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dkarnath
Posted 2019-09-16 4:57 PM (#6829 - in reply to #6828)
Subject: Re: #324


Extreme Veteran

50025
Location: Medford, OR
Lou, No blue colored brake fluid came out of it?? Everything I blew through it looked like normal clean looking brake fluid. So apparently it was already done before me. Do I still need to flush the system? I re-read what you wrote, your pretty adamant on flushing it....dam. I have a nice vacuum pump for evacuating. I like the sound of using DOT5 anyway...

Darrell, Yes same nice pan. I changed out the cork gasket for a rubber. The exhaust does sound nice, it rattles on idle pretty good, I noticed the rubber washers on the rear most mount is really loose, I think it's missing a couple rubber washers? You can send me pictures to my email, I'd like to see what you did.

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hemi354az
Posted 2019-09-16 5:13 PM (#6830 - in reply to #6829)
Subject: Re: #324


Extreme Veteran

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Location: Scottsdale, Aridzona
Dan,
https://www.google.com/search?q=mixing+dot+5+and+dot+3+brake+fluids&...
Lou #120
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BigRabbitMan
Posted 2019-09-16 5:16 PM (#6831 - in reply to #6736)
Subject: Re: #324



Elite Veteran

1000252525
Location: Cottage Grove, OR
Based on Dans above post, it doesn’t sound like it had DOT 5 in it.
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hemi354az
Posted 2019-09-16 5:49 PM (#6833 - in reply to #6830)
Subject: Re: #324


Extreme Veteran

10010010010025
Location: Scottsdale, Aridzona
If you do change to DOT 5 . . . shop around the Nets for it. Prices are all over. Convert every items price to Dollars per Ounce . . . then compare.
Lou #120
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andy1canada
Posted 2019-09-16 7:29 PM (#6834 - in reply to #6833)
Subject: Re: #324


Extreme Veteran

100100100100252525
Location: Victoria, BC. Canada
After going through this a few years back I spent about $30 bucks and built this: http://www.fmcowners.com/mbbs22/photos/show-album.asp?albumid=145&p...

There's a couple of pics of it in the Album. Not much to look at but it works like a hot-damn!

If purging the system (with de-nurtured alcohol) before the DOT 5 goes in - which IIRC back then Billy said was a 'must-do' - I reckon it makes more sense to 'push & flush' all of it out vs trying to suck it out.

Not sure how you'd get the alcohol out for sure. Maybe air? Opinions on doing this would sure help?

Just my 2-bits.

Terry
#846
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darrelldubree
Posted 2019-09-17 7:49 AM (#6835 - in reply to #6834)
Subject: Re: #324


Contributor


Location: Bowling Green Ky.
Lowering the atmospheric pressure with vacuum will boil off the residual alcohol
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darrelldubree
Posted 2019-09-17 7:59 AM (#6836 - in reply to #6829)
Subject: Re: #324


Contributor


Location: Bowling Green Ky.
Copy that on the pan. I put a newer version on my old 92 first gen Dodge. Simple and very effective design.
Dan, back to the brake fluid color. Drain a sample into a glass or clear plastic container. It will be a transparent purple/blue color. There was a container in the storage compartment with the silicon brake fluid. If you have some pour a sample into a jar and compare the two. Pushing alcohol or pulling it through, either will work. The vacuum will boil off the remaining residue when you are finished. Just as a vacuum on a air cond or refrigeration system boils off water residue in the system, by lowering the pressure, which enables it to reach the boiling point of the liquid residue left behind, or which entered the system when opened up for service repairs. Hope that makes sense. Lol
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andy1canada
Posted 2019-09-17 8:41 AM (#6837 - in reply to #6736)
Subject: Re: #324


Extreme Veteran

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Location: Victoria, BC. Canada
Sounds plausible.

I've previously leaned towards 'pressure-bleeding' mostly because Jim Black recommended it along with a few other's on the Forum's. Of course, both methods (vacuum & pressure) enable one to mostly do the job alone.

I guess there's pro's & con's to both methods and if any of you'd care to chime-in with a vote (and why you choose one over the other?) that could be useful to many.

Pressure Bleeding.

Pro's:

- if your canister is big enough you only have to fill it once to do the entire coach.
- 'pushing' the old fluid (and anything else in the lines) out ahead of the new incoming fluid might have a superior 'flushing' effect. Not positive on this, just a suspicion. There's physics at play here that are way above me.

