Working On My Six Pack

Topic: Working On My Six Pack (Read 8585 times) previous topic - next topic

Re: Working On My Six Pack

Reply #25 – February 25, 2016, 12:04:58 am

Quote from: John Haygarth – February 24, 2016, 11:39:50 pm

Good find guys, but looking at the type of material would not the Viton be a better choice as it is good for synthetic oil too??
JohnH

The site lists the Buena as best for petroleum oils which is what I am using for my hydraulics. I have Transynd in the tranny but using Delo for the hydraulic system.

Re: Working On My Six Pack

Reply #26 – February 25, 2016, 12:27:27 am

Am I missing something? These "O" rings are internal to the Six pack, right? In which case, their job is to seal clean, dry (ideally) air. Perhaps I missed a transition to seals in the hydraulic system... have to go back and read through the thread again.
Don

Quote from: craneman – February 25, 2016, 12:04:58 am

The site lists the Buena as best for petroleum oils which is what I am using for my hydraulics. I have Transynd in the tranny but using Delo for the hydraulic system.

Re: Working On My Six Pack

Reply #27 – February 25, 2016, 12:47:58 am

Quote from: Don & Tys (AKA acousticart) – February 25, 2016, 12:27:27 am

Am I missing something? These "O" rings are internal to the Six pack, right? In which case, their job is to seal clean, dry (ideally) air. Perhaps I missed a transition to seals in the hydraulic system... have to go back and read through the thread again.
Don

You didn't miss anything I am still focused on my hydraulic fan motor and slipped up. I hope I don't have any oil of any kind other than the lube I put on the seals. On my cranes I do get some engine oil in the air system but that is because the old type compressors bleed oil and I have to drain the tanks periodically.

Re: Working On My Six Pack

Reply #28 – February 25, 2016, 08:38:59 am

Quote from: Don & Tys (AKA acousticart) – February 25, 2016, 12:27:27 am

Am I missing something?

No, we're still on track - talking only (please) about the air system. I assumed JohnH's comment had to do with the type of O-ring lube, which is the only "oil" these seals should ever see. Since Buna-N is one of the most common O-ring materials, I am sure there are a number of excellent installation/lubrication products that will be compatible with these seals.

Re: Working On My Six Pack

Reply #29 – February 25, 2016, 10:40:43 am

Quote from: Chuck & Jeannie – February 25, 2016, 08:38:59 am

I assumed JohnH's comment had to do with the type of O-ring lube, which is the only "oil" these seals should ever see.

So are using any type of O-ring lube? In the past I've used Vaseline & lately started using silicone grease. Probably not the best stuff to use.

see ya
ken

Re: Working On My Six Pack

Reply #30 – February 25, 2016, 11:01:56 am

Ken,

I'm going to town today - plan to stop by the local O-ring Emporium, and pick their minds. I live in OILFIELD country, and every single piece of equipment used in the Patch has a multitude of rubber sealing devices. I am sure they will be able to recommend a good installation lube for our rather simple application.

PS: When I worked for Schlumberger, we routinely worked with flow lines, manifolds and valves which were rated at 10,000 PSIG working pressure. Every single piece was fitted with O-rings. You should see what happens when you remove a rubber O-ring from a joint of tubing that has been exposed to high gas pressures. Due to gas permeation, it swells up to about 10 times the normal size - looks like a big rubber Donut!

Re: Working On My Six Pack

Reply #31 – February 25, 2016, 11:53:30 am

Still waiting on parts, so, another dissertation...

One of my biggest concerns in doing this project is the worn sealing surface on the "plungers". (See photos below) I have been careful, as I do my cleaning, to keep all the parts of each individual valve together. However, when you disassemble the valves to replace the inner seal, it is impossible to avoid disturbing the relationship between the plunger sealing surface and the valve seat. If the seat and the plunger are not perfectly concentric (they are not), then it is possible they may not seal properly when the valve is reassembled.

Plan "A" is to hope for the best (Murphy was a optimist). I will install the rebuilt six pack in the coach, and give it a try. If it holds air, all is good. If it leaks, I'll remove it (again) and go to plan "B": Replace the plungers.

