74 bus brake problem, brakes lock up booster ? fixed?

[joghia]

hi everyone, this is my first post on the samba! long time viewer, first time.... i apologize for the long intro! just some background info:
i'm from Belgium , and have a '74 1600 bay window bus, i bought it a year ago , it was far from original !


i replaced the front discs, new calipers (incl new pads) all from ate germany, new soft lines and hard lines, and in the rear new softlines, brake shoes and cylinders!everything but the master cylinder and the booster !

my wheels lock up after a short drive (say 15 to 20 minutes) the front go completely stuck, the rear ones also ,so i bought a ate master cylinder and replaced my old one, I checked everything beginning with my pushrod (shortened it again), it looks better now but still have a drag issue, they are not stuck now but after a drive they tend to drag more, sometimes I drive 200 kms and don't have a problem , other times only 25 km's and i can feel it in my performance, not to mention the smell and the hot wheels and brakes

Could this be a brake booster / SERVO issue ??

my booster isn't connected to my engine,(it's a bug engine) i don't have a valve in my vacuum line, when i changed my MC i noticed a booster with filth in it, but from what i understand is that a disconected booster shouldn't be a problem ?the rod in the booster was moving !


i searched and searched and... lot's of people have the same problem but there never seems to be a clear, answer when it is fixed

from what i found was

a spacer between booster and MC ?
a restored booster?
pushrod adjustment?
?;;;;
that's it !!

hopefully if things go well, the samba gods here and old school bonanza bay lovers will come up with an answer !


thanks in advance, excuse me for the long post, looking forward to some answers and help,

jo van dessel
geel
belgium


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[busdaddy]

Welcome! since you've replaced most of the usual suspects the next on the list is the pushrod between the pedal and the booster, is there a slight bit of freeplay when you push the pedal with one finger before it becomes hard to push?
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[joghia]

thanks busdaddy !

well I changed the rod distance a few times (always shorter) and always in little steps, seems to make no difference at all ? there is some freeplay ! i would say 1 cm or so (0.5 inch )while pressing on my pedal with my finger till i feel some resistance

now the pedal gets stuck in 5 minutes of driving! with the old mc it sometimes took an hour or so, with the new one i drive down the block and back and then i have to stop and bleed one of the wheel cylinders just to get home!

i also disconected the hoses from my booster, didn't change anything!

i lubed everything up (once more) the spring, the pedal connection, rod connection....
also when i shorten the rod so to speak, my pedal goes a little bit lower, this is normal i suppose ?

i 'm almoust out of ideas here,

if everything is new( and hopefully working correct) the only thing that is left is the booster servo ,
also considaring of changing to a set up without the booster, different mc with just a rod, could be cheaper in the long run, we don't have a " send you booster to ...place here in europe) but that's an el punto final idea !

anyone ?

[busdaddy]

Sounds like the pushrod is not the problem (yes, the pedal will be lower with more freeplay).
When you say "disconnecting the hoses" I'm guessing you tried disconnecting the vacuum hose from the engine (capping the engine end) and seeing if it still occurs? Remember the braking will be more difficult with the vacuum disconnected.
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[joghia]

when i bought the bus it had a 1300 cc bug engine . i upgrated to a 1600 engine with an inlet manifold for the vacuum hose(it wasn't connected to the engine before )
however when i connected the hose to the inlet manifold, my engine stalled so i drove like that for 5 months disconected and the manifold tube blocked

am i correct that when i disconnect the booster at the hose in the back and leave the hose open , i brake without the booster and it would be the same as just a long rod and a master cylinder?

[busdaddy]

Yes, although the non booster European master cylinder may have a different internal diameter to aid in braking force, I've never compared the 2 side by side to confirm that.

