First fix what is obviously needing fixing - there seems to be something up with the brakes, so go down that road first.

Something about hydraulics and a red ****, too.

It is unknown how a failure in your brake system might affect engine vacuum or running ability and what kinds of noises it might make, but you can hear changes as you step on the pedal so there is definitely a problem there.

Fix that, then see what other problems remain.

Nobody here on the Internet can hear what you can, people can only do their best to help you locate & determine the problem on your own.

I personally would leave the manifolds alone, don't touch them for now as I really doubt they're involved.

Instead, fix what is obviously wrong, then work on any remaining problems.



Also, please click on User CP in the top-left corner and finish filling out your profile so people can see where you're at. Vacuum readings mean different things at sea level vs at 10,000 feet.



Finally, I'm gonna suggest you ask in one (or maybe both, I dunno) of the larger truck forums (after finishing your profile), people there might be more familiar with the devices & gizmos you have on your RV.

Post your pictures there, explain your problems and see if people can help.

We have some good guys over in this neck of the woods who will try their best to help you, but it's kinda like going to an eye doctor with gastrointestinal pain.

Super Duty/Heavy Duty - Ford Truck Enthusiasts Forums



If people there can't help, I went googling on "winnebago forums" and found some stuff, this one in particular at least had some postings today:

http://www.irv2.com/forums/f101/

 

As I understand it.. If the manufacturer no longer offers a replacement part for emissions. Then you're permitted to remove that part/system. You just need a statement from the manufacturer stating so, and show that when getting ur state inspection (but i could be wrong).


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My 85 F-350 has the same setup "non-catalyst" with both smog pumps, muffler shops keep turned down my business. They claim that i replaced the sticker or something and the truck should have cats.. because it has the two smog pumps.. lol

 

1. The brake and parking brake system is entirely hydraulic, so this could not have anything to do with vacuum. The only braking stuff under the floorboard is the master cylinder and Bendix pump. There is definitely an electric pump attached to the underside of the master cylinder with a relay.

2. The vacuum thing is anybody's guess. The problem is that it goes away pretty quickly after stopping, and I gotta drive some distance before it kicks in. I'm guessing this has something to do with the lousy gas mileage.

I found a smaller but nicely run shop not far from here that works on a lot of RV's and does Ford and is familiar with older engines. Since I'm not equipped or trained on brakes, and mistakes there are fatal, I'm going to take it there and give them a shot at both problems.

I have a very nice RV here, all ready for prime time. All I gotta do is get it to move, and all will be well. Thanks again for all the help, guys!

 

I had to order a new sticker for mine, Ford needed the VIN and the PN before it could be ordered.

 

Glad you've found someone you can trust.

How about a picture of the whole rig?
I'd love to see what it looks like.

 

I took it to an RV shop this afternoon. These guys know RV's. I also found out that the thing that I thought was an electric booster pump mounted on the bottom of the master cylinder is an electric brake pump backup that kicks in to provide braking if the engine is not running. this has not worked since I bought the unit about 11 years ago.

No readout on the bad gas mileage, they say the new gas really hurts mpg on the older engines. But I don't think this means a 50% drop. Their first guess is that the engine is worn internally and that is why it is losing vacuum. They will do some tests. I just got a promotion at work this week so that will pay for a new engine if that is where we end up.

Here is a photo of the rig. This is Winnegabo's top of the line 34' Chalet in 1987. They only made 12 of them. It has chrome all over it and extra goodies inside the interior. Somebody offered me 15K for it at a truck stop three years ago. It is a bit of a collector's item for RV freaks. The frontend was replaced 2 years ago after hitting a deer. that part now looks new.

 

NICE RIG!!!

I was saying... about the fuel.
But even I wouldn't expect a 50% drop.

Somethings going on with the vacuum situation.
Let's figure it out.

 

The guys at the rv shop said that when engines get old and the parts wear internally, the engine can lose vacuum when hot. It does have a small oil leak out the rear seal that drips into the tranny case and out a weep hole. The oil pressure always reads low, espec. after warmed up, suggesting bearing wear. this might be the original engine, has about 77k miles on it. they are doing some exhaust and pressure tests on it for starters to get a read on things. they say the groaning is definitely in the braking system, and I know the electric brake backup pump isn't working. I should have a readout soon.

 

Sounds like you are on the right track getting people who know those rigs on the job. Having said that, I've never seen the vacuum drop off that way after an engine gets "warm". If it gets truly hot, then things do go south, but not when it is just up to operating temp.

Anyway, I've already proven I don't know what I'm talking about, so......

 

Neither have I.

Personally, I worry that these guys are blowing smoke up your azz so they can get your $$$$$$, and I agree with Jim - try and figure it out.

A worn-out engine that doesn't have any vacuum is worn out both when it's just started as well as when it warms up.

The fact that you don't have problems until it's warmed up makes me suspect a temperature-actuated vacuum thingy and/or the vacuum lines connecting it up as the source of the engine dying when warm.



I also suspect the loss of vacuum when coming to a stop is the result of the engine dying, not the cause of the engine dying. Perhaps because there's a huge vacuum leak that's keeping the engine from idling.

I would put a known-good oil pressure gauge on it and get some real numbers, especially since you say the gauge has always read "low."

I'd then want to do a compression test, maybe followed by a leak-down test.

Don't let these guys rip ya off.

However, get the hydraulics fixed, that very well may cure the whooshing sound you hear.

 

I actually waited to say something about it until someone else suggested the leak-down test. I'm a really big fan of that process, and here's why:

First, when I bought my truck it ran very poorly and everyone that tried to help me diagnose the problem(s) pointed in a different direction. I ran a compression test and 7 of the cylinders were excellent and one was a bit lower but still within Ford's acceptable range. Then I built a leak-down tester and discovered 3 cylinders with bad intake valves and 2 with bad exhaust valves.

I repaired all of those problems awa replaced the cam when I discovered it had 2 flat lobes, and the engine ran great - until I overheated it. At that point it would run fine around town but above 45 mph it got hot. Back to the leak-down tester and I found I had several cylinders leaking into the cooling system and some leaking into an adjacent cylinder. Further, none of the cylinders had a good seal between the rings and the walls. Got the engine apart today and found signs of leakage past the head gaskets, so I'm sure that the diagnosis was correct.

You can do the test yourself with a bit of effort making the tester, or you can buy one. In fact, you may be able to "borrow" one from a parts store for no cost. But, that may save you a bundle of money if you find the engine is ok.

 

My 460 went 300k before a winter cold start spun a rod bearing.
At 77k yours is barely broken in.

Unless it ran out of oil or was run without an air filter there's no reason for it to be so 'worn' internally that it shouldn't run well.

I'm going to suggest again that you check for intake manifold leaks when the engine is hot and it's running poorly.
Some carb cleaner should pick the revs and vacuum right up if the head to manifold joint is leaking, UNLESS it's leaking INTERNALLY.

These engines have the "turkey pan" intake gasket from the factory.
The idea is to keep oil from splashing out of the lifter valley and cooking on the heated intake manifold crossover.

In my experience these don't seal that well for the long term, but you might be able to tell if you see the remains of oil vapor on the plugs.

I agree with Gary, A leakdown would show a lot about the overall condition of your engine.