Power-assist brakes w/ Weber 40idf carbs??

72SuicideRag · Post by **72SuicideRag** » Sat Jul 27, 2002 6:31 pm

Hi all,

Hmm... just realized something and I'm hoping someone here can help me out. I just upgraded the carbs on my '72 Westy. Took the stock carbs/manifolds off and just got done installing a set of Weber 40IDFs/ new manifolds.

Question is this... the brake servo vacuum line hooked into the original intake manifold. What do with the servo line with the new manifolds?

Thanks in advance for any help!

~Steve

germansupplyscott · Post by **germansupplyscott** » Sat Jul 27, 2002 7:18 pm

72,

you need to plumb a vac line similar to what was on the stock setup. i have not done this as my van is FI, but i believe you are supposed to run a line from both manifolds to a tee, and take off of that to the servo line. you should use either rigid hose or metal pipe.

scott lyons

72SuicideRag · Post by **72SuicideRag** » Sat Jul 27, 2002 7:31 pm

Yeah, there's a line connected to each manifold, then they come to a T and head up to the servo.

So, it looks like I'll have to drill and tap the new manifolds? Well... that sucks.

Bummer, I was hoping for an easy fix like an available spacer or something with the outlet already plumbed in between the carb and manifold. Oh well... wishful thinking. The power-assisted brakes spoiled me... I gotta keep em.

Thanks for the response, I appreciate it.

~Steve

------------------

Purists are funny...

Das Panty Büncher
'72 Suicide-rag'd Super

kps73 · Post by **kps73** » Sun Jul 28, 2002 8:15 am

Yep you have to tap atleast one, all are better.I have a 78 with webers and it would not stop and the pedal felt real soft without it.Now I have great pedal pressure and can do a skid if I want.You can pick up the 1/2 plastic tees from homedepot in the plumbing department.Make sure you use the german cloth covered hose,It doesnt crush under high pressure like the cheap rubber stuff.Hope this helped.ken

72SuicideRag · Post by **72SuicideRag** » Sun Jul 28, 2002 10:15 am

Man that sucks. Can't believe someone hasn't come up with a proper adapter (between the carb and manifold maybe?) or an available manifold with this already on it. But, I supposed it's a supply and demand thing... This conversion is probably a drop in the bucket compared to the more common applications.
Thanks for the tip on the heavier German hose, Ken. I didn't think about that.

~Steve

Volcano · Post by **Volcano** » Mon Jul 29, 2002 3:17 am

The Euro Forum put me on to Welwood.They mention a duel cyl.being able to eliminate the booster.Could this be used on a Weber Bus?Adrian,I'm interested in what you'r up to as far as super brakes go.I love great brakes.My old Alfa would stop from 60 to 0 in 2.5 sec.with no lock up.Thanks

Pillow · Post by **Pillow** » Mon Jul 29, 2002 8:41 am

Just go to the gym and do some leg presses to get beefed up for better braking

You do not need the power crap anyway.

------------------
Adrian Pillow
'66 VW Westfalia - "Biscuit"
'67 VW Deluxe Westfakia - "Dino" - FS
'79 Porsche 911 SC - "Cochese" - FS

Post by **Marc** » Mon Jul 29, 2002 8:53 am

Tap both manifolds for 3/8NPT x 1/2" barbed fittings; unlike Solexes, Webers don't need or want an equalizer tube connecting the two sides so use 2 check valves before the tee fitting. Best source of HD hose and checkvalves for cheap is from a Rabbit or Audi at a wrecking yard.
I hope Adrian is kidding - I'm no frail and I wouldn't want to drive a disk-brake bus without power assist, let alone have my wife need to drive it.

Dave R · Post by **Dave R** » Mon Jul 29, 2002 10:25 am

I put disc brakes from a post-'73 on my '69. Since I am running DCNFs, I had no ports for the hose, but I wasn't bashful about drilling & tapping. I did all four & checked things out: Hooking up one was marginal, two sucks plenty. 3/8ths barbed brass fittings on the back two manifolds are now dedicated to the vacuum servo. The front two are capped off except for tune up time when I use them to synchronize carbs.

Pillow · Post by **Pillow** » Mon Jul 29, 2002 6:13 pm

Really no vacuum is needed. I am running 944 front discs in my split with no problem, actually easier to use than the previous drums in front.

Even my '71 Chevy truck has disc/drum and no power brakes... Granted you really need some leg for that, especially when towing junk bus (which I end up doing about 3 times a year).

I think the vacuum booster screws it up when not connected and makes normal braking much harder. Get rid of it and I think braking will be easier.

A buddy has a '71 Westi w/o the booster hooked up and it is not that big of a deal to stop it (but much harder than my '66 with discs).

Just some food for thought... But I will still take mine w/o vacuum

------------------
Adrian Pillow
'66 VW Westfalia - "Biscuit"
'67 VW Deluxe Westfakia - "Dino" - FS
'79 Porsche 911 SC - "Cochese" - FS

Volcano · Post by **Volcano** » Wed Jul 31, 2002 4:08 am

I have been talking with Dean Oshiro @ www.Wilwood.com.He said I might try either a dual master cylinder or a step bore thet has 1.125" initial that reduces down to .75".I'm just beginning to look into brake systems.I know I should be content with what I have.But... You guys seem to have tried everything.I just want to find out how to put great brakes on a late bus (78).Thanks

Post by **Marc** » Wed Jul 31, 2002 4:40 am

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Pillow:
<B>Really no vacuum is needed. I am running 944 front discs in my split with no problem, actually easier to use than the previous drums in front....
But I will still take mine w/o vacuum

</B><HR></BLOCKQUOTE>

Oh, I can see how that could be tolerable.
But that's hardly comparable to a bay with stock VW disks and no vacuum. Drive one before you make recommendations like that.

72SuicideRag · Post by **72SuicideRag** » Wed Jul 31, 2002 5:02 am

Thanks everyone for your replies. I'll be tapping the manifold for a new fitting.

I appreciate the help!

~Steve

bajabusdoc · Post by **bajabusdoc** » Sat Aug 24, 2002 7:45 pm

running dual fortyeights, only tap one the one over number 4 is best then brass barb fitting then chevy truck check valve (one way) chnages to stock VW size large vacume hose. this prevents equalizer tube between carbs issue (pain to set idlebypass as 3 steals air from 4 and 1 from from two and all from each other then 3 runs lean and melts as does 1, what a mess! serious just tap one and install chevy valve. vacume takes 15 seconds to build when engine starts and keeps solid despite your RPM. same thing fixes that my breaks are good when i step on them to stop but as the engine idles down they loose the power break function and are hard to hold ( no more power breaks but come back when you rev the engine)