Hey all,
I'm working through replacing my rear air bags since they are in rough shape. I know the go to is to cut the old bolts with an angle grinder and I do that where I can but what about the ones where the angle grinder doesn't fit? What do you guys do to get them loose? I also know that when its time to do the fronts there is at least one that is recessed with a deep hole in the bottom of the rail attached to the axle. I obviously won't be fitting any sort of cutting device in there so there must be a better way. Any ideas are appreciated.
Ben
Maybe a dremel with a cutoff blade?
Quote from: chessie4905 on September 03, 2020, 06:09:19 PM
Maybe a dremel with a cutoff blade?
That's how I got to some of them. I just figure there has to be a better way than a dremel. I also used a sawzall for a couple. The Dremel also ends up getting pretty toasty and breaks a few wheels.
Maybe a multi tool with a carbide or titanium blade. Wear ear plugs.
https://www.harborfreight.com/variable-speed-oscillating-multi-tool-63113.html
https://www.harborfreight.com/variable-speed-oscillating-multi-tool-63113.html
Buy some spare blades.
A torch is one of my very good friends under the bus.
Especially for bolts.
Pretty simple to blow bolts through the hole with a good torch
If it won't come loose I tighten them up till they snap off YMMV ;)
I actually bought and tried an oscillating tool. the cutter I got was a toothed metal blade. might not have been the best as it mostly just bounced around. What blades would you use?
A torch would likely make quick work of most of them but the only torch I have is oxy-propane which doesn't quite cut it for cutting.
Tightening until it breaks hadn't occurred to me yet. I might give that a go tomorrow. that will work for the one in the hole too. If it works well I might just use it on all the easy to access ones too with the impact. a 1400 lb impact will be much faster than the cutoff wheel and I wont be burning through wheels.
Get a nut splitter.
https://www.amazon.com/s?k=nut+splitter&ref=nb_sb_noss_2
Torches are friggin dangerous near flammable material. There is a wooden floor and an air space above those nuts. If that ever caught on fire, it would be very difficult to put out.
An impact tool is always 5x better than applying brute torque. Add in a good penetrating oil and 80% of them will come lose. The rest will twist off.
If you have time, apply penetrating oil and test with an impact every day for a week.
Have you had any luck replacing airbag bolts with one? as far as oil goes as soon as you get the nut backed up a bit the top begins to spin. None are stuck enough that I can't make them spin. There is no floor above or anywhere near the nuts.
I assumed you were talking about removing a nut from a stud on the top of the bag.
Sounds like you are removing a bolt and the threaded insert inside the bag mount is spinning. You can cut the bolt with a hacksaw, chisel, grinder or torch.
A good, sharp chisel is very effective on bolts 1/2" or less.
Plasma cutter make short work of those yoo can buy one that will work good for you for under 200 bucks, oxygen and acetylene is exspensive now,I have 2 plasma cutters a real good one $$$$ and a cheap one
someguy: I think we may be talking about a different type of bag on a different type of bus. There is no threaded mount inside the bag ring. I do plan on buying an air chisel tonight that I'll have a go with.
luvrbus: Any recommendations on what kind of model to get? Sounds like a good addition to the tool box.
Quote from: benherman1 on September 04, 2020, 08:20:32 AM
someguy: I think we may be talking about a different type of bag on a different type of bus. There is no threaded mount inside the bag ring. I do plan on buying an air chisel tonight that I'll have a go with.
luvrbus: Any recommendations on what kind of model to get? Sounds like a good addition to the tool box.
[/quote
I got mine portable Plasma from Amazon for $159.00 it works good.the board went bad when I 1st got it and the out fit overnighted me one the brand I would need to look and I am not at the shop right now
Actually the chisel suggestion is a good one, although a good cold chisel isn't always easy to find, and you have to have room to swing the hammer. Grind the tip of the cold chisel at an angle that is about twice as sharp as it came with (half the angle) and it'll cut a lot faster. You can use that to split the nut, maybe on both sides. With a good edge it will cut quicker than you think.
Jim
sometimes a long cold chisel works. gets the hammer back where you can swing it. use a two pound mini sledge. a smallish hammer makes the work last twice as long.
Someguy' the air bag bolts have a partially rounded head with a bump on the underside to keep it from spinning when you install and tighten them. Old rusted ones spin the head within one or two turns.
They also make mini air operated hack saws that can work. get extra blades. Harbor Freight has them.
Quote from: chessie4905 on September 04, 2020, 10:11:43 AM
Someguy' the air bag bolts have a partially rounded head with a bump on the underside to keep it from spinning when you install and tighten them. Old rusted ones spin the head within one or two turns.
Carriage head bolts and the square shoulder is rotating in the housing ? Tack weld the head so it can't rotate.
A picture would really help us help you.
it is not a square shoulder. it is a 30 to 45 degree angled slightly rounded head with a small bump on one place.
