1977 Bus - Brakes Drag & Pull

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Amskeptic
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Post by Amskeptic » Sun Feb 07, 2010 10:29 pm

Latest post of the previous page:

Sluggo wrote:Brakes have firmed up a little.
retaining plates serve any purpose aside from stopping squealing?
Keeping the pistons located is a good thing. Get them.

Brakes do firm up as the shoes/pads settle in.

Congratulations, ensuring excellent brakes is step one for responsibility to yourself and others.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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Sluggo
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Post by Sluggo » Mon Mar 08, 2010 8:43 am

So my brakes are still wacky. sometimes I barely touch the pedal and they work. Sometimes I am all the way down before I start to stop. Replaced the master cylinder last night and still have the same problems. Could it be the booster? It's the very last link in the chain. Everything else is new at this point.

My booster from my '72 is almost new. What's the difference? I can see that it is smaller. Would it still work?
:vwgauge420:

1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
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Crunched Slider Door.
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Post by hambone » Mon Mar 08, 2010 9:17 am

Bleed the brakes again. Also check the rear adjustment.
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Post by Sluggo » Mon Mar 08, 2010 9:35 am

hambone wrote:Bleed the brakes again. Also check the rear adjustment.
On it tonight. Found these instructions from Colin on an old Samba post. I used a power bleeder. I'll try doing the master cylinder manually.
Amskeptic wrote:a low pedal with correctly adjusted rear brakes and fresh pads up front is air in the lines. (a leaky booster circuit contributes to a hard pedal) I do not know if you bled the master cylinder itself before installing it, but it is a critical step. If you have air in the vicinity of the lines where they attach to the master cylinder, most of your pedal travel is taken up compressing the air instead of moving the fluid.
You may bleed the master cylinder at the lines. Just crack loose the 11mm nut at the brake line that is closest to the back bumper and pull down hard on the brake pedal lever which you can reach from underneath the bus. Tighten the 11mm line before letting go of the brake pedal lever. Do some slow pumps of the lever then crack loose the 11mm nut again, pull down hard on the lever and tighten the 11mm nut before letting go. Listen for spits and look for "carbonation" in the fluid.
When fluid is clear, tighten that 11mm nut and check your fluid level in the reservoir, then move on to the 11mm nut that connects the brake line closest to the front bumper. This time, you must pull down on the lever before you crack loose the line then tighten the 11mm nut before you release the lever. You must have an air-free master cylinder-to-brake lines before you can successfully bleed the rest of the system.
You will need an assistant who obeys you to bleed the rest of the system.
If you have a bleeder that is stuck, or broken, just loosen the 11mm brake line nut at the offending wheel cylinder or caliper and bleed from there. It is messy, so have plenty of rags to catch the fluid. I bleed the front circuit first. That is the circuit that has the brake line on the master cylinder that is closest to the rear bumper. When that circuit is bled, it will act like a stop that then allows you to mash the brake pedal down to pressurize the rear circuit. Otherwise you are losing precious pedal travel.
:vwgauge420:

1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
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Sluggo
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Post by Sluggo » Fri Mar 12, 2010 10:27 am

I bleed the master cylinder again and got no bubbles. But....I decided to just let the power bleeder run a minute and got tons of bubbles out of each cylinder/caliper. I guess I cut it off too quick not giving bubbles at the beginning of the lines to make it to the calipers/cylinders. Brakes are much, much better. Not perfect though. I think the booster may be going out. Pedal still travels halfway to the floor.

Also, I had a small leak from the reservoir hose. Fixed it but the fluid filled the rear lower switch plug with fluid. Emptied it out. Now my warning light doesn't come on and my brake lights don't work. Could the brake fluid have ruined the switch/plug?
:vwgauge420:

1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
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Amskeptic
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Post by Amskeptic » Fri Mar 12, 2010 10:52 am

Sluggo wrote:I bleed the master cylinder again and got no bubbles. But....I decided to just let the power bleeder run a minute and got tons of bubbles out of each cylinder/caliper. I guess I cut it off too quick not giving bubbles at the beginning of the lines to make it to the calipers/cylinders. Brakes are much, much better. Not perfect though. I think the booster may be going out. Pedal still travels halfway to the floor.

Also, I had a small leak from the reservoir hose. Fixed it but the fluid filled the rear lower switch plug with fluid. Emptied it out. Now my warning light doesn't come on and my brake lights don't work. Could the brake fluid have ruined the switch/plug?
Boosters either give boost or do not give boost. They are not responsible for a pedal that goes halfway to the floor.

Pump the brakes quickly with the engine running.
Does the pedal travel less after a couple of pumps? Wait a minute. Now apply the brakes again. Soft again?

Now apply the ebrake. Pump the brakes again. Does the pedal travel less? And does it now stay in this shorter travel even after waiting a minute?

If the pedal remains shorter travel, you need to adjust the rear brakes.
If the pedal goes soggy after your wait, with the ebrake on, you need to bleed again.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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Sluggo
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Post by Sluggo » Mon Mar 15, 2010 3:55 pm

I had meant to post this here but I posted it in another thread. Regarding my no brake or idiot light problem. Doesn't matter. I was wrong anyway.
Sluggo wrote:Brake fluid from the small hose leak that worked it's way into the cup created by the lower brake light switch plug & boot caused a short that blew the fuse.
Actually it was a bad switch. Aftermarket crap made by FEBI I think. The fuse blew repeatedly until I put in the old factory switch.

Followed Colin's instructions and it was both the rear brake adjustment and need of more bleeding.

Brakes are very nice now except that the idiot light randomly comes on then off again 20 minutes later. It turns off when I step on the brake.
:vwgauge420:

1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
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