Packard Forum Index » V-8 (1955-56)

My car is still in the shop being admired by passers-by.

When one of our members asked for cars for a presentation at a local old folks home, I ended up taking my neighbor's 56 Caribbean to the event.

I was terrified by his brakes--or the lack of them.

Both cars have the usual power brakes, Mine stop on s dime and give change if you blow on them. In his car, If you stiffen your body pushing the pedal down with all your might, the car gradually eases to a stop.

What do you see as normal/appropriate stopping?

Kindly do not launch into a diatribe on the Bendix system; that isn't what this post is about. Just want to know what constitutes good behavior in a properly functioning system.

My cars always stopped very nicely with the BTV as long as the engine was running. Maybe not as nicely as my modern car though. It was very iffy to even somewhat scary on a dead engine or no vacuum.

Does your friends car seem like it has assist and feel similar to yours when applying ie an easy pedal or does it have a hard pedal and feel like maybe his booster section has given up.

The BTV on my 56 Executive was exactly as u describe on YOUR car. Stopped on a dime and gives change if u blow on it". As far a braking performance goes i would classify it as superb and most desireable above even any modern day car. But then again, i prefer a very powerful and touchy power brake which the BTV fits that bill just fine. It's all of the OTHER bills it does NOT fit.

Your neighbors Carib brakes needs attention. I wouldn't make any attempt to serious driving until it is fixed.

I don't know how much u drive your Patrician. But be advised to check the brake fluid level on somekind of a regular basis. I would advise no less than once every 500 miles. Preferably once every 200 miles until u get a feel for how often it has to be topped off.

I say this because there has been numerous reports of fluid sucked from the MC into the power unit. MIne did it.

Since u have a mechanic doing the work for u it mite be that he has topped it off and just didn't tell u.

'54 here, but TRV nonetheless. I, too, find the brakes superb, the car just settles to the ground without drama. Your friend's Carib needs a careful assessment, what you're describing cannot be at all close to "Normal" or acceptable.

The key to good stopping is to make sure brake fluid is topped, but this won't help much if the MC or the booster itself is corroded and needs replacement, along with leaky wheel cylinders. Also, brake fluid should be replaced and the lines flushed every 2-3 years, depending on how dark yellow the fluid appears.

Some 2 - 3 years ago the BTV on my '56 Pat decided to reject all power assistance and the result was a pedal so hard that I wasn't game to drive the car out of the shed. I bought a newly rebuilt unit (by Karps, in LA I think) from the previous owner of my car and fitted it, as well as reconditioned wheel cylinders and new front hoses. Braking performance was improved significantly, but not to what it used to be with the old BTV before it gave up the ghost. Still too heavy for my liking!

Replacing the vacuum hoses and the carby check valve improved things a little, but still not to the standard mentioned by others in this topic. In other words, I still have to press the pedal harder than I'd prefer. As I understand it, The way the BTV was setup by Karps is the way that it must stay, unless pulled down and modified somehow.

I read in a recent post that somebody had replaced their wheel cylinders with ones that had a 1/16" oversize bore, and I was wondering whether this might be an option for me to pursue to reduce the amount of leg power required to pull up in a hurry. I would be grateful for any advice about this as a possibility as it's certainly something that is withing my technical capabilities to do. However, if removing the BTV is the only viable option then I might have to investigate more thoroughly the other alternative braking systems discussed in this forum. Regards, John

JP:

What size wheel cylinders does the car have on it now???? Assuming wheel cylinder size that is OEM spec then a 1/16" variation is not likely to make much noticeable difference. 1/8" will. But i would hesitate to vary from OEM spec.

Auto parts stores during the 60's and 70's and 80s' mite often sell replcaement wheel cylinders (for ANY car) that could vary by 1/16". THAT is when store looked up wheel cylinders by model make and year. I ran into that quite often.

BEst to diagnose the problem u are having with the less than powerful power brake than to begin changing other parts to accomodate a faulty BTV IF the problem is in the BTV.


HOWEVER, i don't quite understand your following statement:
"The way the BTV was setup by Karps is the way that it must stay, unless pulled down and modified somehow."

Was the BTV set up by the rebuilder in someway different from OEM specs?????

JP, if a TDV is rebuilt correctly (to OEM specs by people who have knowledge and experience), and assuming that you've correctly replaced wheel cylinders (Again, with correct ones, Kanter has them), hoses are tight and unbroken, etc, then your brakes should operate as advertised.

If your TDV was rebuilt incorrectly (as you say, they 'Set it up'...if done correctly, it should have been 'set up' to factory specs by using correct replacement parts, and it should feel like factory), if you used wheel cylinders that aren't exactly correct, then your pedal feel will be different. If it's just a matter of 'feel' and not actual performance, you might choose to live with it. But, if you find that stopping distances are longer, or you feel less safe, then I'd recommend you at least have the TDV unit properly rebuilt...or just replace the whole thing.

Not everyone in the automotive service world that works of Fords and Toyotas has the experience and know how to work on a 60+ year old car, and know where to get the proper replacement parts.

I too have experience high variance in BTV boost and attribute it to valving problems.

All power boosters have shuttle valves that regulate the amount of atmosphere (boost) being displaced.

If you look in the manual there are exploded parts views, but not a lot of theory. I suppose if you could get those little valves and springs you could fix the problem. However, when the manual states "break if necessary" as regards disassembly, extreme caution is the order of the day. It could also be the, all to common, problem of vacuum leaks due to worn castings in the shuttle assembly.

Quote:

Hard to say as I have neurapathy in both feet. With my car all that is ever needed is a simple heel and toe pivot; on his car you stomp on the pedal.

As to other points raised about parts, I would find it hard to believe that non stock parts had been introduced. He stays carefully original. The funny thing is that he just had his brakes done last spring. On thinking about this, I wonder if the power unit is not working, so has non-power brakes...although they still seem poor. I'd expect better either way (power or non-power),,,,



I pointed to him that his car and mine do not stop in the same way at all, but am not sure it made a dent. Hope so. Meanwhile, I intend to stay well behind him.....