Quote from: chessie4905 on September 04, 2020, 02:32:57 PM
it is not a square shoulder. it is a 30 to 45 degree angled slightly rounded head with a small bump on one place.
Can you tack weld the bolt until you get the nut off ? Or sheer it with a chisel.
I'd love to see a picture of this bolt.
These pictures show the before and after of removing them. Welding the heads to the ring would be a pretty bad idea unless I want to make a bunch more work for myself or have to buy new rings. You can see the tops of the bolts in the ones laying around the loose bags.
I just got home from getting the air chisel. I may or may not decide to try it tonight depending on how lazy I decide to be. I also have a pretty decent cold chisel and a 4 lb sledge that I usually use to break up whats left after my cutting on the nuts. I could try sharpening it up and skipping the cutting.
Absolutely second the air chisel. I took off most of mine that way at about 10 minutes per bellow. Don't try to loosen the nut, it will just make it spin.
The lower ones you can get at from the bottom, try cutting the nut straight up inline with the bolt, then they can't spin. The nuts were very soft on mine and would spread enough from one cut to fall off.
The same idea of re-grinding the chisel tip would work on the air chisel also, reducing the angle by half will make it cut four times faster. It's a good bit of grinding but I've always found it worthwhile. If you like you can grind a shallower angle on the very tip to make the cutting edge last longer.
Jim
If you look close you will see that even though the bolts can go in either way, one way the heads conform perfectly to the curve of the ring and the other way it sticks out a bit....make sure when you put it back together that they conform to the curve or they will start leaking after a while. Only use the bolts made for that......stove bolts, carriage bolts, etc. will leak. A while after i bought my bus a found that i had an air leak and it was one bolt that had been put in facing the wrong way.
Good point Ed. They can be easily mis-indexed if not careful. Note where the recess for the bump under bolt head is before inserting. Also make sure they dont rotate when tightening. Ad neverseize to the threads in case you need to take apart in future. They make a longer bolt if you need to use block off plates.
When i first heard one of my airbags leaking the second year that we had the bus, i felt around until i could feel the air leaking on the back side of it. My first thought was that somehow a sharp rock had gotten between the bellows and worn a hole in it. I was really surprised after i pulled the wheels to get to it that it was just a bolt that had been put in wrong. Since i had ordered new bags, rings, and bolts, i just replaced them all and kept a few of the better old ones as spares, which i never needed in the following 10 years that we had the bus. As a footnote, i did all of this while recuperating from a dislocated shoulder......learned to move really slow and think about how i was going to move wheels and jacks and cribbing and a lot of little things like reaching behind you to grab a tool......did all this during the 2nd month of healing, took me 7 months to completely heal up to where i could do things like i had done them before. Found out it takes longer to heal as you get older! :)
I've been getting my bolts and bags from Luke so no problems there. I had just finished bag 2 and was getting started on bag 3 when I started this thread so the crash course parts are over at least. I'm pretty jealous of the buses where re-using bolts is an option on the bags. I wouldn't be surprised if the ones on there were factory installed from the way they look. One had a bad leak on the way home. You would have to block the bus before turning it off to give you an idea. I had to be careful with my braking to make sure I didn't run the air down too fast. The ones I'm doing now actually hold air fine but are de-laminating the inner and outer layers and the outer part was expanding like a balloon. I figured I'd rather do them now and be done with it than wait and see if I end up doing one on the side of the highway...
The mention of & seeing photos of some of the air bellows - de-laminating & ruptures causing bubbles can be caused by oil, grease, or any petroleum being slung on the air bag. A good example is where a rear bag is adjacent to a universal joint. A simple shield of any sort will protect a new bag from this issue... We've put them is a couple places.
Quote from: dtcerrato on September 05, 2020, 06:44:42 PM
The mention of & seeing photos of some of the air bellows - de-laminating & ruptures causing bubbles can be caused by oil, grease, or any petroleum being slung on the air bag. A good example is where a rear bag is adjacent to a universal joint. A simple shield of any sort will protect a new bag from this issue... We've put them is a couple places.
The rear pair actually have shields already. They looked dry but I wouldn't rule it out. I'll have to keep an eye on it after I get it on the highway he first time and see what gets wet. It would be pretty easy to fab some more shields and just attach them with the extra threads on the bolts. I'm hoping in this case it was just age. Pretty much everything rubber is in similar shape. I also just replaced all the air brake lines and the foot valve for similar reasons. I was able to snap some of them in half by hand.
The rubber used on air bags is impervious to petroleum products.
I would agree with Someguy here. My rear bags get splattered with grease flung from the drive shaft Ujoint and it hasn't hurt them in the many years they have been there.
Going by chemical resistance charts for various kinds of flexible products, petroleum products under 250 degrees F are not recommended to be on rubber products other than ones such as Nitrile, Hypalon, Silicone, or Viton. From what I have seen, airbags are generally made of a combination of natural rubber and polyurethane. Grease might have less affect than oils, but I suspect that over time exposure to splashed oils would have an effect. I don't think it is accurate to state that airbags are impervious to petroleum products, rather, they may be resistant to oils (and ozone) to some extent.
