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Danwvw
Samba Member
Joined: July 31, 2012
Posts: 8892
Location: Oregon Coast
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 Posted: Fri Dec 26, 2014 10:09 pm Post subject: |
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My 71 is loosing about 1 reservoir refill every 6 months too! No sign of leaks at the wheels. I think it may be at the bottom of the reservoir and it's being soaked up by my carpet under there! Hope it's not the Booster!
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Dec 26, 2014 10:23 pm Post subject: |
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| SGKent wrote: |
| I seem to recall using that combination of rags and alcohol on a 1971 booster at 75,000 miles+/- in 1976, and it was still going strong with no leaks at 400,000 miles. |
Yes....especially alcohol for the final cleaning. To start with its worth it to remember that brakea fluid is hygroscopic as well as self emulsifying in water.
If it had a lot of fluid....hose it out with hot water.
Then dry it as best as possible with compressed air.....then lots of alcohol ...several distinct rinse stages....because it will displace the water by blending with it (its cosolvent with water). The alcohol should dry out fast but you can hit it with a blow dryer to speed it up. Ray |
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vwwestyman
Samba Member
Joined: April 24, 2004
Posts: 5688
Location: Manhattan, Kansas, USA
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| Posted: Fri Dec 26, 2014 10:32 pm Post subject: |
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| Tcash wrote: |
| vwwestyman wrote: |
I ordered a rebuilt MC from the FLAPS. I've not had problems with other parts from them yet, so we'll see how it goes, I guess.
When I pulled the MC, I did find a bunch of fluid inside the booster (filled nearly to the MC hole, so diagnosis: correct.
To clean it out, what if I sucked out all the fluid, spritzed some denatured alcohol in there, suck that out, and repeat a couple times? Bentley indicates needing to replace the boot and other parts if the booster is pulled.
Seems like it might be worth a shot. What do y'all think? |
I would say it is worth a try. All you need is the o-ring between the booster and master cylinder. If it fails six nuts a clevis pin and two hoses and it is out.
Good Luck
Tcash |
The Bentley recommends changing "the filter and damping ring, the rubber boot, and the sealing ring" when r and r-ing the booster.
Though it also says something about not using solvents to clean it...
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Dave Cook
President, Wild Westerner Club
1978 Champagne Edition Westy, repowered to '97 Jetta TDI
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Alex6373
Samba Member
Joined: August 05, 2007
Posts: 882
Location: Vancouver Island,B.C.
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| Posted: Sat Dec 27, 2014 6:56 am Post subject: |
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Been there , brake fluid  |
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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
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| Posted: Sat Dec 27, 2014 9:22 am Post subject: |
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| vwwestyman wrote: |
The Bentley recommends changing "the filter and damping ring, the rubber boot, and the sealing ring" when r and r-ing the booster.
That would be nice if you could find them.
Though it also says something about not using solvents to clean it...
No solvents, water and denatured alcohol. |
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vwwestyman
Samba Member
Joined: April 24, 2004
Posts: 5688
Location: Manhattan, Kansas, USA
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| Posted: Sun Dec 28, 2014 5:45 pm Post subject: |
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| Tcash wrote: |
| vwwestyman wrote: |
The Bentley recommends changing "the filter and damping ring, the rubber boot, and the sealing ring" when r and r-ing the booster.
That would be nice if you could find them.
Though it also says something about not using solvents to clean it...
No solvents, water and denatured alcohol. |
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I sucked it out, and spritzed a bunch of alcohol in there, sucked that out and repeated several times.
Hopefully that will be good!
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Dave Cook
President, Wild Westerner Club
1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
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vwwestyman
Samba Member
Joined: April 24, 2004
Posts: 5688
Location: Manhattan, Kansas, USA
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| Posted: Sun May 24, 2015 9:56 pm Post subject: |
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So that MC or something crapped out.
Just like before, the brake pedal was gradually traveling further and further to stop the bus, and the warning light started coming on.
I had to top off the reservoir, expecting that this (replaced in December with a rebuilt) MC was bad.
Again, no visible leaks outward.
So I had them order another (lifetime warranty, though this will be last try before getting a spendy one) and removed it today. I was fully expecting to find a bunch of brake fluid in the booster, but it seemed to be empty.
Though there was some "greasy" feeling stuff in there, so I do think that some fluid may have gotten in it, if not tons like before.
But I'm puzzled as to where the fluid did go?
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Dave Cook
President, Wild Westerner Club
1978 Champagne Edition Westy, repowered to '97 Jetta TDI
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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
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| Posted: Mon May 25, 2015 7:14 pm Post subject: |
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| If the fluid level is going down. Check the lines and hoses pull the wheels and check the wheel cylinders. |
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vwwestyman
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Joined: April 24, 2004
Posts: 5688
Location: Manhattan, Kansas, USA
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Otis2
Samba Member
Joined: March 19, 2015
Posts: 15
Location: Pacific Northwest
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| Posted: Tue May 26, 2015 3:56 pm Post subject: |
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Wow, I put in new rear cylinder and brakes as well as front brake pads on my 71 Westy. Had all the lines open as I purged the Dot3 and put Dot5 in. Pre-filled the cylinders with Dot5. Took the front calipers off to do the same with them: purge and pre-fill. Started bleeding with a helper only to find that the brake piston of the MC does not return to it's rest state. lots of front play in the pedal. Initially I thought the booster went out because I couldn't get the engine started/ running afterwards. Finally disconnecting the booster vacuum line allowed me to start the engine again. But now I also think the MC is toast as I am unable to push break fluid back into the MC. This car has been sitting by previous owner for 13 years.
