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55veedub
Samba Member
Joined: May 12, 2008
Posts: 583
Location: North Bay, Ontario, Canada
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 Posted: Wed Oct 13, 2010 6:25 pm Post subject: 67 braking |
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Much like the 67 beetle i see the 67 bus is no different for "one time only" stuff.
$255.00 for the German 67
$120.00 for the German 66
Can a 66 master cylincer be used on a 67 bus? if not, why?
thanks,
Mike |
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RyanRodman
Samba Member
Joined: February 07, 2009
Posts: 444
Location: Gig Harbor, Wa
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| Posted: Wed Oct 13, 2010 6:27 pm Post subject: |
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| 67 has a dual circuit master cylinder while 66 is only single circuit, thats why 67 is more expensive. |
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55veedub
Samba Member
Joined: May 12, 2008
Posts: 583
Location: North Bay, Ontario, Canada
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| Posted: Wed Oct 13, 2010 7:05 pm Post subject: |
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| Do i have to use it or could i use an earlier one? |
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RyanRodman
Samba Member
Joined: February 07, 2009
Posts: 444
Location: Gig Harbor, Wa
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| Posted: Wed Oct 13, 2010 7:18 pm Post subject: |
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It would be smarter/safer to stick with the dual circuit master cylinder. If you downgraded to a single circuit master cylinder and you where drivng down the road and blew out a wheel cylinder or something you would loose 100% of your braking, but with a dual circuit you would still have 50% to stop you. If cost is a factor i hear its pretty cheap and easy to convert to a bay window dual circuit master cylinder.
http://www.aircooledtech.com/dual_MC_upgrade/ |
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kingodirtp3
Samba Member
Joined: December 07, 2007
Posts: 1062
Location: Monterey CA
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| Posted: Wed Oct 13, 2010 7:31 pm Post subject: |
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wagenswest has an adapter kit t hat will allow you to bolt up a 71 master
cylinder with no issues. i did it to my 67. works great. much better than
spending 250. cost me abot 130 total |
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 25874
Location: Olympia Wash Rinse & Repeat
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OG Velvet
Samba Family Man
Joined: February 24, 2003
Posts: 2174
Location: Portland, OR
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| Posted: Thu Oct 14, 2010 12:07 pm Post subject: |
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Keep in mind that the bay window master cylinder has one of the plugs set at an angle. Your splash pedal pan will not fit without cutting it.
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream |
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 25874
Location: Olympia Wash Rinse & Repeat
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| Posted: Thu Oct 14, 2010 12:57 pm Post subject: |
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Or do the job correctly, and you can have your splash pan and post 71 MC without cutting holes in the pan!
http://type2.com/library/brakes/dualmas.htm
Lots more good info in the type2.com library.
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In Stereo, Where Available! |
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420GOAT
Samba Member
Joined: March 31, 2006
Posts: 3343
Location: Wilmington, CA on a nice quiet street but still in the 'hood
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| Posted: Thu Oct 14, 2010 1:18 pm Post subject: |
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you have a 67 only pushrod. you can not use a 66 master. get the bay master and someone sells spacers for the conversion...in split bus section...since its the only one that needs this. im running a varga brand(get a current one) not older nos as those have been sitting and the rubber may be hard or cracked. my varga has been goo so far as the wheel cylinders too.
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once you realize im not impressed we will get along just fine |
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zozo
Samba Member
Joined: October 15, 2005
Posts: 5217
Location: South of Ol' San Antonio
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| Posted: Thu Oct 14, 2010 1:37 pm Post subject: |
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| Not to beat a dead horse, or go into any amount of detail, but I'm guessing the conversion, as far as the lines go, would be limited to a "T" and a short hard line being added to feed the fronts? |
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kingodirtp3
Samba Member
Joined: December 07, 2007
Posts: 1062
Location: Monterey CA
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| Posted: Thu Oct 14, 2010 1:41 pm Post subject: |
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to convert to 71 MC nothing needs to be done to the lines. with the
conversion kit it is a straight bolt on expect for modifying the splash pan |
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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 Oct 15, 2010 7:09 am Post subject: |
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Doing the job correctly would be installing the correct 1967 master cylinder that was designed to work with the drum brakes.
The later master displaces more fluid making the front brakes come in quicker than with the 67 master. |
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Andrew
Samba Member
Joined: October 27, 2000
Posts: 5865
Location: Who in the what now?
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| Posted: Fri Oct 15, 2010 7:32 am Post subject: |
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| 55veedub wrote: |
| Do i have to use it or could i use an earlier one? |
It's not a good idea, but yes, you can use it. I've done it before.
As mentioned earlier, you have a one year only master cylinder pushrod, so you'll have to either get an earlier one or shave the end off of yours and you will have to replace both of your front hard lines so that they'll reach all the way to the master cylinder.
As I said, though, it's a really dumb idea to skimp on maybe $50-75 (gotta buy a new pushrod and front lines) to convert to single circuit. Think of it this way, if you're barreling toward a red light at a busy intersection with no brakes, at that moment, would you pay $100 to have brakes in half of your bus?
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-Andrew |
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 25874
Location: Olympia Wash Rinse & Repeat
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| Posted: Fri Oct 15, 2010 9:59 pm Post subject: |
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| ToolBox wrote: |
The later master displaces more fluid making the front brakes come in quicker than with the 67 master. |
Interesting theory. Problem is the front circuit in the dual MCs applies pressure to the rear at same time. So pressure build up in both front and rear circuits is at same moment.