But if the brakes don't lock up with the vacuum hose off and you're OK with the way it stops leave it that way until you can locate a replacement.
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[joghia]

no luck ,
makes no difference now that the booster is connected or not,

now it only takes 5 minutes of drivin' and all is locked up .
tomorrow morning i am going to bleed the brakes one more time and check rod again,

really out of other ideas,

[busdaddy]

Were there any problems fitting the calipers? as in odd sized bolt holes? How easy was it to get the pads into thier slots? If you have 71-72 calipers on later rotors or another mixture of parts and there's almost no clearance they could bind when they warm up. How tight are the rear brakes adjusted?
Next time it binds up jack it up and see which wheel/wheels are locking, feel them for excessive heat as well.
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[joghia]

i think there is a small progress now,

there always is heat on 4 wheels (the front warmer than the back)
but yesterday evening, i didn't went for a drive, just braking in the bus (stupid , i know)without the engine on! after 5 minutes i allready noticed the same thing when driving, so i jacked up the bus and again 4 wheels serious drag !

that was yesterday, so now i unscrewed the rod out of the booster, no difference, wheels still tight after a night , then i unscrewed the two bolts connecting the mastercyl with the booster, i didnt hear any noise but now the wheels spin loose again!

what is this telling me ?
should i put a spacer between the master cyl and booster?
could there be an internal part somewhere i am missing ?
i'm going to lube the rod in the booster right now and clean my new mastercylrod (outside) maybe a rust issue on the rod in the booster that is binding with the rod from the mastercyl ?

thanks for all the advice so far !!
any ideas ? tomorrow i'ld like to go to a vw meeting in belgium,( i sell and buy old school alloy rims and odd accessorries for air and watercoolers) i have a ghia too but theres no space for wheels....

[busdaddy]

Hmmmm..... interesting, I don't believe there's any adjustment inside the booster so that can only indicate somethings wrong internally. Shimming isn't the way to fix it right but seems like your best option for the moment, whatever you do it has to be solid and secure.

A washer over each stud before the master cylinder goes on would work but you'd have to leave the vacuum line disconnected, or possibly a double gasket to allow the use of vacuum if you're bent on using the boost.
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[joghia]

there could be a breaktrough!
i removed the vacuum booster, it was filled with rust and fluid
it is a mess, i tried to clean it and let it sit overnight,
when i move the rod back and .. , it gets stuck a lot of the time due to the rust! hopefully this is my problem and it 'll get fixed !

now looking for a good usuable booster in belgium !
'll keep you posted

[Runamuck Bus]

On this side of the big pond, it is common for bus owners to have the brake booster rebuilt. We even have a notable 'guy' in the Great State of Texas who comes well recommended. I recently sent him one of mine and, honestly, I can't tell you all of what he does. The booster came bad very clean, sporting new seals (per discussion), new boot, painted and it moved very well. I was told, at the time, that he had found fluid and rust in mine so I suppose he actually opens them up, although I don't know how.

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[jbcuny]

who is the guy in texas that rebuilds the brake boosters

[Runamuck Bus]

H & R Automotive Parts
10328 Oakwood Dr
Dallas, TX 75217
972-286-5516

Here is a story :
http://www.itinerant-air-cooled.com/viewtopic.php?t=3990
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Endeavor to persevere.
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[joghia]

thanks all for you help !

you'll understand tha sending a booster to h&r from europ is a costly and long matter, so i searched a good used one here, for a few bucks, i thought , if its better or solved i'm 100 procent sure and a new one is available in germany for 350 euros ! i found a good used one for 50 euros, i believe roughly 40 dollars incl dry mc and rod, since i had a new mc i only fitted the booster and voila!!!

my problem was the booster, my original booster was so rusted on the inside, little particles were between the plastic and the tube so it was always a little bit stuck?

i drove with the second booster 60 kilometers and nothing, jacked the car up and all wheels are loose !!

glad i found it, next weekend some long drives ahead so, if all goes well, you won't be reading me no more!!!


i attached everything, boost works well, i can't believe that i hadn't had those brakes before !!!!



one more question perhaps, with everything hooked up the same as before (probably better)
i now have a flat spot when i want to pull up fast, the first second or two, then it's all good, only loooks ridiculous when someone is watchin because my bus rocks back and forth ! do i need to tune my carb again with the vacuum connected ?

[busdaddy]

Good news!
The hesitation may be due to things being tuned to work with the leaking booster, now that it's sealed the idle may be too rich.

If you pump the brakes rapidly while idling and the idle increases alot it's too rich, if it increases a tiny bit and then starts to drop it's just right and if it immediately drops it's too lean.
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[SGKent]

Good Job!
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