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tevake · 05-06-2016, 05:11 PM

Don't dispare if the manifolds need work, access thru the wheel wells make them quite reachable.

Cheers Richard

Tap · 05-06-2016, 05:21 PM

Cool. Thanks guys.

I'm just desperate to get it fixed before the lonnngggg drive to PA, or else it will be an extremely loud and dangerously exhaust-filled road trip.

On a happy note, I'm getting the brand new tires tomorrow!

Tap · 05-07-2016, 02:54 AM

Regarding my new tires for my 1981 280, they are 8r-19.5

What air pressure should I keep them inflated at?

Also where do I look that up? I don't have a manual for my 280.

Thanks!

bkahler · 05-07-2016, 05:17 AM

On my 310 I used to run 75 psi in the front and 60 psi in each of the rear tires.

Seemed to ride nice at those pressures.

Tap · 05-08-2016, 01:06 PM

Just double checking.

Does everyone else agree that the air pressure for my 280's brand new tires should be 75 psi in the front and 60 psi in each of the rear tires?

Thanks again Bkahler.

mayco · 05-08-2016, 03:09 PM

Tap, people run a wide variety of psi in their MOHO tires. I believe in the owners manual it calls for pressure as low as in the 55psi range, and some folks run them that way. Ive read others who run at maximum tire pressure which is over 100psi. So, to get a spot on answer depends on who you talk to I suppose. There are good arguments to be made on both sides of that fence. Personally I run 75 up front and a bit higher in the rear. Youll find what youre comfortable with once youve had it out a few times. I believe you are quite safe to start out with 75psi all the way around. Lower pressures will give you a softer ride. Youll need to consider manufacturer specs, comfort of ride, wear patterns, handling, etc etc. I wish there was a dead on answer on tire psi but not sure there is.

Mike

Tap · 05-08-2016, 03:36 PM

Mike, thanks, that's helpful.
I just don't have an owners manual, so I don't have anywhere to look for my exact machine.

Thanks so much!

Isuzusweet · 05-08-2016, 04:25 PM

Mike is right as everyone has his or her personal taste and ride comfort. It would also depend on what model coach you have, as a 350 is considerably heavier than a 250 and a diesel is 400+ lbs heavier up front than a gasser.

FYI I did come across an Airstream placard with my paperwork somewhere that stated air pressure of 70 PSI front and rear for my 310; HOWEVER I query that since the diesel was very much an adhoc option and rare, I'd be thinking 70 PSI is for the gasser.

I know John runs higher pressures as higher PSI's lower tire temperature and you don't want the rears bellying together as that will increase heat in the tires, so I have just bought an infared thermometer and will start taking temps of the tires at different pressure ranges until I find that sweet spot.

Cheers
Tony

Smartstream · 05-08-2016, 04:59 PM

When you buy your tires have the dealer provide you with the Load/Inflation chart for your tires. Every manufacturer will have a weight capacity per inflation usually in 5 psi. increments. There will also be a different capacity if the tire is used as a single or dual.

For your 280 I would guess a ball park weight at 5000 on the front and 10000 on the rear. My 280 has a 14500 GVW and is a little heavier on the front with the diesel but real close to 10000 on the rear. If you find a scale weigh it but the above numbers will get you a starting point if you can't find a scale.

I run mine at 70 front and 65 rear which is about 5 psi. high just for a little margin of error.

By the way I'm starting to get around better and I think I found a box to ship the seat bases in. PM me your address and I'll try to get them ready to go.

Tap · 05-08-2016, 10:09 PM

Thanks for all the tire info everyone!

My mechanic noticed that the belt behind the grill for my air conditioner was missing. But he was out of that belt at the time.

What belt is that? Is it a common size that I can find in any auto parts shop?

Or will I have to order it online and not get it in time for my long drive to Penn Wood?

Thanks!

Isuzusweet · 05-09-2016, 04:38 AM

Tap

There probably is a bigger reason your A/C belt is missing. Mine is missing also as the compressor is seized, I would do a system load check for leaks before spending large coin in getting a poor system design up and running.

You're not going to need it on this trip as you'll have plenty of air flow with the windows.

Just MHO
Tony

PeterH-350LE · 05-09-2016, 05:22 AM

Quote:

Originally Posted by Tap

Just double checking.

Does everyone else agree that the air pressure for my 280's brand new tires should be 75 psi in the front and 60 psi in each of the rear tires?

Thanks again Bkahler.

Over-inflation gives you a rough ride and is hard on the Airstream structure
Under-inflation is a tire killer due to heat build up.
A good estimate to use when comparing tire pressure to air temperature is for every 10 degrees F, tire pressure will adjust by 1 psi. For example, if the outside air temperature increases 10 degrees, the tire pressure will increase by 1 psi. Conversely, if the air temperature falls 10 degrees, the tire pressure will decrease by 1 psi.
Considering these facts, you want to make sure that your tire pressure does not exceed +~10% of cold inflation.
Here is an example that will surprise you:
You start out in the morning with 70 psi on the front @ 60 degrees F
By noon it is 100F and your tire pressure 84psi
You would think you overinflated your tires and make the huge mistake to lower the PSI even more. The reality is that you underinflated the tires, which caused the psi increase due to excessive heat
70 psi plus Temp increase (4psi for 40F)=74psi
But 70psi to 84psi=20% increase
In the above scenario you would want to see ~77 max psi at noon

Moral, check your cold inflation versus warm, considering outside temp

Gregsch · 05-09-2016, 06:03 AM

Tap, Whenever I look for a noise like a bearing squeal, a ticking sound or an exhaust leak I use a stethoscope to pinpoint the source of the noise. I got mine with a blood pressure cuff at the local drug store. You will be surprised how a loud noise like an exhaust leak will echo around under a vehicle and give you the impression it is coming from somewhere else. With a stethoscope you can pinpoint the location.

