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Major Woody
Samba Enigma
Joined: December 04, 2002
Posts: 9010
Location: Portland, OR
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 Posted: Tue Jul 31, 2007 4:39 pm Post subject: 67 dual circuit MC options |
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I was hoping that I wouldn't have to replace the MC on our 67 bus which is completing its restoration process and only has 58k on it. But then I noticed the other day when rolling the bus back into the garage that the brake pedal is very hard and vague and a little puddle of brake fluid was dripping off of the seal at the front of the MC, so I guess it has issues.
I did a forum search and found the following options:
1. retrofit back to an earlier single circuit MC, which I won't do.
2. if my bore is not pitted or scored, buy a 70s bug MC and take the seals out of that for use in my existing MC
3. buy a new german dual circuit 67 only MC for about $200 or possibly less on ebay
4. buy the retrofit spacer thing and use an early fat chick dual circuit MC.
Are these my options? Are there safety reasons why I should not attempt to put new seals in the old MC if the bore "looks" good?
Thanks all. I'm not real experienced with brakes and don't want to make poor choices here.
Chris |
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67stang302
SBS Hit Squad
Joined: February 08, 2005
Posts: 1236
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| Posted: Tue Jul 31, 2007 4:47 pm Post subject: |
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First I would tear the old master cylinder down and check the bore and re hone it. Check and make sure there are no pits or scrapes. If the bore appears to be good then reseal it and call it good. No reason why a resealed master cylinder is less safe. Unless it is improperly done.
On my 67 I put a baywindow mastercylinder on it and have not looked back.
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SBSeven 1 YR and still going
59 Kombi laying beam
64 type 34 |
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Culito
11010101
Joined: December 07, 2006
Posts: 5865
Location: Columbia Missourah
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| Posted: Tue Jul 31, 2007 4:54 pm Post subject: |
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Second the baywindow option.
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Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
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LittleThunder
Samba Member
Joined: May 21, 2006
Posts: 1015
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| Posted: Tue Jul 31, 2007 6:02 pm Post subject: |
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| Aren't rebuild kits available to fit your specific cylinder? |
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chrome
Samba Member
Joined: March 21, 2003
Posts: 746
Location: back in NorCal
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| Posted: Tue Jul 31, 2007 8:16 pm Post subject: |
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a $39. 71 master cylinder is a lot easer to get one brake job at a time is enough for me
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65 21 window
57 T1 ragtop
58 ghia vert
68 fastback
73 Thing
74 Thing
54 chevy 210
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Major Woody
Samba Enigma
Joined: December 04, 2002
Posts: 9010
Location: Portland, OR
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| Posted: Tue Jul 31, 2007 11:12 pm Post subject: |
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| LittleThunder wrote: |
| Aren't rebuild kits available to fit your specific cylinder? |
I don't think they are. If anyone knows where to buy one, please speak up!
How do you hone a master cylinder? Do I need to buy a hone that fits on a drill or something? |
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67stang302
SBS Hit Squad
Joined: February 08, 2005
Posts: 1236
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| Posted: Tue Jul 31, 2007 11:33 pm Post subject: |
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| Major Woody wrote: |
| LittleThunder wrote: |
| Aren't rebuild kits available to fit your specific cylinder? |
I don't think they are. If anyone knows where to buy one, please speak up!
How do you hone a master cylinder? Do I need to buy a hone that fits on a drill or something? |
Yep they sell hones that fit on drills for wheel/master cylinders. Just make sure you keep the hone lubed. And check for imperfections in the cylinder mainly where the seal on the piston rides. If there is porosity or a gouge it could tear the new seal and you would be back at square one.
There is an outfit in the midwest that is resleeving master cylinders. A customer of ours sends in 4 mercedes cylinders at a time and they end up costing about 40 bucks each. Currently I have two 67 masters that need resleeved and I need at least two more to send them off. And grand total I will be into each rebuilt cylinder for about 60 bucks.
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| EverettB wrote: |
| Hondaz rulez my lifez |
SBSeven 1 YR and still going
59 Kombi laying beam
64 type 34 |
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dstefun
Samba Member
Joined: February 20, 2002
Posts: 3338
Location: Sacratomato
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| Posted: Wed Aug 01, 2007 2:15 am Post subject: |
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| Major Woody wrote: |
| LittleThunder wrote: |
| Aren't rebuild kits available to fit your specific cylinder? |
I don't think they are. If anyone knows where to buy one, please speak up!