Plan "B". The problem we Foretravel owners have with these HWH valves is not unique. Other SOB's use the same valves. Search the Net and you will find numerous references to these valves, and the attendant problems. HWH will not sell individual replacement parts for these valves, other than O-rings. You must buy a complete valve assembly (expensive), even if all you need is a new plunger. One of our own, Jim McNeece, several years ago posted a alternative source for a possible replacement plunger. I have just touched base (PM) with him, to get a update on his experience. I will relay his reply, or perhaps he will add a note to this thread. Jim's old post:

Possible HWH Solenoid Replacement Plungers

Re: Working On My Six Pack

Reply #32 – February 25, 2016, 12:22:53 pm

Chuck, I was referring to the rings being lubricated by a syn' grease, not moving syn' oil as I was aware of the valves job in service. Got to commend you on this job and documentation too as it really helps all of us try and save money and learn more about parts of our coach's. Mine do not leak (as far as I know) but it would be a nice little project to do one nice day in the pit, after others are done I have listed.
JohnH

Re: Working On My Six Pack

Reply #33 – February 26, 2016, 07:31:53 pm

SIX PACK REBUILD - COMPLETE PARTS LIST

Reminder: Everything I list here pertains to the FRONT six pack manifold on our '93 model coach, with the HWH 600 Series leveling system. It is up to you to verify if these items are the same on your coach. Newer models might differ, but I think the HWH hardware is pretty consistent over the model years.

O-RINGS

All the O-rings I have encountered are standard AS568 sizes. These are readily available online, and possibly from local vendors. Online prices change, sometimes daily. I will link where I purchased my O-rings, but you should shop around for the best current price.

Air Inlet Check Valve (2 in front manifold): AS568-10
-010 N70 Buna-N Nitrile 70 O-ring [B70010] : The O-Ring Store LLC, We make...

Air Inlet Check Valve Retaining Plug (2 in front manifold): AS568-13
-013 N70 Buna-N Nitrile 70 O-ring [B70013] : The O-Ring Store LLC, We make...

Between the brass valve and the aluminum manifold (small O-ring): AS568-15
-015 N70 Buna-N Nitrile 70 O-ring [B70015] : The O-Ring Store LLC, We make...

Between the brass valve and the aluminum manifold (large O-ring): AS568-28
-028 N70 Buna-N Nitrile 70 O-ring [B70028] : The O-Ring Store LLC, We make...

Brass valve internal seal, under the stainless armature tube (square O-ring): AS568-19
019 Buna-N Square O-rings - Tetraseals [SN70019] : The O-Ring Store LLC, We...

PRESSURE SWITCH

On the front six pack, there are 2 pressure switches, 10 PSI, Normally Closed: Originally made by Honeywell, part # 76578-10 NC
Stewart Warner-Stewart Warner - Hobbs Pressure Switch 10 psi Normally Closed...

AIR CONNECTIONS

Our front manifold was originally fitted with compression-type air connections. With my rebuild, I have elected to change over to more modern Parker Prestomatic "push to fit" air connections. These are now quite common on over-the-road trucks, are fully DOT approved for all air brake systems, and have a max pressure rating of 250 PSI. They are reusable, which will be handy if I ever need to remove this manifold again. You just push in on the tube and the retaining ring, and the tube pulls right out. Push the tube back into the fitting, and it is ready to go again. EASY!

There are six air hose connectors, size 3/8" tube X 1/8" NPT
Parker Male Connector, 3/8 x 1/8 In 68PMT-6-2 | Zoro.com

There is one air hose connector, size 3/8" tube X 1/4" NPT (the air inlet fitting)
Parker Male Connector, 3/8 x 1/4In 68PMT-6-4 | Zoro.com

You will also need one (or two) brass 1/8" NPT male X 1/8" NPT female 45 degree fittings. This is necessary because the mounting holes for the 2 pressure gauges are too close together to screw them straight in. One gauge must be offset to the side slightly. You can buy this fitting online (Amazon or eBay), or at your local NAPA store. I am planning on using 2 of these 45's, one for each gauge. This will allow easier access to the exhaust ports on the manifold, for the purpose of keeping them clean. See photos below:

Re: Working On My Six Pack

Reply #34 – February 26, 2016, 07:39:03 pm

Additional photos of parts listed above. The "cigar cutter" is a cool little Parker tool for trimming the end of the air hose. It insures a clean, straight end cut, without squeezing or deforming the tube. A necessity when using the Prestomatic connectors.

PTC-001 Parker Tube Cutter | MRO Stop - Industrial Supply + Technology

Re: Working On My Six Pack

Reply #35 – February 26, 2016, 11:07:54 pm

Quote from: kenhat – February 25, 2016, 10:40:43 am

So are you using any type of O-ring lube?

@kenhat
You asked about lube. As promised, yesterday I stopped at the local O-ring store. They had both of the small O-rings needed for the check valves in stock, so I asked for 5 of each. The nice lady behind the counter tossed them in a plastic bag, and also threw in a 1 ml "sample" tube of Super Lube. She said that's what they recommend for all gasket & O-ring installations. When I got out my wallet, she said "Don't worry about it - just have a nice day". Can't beat that kind of service!

