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Power booster for brakes issue in a '62...

Started by Edward Kenny, May 19, 2012, 10:55:04 PM

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Edward Kenny

In reading my Haynes Techbook Automotive Brake Manual, I've come across some info which pertains to the possible reason the brake pedal is quite hard in my '62. The manual claims that there in fact may not be enough vacuum being generated for the power booster due to the age of the engine. When I checked, the engine was generating 12 in-Hg of vacuum. The manual calls for at least 15 in-Hg.  The manual also says that in some cars there is a vacuum pump to generate the proper vacuum for the power booster.

Does a '62 CDV normally have such a vacuum pump? I've never heard of this before, so this is why I'm asking.

I don't hear any leaking vacuum (hissing), so I'm under the impression that the system is airtight.

Comments? Thanks in advance for the due diligence.

quadfins

#1
Hi Ed,
   Vaccum pumps were found in earlier models, particularly when the wipers were run by vacuum. I forget which year was the transition - 1958, I think, but by 1961 & 1962, there was no longer an auxilliary vacuum pump. The vacuum source on your '62 should be from the back of the carburetor. I am by no means an expert, but it seems to me that 12" of vacuum should be adequate for brake power boost. I don't know why you have "hard pedal syndrome". I'd like to test-drive it for you, and compare with my '61. Will you be at the GN?

Jim
Jim Eccleston
1961 Coupe de Ville
BATILAC
Senior Crown
DeCou Driving Award x 4

Edward Kenny

Sad to say I will not be at this year's Grand National. I'm sorry.

Dave Shepherd

If that is 12 in of vacuum at idle something is amiss here, on that engine in good shape, properly tuned no vacuum leaks, at idle should be 17-19.

62droptop

if the booster diaphram you will have low vacuum reading if you are reading other than the booster hose

i mistuned /worn engine will have low vacuum


how does the engine run,specially at idle

try blocking off the hose to the booster ,check vacuum reading of engine again at outlet just in front of the distributor
if the hose to the car accessories is leaking,that will also give low vacuum
does your car bave power locks??

in reality, if the booster has never been rebuilt,that is most likely the issue as it is a half century old

siezed /leaking wheel cylinders and leaky axle seals will also cause a hard to stop car requiring more pedal effort