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So I have replaced the BTV unit with a rebuilt unit. All new brake lines, cylinders, etc. I've adjusted the breaks as far up as I could with the adjusters. The problem is that the brakes are hard to push. It seems like I have to exert a lot of force to push the pedal down and the car doesn't seem to be stopping like it should. From studying other posts on her it looks like it should be stopping very easily by just laying my foot on the pedal. In fact some I have read say it will put you through the windshield it stops so quick. Any suggestions on what else I should check? Could it be a vacuum problem? Thanks for any help you guys can give.

If the rebuilt came from a reliable source then most likely it is a vacuum issue. It definitely does not take much pedal pressure or travel to make the car stop if vacuum is working. How far do you have to push the pedal before the car stops and is the pedal firm? Typically it won't take more than an inch -- usually less -- before the wheels lock. With no vacuum you do have to really push but with vacuum it should require not much more than a toe on the pedal.

Make sure there are no leaks in the reserve canister and hoses are in good shape. Also verify the check valve at the intake manifold fitting is in good condition. The canister can corrode at the bottom or the hose fitting at the top connection can get knocked loose or cracked where it joins the can. The check valve has a diaphragm or plunger depending on type which can get stuck so it doesn't allow any air flow so no vacuum or it can corrode so it doesn't seal. Usually not sealing results in a fluttering or pulsing but some assist is still available. As a crude check you can pull the hose off the BTV and place your finger on the end. There should be good strong suction.

There is one other place a problem is possible but not likely with a good rebuild. If the unit had rough shipment there is a hose internal to the unit which can come off a fitting. You should be able to hear a continual hiss at the unit if that has happened.

Here is a site that has collected and posted several commercials on various cars.tvraaca.org/oldmovies.htm#movie For an idea of the amount of pedal effort needed check out the 53 Packard commercial about 2 dozen down from the top

Thanks Howard. As always very useful information. I bought the rebuild from Tucson Packard. The pedal is very firm. It travels about 1 inch. I checked the suction at the canister and I wouldn't say it's strong. It has suction but it feels weak to me.

I checked the suction at the canister and I wouldn't say it's strong. It has suction but it feels weak to me.

No need to guess, why not just buy or borrow a vacuum gauge and then you'll know for sure if it's adequate or not.

I found the vacuum leak right at the canister. The hose didn't fit snugly enough. I got a smaller hose installed and and boy does she stop now. I mean barely touch it and you're about go through the windshield. I wasn't expecting that much brake! It does correspond to earlier posts I have read on here though. Thanks again for the help!