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Topic: HWH Six Pack Manifold Corrosion Repair (Read 2124 times) previous topic - next topic

HWH Six Pack Manifold Corrosion Repair

Upon pulling our front six pack, it was hard to miss some heavy corrosion near the top of the port side, starting where it makes contact with the steel mounting bracket. Intergranular corrosion, a term I had never heard of until Jet Doc made mention of it in another thread. There was also some lighter corrosion in a few  places on the valve side, including the spot faced area under the outer o-rings for both lift solenoids. This corrosion is porous. Even if a good seal is obtained by the o-rings, air would likely migrate through through the corrosion. Being these manifolds are made from 2024 alloy, welding is not an option. What to do?

IMO, the only reliable fix is to replace the manifold, or remove all of the corroded material. Using a mill, I took a minimal cut on the mounting face, removed a fair amount of material on the port side, and, since I don't have the proper spot face tooling for the valve side, milled that entire side with an end mill. Although the o-rings WILL seal to a milled surface, (been there, done that, many a time) I took a fine table stone to it for good measure. For areas with smaller spots of corrosion, not where a sealing surface is, I used a die grinder with an oval single cut burr. The limitation of how much can be removed from the valve side is dictated by clearance between the raise valve spigots and the two isolation check valves under them. If too much material is removed, the spigots will interfere with the plastic check valves. I needed to remove .045" form the valve side, and that's pretty close to the limit. YMMV. Anything more than a light cut on the valve side will require a re-chamfering of the six valve holes (to accommodate the fillet radius on the valve spigots) and re-tap the 1/2"-20 holes to the original depth with a bottoming tap. This manifold needed an additional half turn of the tap in order for the valves mate up. After machining, I soaked the manifold in vinegar, overnight, and then washed in soapy water, rinse ...blow dry with air gun.

While the manifold was available, I reverse engineered it. Crude (but accurate) drawing on hand, should the need arise to make them in house. BTW, on our coach, the front and rear manifolds appear to be identical, though I didn't verify that 100%

Greg

Re: HWH Six Pack Manifold Corrosion Repair

Reply #1 –
I replaced one a few months ago. It was not salvageable. They are made to order (at least mine was) and it took a couple of weeks. If I recall is was about $550. :o

I was constantly fighting leaks and that now seems to be resolved.

Re: HWH Six Pack Manifold Corrosion Repair

Reply #2 –
Nice job!  Wonder how many others have had the same corrosion on the manifold?
A friend recently moved his front manifold into the side basement bay, had to extend the air lines and wires and build a mounting bracket.  But it will protect it from road grime.  This is on a Newell but they use the same HWH system. 
I'm thinking of moving mine this winter and will post pictures when I do.

Re: HWH Six Pack Manifold Corrosion Repair

Reply #3 –
Quote
Wonder how many others have had the same corrosion on the manifold?
My front one is awful. Couldn't even get the solenoid bases unscrewed. I did put in o-rings and it is working fine (knock on wood) but I'm still on the lookout for a replacement.

Excellent post, Greg. I predict you will be a real valuable member of the forum. Glad to have you aboard.
jor

Re: HWH Six Pack Manifold Corrosion Repair

Reply #4 –
Quote from: Jeff & Sandy –
I replaced one a few months ago. It was not salvageable. They are made to order (at least mine was) and it took a couple of weeks. If I recall is was about $550. :o
Yeah, a bit expensive, but HWH has to make a profit or no point in being in business. That being said, when I have some free time (haha) I may make a few of them and sell for my cost of acquiring the material, plus a small amount to maintain tooling. Likely would end up in the $100 ish range. I can get a 3' bar of stock for about $250 plus shipping, which will yield 5 manifolds....pretty efficient use of material (little waste), without a large outlay of $.

Could maybe keep a few in stock (of this particular manifold) and do an exchange deal where someone in need can have one in a few days, send me their old one for evaluation/repair. Those who's manifold is a different version would have to send it to me for reverse  engineering, repair, or replacement. Due to setup time, I would not want to make less than two at a time, so next person in need of that version would have a faster turn around time.

First, let's see if there's any interest/need.   

Re: HWH Six Pack Manifold Corrosion Repair

Reply #5 –
Put me down for 1.  Thanks for your offer!

Re: HWH Six Pack Manifold Corrosion Repair

Reply #6 –
Greg, our coach was made just 5 units before your's!  If we develop an issue with our HWH, will certainly give you a shout!  Thank you for your generous offer to assist others on this forum!

