency, they show clearly what stuff you may want to keep in your kit of spare parts.

Most frequently I end up with a Schrader valve stem core that leaks. That is followed by the actual seal at the valve stem where it passes through the wheel, and a distant third in frequency is something in the tire such as a nail or screw. If the core leaks, caps are essential. If the stem seal at the wheel leaks, the fix is almost always as simple as deflating the tire, pressing the tire off the bead at the valve stem, and reaching in with a wrench and tightening it up a little. For punctures I carry the tools and materials needed to put a plug in the tire.

[JIM CHALOUPKA]

Jon, I think you are boyond this fix for your situation but it might help someone else wanting a quick and if not a permanent one, something that could take the worry out of the situation until other measures would be implemented. Here it is. Slip over the stem extension a length of nonferrous spring or a piece of heat shrink tubing or even rubber or plastic tubing. This would eliminate the wear on the stem caused by the contact with the wheel. I also have a question I will ask here even if it is not in the correct place:D From your photo of the worn stem I think that I see that the inner drive wheel is steel. Is that so? If I am correct what is the reasoning and is that standard or common practice. If it is have you seen any coaches that have 8 aluminum wheels. Please someone elaborate on this topic.

[garyde]

Jon, I think you are boyond this fix for your situation but it might help someone else wanting a quick and if not a permanent one, something that could take the worry out of the situation until other measures would be implemented. Here it is. Slip over the stem extension a length of nonferrous spring or a piece of heat shrink tubing or even rubber or plastic tubing. This would eliminate the wear on the stem caused by the contact with the wheel. I also have a question I will ask here even if it is not in the correct place:D From your photo of the worn stem I think that I see that the inner drive wheel is steel. Is that so? If I am correct what is the reasoning and is that standard or common practice. If it is have you seen any coaches that have 8 aluminum wheels. Please someone elaborate on this topic.
Yes, on all of the coaches I have owned, they use steel Rims on the inner dually. Gary

[JIM CHALOUPKA]

I have been under the impression that the lower the unsprung weight the better. Is this a cost thing where the converter doesn't think the clientell would know the difference, or what?

[Jon Wehrenberg]

For race track handling you are correct about unsprung weight. According to Prevost, when the change to 315R 22.5 size was made they went to steel inner wheels to stay within the width requirements. I'm just reporting what was said so address all comments to Prevost.

The coaches with 12.00 22.5 tires had a pair of aluminum wheels.

[lewpopp]

FWIW My 90 has 8 aluminum wheels. Still can't get it over 95 MPH.

Lew

[Orren Zook]

Don't you have more payload with all aluminum rims? Maybe you could get on the turnpike in class 4!

[win42]

John : The picture of the wheel and valve stem looks almost like electrolosis set up between the different metals and eat it rather than rubbed it. I know that sounds strange or even impossible. Were dragging those ground strips for a reason other than knocking hell out of the toll takers.

[JIM CHALOUPKA]

Lew, You probably need to polish those inner wheels more to get over 95 mph.;)

[Jon Wehrenberg]

Harry,

Since this was the first time I pulled my drives since I bought the coach I was surprised by a few things. First the valve stem extensions. I kicked myself for not pulling them immediately.

The second was the lack of corrosion. The rust you see is the cast hub. The wheels looked great. I have more damage to the aluminum wheels that mount on the front and tag.

I was also happy I did not break any studs. The studs that hold the inner drive wheels are prone to break. When that happens you have to disconnect all bus computers, and then weld a nut on the end of the stud so it can be removed. Over the past 16 or 17 years I have had to weld three of them and a tire shop had to do one.

[Orren Zook]

Jon,

Euclid/Meritor makes a kit for wheel stud removal that eliminates the need to weld a nut to the broken stud.
Were all those studs broken on the same coach? Same timeframe? By the same people? Maybe it was a bad production run from the factory?

Don't forget the Never-Seez when you put it back together.

[Joe Cannarozzi]

Yes Orren, It is simply a wheel nut and instead of threads its "rifled" on the inside. You beat it on the broken inner nut with a 2-pounder and then impact the broken inner nut off the stud. They also make what is called a CROWS FOOT that helps in removal of a broken stud/inner and outer nut when stuck on the outer rim.

[MangoMike]

You guys have a link for this neat stuff. Sounds like we should add to our Ace Bay.

mm

[Joe Cannarozzi]

Mike, Ill just add it to the list:rolleyes:
564
This works when the stud has cracked off remains inside the inner nut and this all comes off still attatched to the outer wheel. The crows foot locks in to the next hole in the rim and holds the outer nut so you can take your impact or tourk multiplyer and turn the inner nut down.
565
I cant seem to find the other tool that pounds on a broken inner nut to remove it from the stud. I can get this stuff for you when I go to replace my loss? Let me know.
Your tire guy can land these(thats pilot lingo;) ) for you or we will be going past Disney on the 31st. We will be with some friends in Lady Lake Saturday.

