78 Camper Backfiring Low Power

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Amskeptic
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Re: 78 Camper Backfiring Low Power

Post by Amskeptic » Mon Apr 21, 2014 7:30 am

pdlrofdrms wrote:Okay so there is a vacuum leak in the brake system.

I found this out by removing the check valve plugging the line to the engine with bolt and clamping it down.
Engine ran great.

All cylinders firing even and participating. No more lumpy idle.

So now I have crawled under the car with a big ol flash light. I checked the connections and looked for tears, holes, etc.. none that I can see.

I called my VW friend in SD. He said its not super common but sometimes the metal tubes can get holes in them and to run my hands along all the metal tubes and check for any rust and holes.

Sigh...
I did get a new brake booster and Master cylinder I was hoping to store it away until I actually needed it.
Maybe I actually need them.

I do not see any oil leaks at all around the seals and or connections.

So I feel a little stuck.

Back out to re examine the hoses.
Separate each connection from the check valve forward, one at a time, and plug the engine side. When you reach the spot that makes the engine run poorly, that last run is your culprit. I seriously doubt that the metal tube has holes. The hose from the metal tube to the booster itself is a possibility. IF you plug that hose right where it joins the booster, and the engine still runs well at idle, then the booster itself is leaking OR the rubber o-ring between the master cylinder and the booster may be leaking. Do not just tighten the master cylinder-to-booster nuts in the hope of fixing it. It would require removing the master cylinder from the booster and cleaning up the connection and installing a new o-ring.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Mon Apr 21, 2014 11:27 am

okay I have read and read and read some more about the check valve direction.

On my check valve there is writing it says Engine and then arrows pointing away from the word. In the Bentley manual it says these arrows point towards the booster.

However if I install it this way no vacuum can get to the booster. If I suck on the booster the vacuum happens on the side that does not have writing.

Meaning the arrows point towards the engine and the engine word on the booster side.

IF I install it that way I get a hand full of brake fluid and chunks of rubber.

:shaking:

If I install it the way the book says yes the car runs better. Not great but better but now no vacuum is produced to get to the booster so doesn't this work similar to the nut I put in the line? I say tis because when you suck on the side the side with the Engine print and the arrows pointing to the booster no suction can happen.


I am totally confused.

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Amskeptic
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Re: 78 Camper Backfiring Low Power

Post by Amskeptic » Tue Apr 22, 2014 6:39 am

pdlrofdrms wrote: On my check valve there is "Engine" and arrow.

In the Bentley manual it says these arrows point towards the booster.

:shaking:

I am totally confused.
The arrow, regardless of the word, must point towards the engine (the vacuum supply), not the booster (the vacuum's "destination").

If you apply vacuum to the arrow tip side of the valve, you will be able to draw air. If you apply vacuum to the other end, the valve should prevent any air.

We are *expecting* the engine to run poorly when you correctly install the check valve, because there is a leak somewhere upriver. We are going to find the leak.

A) Install the valve. Make sure plastic tube is seated in the rubber "wye" on the intake manifold.
Go to the first connection upriver. I think it is the black plastic booster tube-to-metal pipe under the bus. Carefully pull and twist it off. Plug the end that leads to the engine.

Does it run well? Hose/valve/plastic tube are all OK.
(Run poorly? This is the leaky part)
Reconnect and clamp.

B) Disconnect the hose from the front of the metal pipe (near the booster now). Plug the metal pipe.
Does it run well? Pipe/hose/valve/plastic tube is OK.
(run poorly? this is the leaky part)
Reconnect and clamp.

C) Disconnect the hose from the booster (look carefully for grommet or any sleeve damage). Plug the hose.
Does engine run well? Hose/pipe/hose/valve/plastic tube is good.
(run poorly? Hose is leaking)
Reconnect and clamp.
Now we have checked the entire run.

If you have brake fluid and crap in the hose, I think your master cylinder/booster is a problem.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Tue Apr 22, 2014 9:32 pm

Okay well today I thought I was ready to get down to it. I had been collecting parts the last couple weeks.
I even found hard plastic vacuum line at the local Peterbuilt shop.

BUT! a couple things.
1. the hard plastic tube I had was the right size but douh no flair at the end. Okay no worries I figured. I will use the rubber vacuum line I got from oriellys and make my own with clamps.

Seems to work Great.

Got all the vacuum lines patched and replaced. Colin I will be thrilled to get your thoughts in June to see if what I did will last or if I should amend my attempt.

2. I replaced the brake booster and Master Cylinder today. Got it all put back together.

I think the new Master cylinder is leaking in two places.
1. at the reservoir grommets,
2. at the nut closest to the rear that is for the brake lights.

I will check in the AM again.
They are both on securely and I can not tighten them any further.
I am thinking I maybe overfilled?

3. I am a 7mm wrench away from bleeding the system. It was my last step and frustration hit me when my vw bug brake bleeder did not fit my vw bus bleeder nut. UGGG.. and everything is closed so I must wait till the AM.

BUT so far the car idles better.
I have some tuning to do I think but overall I think I capture the leaks. I will bleed brakes and report back tomorrow.

It must of been the booster too. Every line I took off held air and had no holes or cracks. However every place where the hose flared was too big for the fitting so maybe that is where some of the leaks where happening too.
I will try and take and post pics of what I did as a replacement.
I am a little frustrated I wanna take it for a test drive so bad after all day of tinkering. Oh well.
And random question.

on the driver side axle? (Gigantic round metal shaft that both wheels are attached too) there is a tiny nut with a spring coming out. What is that for?
I ask just because I was stabbed by it today and was like what the heck is that. Then I saw oh its suppose to be there. Then I wondered what the heck is that for anyways?