Quote from: DoubleEagle on September 06, 2020, 01:02:43 PM
Going by chemical resistance charts for various kinds of flexible products, petroleum products under 250 degrees F are not recommended to be on rubber products other than ones such as Nitrile, Hypalon, Silicone, or Viton. From what I have seen, airbags are generally made of a combination of natural rubber and polyurethane. Grease might have less affect than oils, but I suspect that over time exposure to splashed oils would have an effect. I don't think it is accurate to state that airbags are impervious to petroleum products, rather, they may be resistant to oils (and ozone) to some extent.
Engine oil from the compressors takes a toll on air bags from the inside out,most are such a pain to change people get every mile they can from the air springs before changing
Quote from: someguy on September 06, 2020, 11:48:05 AM
The rubber used on air bags is impervious to petroleum products.
Your statement couldn't be farther from accurate.
You may want to review the following links as to the possibility of adverse effects of lubricants on air bags. fwiw
Sneak preview from an air spring manufacturer:
"Although the materials are robust in normal use, the bellows should not be constantly in contact with hydraulic oils, lubricants, solvents, metal cuttings and welding sparks."
https://support.newgatesimms.com/lubricants-and-possible-plastic-or-rubber-compatibility-issues/
https://www.norgren.com/uk/en/expertise/industrial-automation/what-are-air-bellows-and-how-are-they-used#:~:text=How%20are%20air%20bellows%20constructed,depending%20on%20the%20stroke%20required.
Go look at the air bags on an asphalt trailer.
The first link has nothing to do with airbags. What kind of hose is used for fuel line ? Rubber.
I've never heard of Norgren air bags. And the key word is "constantly". A little bit of oil and grease isn't going to hurt an airbag.
Not a single mention of oil and grease being a problem here:
https://www.truckinginfo.com/156492/maintaining-air-springs-and-shock-absorbers
Going to go make some popcorn.
Quote from: chessie4905 on September 07, 2020, 04:45:08 AM
Going to go make some popcorn.
Yup, it has taken a long time, but the "good old daze" seem to have returned...
Intollerance has crept into every aspect of life, including hobbies...
Happy coaching!
Buswarrior
Quote from: chessie4905 on September 07, 2020, 04:45:08 AM
Going to go make some popcorn.
And I'm going to spritz some oil on someguy's impervious airbags, if he ever gets any, in order to keep him from having to chisel off the airbag bolts. ::)
I'm no petroleum engineer and I wouldn't want to be but I've picked up some useful information over the years. Vulcanization is an interesting process. It is essentially thermosetting combined with polymerization in an incomplete way. So you have this great viscous mass that has some of the molecules locked up pretty solidly and some that are still fluid. The ratio depends greatly on the inclusion of carbon black and plasticizers. Plasticizers are oils, and they continue to outgas during the entire life of the product at the end of which the flexible bonds are gone and the rubber crumbles. So if you introduce a solvent to the product what do you suppose will happen? A solvent in this case is nothing more than a light oil and the lighter the better the penetration, and the more effective at carrying off plasticizers or diluting them.
That's a great simplification and like I said, no P-engineer here, those guys have done wonders with air bags to get such a long life out of them. But completely impervious to oils? Hardly.
Jim
Makes me no difference what you guys do or believe. Build all the airspring guards you want.
https://www.youtube.com/watch?v=E7-__aXC4z0
Too late to help but maybe the next guy that searches this topic may benefit.
Those single nuts up in the 3 inch deep hole gave me no end of grief. I finally
drilled out a piece of round stock with a 1/4 hole to act as a drill guide to drill out the bolt.
I added a little electrical tape to make a firm fit.
They didn't drill out bulls eye on dead center but close enough to drill out the stud and nut.
The rest I cut off with a 3" cut off wheel.
When I installed the new bags Luke had sent me 12 of the longer bolts because he didn't have enough of the regular length.
Turns out using 1 long bolt on each upper ring made them a breeze to install.
YMMV
I've actually been slacking and haven't even finished the rear bags. I wouldn't have though of that idea. I'll give it a try when the time comes.
I thought there was discussion in the past about converting to the new style air bags.
I saw a website selling a conversion kit a while back but if I remember correctly it was $$$ compared to just replacing bags. It was also marketed towards folks who had to install block off plates advertising a better ride. Since I don't need block off plates I decided to just keep it OEM.
http://busconversion101.com/air_suspension.htm
Isn't that a site owned by Sam Walker?
If so, please read the various threads about this before doing business.
I thought it sounded familiar. I think I'd rather just ratchet strap the rolling lobe bags on from what I've read about him...
The rear bags don't have that pesky pocket hole so you're in luck there.