Cons:

- more cumbersome and time-consuming hooking up the bleeder connections to the two switch-block inlets.
- you need to keep a close eye on the level of fluid in the container. If it gets too low - you're pushing-air!
- you need to keep an eye on the pressure and maintain it with a few pumps every now and then, depending on the size/integrity of your pump. (I usually only have to pump mine back up once for the entire job. I start around 15-psi)
- when you're done and you hook the two lines from the master back up to the switch block, you'll still need a helper to 'pedal-bleed' the last of the air and old fluid out of the master and those two short lines.

Vacuum-bleeding.

Pros:

- no need to unhook any brake lines at the master or switch block.
- if canister is large enough could likely do the whole coach in one shot.

Cons:

- have to be vigilant on checking and maintaining the fluid level in the master reservoirs, or, you could 'suck-air' in and you'd have to start all over. If you don't have a helper to do this, I could envision a lot of climbing in & out from under the coach and back & forth etc. (I'm envisioning a brake-fluid container positioned securely over the master to use gravity to feed both reservoirs, same principle as those upside-down watering containers for chickens (and dogs and cats and people) that simply 'burps' more fluid downward as required)

- maybe more pumping action required to maintain vacuum, especially if you do it with one of those smaller pistol-grip jobs. I have one of them 'Mighty Vac' jobbies for oil-extraction etc and it has a larger globe-shaped canister and perhaps that would do the job with less pumping, especially if you could put a shut-off valve on it (to hold vacuum) when you were done each bleed.

Anyone else added to this, would be cool.

Terry
#846
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darrelldubree
Posted 2019-09-17 8:51 AM (#6838 - in reply to #6837)
Subject: Re: #324


Contributor


Location: Bowling Green Ky.
I prefer pressure bleeding for the final method.
My example for vacuum was to remove the dot 3 fluid , then flush and evaporate the residue in the system with the vacuum.
Hard to beat the old school, with one on the pedal and one underneath. The only negative is, how much life do you use up of your new master cylinder with all of the pumping during the bleeding process. They also have the plates that can be put ontop of mc to force fluid through. Just a lot of work either way. Lol
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andy1canada
Posted 2019-09-17 8:57 AM (#6839 - in reply to #6736)
Subject: Re: #324


Extreme Veteran

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Location: Victoria, BC. Canada
Thanks Darrell.

Good thing to know. Was wondering since a vacuum would remove the alcohol then does it follow that compressed air would also work? Less pumping ;-0

The thing is, same as when spray painting etc, you'd have to have a good water-trap/filter on your line so you're not sending more moisture into the system. That would suck... but not in a good way.

Terry
#846
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darrelldubree
Posted 2019-09-17 9:16 AM (#6840 - in reply to #6839)
Subject: Re: #324


Contributor


Location: Bowling Green Ky.
If you wanted to flush with pressure after the vacuum. Nitrogen would be the best gas. Cheap and , zero moisture. As common practice in low temp refrigeration systems. Vacuum to 30 inhg. Bring back to 0 psi atm, with nitrogen. Repeat three times to sweep all moisture from the system. Of coarse this is extreme because of the no moisture allowed in a low temp refrigeration system. A simple flush with nitrogen would do the trick on a brake system.
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andy1canada
Posted 2019-09-17 9:36 AM (#6841 - in reply to #6736)
Subject: Re: #324


Extreme Veteran

100100100100252525
Location: Victoria, BC. Canada
Interesting. I think I like the 'using atmospheric pressure with vacuum' to blow off the alcohol idea better. Not sure where I'd get a bottle of nitrogen and/or what the hell I would do with it after the brake blow-out thing? Fill my tires? Take it to a kids birthday party and let'em all inhale it so they talk-funny? No wait... that's helium.

Terry
#846
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darrelldubree
Posted 2019-09-17 9:43 AM (#6842 - in reply to #6841)
Subject: Re: #324


Contributor


Location: Bowling Green Ky.
Rental or, if you know someone in the ac/ refrigeration trade. Probably let you borrow one. Wish I was closer, I could lone you mine. It is similar to oxygen or propane, tank with regulator. Oxygen regulator may work the same tank. Check with your local bottled gas distributor.
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andy1canada
Posted 2019-09-17 9:50 AM (#6843 - in reply to #6736)
Subject: RE: #324


Extreme Veteran

100100100100252525
Location: Victoria, BC. Canada
Driving there as we speak!

Terry
#846
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darrelldubree
Posted 2019-09-19 8:35 AM (#6867 - in reply to #6826)
Subject: Re: #324


Contributor


Location: Bowling Green Ky.
Dan here is some pics of the homemade vacuum extractor
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dkarnath
Posted 2019-09-19 7:09 PM (#6869 - in reply to #6867)
Subject: Re: #324


Extreme Veteran

50025
Location: Medford, OR
Thanks for all the vacuum/pressure bleeding advice, I may put DOT5 back in it soon. idk.

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