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Amskeptic
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Re: 78 Camper Backfiring Low Power

Post by Amskeptic » Wed Apr 23, 2014 7:15 am

pdlrofdrms wrote: I replaced the brake booster and Master Cylinder today. Got it all put back together.
You are a warrior mechanicprincess . . .
pdlrofdrms wrote: on the driver side axle? (Gigantic round metal shaft that both wheels are attached too) there is a tiny nut with a spring coming out. What is that for?
This is fascinating but I am stumped.

Rear axle? There is a large torsion bar tube with two spring plate arms leading to each wheel carrier, yes, but wheels are not attached to no gigantic round metal shaft, no sir, they are independently sprung! So . . . tiny nut with a spring coming out? More descriptiveness, a photo? a page in the Bentley that you can refer me to? ex. transmission and rear axle diagram 6.3 part # 22 etc.
Colin Hang In There
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

pdlrofdrms
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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Wed Apr 23, 2014 8:16 am

Well in the Bentley the part is the front axle beam.
On page 17 of the front axle chapter.

It definitely looks like in figure 7-15
Which says set screws for the torsion bars.

The little spring thingy poking out can be pulled and shoved back in .well at least by a couple MM or so. I did not really yank on it.
I only messed with it a tiny bit because at first I had no idea because of build up on the beam that it was attached to a small nut.

After getting out my wire brush I noticed it was suppose to be there.

Well. I guess cool? learned a new thing and now more homework.

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Re: 78 Camper Backfiring Low Power

Post by airkooledchris » Wed Apr 23, 2014 9:01 am

im thinking maybe that is just the cotter pin sticking out? perhaps it isn't bent anymore, or the bent bits at the end snapped off.

you usually replace those when you R/R anything that uses them, if that's what it is.
1979 California Transporter

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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Wed Apr 23, 2014 11:17 am

Chris:
Not a cotter pin.
Its def a tiny spring of some sort.
as for the Brakes:
OKAY I THINK I AM DONE!!!!

I drove it this AM.
My brakes are so responsive I am not use to it.

Like holy smokes is this what brakes are suppose to feel like?

I barely tap of them and its stopped. I am gonna have to get use to that.

brake lights work.
Reservoir is full.
I will keep my eye on the Master Cylinder leaks see if it continues at the grommets.

Off to double check the vacuum leaks but so far she is running smooth.
I think I just might of solved the problems!!!!

:bounce:

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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Wed Apr 23, 2014 4:59 pm

OH and BTW my brake booster was so full of brake fluid!

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Amskeptic
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Re: 78 Camper Backfiring Low Power

Post by Amskeptic » Thu Apr 24, 2014 5:09 am

pdlrofdrms wrote:OH and BTW my brake booster was so full of brake fluid!
Congratulations! Boosters are very forgiving when you catch a bad (bad master cylinder, bad!) master cylinder in time.

I fear your little "springy" may be threads? stripped threads? Where the torsion bar set screw goes into the middle of the tube with that serious 17mm lock nut? Chris, ideas? I am off to marathon with appetite.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

pdlrofdrms
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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Fri Apr 25, 2014 8:53 am

Well I guess it could not go perfect the first time.

I dont know what is happening but my new Master Cylinder is leaking alllllll over the place.

UGGG..

Crawling under the bus this AM then off to work.

Hopefully its an easy fix.

But its dropping fluid faster than I can put it in the reservoir :shaking2: .

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Re: 78 Camper Backfiring Low Power

Post by airkooledchris » Fri Apr 25, 2014 10:49 am

is it coming out of the brake light switches by chance?

the new switches are complete garbage, and will often leak as soon as installed.

if you replaced those when you did the rest of the parts, put the old ones back in.

EUROMAX is the brand for the complete garbage ones...
1979 California Transporter

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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Fri Apr 25, 2014 8:38 pm

well I took the MC out again. Dried it off and located the leak at the grommets that hold the reservoir in.
I put the old ones back in seemed to fix the issue.
Came home and it was leaking like a sieve again!
UGG...

Any thoughts? Ideas? work arounds?

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Re: 78 Camper Backfiring Low Power

Post by Amskeptic » Sat Apr 26, 2014 7:26 pm

pdlrofdrms wrote:well I took the MC out again. Dried it off and located the leak at the grommets that hold the reservoir in.
I put the old ones back in seemed to fix the issue.
Came home and it was leaking like a sieve again!
UGG...

Any thoughts? Ideas? work arounds?
I can only guess.
New reservoir grommets have too big a hole for the reservoir nipples? (reservoir should be a tough press fit)
Reservoir is not fully seated?
Blue hose from upper reservoir under seat is not properly sleeved where it joins the master cylinder reservoir?
Clean it up and look closely for where the new fluid leaks starts from. Then fix it. :blackeye:
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

pdlrofdrms
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Location: Humboldt County Ca
Contact:
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Re: 78 Camper Backfiring Low Power

Post by pdlrofdrms » Sat Apr 26, 2014 9:42 pm

The hose that went from my upper to my lower was a clear molded hose. It was leaking there. So I went to the parts store they sold me transmission line which apparently will work for brake line? I said are you sure cause my life depends on it. LOL they swore it would work,
It wasnt cheap but I got that leak to stop.

Now the still persistent grommet leak.
Grommets and MC are from Wolfburg West.
They seem to fit snug.
But I am not sure now I feel like i am going insane.
I have taken this thing out four times now.
Sorry. I am just really sad and frustrated.
I will take it out again.
Next step is to plug all the holes in the lower reservoir let sit for a while maybe it has a small crack that I just can not see????
It seems to be the grommet closest to the rear of the car.
both are wet on top but only the rear one seems to be pouring out fluid.

:shaking2: :angryfire:

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