On the other hand, all drum brakes on both axles in the buses have a greater stopping power in the front due to factory design in bigger drums, shoes and dual slave cylinders facing in direction of forward rotation of the drum. This keeps the bus from spinning out of control when braking so hard the front brakes lock up, but not the rears as easily. Kind of like putting fins on a dart.
Later disc brake buses did use a pressure regulator to lower pressure to the rear axle because the rear drum brakes would otherwise lock up first before the disc brakes. This was due to the discs requiring more pressure that the rears to lock up.
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In Stereo, Where Available! |
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Augsburg57
Samba Member
Joined: June 30, 2009
Posts: 90
Location: Seattle
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| Posted: Sat Oct 16, 2010 7:57 am Post subject: Creative Engineering Brake Servo |
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Has anyone experience with the Creative Engineering brake servos for power assist?
http://creative-engineering.com/index.php?option=c...;Itemid=26
I have the CSP front disc kit installed in my '67 Split (with original 14" wheels) and they work great - but peddle effort is high. I'm curious about the power assist. At the time of my disc install, I bit the bullet and purchased a new '67 master cylinder. Now I'm wondering if I can retrofit the servo.
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'67 VW 11-Window Standard Bus, 2027cc Stroker with Dual 40 IDF Webers |
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BarryL 
Samba Member
Joined: November 01, 2004
Posts: 15187
Location: Casa de Oro, California
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| Posted: Sun Oct 17, 2010 7:07 am Post subject: |
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| Eric&Barb wrote: |
| ToolBox wrote: |
The later master displaces more fluid making the front brakes come in quicker than with the 67 master. |
Interesting theory. Problem is the front circuit in the dual MCs applies pressure to the rear at same time. So pressure build up in both front and rear circuits is at same moment. |
Could you please elaborate a little? This reads you are saying the forward circuit feeds both the front and rear at the same time. |
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 25874
Location: Olympia Wash Rinse & Repeat
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| Posted: Sun Oct 17, 2010 9:33 am Post subject: |
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Check out section B-14, page 1 in the Workshop Manual Volkswagen Transporter.
See the two opposite facing seals #27 & 15? Those keep fluid from transferring from circuit to circuit.
When you apply pressure in the rear circuit the pressure is against seal #27, this in turn presses against the fluid in the forward circuit chamber. Kind of like having two bags of fluid that you can push against.
Only time pressure should be applied via push rod #21 is if you blow out the rear circuit brakes or if you adjust the fronts properly and unadjust the rears brake stars.
If you ever have one of the brake circuits blow out you will notice how much lower the brake pedal is. This is due to the now missing fluid pressure, and you are relying on the push rod #21 to transfer pressure through the rear circuit to the front piston. If the front cicuit blows the stop built into #28 which keeps the forward piston from going too far forward with the loss of brake fluid pressure.
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In Stereo, Where Available! |
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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: Sun Oct 17, 2010 5:25 pm Post subject: |
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| Eric&Barb wrote: |
| ToolBox wrote: |
The later master displaces more fluid making the front brakes come in quicker than with the 67 master. |
Interesting theory. Problem is the front circuit in the dual MCs applies pressure to the rear at same time. So pressure build up in both front and rear circuits is at same moment.
On the other hand, all drum brakes on both axles in the buses have a greater stopping power in the front due to factory design in bigger drums, shoes and dual slave cylinders facing in direction of forward rotation of the drum. This keeps the bus from spinning out of control when braking so hard the front brakes lock up, but not the rears as easily. Kind of like putting fins on a dart.
Later disc brake buses did use a pressure regulator to lower pressure to the rear axle because the rear drum brakes would otherwise lock up first before the disc brakes. This was due to the discs requiring more pressure that the rears to lock up. |
Wrong again. The FLUID DISPLACEMENT of the master has nothing to do with how pressure is achieved in the master cylinder.
Fluid displacement has to do with the volume of the chamber in the master cylinde. It is basic physics and not mechanical actuation.
Please keep fixing you VW with roofing tar and old phone books and I will keep doing my 9-5 as a test engineer/technician at a brake system supplier. |
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Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 25874
Location: Olympia Wash Rinse & Repeat
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| Posted: Sun Oct 17, 2010 8:10 pm Post subject: |
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| ToolBox wrote: |
Wrong again. The FLUID DISPLACEMENT of the master has nothing to do with how pressure is achieved in the master cylinder.
Fluid displacement has to do with the volume of the chamber in the master cylinder. It is basic physics and not mechanical actuation.
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Fluid displacement is great, but there comes the time when the brake shoe springs are expanded, shoes hit the drums and pressure is achieved. In the dual MC that happens front and back at same time, unless one of the two circuits is blown or so out of adjustment that the internal push rods in the dual MC are shoved up against.
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BarryL
Samba Member
Joined: November 01, 2004
Posts: 15187
Location: Casa de Oro, California
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| Posted: Mon Oct 18, 2010 7:47 am Post subject: |
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| BarryL wrote: |
| Eric&Barb wrote: |
| ToolBox wrote: |
The later master displaces more fluid making the front brakes come in quicker than with the 67 master. |
Interesting theory. Problem is the front circuit in the dual MCs applies pressure to the rear at same time. So pressure build up in both front and rear circuits is at same moment. |
Could you please elaborate a little? This reads you are saying the forward circuit feeds both the front and rear at the same time. |
After reading your following post to this I see what you meant about the "front applies to rear at same time". I thought you were saying that the pipes all came from the front circuit and thus fed at the same time.
Fwiw, you might want to edit the Bentley post description, as the circuit on the left in the drawing is the "front" circuit and your dialog says "rear". |
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