TheSamba.com :: View topic - How to: Install power brakes into 1968-1970 Bus (Pic heavy)

Fri May 11, 2012 7:31 am

I've done two of these and am about to start a third today. So, I'm going to try and describe the process and provide pictures to help. Here goes...

1) Locate the following parts. I had good luck contacting people parting buses and advertising in the samba classifieds. The going rate was about $100 for the booster, rod, and lower reservoir.

a) Brake booster
b) Rod from booster to pedal
c) Lower fluid reservoir
d) Rubber bungs for reservoir to mc (2 ea.)
e) 1971 master cylinder
f) 15 feet of Gates 27231 power brake vacuum hose 15/32"
g) Vacuum line check valve
h) 1 ea. straight hard brake line about 2 feet or so long with metric ends
i) 2 ea. 3/16 Swagelok unions with B nuts
j) A plate to weld to the beam
k) 1 ea. hard brake line T fitting
l) A fitting to install in your intake manifold

So, that's pretty much what you need in the way of parts unless I forgot something. Let's get started with the process with pictures to illustrate.

Fri May 11, 2012 7:40 am

Here's some pics of the parts
Booster

Booster with parts assembled

The plate

Check valve

Vacuum line

The rod (must be lengthened 1 inch)

T fitting

3/16 Swagelok union and hard brake line

Vacuum fitting to intake manifold

Check valve installed

Fri May 11, 2012 7:54 am

Okay, once you have all the parts you need to:

1) Weld the plate to the beam.

2) Make sure your booster is good. I sent these out for overhaul at $150 each.

3) Get the rod lengthened by 1 inch
4) Mount the booster assembly to the plate. The left parking brake cable will rub.

5) Remove the old MC and install the T fitting. Best to cut the rear line first. More on that later.

6) Install the rod to the pedal and booster and adjust freeplay

7) Lengthen the wires for the brake switches so they reach the new mc

8) Cut the rear circuit brake line next to the new mc and install the 3/16 swagelock unions using the hard brake line you bought. You'll cut the new brake line to fit.

Fri May 11, 2012 8:04 am

Next,

9) You'll need to run a line from your upper brake reservoir to the new lower reservoir. I use the same vacuum line and am assuming that since Gates made it for use in brake systems that it's resistant to brake fluid.

10) Begin routing the rest of the brake vacuum line back to the engine. I use a hole saw

11) Whatever set up you have in the way of carbs install the fitting and hook up the vacuum line and check valve.

12) The splash pan may or may not need to be cut slightly for fitment.

Fri May 11, 2012 8:06 am

Well, I think that's it in a nutshell. I can't give you a idea right now of what this costs but might be able to next week when I finish the third installation this weekend. The mod makes a huge difference in driving comfort.

Fri May 11, 2012 8:52 am

Great post... thanks for taking the time to document so carefully!!

Fri May 11, 2012 9:10 am

I thought you posted this job before aeromech it good to see it again. I have all the parts to do my SC (thanks to you) but first I need to get the engine and trany in it I can't wait to see what power drums feel like. vw did it back then but I guess none were imported to the US my friend in New Zealand side there are some there.

Fri May 11, 2012 9:20 am

I thought you posted this job before aeromech

Did I? I know I talked about it. I just turned 55 so the mind is going and I never really had much to begin with.

Fri May 11, 2012 9:23 am

ya well Iam 51 and I imagine things so that could be the case.

Fri May 11, 2012 9:50 am

Very nice presentation Gary. It's a great topic and your pictures and info are great. I'd sure like to test drive an early drum brake bus with power assist.

I'd take issue though with using that particular Gates hose for the refill line. Very slim chance it's brake fluid compatable. Because someone has used it and a year later it's still working doesn't make it good. A vacuum application has nothing to do with a brake fluid application.
The difficulty is that tracking down a Gates product listing is about impossible. It's probably more difficult that getting Parker hose tech info. But the bottom line is that very very few hose materials are listed as acceptable for brake fluid use. EDPM is a material that usually is on the good list. Plain vinyl hose or rubber hydraulic hose isn't. We've gone thru the "reservoir refill hose" topic a few times and the bottom line is always stick with the clear original line and specialty end seals that VW used. The only acceptable rubber hose is the VW Blue hose specific for brake fluid use, unfortunately it's the wrong diameter for what you are doing. I'll keep an eye out for Gates brake fluid compatable hose. Unless their spec sheet says so the 27231 is not good. :cry:

You mentioned the parking brake cable rubbing against the booster. We talked about it but did you ever try the stock cable spacer bar used on '71's to eliminate that problem?