How do you hone a master cylinder? Do I need to buy a hone that fits on a drill or something? |
Honing is pretty easy, Chris, it's getting the proper parts to put it back together again that is the real problem. Remember cleanliness. Here's how to do it from another website - OK, this is for a Pantera clutch master cyclinder, but the principles are exactly the same.
http://www.panteraplace.com/page153.htm
You can use a stone hone as pictured on that site, or a flex-hone like this which I find much easier to use.
http://www.mytoolstore.com/kd/kdbrak08.html
But you still need the seals. Where did you read that later bug seals were the same? They might be, I just can't confirm the data by part number. Yes, you can get the old M/C sleeved if it is pitted too badly, but you still have the problem of finding proper new seals. |
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ricekooker
Samba Member
Joined: April 09, 2006
Posts: 1788
Location: Winter Park, FL
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| Posted: Wed Aug 01, 2007 3:36 am Post subject: |
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I'm going through the same dilemma...
I weighed out the options and went with a 71-79 MC and the adapter kit from Wolfgang. $95 |
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TinCanFab
Samba Member
Joined: April 04, 2006
Posts: 2743
Location: Waterford, California
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| Posted: Wed Aug 01, 2007 7:32 am Post subject: |
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I cut the mounting section off of a dead single circuit bug master cylinder and modified it to work like the wolfgang adapter (dremel tool and patience). Then I went to pick and pull grabbed a rabbit reservoir and master off of a 79 bay. Less than $20 for an OG german dual circuit setup.  |
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pyrOman
Fire Master
Joined: July 21, 2003
Posts: 12408
Location: Over 2002 posts deleted!
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| Posted: Wed Aug 01, 2007 8:26 am Post subject: |
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| 67stang302 wrote: |
| Currently I have two 67 masters that need resleeved. |
Key term right there!
Unless you use a bore scope to inspect it, you can't really tell how good or bad it is. As already mentioned, you could be back to square one even AFTER a hone. I've had one honed before and tried my luck but at least it was done for free here at work. If I was the stock nazi and wanted a true '67 MC, I'd have it resleeved. But since I'm not, a fatchick one will do just fine! 
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70 140
Samba Member
Joined: September 22, 2002
Posts: 8471
Location: Ontario Canada
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| Posted: Wed Aug 01, 2007 8:52 am Post subject: |
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| $200 for a new german M/C doesn't seem crazy to me... |
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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: Wed Aug 01, 2007 9:52 am Post subject: |
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| I am having a 1967 master sleeved and rebuilt by Whitepost Restorations. It will run about $200. |
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inkstain
Samba Member
Joined: May 17, 2006
Posts: 28
Location: charlotte,nc
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| Posted: Thu Aug 02, 2007 8:09 pm Post subject: |
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i am also wanting to upgade my 66 scmc and was wondering whats the reasoning behind using the 72-79 dcmc with servo. atleast thats what i've been reading. whats the servo? the brake booster.?. don't have one, so wouldn't i use the non servo dcmc?
thanks ahead for any help!!
shawn |
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Jerry J
Samba Member
Joined: June 12, 2004
Posts: 1257
Location: Portland, OR
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| Posted: Sat Aug 04, 2007 3:04 pm Post subject: |
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| Major Woody wrote: |
| LittleThunder wrote: |
| Aren't rebuild kits available to fit your specific cylinder? |
I don't think they are. If anyone knows where to buy one, please speak up!
How do you hone a master cylinder? Do I need to buy a hone that fits on a drill or something? |
Please correct me if I'm wrong but rebuild kits at not available for the '67 dual circuit mc's. There was a thread where somebody that had connections in Europe was going to hunt some down. He came up empty handed.
Me I paid the price for an ATE new in box for the day when mine gives up the battle. I figure that if the one in my bus has lasted this long then the day the new one would have to go in would outlive me.