I'm on the verge to send booster off for overhaul, and ordered a new MC from Avery's in Kelso WA. Is there a reputable 'resleaver' for the booster in the Puget Sound area? Sending things off to Karl's seems far away. Bert |
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ToolBox
Samba Member
Joined: January 27, 2004
Posts: 3439
Location: Detroit, where they don't jack parts off my ride in the parking lot of the 7-11
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| Posted: Fri May 29, 2015 9:54 am Post subject: |
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| Otis2 wrote: |
| . Had all the lines open as I purged the Dot3 and put Dot5 in. Pre-filled the cylinders with Dot5. |
Should have just gone for a quality DOT4. The DOT3/4 is incompatible with DOT5 and will cause lots of issues when mixed.
| Quote: |
DOT 5 is one of several North American designations of automotive hydraulic brake fluid, denoting a particular mixture of chemicals imparting specified ranges of boiling point.
DOT 5 is a silicone-based brake fluid (contains at least 70% by weight of a diorgano polysiloxane[1]).
Unlike polyethylene glycol based fluids, Dot 5 is hydrophobic.[2] An advantage over other forms of brake fluid is that silicone has a more stable viscosity index over a wider temperature range. Another property is that it does not damage paint.[citation needed]
Using DOT 5 in a DOT 3 or DOT 4 system without proper flushing will cause damage to the seals and cause brake failure.[citation needed] DOT 5 brake fluid is not compatible with anti-lock brake systems. DOT 5 brake fluid absorbs a small amount of air requiring care when bleeding the system of air.[citation needed] |
You should remove and flush/clean all for your brake parts and lines with denatured alcohol and fill with a quality DOT3 or 4 fluid.
It takes me one 8 hour shift to prep one test stand (we have 10) if the manufacturer specs a DOT5 fluid for their testing. This is something I do not like to see on the test requests.
DOT5 will also result in a spongier pedal feel due to it's compressibility. It also does not absorb water and can form slugs of water in the system causing corrosion.
But it won't eat your paint. |
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kreemoweet
Samba Member
Joined: March 13, 2008
Posts: 3899
Location: Seattle, WA
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| Posted: Fri May 29, 2015 6:03 pm Post subject: |
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I've had DOT5 fluid in my bus brake system for over 15 years. No special prep was used on the lines, just a thorough draining.
No problems of any sort, no more corrosion anywhere, no need to change fluid every year or two. Pedal is not the slightest bit "spongy".
That talk above about "compressibility" and "slugs of water" is pure hogwash.
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busdaddy
Samba Member
Joined: February 12, 2004
Posts: 51153
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Fri May 29, 2015 6:29 pm Post subject: |
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I don't buy the compressability claim, but DOT5 does pick up a shitload of little micro bubbles if you rush the install, it takes a few weeks for them to fully settle out of the system.
The water thing is only plausible if there was already some in there, unlike glycol based fluids it's not hygroscopic so it doesn't pick up moisture from the atmosphere.
I'm still not comfortable leaving any fluid in any system for more than 5 years regardless of it's longevity claims or track record, things like brakes need a poke with a wrench now and then just to make sure they are ready to act when you need them, that's the airplane mechanic in me talking, maintenance is much easier than repair or the results from the lack of therof.
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Fri May 29, 2015 8:39 pm Post subject: |
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| busdaddy wrote: |
| The water thing is only plausible if there was already some in there, unlike glycol based fluids it's not hygroscopic so it doesn't pick up moisture from the atmosphere. |
Straight gasoline isn't hygroscopic either, but water condenses from the air in a tank of gas and then settles to the bottom where it collects and causes rust. It is my understanding that DOT 5 will do the same. Water will condense onto its surface, settle to the bottom, and once enough collects cause rust..
The idea with DOT 3 & 4 is that the water will be held in suspension and will not cause a problem until there is so much it begins to settle out.
When it comes to brake fluid a lot depends on where one lives. If you live in Georgia or Florida then changing the brake fluid every two years is pretty much a must do, while in eastern Washington or Oregon changing the fluid is more of a feel good thing. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri May 29, 2015 9:44 pm Post subject: |
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Yes...DOT 5 picks up water. All Brake fluids do. Hygroscopic simply means that the fluid is water miscable (which means that water fully dissolves intothe fluid or vice versa) and readily combines with the fluid like, DOT 3 and 4.
The water still combines with DOT 5 and DOT 5 still attracts water..... it just does not become a "dissolved" solution with the brake fluid....trust me... I work with water miscable fluids daily.
The, DOT 5 fluids "entrain" this fluid in small micro bubbles.....which can cause rust and cause a slushy compress ability. ....not because liquids are generally compressable...but because each fluid...water and brake fluid....each has a different density.
The high point of DOT 5...its whole reason for being.....is that because water does not "dissolve" into DOT 5.....it does not lower the wet boiling point. The problem is that the water remains in the DOT 5 as bubbls. When those bubbles come into contact with metal parts in high enough concentration......you get rusting.
I had a failure from using DOT 5 fluid without extreme thourough cleaning....that almost costcme my life in rush hour traffic in Memphis. Get it out of there and flush with at least two quarts of DOT 3 or 4.
This may not be your issue right now.....but its an issue. A big issue. Ray |
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ToolBox
Samba Member
Joined: January 27, 2004
Posts: 3439
Location: Detroit, where they don't jack parts off my ride in the parking lot of the 7-11
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| Posted: Mon Jun 01, 2015 9:48 am Post subject: |
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What he said/\ /\ /\ /\.
Ray explains it way better than I can. I just listen to what the engineers at work have told me can happen due to incompatibility. |
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