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Re: Bus master cylinder conversion
Posted: Fri May 04, 2007 9:59 pm
by Bill K.
Bill K. wrote:Ray has posted on his 412 conversion to a late bus master cylinder:
click here for link
I'd like to do the same and report here. I'll have 38mm rear and 48mm front disk brake pistons.
First, picking the correct master cylinder. Ray - is this the one?

from busdepot.com (
click here for link) it's p/n 211.611.021 AA from Brazil. It has bore of 23.81mm designed for disk brakes of 71+ bus.
Looks like this master cylinder for power brake buses works on manual brake buses, why not for the type 4?
http://www.aircooledtech.com/dual_MC_upgrade/
Posted: Sun May 06, 2007 10:26 pm
by SureFit Travis
So, my mistake.....I finally looked into my brake fluid leak, and it is indeed the brake master cylinder, and not the clutch master as I first thought. I guess it leaked enough to drop the fluid level in the resevoir over winter....enough to get air into my clutch system.
Anyway......my master cyl is FAG......anybody have any tips on who is guaranteed to have stock on rebuild kits?
Thanks again,
Travis
Posted: Mon May 07, 2007 1:19 pm
by raygreenwood
You could use....if you can find it.....the seals and flap valves from an FAG type 3 cylinder. Works great. But...finding anything other than a Varga brand type 3 cylinder for less than a bar of gold...is about as hard as finding a type 3 cylinder.
Schafer used to make very excelent quality repair kits specifically for both ATE and FAG cylinders. Don't know if they are still around.
The seals from an FAG late rabbit cylinder will work great. Cost for the whoel cylinder is generally about $50. Again...finding other than Varga.
Most any FAG 19mm dual circuit should have the parts you need. Ray
On topic please
Posted: Mon May 07, 2007 3:57 pm
by Bill K.
Ray, please take a look at the on-topic questions:
http://www.shoptalkforums.com/viewtopic ... 636#793636
* M/C trunk mounting location? Upper (flat) or lower (angled) firewall recess?
* Reservoir for 68-70 m/c? These take 100mm nipple spacing. Any direct mount reservoirs with 100mm spacing with caps?
http://www.shoptalkforums.com/viewtopic ... 733#793733
* Why is a power brake M/C not suitable for manual brake application?
Thanks,
Bill
Posted: Sun May 13, 2007 8:11 pm
by vwbill
Hey Guys, suppose to get the master tomorrow from Napa from UPS(Brake Master Cylinder - Remfd
Product Number: TS 111648) What should I measure and what numbers or specs and pics do you guys want to see? Bill
Posted: Mon May 14, 2007 3:46 pm
by vwbill
Hey Guys, received the master cylinder today... It does not come with brake light sensors which is normal, the boot either was a light black grease nos or old since I compared with one I bought from FAG direct and they did not wipe off showing anything... There was small black particles inside the bore about five or so and the liquid on the piston cups of each piston assemble had a black look maybe from the cup??? The fill hose nipple grommets had black grease on the area that the nipple is inserted in and they looked original?? I still need to pull the piston cups off to inspect and record the numbers... The inside of the cylinder bore does look good but still need to know or figure out how to measure it...
The pistons did have FAG numbers.... There was a mark from the piston stop screw that was minor but that area of the piston has some lines so I don't know if that screw depth should be checked so it only stays in the cut out area of that piston and not allowed to move into the edge of the the metal cup lip area... I will list a link of some pics but it is hard to see the interior...I would inspect and clean any reman part like Ray says.
I would say from a good core and inexpensive temp brake master solution I would use it. I would guess that most of the interior debrie would flush out and give you a temp brake solution.... Bill
Master cylinder Pics of reman
Posted: Tue May 15, 2007 7:42 pm
by vwbill
Hey Guy, here are some pics of the master cylinder reman I got. It is the page 8,9,10 pics I think...May2007-013 on...
http://groups.msn.com/vw412/shoebox.msnw
p.s.Hey on the ebayer master rebuild kit it shows two metal cup cover looking peices??? What and where would these go????
Posted: Wed May 16, 2007 9:01 am
by raygreenwood
They should go between the spring and the cup at the end of each piston. They are spring seats. The open side or cup side goes into teh under side of each rubber cup. Ray
Re: Bus master cylinder conversion
Posted: Tue Feb 01, 2011 1:48 pm
by Hulken
A fellow Austrian type 4 entusiast (Andreas Freitag) has come up with a nice solution for mounting the more common bus/Porsche 914 MC. Text in link is norwegian, but the pictures are sort of self explaining.
http://www.vwnorge.no/index.php/topic,32276.0.html
Re: Bus master cylinder conversion
Posted: Sat Feb 05, 2011 1:55 pm
by raygreenwood
Before I did the bus mod....I did the same modofication that genetleman did...but using a late superbeetle cylinder.
The only problem I see with his mod is the off-angle pushrod. Ray