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Jerry
'58 Bug
'63 KGhia
'67 Squareback
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Culito
11010101
Joined: December 07, 2006
Posts: 5865
Location: Columbia Missourah
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| Posted: Sat Aug 04, 2007 5:02 pm Post subject: |
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No, you don't need the servo.
There should be a sticky how-to thread or a place in the FAQ's for dual circuit upgrades; this topic seems to me coming up often lately.
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
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BarryL 
Samba Member
Joined: November 01, 2004
Posts: 14259
Location: Casa de Oro, California
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| Posted: Sun Aug 05, 2007 10:28 am Post subject: |
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My opinion:
| Quote: |
| 3. buy a new german dual circuit 67 only MC for about $200 |
It would be different if they weren't available but they are and they are og ATE. They even come with new brake light switches, bolt right up, and are worry free. Reservoirs are reusable if you're careful. If it's the money issue then that's a whole different dialog. Don't toss your old one 'cuz the future is rapidly approaching and no one knows how rare they will become. The kits are no longer available but I think a person could find the seals. Should I be the one to find them? I'd take the M/C to any brake shop and have them hone it on their machine. I do my own and take them out. Either way works. I have some resleeved locally and I have a place that redoes them in the midwest also. |
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bastardbus
Samba Member
Joined: July 13, 2000
Posts: 1768
Location: Toledo, Ohio
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| Posted: Sun Aug 05, 2007 10:46 am Post subject: |
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What I would like to know is the specs on the `67 MC and the `71-`79 Bay master cylinder. I am not a hydraulics expert but I know enough about them of what NOT to do.
The MC bore diameter and the stroke are extremely important when using a MC with a specific system. For instance, and most folks do not know this. The early 3/4 ton bus MC `55-`63 is different then the 1 ton `64-`66 MC as well. According to Bentley..single circuit MCs...
Early
22.2 mm Bore
30 mm stroke
Late
22.2 mm Bore
36 mm stroke
What one needs to do when replacing the `67 MC or even the earlier single circuits is to find a new master cylinder with the same specifications of brake effeiciency will drastically suffer. Slight changes in Wheel cylinders, brake shoe size and travel all effect this.
I found out about this the hard way with my `52 beetle. Original equip MCs are not made for the `52 so folks use whatever fits. Most split bug folks used the Bus MC because of the resevoir position same on top of the MC which is same in the splits. Though while the split original had a 19mm bore the bus is 22.2 Extremely stiff pedal and almost non existant stoping power was the result, most folks in the past said this was just "how splits are". After much research I found a certain 356 MC with the exact same specifications the split had. I replaced the 22.2 mm bus MC with porsche unit and the `52 stopped so amazingly well with the correct MC I was stunned and amazed.
I have read so many posts about updating the split bus MC with the later 71-79 unit yet not once has anybody posted the specs for the MCs. I would really like to see those specs and compare them to what they should be for each vehicle.
EDIT-According to my parts manual the `67 dual circuit is a 22.2 mm bore as well (but no stroke is given) which would make sense it has the same specs as the `64-`66 single curcuit as the rest of the brake system is identical for the buses. From what I have "heard" the bore is the major factor with the MCs compatibility. Anyone have specs for the 71-79 yet?
Todd
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Last edited by bastardbus on Sun Aug 05, 2007 3:03 pm; edited 2 times in total |
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Culito
11010101
Joined: December 07, 2006
Posts: 5865
Location: Columbia Missourah
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| Posted: Sun Aug 05, 2007 10:54 am Post subject: |
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I don't know the specs for the '71-'79 MC, but I have done the conversion.
I do know that there are two different bores on the newer one and the larger bore must be hooked up to the front wheels...
I have a nice solid pedal response and plenty of stopping power. It's not like power brakes or anything, but it feels safe nonetheless.
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
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BarryL
Samba Member
Joined: November 01, 2004
Posts: 14259
Location: Casa de Oro, California
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| Posted: Sun Aug 05, 2007 11:24 am Post subject: |
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Major Woody
| Quote: |
| I noticed the other day when rolling the bus back into the garage that the brake pedal is very hard and vague |
Hard could be collapsed hoses or glazed shoes. I've had many the time when the '67 dripped at the rod, bled the whole system clean, and went another 30,000 miles with nary a drop anywhere. |
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