[T2] Vacuum assist

[Bob Pratt]

Is it possible that the rear wheel cylinders are leaking? How does one know that that adjustment is correct? I really want to spend more time in the driver's seat than under it!

Bob Pratt

> On Sep 1, 2015, at 7:58 PM, Bob Pratt <ka1dza at verizon.net> wrote:
> 
> Hi Jamie,
> 
> As I was writing that, I was confusing myself.
> Is the adjustment in front of the master cylinder? How does one adjust it correctly?
> It was suggested to me that the check valve might be bad. I removed it today and tested it. It was fine. So I'll send the new check valve back when it comes in.
> Bentley said that no adjustment would be needed if I was just changing the master cylinder. 
> I'm confused and frustrated!
> 
> 
> Bob Pratt
> 
>> On Aug 31, 2015, at 10:06 PM, Jamie <jrivers at globalserve.net> wrote:
>> 
>> maybe it is just semantics or typos,, but i am not clear on a few things..
>> 
>> ______point_1__________________
>> you said...
>> "The bus 1971. According to Bentley, the adjustment is on the front side of the vacuum assist as it doesn't have the short adjustment rod like the pre-1972 busses have."
>> 
>> I don't understand what your wrote..........  a pre 72 is a 71 ??  ,,, did you mean pre 71 ?
>> 
>> any year bus with disc brakes on the front should have a booster..... but not all........
>> so,, usually a 71 and newer has disc brakes on the front.. so a71 should have a booster
>> 
>> your 71 has a booster......
>> 
>> the rod adjustment is critical...... on the booster style... there is a 0.040 clearance required... that adjustable rod is part of the booster...
>> if i remember correctly,,  you have to "feel" the clearance .. as you can't see or measure it.  elaborated a bit more below...
>> 
>> ______point__2__________________
>> 
>> you caid
>> "I disconnected the brake pedal from the shaft that goes into the front of the vacuum assist and there was no movement of the pedal. "
>> 
>> I don't understand that ...... if the brake pedal is disconnected from the shaft.. the pedal should have lots of movement.
>> 
>> I think you are trying to ensure there is clearance 0.040 thou... which means you remove the master cyl.. and measure the depth of the hole.. and measure the length of the rod.. and adjust the rod to be 40thou shorter..
>> or
>> you "feel" that 40thou by adj the rod tooo long,, put the master in place without the O ring .. and measure the gap.. then shorten the rod... until there is bearly a gap,, then shorten it 40thou more..
>>