Packard Forum Index » V-8 (1955-56)

Very good thread - informative and to the point.
I notice that the compensator port spring is not listed anywhere, but believe that Mcmaster-Carr should list one very close to original.

Did you ever drive a 55-56 Packard when they were fairly new?
If so, do you recall how touchy they were back in the day?
Why are they no longer that way?

Friend Chris had a saying that you couldn't drive a 55 or 56 Packard, that had power brakes, with the windows down in the summer time.
He claimed (with a straight face) that a fly might enter the vehicle and if it landed on the brake pedal it would put you through the windshield.
I drove a 56 400 as my daily driver from 62 thru 65 and it was very touchy. I warned my wife about that when she first drove it. She almost put me thru the windshield.

What is different today - no asbestos brake lining??

Randy, I've got two friends with BTV-equipped Packards that have EXTREMELY sensitive units - so much so it's very unnerving to drive the car though I guess that over time you get used to it. The unit in my 56 Carib is just the opposite which I attribute, right or wrong, to lower than normal manifold vacuum.

I'd be curious to know what manifold vacuum other owners of 2x4 bbl 374 engines get at idle. My engine has 93,000 miles without a rebuild, is due for a valve grind, and has manifold vacuum of about 15 inches. Whether or not that's enough of a drop in vacuum to give less pedal boost than normal I don't know.

I drove my 54 Pat when it was a fairly new car, less than 10 years old, and it did not have particularly sensitive brake action.

Those boosters use a shuttle valve that modulates the amount of vacuum being metered into the power chamber. I reckon the unit provides around 290psi of boost for full demand below 22mph and up to 365psi in direct drive. If that valve is out of kilter it may be applying full boost too easily.

The manual doesn't have a symptom for touchy brake pedal so I'm relying on judgement.

I've always noticed a fairly wide variance from car to car with Treadle-Vac. But that is true of cars coming off the truck today as well. Some of them were really good.

Where is that valve? Is it internal to the TV?
I have seen several TVs that way back in the day.

The 55-6 units use poppet valves to control the admission of vacuum/atmosphere. They went to that system to prevent the leakdown of the reserve vac tank while the car was parked. The rubber seals on those poppets develop little grooves from being pushed up against the seats for 50 years. That makes the the unit not modulate so nicely, ie, touchy brakes. There is also a wee tiny diaphragm operated by a pin the size of a finishing nail. I have never quite figured out how it works, but it is also part of the modulating function and that little pin is often stuck in its hole. When it is stuck, you get a sort of on/off feeling when applying the brakes. All the above mentioned components are within the power piston.

That said, when those items are serviced correctly the units modulate nicely and are not a problem to drive--though as Tim mentions there are differences unit to unit.

Once again, 50 year old components have to be brought back to standard operating condition before they can be judged. A car with a completely unserviced Torsion Level system with bad bushings and inop leveler is an absolute pig to drive, but in its standard operating condition is a delight.

As a footnote, the 52-54 units used a sliding spool valve instead of the poppets. I prefer them for feel and ease of service.

Further footnote, it is easy to restore the poppet valves by removing the old rubber and cementing on a new one cut from sheet rubber.

Ross- Great addition. That was the point I was trying to make. I think we all want to get our 50+ year old treasures out on the road however, they need a little TLC to restore them to spec and proper operation. My find for example drove from 56-69 and then was parked in a heated factory for 45 years having only mothballs put inside to protect the interior. yes, I was able to stick the fuel line in a fresh gas can, install a new battery and she fired right up. however decay on service parts takes place over the decades and she needs a little TLC to find her way back to glory. I am enjoying this project very much. the only other restore that was this enjoyable was when I restored a WWI Eindecker EIII airplane. Now you want to talk about finding parts......... The patrician is a piece of cake but just as excited to see new life.

Randy.......ah hem! While checking threads this A.M. I about spewed my coffee across the room when reading your fly on the brake pedal vignette. That was funny! Cannot wait until we cross paths.

Interesting read!

My car has a putty knife in the glove box; neighbors Carri bean barely stops at all. I see this as his car needing help...

if anyone wants one of these to make bleeding the system a lot easy er, let me know,

need a tee, with a valve at cap to bleed air out, then put s clear container on fender and pump away, as to, Ross's system of bleeding. you can watch the fluid ,,so you don't run out.

will make them out of alum. that stainless which is the picture, too, hard to work with.

the cost is whatever its worth to you. turn around time depends on what i am into.

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Let me know when and ballpark price. I am interested.