I was supprised to see the old style inner and outter nut set up on a 97. When did they change over?

[Joe Cannarozzi]

In an effort not to confuse-I refer to this piece the inner-wheel nut. It is not the stud, it threads over the stud, securing the inner rim, and then the outer wheel nut threads on to it securing the outer rim. You will hear people refer to this as the old style.
The new style is much more conventional, one nut holds both rims.
566

[Jon Wehrenberg]

Orren,

The first time the "inner wheel nut" broke was at a tire shop. The ace of the place had the kit you talked about and he proceeded to waste a couple of hours of his employer's time because he couldn't get that sucker to work.

In the end he just welded a nut on it and zip, it came off.

The three I have broken were spread out over my 16 years of owning that coach, and I have a welder in my garage and after watching the crap the ace of the place went through I don't even mess around. I pull the computer connections, weld the nut on, and I'm done.

BTW....I know there are a bunch of folks out there greasing up their studs or putting on Never-Seez, (arguing about the merits of the copper type versus other types) but the guys that engineer wheels and specify torque values are always talking about dry thread torque. Since I read that all studs and nuts are to be clean and dry that's what I have been doing.

[Joe Cannarozzi]

I have seen that problem also. But with proper technique it does a pretty good job if you dont have a welder. I never use the neversieze here either. I always just wirebrush the studs and nuts. What year did they switch to the new style rims?

[JIM CHALOUPKA]

Jon, Your right about the never-seez requiring different torque readings. I never use the stuff where torque is critical unless I have the correct values. Awhile back you said you did not use a torque multiplier since you got your 1" impact wrench. Is that to mean a 1' drive? If you ever get the oppertunity to photograph it I would like to see a view. That bugger must be quite large. Do you carry it out on the road? Thanks, JIM ;)

[Jon Wehrenberg]

The impact wrench is a typical 1" man tool. It weighs almost as much as the bus so I leave it home. I got it a long time ago at Northern for about $400. Roger recently bought one that looks like good quality, and it works good from Harbor Freight for about $99.

The impact wrench works good, because I have the garage plumbed for 3/4" pipe, and the hose to the impact wrench and the fittings are 1/2". The wrench needs good air flow.

But I do have my X12 with me in the bus all the time.

[Orren Zook]

Right you are Jon,

The correct air volume is a must for impact tools to function properly. On the topic of impact tools, Ingersol Rand has a new 3/4 gun (IR2141) that produces 1200 ft.lbs. of torque and weighs only 7 lbs, much lighter and smaller than those old Rodac or CP guns.

[JIM CHALOUPKA]

Orren, That ought to take care of anything on a bus! :D

[Orren Zook]

I have seen that problem also. But with proper technique it does a pretty good job if you dont have a welder. I never use the neversieze here either. I always just wirebrush the studs and nuts. What year did they switch to the new style rims?

Does Prevost use standard 33mm unimount stud & nut attachments or something proprietary?

[Jon Wehrenberg]

If the kid that installed your highly polished and expensive aluminum wheels followed the torque requirements a 1200 ft. lb. wrench will be more than adequate, but if he ignores the Alcoa torque specs and rams the nuts on the wheels at full power from a 1" impact wrench with good air delivery the 3/4 inch impact wrench won't do the job.

I don't know which is worse.....watching idiots abuse your coach, and hoping you can react quickly enough to stop them from doing stupid things, like flipping your wheels on a concrete floor, or leaving your coach in their hands and going away to avoid the pain of seeing them treat it like they do their 67 F150.

BTW, these are the rocket scientists that tell you to use Never-Seez on the studs and to dispose of your drain oil just dump it in the fuel tank. (No I'm not kidding.)

[Orren Zook]

Well, I can't weld so the Euclid/Meritor stud tool kit is right up my alley....it's comes with 5/8, 3/4 and 1 1/8 adapters and a driver to install the remover on the stud of your choice.... see the attached photo, we don't need the 5/8 stud size but its cheaper to get the kit and throw that one out than buying the other two and the adapter seperately.

[truk4u]

Your dead on Jon, my 3/4 impact using 1/2 hose from the compressor won't budge the wheel nuts.

[Jerry Winchester]

Time for the big ass 4 way and the companion cheater pipe. And Jon, the last mounted tire I saw flipped flat on the shop floor blew the split rim ring off grazing the offending moron's face. His glasses cut his forehead, but I'll bet he never let another of those drop like that. The other two accidents with those rims resulted in (1) broken arm and (1) hole in the top of the shop. At least we don't have that problem to deal with.

Or maybe Lew still has those on the Ace Hardware Delivery Bus?

[matsprt]

In an effort not to confuse-I refer to this piece the inner-wheel nut. It is not the stud, it threads over the stud, securing the inner rim, and then the outer wheel nut threads on to it securing the outer rim. You will hear people refer to this as the old style.
The new style is much more conventional, one nut holds both rims.
566

To all,

I think those are called "thimble nuts" if you ever need to buy them...and they come with both left and right hand threads.


Michael