SpiceStream · 05-09-2016, 08:51 AM

Quote:

Originally Posted by tevake

Both the exhaust manifold to head connection and the back of the headers connection to the tail pipe are suspect and common leak points.

Hopefully the parts are OK. So you can get gaskets and just bolt things back together.
There is some question about the use of gaskets between the manifold and the heads. I just installed gaskets there and am happy with the results.
Between those and new donut gaskets at the collector pipe the noise as well as fumes in the cabin are MUCH MUCH IMPROVED!

It's nice that there is so much clearance under these coaches that its possible to crawl around and check out these things with out a lot of jacking etc.

CHEERS Richard

I have used Remflex exhaust manifold gaskets in the past with 100% success, even in applications that "ALWAYS LEAK". They are great. I would not consider pulling an exhaust manifold without having a set to go back in. I have spent up to a month of weekends drilling out broken exhaust manifold bolts, tapping heads, and replacing all hardware with stainless studs and brass nuts. It can be an easy job, but that has not been my experience every time. http://catalog.remflex.com/
Good luck.

shepherd57 · 05-09-2016, 10:23 AM

Tap any news on the exhaust leak . Is it the manifolds or just the donut gasket

tevake · 05-09-2016, 12:49 PM

Good link there Spicestream. If I ever have to revisit that part of the exhaust again I'll round up a set of their gaskets and a set of new bolts.

I too have had challenges while working on old exhaust parts and was dreading the possibilities on the 454. This actually held me off of starting the job for a while. Once I realized there was pretty good access thru the wheel wells my reluctance eased a lot. With a straight shot at the bolts with an impact wrench the removal became quite doable. And all of the bolts came out cleanly.

It turned out there were no gaskets in place, and clear signs of leaking on both sides of the engine.

I've driven over 500 miles since doing the gaskets and all is going well so far.
Replacing the donut gaskets done earlier in my ownership made the most improvements in noise and fumes. But getting the manifolds well seated really finishes the process nicely.

Cheers Richard

SpiceStream · 05-10-2016, 08:06 AM

Quote:

Originally Posted by tevake

Good link there Spicestream. If I ever have to revisit that part of the exhaust again I'll round up a set of their gaskets and a set of new bolts.

I too have had challenges while working on old exhaust parts and was dreading the possibilities on the 454. This actually held me off of starting the job for a while. Once I realized there was pretty good access thru the wheel wells my reluctance eased a lot. With a straight shot at the bolts with an impact wrench the removal became quite doable. And all of the bolts came out cleanly.

It turned out there were no gaskets in place, and clear signs of leaking on both sides of the engine.

I've driven over 500 miles since doing the gaskets and all is going well so far.
Replacing the donut gaskets done earlier in my ownership made the most improvements in noise and fumes. But getting the manifolds well seated really finishes the process nicely.

Cheers Richard

The last set I did was on a class C SOB last summer, there was only 1.5" clearance between the firewall and Exhaust manifolds, it was no fun. it was also a 351 which is allot more prone to exhaust manifold warping and cracking than the 454. All of my smashed fingernails finally grew back in.

Tap · 05-10-2016, 02:28 PM

They are checking out my exhaust manifold issue right now.

Question...

If it becomes impossible to get it fixed before the rally, is there anything bad about me taking the trip with it as is?

It's loud and a bit exhaust-y, but if I don't mind the noise and I ride with the windows open so that I have fresh air to breathe (I have to anyway, because I'm missing Windows, hahaha!), then is there anything wrong with me taking it to the rally as is?

Or is that a huge mistake?

bkahler · 05-10-2016, 06:20 PM

The answer probably depends on where the leak is in relation to the cockpit. Assuming its behind the cockpit then fumes shouldn't be a problem as long as you're moving forward.

As far as whether or not you'll enjoy the trip is a whole different issue

bpg_austin · 05-11-2016, 04:50 AM

Tap, last summer we road tripped from TX to MN in our Argosy. Thankfully with a brand new exhaust system.

On our way up we got caught up in a 3 hour traffic jam outside Oklahoma city. Creeping just enough that we had to idle for the entire duration. Even if we had all our windows open, had we still had the horrible exhaust leak underneath, the fumes would have made us all completely sick. I know one never plans on being stuck in traffic like this, but I can't tell you how happy I was to have that new exhaust. I've got 2 little kids, but even if it was just me and the wife I wouldn't have wanted to sit in the fumes. Well worth the expense to have things sealed up. Not to mention the sound difference while on the road. If you're header-back parts are good it shouldn't be too bad to either install some new manifolds or collector donuts to seal up your system. I'm all for fixing it first.

Ben