Fri May 11, 2012 10:09 am

The first installation I did was two years ago or so and I used the Gates hose. So far so good. I'm not disagreeing with you I just used the best thing I could find. The stock plastic hose is not an option. I even have one but unless I relocated the upper reservoir to behind the drivers seat it would be way too short. So, consider this product testing. As we know MC leak into boosters sometimes. I'm assuming Gates knows that and made their hose resistant to the fluid. It's a stretch, I know, but like I said I wanted to get the job done and used the best thing I knew of at the time.

As far as the rubbing of the left brake cable goes I tried using the cross bar last time without any luck. This time I just let it rub. We'll see what happens.

Fri May 11, 2012 10:18 am

aeromech wrote: ...
5) Remove the old MC and install the T fitting. Best to cut the rear line first. More on that later.
...

Howzit Gary?

Nice photos kupuna.
I saw your use of a bug T fitting.

When I did my '69 camper front disc brakes I made this 270 brake line for use with the Tfitting. The one pictured was a first attempt and might not have the correct under/over/crossover.

Aloha
tp

Fri May 11, 2012 10:23 am

Hey Tom,
I got to use that cool tube bender you gave me. It worked great.

Fri May 11, 2012 11:14 am

The only way the cross bar works is if you have the cables with the part crimped on the cable that holds the cross bar in the right place. so far all the replacement cables I have used have had this on them. The line running from the engine I robbed one from a old 71 so I will have the stock line for my SC. My reservoir I was going to mount it behind the seat like the 71 Iam not seeing a problem do that yet at least. Iam also putting the vent line on I got it when I robbed the vac line.

Fri May 11, 2012 11:21 am

bigbore wrote: The only way the cross bar works is if you have the cables with the part crimped on the cable that holds the cross bar in the right place. so far all the replacement cables I have used have had this on them. The line running from the engine I robbed one from a old 71 so I will have the stock line for my SC. My reservoir I was going to mount it behind the seat like the 71 Iam not seeing a problem do that yet at least. Iam also putting the vent line on I got it when I robbed the vac line.

The 1971+ buses had a metal tube running vacuum from in front of the left rear wheel forward. Using an original vacuum line won't work unless to also install the metal tube which is about 4 feet long.

Fri May 11, 2012 1:01 pm

aeromech wrote: bigbore wrote: The only way the cross bar works is if you have the cables with the part crimped on the cable that holds the cross bar in the right place. so far all the replacement cables I have used have had this on them. The line running from the engine I robbed one from a old 71 so I will have the stock line for my SC. My reservoir I was going to mount it behind the seat like the 71 Iam not seeing a problem do that yet at least. Iam also putting the vent line on I got it when I robbed the vac line.

The 1971+ buses had a metal tube running vacuum from in front of the left rear wheel forward. Using an original vacuum line won't work unless to also install the metal tube which is about 4 feet long.
Ya I know I had to cut it out not just a easy removal but I wanted all the stock stuff and not to mention I have a few dead bus here to rob from. :shock:

Fri May 11, 2012 1:03 pm

You are a god among men.

Next time you head out to Colorado, let me know, I'll supply a lot of beer for you to help me with my '71 :)

Fri May 11, 2012 1:07 pm

This was my baby for 26 years

1971's are really nice

Fri May 11, 2012 1:17 pm

Man I wish mine looked that nice maybe someday Alaska is not kind to cars when they are 10 years old they are beat to crap.

Fri May 11, 2012 1:39 pm

Very nice write up indeed! This is one mod I would definitely not mind adding. Among the rest, keeping the bay at a stop light on a steep uphill is a pain, I always use the e-brake.

And if I give you my address, can you send me seeds of the brake booster tree?
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