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Topic: Working On My Six Pack (Read 10756 times) previous topic - next topic

Re: Working On My Six Pack

Reply #40 –
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 –
Quote from: John Haygarth –
...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.  ^.^d

Re: Working On My Six Pack

Reply #42 –
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 –
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 –
@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 –
Thanks, Ken - your vote is recorded.  ^.^d

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

Re: Working On My Six Pack

Reply #50 –
@Chuck,

That six pack is so pretty it belongs in the Industrial Design section of the Smithsonian! Nice work.

see ya
ken

Re: Working On My Six Pack

Reply #51 –
The 10psi switches on the front manifold only come into play when you level the coach and one side in the front sets down on a hard stop. As soon as the pressure in those air bags goes below 10psi the switch actuates and removes power from the other side dump solenoid to stop that side from continuing down and twisting the coach.
These switches were added by Foretravel.

Re: Working On My Six Pack

Reply #52 –
Final report to close out this thread.  Took our coach out for a test run yesterday.  The rebuilt "front" 6-pack is performing perfectly, best I can tell.  I went through a complete test of all the functions on the HWH panel (up/down on all 4 positions, raise, dump), and everything worked great.  Auto-leveling works - travel mode works.  Apparently I got it put back together properly!  ^.^d

Only time, and further operational testing, will tell if this rebuild slows down my general "air leakage" problems.  However, I did not expect this first project to be the "Magic Bullet".  It is only the initial step in eventually going through the whole coach air system.  I expect each component replacement/rebuild to make a small incremental improvement, until I finally get everything back to "factory new" air tightness levels.

Next step will be to replace the protection valves, shuttle/check valves, and double check valve on my "front" & "rear" air tanks.  That will be the subject of another Topic.

Re: Working On My Six Pack

Reply #53 –
Nice job Chuck!
You just can't beat doing it right! It always pay's off !

Re: Working On My Six Pack

Reply #54 –
x2 nice job Chuck.
JohnH

Re: Working On My Six Pack

Reply #55 –
I ordered 25 also and will order other seals before dismantling. This is a very valuable thread to me, thanks for your time and effort.

Re: Working On My Six Pack

Reply #56 –
My protection valves were leaking because the rubber (maybe neoprene) seal had cracked. I cut a piece of bicycle tube to size and installed it on top of the cracked seal. It raised the protection press from 60 to 70 psi. This pressure can be adjusted with an alan wrench. This has been working for 5 years.
The check valves on the front/rear tanks are very high quality. I dismantled them and cleaned the brass seal with 2000 grit and reassembled. Working fine six months later. I bought new check valves but did not install them.
I managed to get my pressure loss down to 3psi per hour which is half of Foretravel standard (6 psi/hour) and 1/20th of DOT standard. I am not convinced that replacing your check valves is necessary.

Re: Working On My Six Pack

Reply #57 –
Quote from: P. Wyatt Sabourin –
The check valves on the front/rear tanks are very high quality. I dismantled them and cleaned the brass seal with 2000 grit and reassembled. Working fine six months later. I bought new check valves but did not install them.
 
...I am not convinced that replacing your check valves is necessary.
Wyatt,
I appreciate your comments.  I am all in favor of restoring and reusing a component, where feasible.  My old check valves, however, were in very "rough" condition internally.  (I already tossed them in the trash bin, or I would add a photo).  In my opinion, they were not fit for salvage, so I installed new ones.

I read, in one of the online HWH documents, that the air systems in RVs are not designed to be "zero loss".  That is, even when functioning perfectly, they are expected to leak.  You have managed, on your coach, to reduce the "leakage" rate to a admirable degree.  Proves it is possible...

Re: Working On My Six Pack

Reply #58 –
I also have taken apart/cleaned etc those valves along with others, but, did replace the check valves on tanks as they are so cheap to do. My pressure loss is around 1.5 to 1.8 lbs/hr and blame some of that on the pnuematic drop down step cylinders. One of these days they are coming apart and get new o rings etc. My biggest loss was the step slide cover cylinder which now is zero due to NC solenoid on it. Another job (for fun more than anything else) is the 6 packs as they must be needing a good cleanup due to install location but they do not leak.
JohnH

Re: Working On My Six Pack

Reply #59 –
Quote from: Chuck & Jeannie –
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.
Chuck this is awesome stuff, thank you for this. Has anyone been able to confirm whether or not the parts are the same on the early 2000 unicoaches?