When I got home, I discovered Super Lube is available at all the Big Box stores, Lowe's, Home Depot, etc. Very highly recommended. Next time I go to town, I'll get a bigger tube. Sounds like great stuff - pretty much does everything...except cure hemorrhoids. Too bad about that... :(

Super Lube 21030 Synthetic Grease (NLGI 2), 3 oz Tube: Science Lab Cleaning...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Working On My Six Pack

Reply #36 – February 27, 2016, 12:41:13 am

Ha! I have a tube of Super Lube in my bicycle tool box! It's probably 10 or 15 years old. That stuff has been around for a while. I just went out and checked and yep I still have about a half a 3oz tube.

see ya
ken

Re: Working On My Six Pack

Reply #37 – February 27, 2016, 01:17:54 am

Awesome write up on a topic of interest to the vast majority of Foretravel owners with a mindset to "do-it-yourself"!

Don

Re: Working On My Six Pack

Reply #38 – February 27, 2016, 08:02:12 am

Some may question my replacing the (front manifold) pressure switches, since they are expensive. Well, what do they do? From my reading, it appears they mainly function as a safety device, to prevent the coach from being severely "twisted" during auto-leveling and manual leveling operations.

"The air bag pressure switches are used as air bag low air pressure warning switches when the system is in the travel mode. When the system is in the leveling mode, the air bag pressure switches are used to protect the vehicle from excessive twisting during the leveling procedure, specifically when the system is doing a lower procedure."

If you have ever traversed a steep driveway entrance/exit, especially at a angle, and heard your windshield panels creaking and groaning in the frames, then you know about "frame twist". Something to be avoided, especially in older GV models. If the pressure switches can help prevent popping a windshield out of place, then I want them in tip-top condition. Plus, there was no way I was putting my shiny clean manifold back together with grimy, cruddy 20+ year-old switches - aesthetics alone demanded they be replaced!

Footnote: Above quote came from Lesson 10, "Air Suspensions & HWH"...part of the excellent HWH Online Technical School. If you really want to learn about and understand your air suspension system, then you need to study the applicable training modules on this page:

HWH Online Technical School

Re: Working On My Six Pack

Reply #39 – February 27, 2016, 09:36:30 am

One Thing Leads To Another:

After being introduced to the concept of a "square" O-ring (the inner seal on the air valve), I got to wondering how these would work in the other two O-ring positions - between the brass valve body and the aluminum manifold. Hmmm... Looking at the O-ring grooves (also called "glands") on the underside of the valve body, it appears they are cut in a "square" shape, with clearly defined "corners" in the bottom. Seems like a square shaped O-ring would drop right in, since it is exactly the same size as the corresponding conventional round ring. The TetraSeal literature from Parker says: "In most static applications, it is a direct replacement for an O-ring and generally will perform a high pressure gasketing function as well as or better than an O-ring."

Since I know the sealing surfaces on my aluminum manifold are not perfect - I had to clean up several areas of chemical etching, and some fairly deep transverse scratches - I am thinking the increased contact area of the TetraSeals might be advantageous. At any rate, I have ordered a set of the square rings in -15 and -28 sizes. When they arrive (probably Tuesday), I will try fitting them in the grooves, and see how they look...

Stand by for (MORE) photos and my (not) "expert" opinion.

Re: Working On My Six Pack

Reply #40 – February 27, 2016, 11:57:18 am

Chuck, looking good and you have the same assumption I had in post 16 that the surface area contact would give you a better seal.
JohnH

Re: Working On My Six Pack

Reply #41 – February 27, 2016, 07:29:50 pm

Quote from: John Haygarth – February 27, 2016, 11:57:18 am

...you have the same assumption I had...that the surface area contact would give you a better seal.

Great minds...

I received my order of the -019 square TetraSeals today. They are without a doubt the correct fit for the inner O-ring position. They drop in the hole in the brass body perfectly, and the stainless arbor screws down and seats exactly like it should. Much better than the -019 round O-rings, which seemed a rather loose and sloppy fit in the same space, at least to me.

Re: Working On My Six Pack

Reply #42 – February 29, 2016, 11:46:22 pm

While I was waiting on my last shipment of O-rings (the square TetraSeals in -015 and -028 sizes), I decided to change out the inlet check valves on both "front" and "rear" air tanks. Both tanks, on our U280, are up front right behind the fiberglass "bumper", so easy to get to. But MAN! were those old valves in there tight. Took a lot of heat, a big wrench, and a long cheater to break them loose. Hard to get a lot of leverage laying on your back, looking up...but I got 'er done.

The old ones I removed were marked Bendix 227871 SC-1. The new ones I installed are Haldex KN23000. I got this part number thanks to a old post by (I think) either Bill Willett or else Pamela & Mike...can't remember which. Anyway, thanks Guys!