Re: HWH Six Pack Manifold Corrosion Repair

Reply #7 –
Greg,
 I would like one for a spare. I will get under the coach and see if mine is the same as yours.

Thanks for posting your project.

Chuck

Re: HWH Six Pack Manifold Corrosion Repair

Reply #8 –
Raising my hand on this one! ^.^d I haven't looked closely yet, but I think ours will clean up. Still, a spare sounds like a good idea to me. My son has a Bridgeport mill in his garage, and if there was a file available, could probably make one for me. But he is so busy, I wouldn't ask him to start from scratch...
Don

Re: HWH Six Pack Manifold Corrosion Repair

Reply #9 –
Quote
Yeah, a bit expensive, but HWH has to make a profit or no point in being in business. That being said, when I have some free time (haha) I may make a few of them and sell for my cost of acquiring the material, plus a small amount to maintain tooling.

Whoa! Put me in for two! If you pull this off, you and TimF will be in direct competition for FMY, Foreforums Member of the Year!

Some clarification on the cost from HWH.  The retail cost is $802. So if you order one directly from HWH that is what they charge. 
jor

Re: HWH Six Pack Manifold Corrosion Repair

Reply #10 –
Quote from: MisterEd –
BTW, on our coach, the front and rear manifolds appear to be identical, though I didn't verify that 100%
Greg,

Really impressive work on cleaning up that manifold!  As you can see, refurbishing old manifolds, or building brand new ones, could turn into a nice little part-time business venture for you.  Even if you charged HALF the price HWH gets, they would be a screaming bargain.

I do have a question on your last sentence (see quote above).  AFAIK the front HWH manifolds on all our coaches have 2 pressure gauges, and the rear manifolds have a single pressure gauge.  Are you saying the manifolds on your coach are interchangeable and could be used either front or rear?  In that case there must be two extra tapped pressure gauge holes on the rear manifold that are plugged?

I have never got around to rebuilding my rear manifold, so I haven't (yet) taken a real close look at it.  Good info to know!

Re: HWH Six Pack Manifold Corrosion Repair

Reply #11 –
Mine looked the same but had plugs in the ports not used.

If mine is the same I'd take two also

Re: HWH Six Pack Manifold Corrosion Repair

Reply #12 –
Great post with fantastic information! Keep up the useful posts!

Re: HWH Six Pack Manifold Corrosion Repair

Reply #13 –
I would take 2 also

Re: HWH Six Pack Manifold Corrosion Repair

Reply #14 –
@All
OK. It sound's like there's some interest so I'll plan to make some of these, later this year. When the time comes, I'll review this thread and determine how many to make (within reason) :o

@ jor
Noted, and thanks. Not interested in any notoriety. Just wanna give something back. Y'all may not realize it, but I do have a LOT of questions. The reason I don't ask is simply because of the great info y'all have provided, here on the forum, I can find most of my answers doing a search....luv it!  ^.^d  No doubt, some questions will be coming.

@Chuck
I'll verify my statement, true or false, of F&R manifolds being the same. Coach is way up for testing HWH leakdown (couldn't do that before), safety blocks in place, and I'm in "full grunge mode" so will go under her and verify this afternoon. The ideal situation would be all manifolds are the same. I've read some have t-handle isolaters on the sides, so I was thinking to make some manifolds that have only those ports common to all styles, and do the balance of machining as needed; faster turn around time for someone in desperate need. We should also determine if your 93 GV uses the same manifolds as the ones built closer to Y2K.

Greg

Re: HWH Six Pack Manifold Corrosion Repair

Reply #15 –
I'm in for a unit..!

Hans

Re: HWH Six Pack Manifold Corrosion Repair

Reply #16 –
Greg,

Another option if they are the same with the exception that one has one or more extra ports, would be to make the new ones to match the one with the most ports and just install a plug in the "extra" hole (assuming the rest of the air channels are the same).

Others who have overhauled both front and back and on different model years can provide more advice. 

OR, HWH could tell you very quickly what PN's is for front/back and for what model years. That would probably be the most accurate.  But, not sure I would mention that you are considering a "cottage industry"!

Re: HWH Six Pack Manifold Corrosion Repair

Reply #17 –
I 'd be interested in one I didn't replace.

Re: HWH Six Pack Manifold Corrosion Repair

Reply #18 –
I rebuilt my manifolds a couple of years ago and they don't leak air as of now, but for the price range you mentioned I would buy two as spares for my future use or for the next owner when ever that happens.

Re: HWH Six Pack Manifold Corrosion Repair

Reply #19 –
Don't leave me out, make me one.