In the continuing saga of my 63 Dynamic 88..... I've been plugging away on it and have run into a weird hiccup. I replaced the stock (toasted) booster and single mastercylinder with a 7" universal dual diaphragm booster and GM dual master cylinder. In the original configuration, there is a metal vacuum canister tucked into the back of the fender that is plumbed in conjunction with the og booster. when I set up my new system, I found that I was losing vacuum when braking. (pedal got hard, engine sounded like it was gonna stall). I put a vacuum pump on the cylinder and it wouldn't even build up pressure, so I'm sure it's rusty. My question is, can I just delete it, or should I replace it with a container of similar volume? Thanks!
Can you post a picture of this other vacuum canister? I’ve never had any success with the tiny 7 inch boosters. Single or dual. And I’ve had to swap them out for 8 inch dual boosters for it to feel right.
here's pics from an ebay listing for one that is the same as the one in my car. It's fairly sizable. probably 8-10" long and 5" wide
That's a vacuum reservoir. Typically there is a check valve between it and the intake manifold, so that when there is low or no vacuum in the intake, the reservoir provides vacuum for one or two power assisted pedal presses. I don;t quite understand your comment "I put a vacuum pump on the cylinder and it wouldn't even build up pressure, so I'm sure it's rusty." Can you elaborate?
I'm gonna guess that a dual diaphragm booster will work just fine without the vacuum can. The vacuum can was OE because the extra vacuum was needed for the stock system. The new booster will do the work of both.
My bad, I should proofread better.... It's been a long day. I connected my vacuum pump to the reservoir, and it would not build any vacuum, so I suspect it has rust holes in it. I haven't had time to remove and inspect it yet.
allways fit the biggest booster for the space provided .. the tinys are bad news ,, if you want a canister you can go aftermarket cheapo bigger the better does the same thing , holds about a hit and a half worth of vac .. check valve could be the prob . bypass n see what happens wont hurt just be carefull ... fabricator john miss you dad
In my opinion, that 7” dual diaphragm booster is not big enough for that heavy of a car really. I agree with fabricator John in that you need to install as big a booster as space will allow.
Had a 7in booster on my 48 sedan and always felt fair at best for boost. Got a 9in booster from NAPA for 78 Caprice and went to excellent, no other changes.
I would send the original out to Booster Dewey at Power Brake Booster Exchange... http://boosterdeweyexchange.com/ I have never had one of those dual diaphragm units work for me or one of those vacuum cans for that matter. The vacuum can did make it better but no where like stock..
Pulled and repaired the original canister. Put it back in, and then added a Mr. Gasket canister to help compensate for the difference between the stock 9" booster and my 7" universal booster. I got much better results! I need to put a vacuum gauge on the motor and tune it a bit and I think I'll be golden!
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