The new valves are a perfect fit. I did have to replace one brass reducer bushing that was stuck so tight in the old valve that I messed it up trying to get it out. Fortunately, I had the correct replacement bushing on hand.

Hopefully, two more potential air leak locations now rectified!

Re: Working On My Six Pack

Reply #43 – March 01, 2016, 09:46:42 pm

My last O-ring order showed up today. Now, it is decision time. I have 2 sets of O-rings that fit the bottom of the brass valve assembly - between it and the aluminum manifold. Conventional round, and square...so the question is, which will seal best? JohnH has already voted, and I give his opinion a lot of weight. Just going by "eyeball" analysis, it is a close call. Both types fit the grooves well, and stick up out of the groove about the same amount. The round ring is a silicon material, which feels softer than the 70 duro Tetraseal, and might conform to a irregular sealing surface better. However, the square profile does have more surface area in contact with both the groove and the opposite sealing surface on the manifold. Will this apparent advantage still be valid when the valve is torqued down against the aluminum manifold? I really don't know, but my "gut feeling" says it will.

I'm leaning strongly in favor of using the square TetraSeal design, but would welcome any opinions, pro or con, from the Forum.

Re: Working On My Six Pack

Reply #44 – March 01, 2016, 10:27:30 pm

@Chuck,

I have no experience or useful knowledge with square or round but I vote square. Take it for what it's worth.

see ya
ken

Re: Working On My Six Pack

Reply #45 – March 01, 2016, 10:45:52 pm

Thanks, Ken - your vote is recorded.

Update: In Post #32 (earlier in this thread), I discussed a possible source of replacement plungers. Jim McNeece answered my PM with a positive report on the Skinner plunger. He replaced all the plungers in his valves about 3 years ago. He says,

"So far, mine have worked perfectly. Never have to mess with the air to level the coach, even after several weeks."

So, unless some other source is located, this might be the best (only) option if you must replace one or more plungers. I also sent a email to the supplier, asking for current prices. They responded with a quote of $20 per unit, and no discount for a volume order.

As I said earlier, my plan is to put my front six pack back in service with the original (worn) plungers, and see what happens. I should get this done in the next couple days, so will make another post when I have some news (good or bad).

Re: Working On My Six Pack

Reply #46 – March 01, 2016, 11:53:00 pm

Chuck I stick with my vote, but there is a simple way to make you see what YOU think. Take a smooth flat steel item and clamp it down across the o ring in the groove and look at the deflection the O ring shape takes to fill the groove. Now the tough part, try and figure how much actual sealing surface is left (after filling the groove) on the o ring. The square one will not need to loose any of its cross section to "fill" the groove so the width of it is actual sealing surface. Then make a decision on what you see.
I think I explained what I want you to see correctly.
John H

Re: Working On My Six Pack

Reply #47 – March 02, 2016, 08:55:17 am

John is correct. The "square" or quad seal fills the groove entirely and protrudes above the mating surface. Thus you have more initial contact and more pressure required to attempt to compress the square seal. With an o-ring a lot of the force merely deflects the round surface to fit a square depression/groove.

Re: Working On My Six Pack

Reply #48 – March 03, 2016, 09:32:44 pm

I reassembled the six pack today, using the square TetraSeals (lubed with Super Lube) in all 3 positions on the brass air valves. They felt real good when I tightened them down - like the seals were making very good contact. Then I reinstalled the manifold on the coach. We shall soon see how it works - hope to get our coach out for a test drive tomorrow.

I had to reuse the old washers that fit between the electric solenoid and the valve body. I could not find a source for that size washer, which is definitely NOT a standard size. They are 1.5" O.D by 0.5" I.D by 1/8" thick. I tried several large hardware specialty supply stores in this area, and did a extensive search online. Based on my findings, the only way to get new ones is to order them custom-made. So I just hit them with a light coat of Rust-Oleum, and put them back in place. Should work fine...

I have to comment on the Parker Prestomatic "push to fit" air connections. They work GREAT! They function just like the SharkBite plumbing connections, which means they are EASY to use. I cut the ends off the old air hoses directly above the old brass compression ring. That way I only lost about 1/2" of length. The Parker Cutting tool I mentioned in a earlier post worked perfectly for this task - made clean, square cuts with very little effort. Then you just push the hose end into the fitting, and pull back slightly. That's all there is to it - can't get much simpler than that.

I had plenty of slack in all the hoses to re-connect to the new fittings. There is no strain or sideways tension on any of them, which is ideal when using this type fitting. I hope they work out well, because they certainly will make maintenance a lot easier, especially if I need to remove a hose at a later time.

Re: Working On My Six Pack

Reply #49 – March 04, 2016, 12:07:54 am

Nice job. Thanks for your excellent write up and pics. It's on my list.

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