Packard Forum Index » V-8 (1955-56)

Just looked at my car and have a couple of questions for Craig also. Granted, Eric's and PV8's firewall solution is easier but I like the thought of it hidden in the original location.

You mentioned it has worked for 7 years but if you were doing it again, is there anything different you would try. I am wondering if the 7 1/2 dual booster would fit for the extra oomph. The 7 single you used looks like it almost touches the steering column and the 7 1/2 dual is slightly longer and wider-- although not as long as the 7 dual. Maybe with a different master cylinder for the frame issue?

Just thinking out loud to try and keep closer to the factory pedal arrangement. If a bracket were made just at the base of column mounted on firewall--maybe with a U cutout for column-- or else at top of toe plate and then with ears extended out and dropped down straddling or parallel to pedal to the pivot point needed to get the ratio, if it would be less obtrusive. A question for ABS but wonder if there is a shorter actuating rod that could be used on booster which would lower the pedal height. Again, just thinking (dangerous, I know) but lots of talented people here might have options.

Quote:



1) The holes in the vertical leg of the L-bracket are 4in from the horizontal leg.

2) The center of the uppermost hole in the pedal arm is 2-3/16in from the closest point of the cross rod. That hole is also centered on the side of the brake arm.

3) The center of the lower hole in the pedal arm is 1-1/2in from the center of the upper hole.

4) The position of the pedal lever is determined by having clearance at the top of the lever to the steering column.

5) FYI, the distance from the lower hole to the center of the brake pedal is 5-1/2in. This results in a leverage ratio of 5.5/1.5 = 3.67:1.

6) The clip on the outside of the pedal crossrod is to hold the return spring. The bottom of the return spring is attached to a hole in the vertical leg of the L-bracket. Its location depends on what length spring you use.

Quote:

As far as mounting the MC/booster, one could obviously go inboard and down to a minor degree, so maybe a 7-1/2 dual would fit. In that case, the constraint would be the forwardmost end of the MC interfering with the frame. Also, I believe that you would still need some pedal leverage above 1:1 though, so you'd have to do something akin to what I did to achieve that.

I have a diagram filed away somewhere that lays out a "scissors" type pedal leverage arrangement. It achieves 3-4:1 leverage and puts the pedal in the original position, albeit significantly further away from the toe plate. I never went further than this diagram because my releveraged pedal works fine for me. So, one thing I might try is to mock up a "scissors" type and see how it works.

I do not think you could use a shorter actuating rod because when fully depressed as hard as possible, the bottom of the pedal barely is above the upturn in the floor as it is currently installed. The last thing you would want is to have the pedal hit the floor before bottoming the MC.

Craig

bhappy wrote: Quote:

I neglected to respond to this part of the original thread.

The 1956 Clipper has a Dana 44 (actually 45, but essentially the same) rear end in it. This is a very common rear end (Jeep, Ford). It is no problem to get a disc brake conversion from one of many aftermarket suppliers for it.

The front is a different matter.

The only caveat is getting the right proportioning valve when using front/rear discs. On my 55 Pat with front discs and rear drums, I did not need a proportioning valve.

One more comment: I agree with PackardV8 (Keith) that converting to disc brakes is NOT an absolute necessity. Only replacing the BTV is a necessity.

Craig

After a phone conversation and a little thinking of the subject of the BTV, I think I may have found a major cause to the Packard versions.

I've read about the Chevy application of the BTV and they don't report near as many failures as Packard people do, why is that?

Well, I'm now wondering if it isn't a result of Packard's location of the BTV. As we all well know, it's down under the steering column. On a Chevrolet, it's up on the firewall like a more modern car is. Now, keep in mind that a conservative estimate would put around 75% of Tri-5 Chevies being updated with modern brake components will skew my theory a little, but bear with me.

Packard put the master cylinder down on the frame next to the exhaust manifold and at an angle on the V8 cars. I think that these two factors right there contribute to the faster degradation of the internal components on the BTV, as well as the poor design of the unit in general.

Now, on the '53-'54 Packard cars, the exhaust is on the other side. I'm curious to know if there's any reported, known failures on these cars.

I'm thinking that the combination of high heat from the exhaust and the angle of the master cylinder is the biggest reason for failures in these brake boosters, and putting a more modern one exactly in it's place may not be the best idea, it would be better to put it up on the firewall to give it more airflow than it would otherwise have under the column. Also, having the master cylinder so low allows moisture to get to the unit easier than it would be on the firewall. We all know that the master cylinders of the '50s are not sealed like today's are, and moisture ingress is almost a certainty when it's down that low.

I'm also thinking that Buick put the BTV under the column, and I'd like to know what their failure rates are too.

Great analysis T'Pacman. But how does the BTV location explain several failures of NEWLY rebuilt BTV's?? Some that were rebuilt by noted BTV rebuiling professionals????

I'll will look closer at my firewall mounted Ford power brake unit to see how close it sets to the exhaust manifold compared to the BTV location and compare the location it to other more modern cars too.

I would like to replace the BTV/MC with a newer dual diaphram booster/MC unit and mount them higher on the firewall. Is there a parts list and detailed instructions on how to do this in my 56 Executive?

Thanks for any help in this. I'm not comfortable driving the car with the current condition of the brakes.

Bob

See post 91 and later in this thread:

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=3867&forum=3&post_id=40877#forumpost40877

bhappy, just curious. You said that before the incident you had changed the brake light switch and noticed the brake fluid was nearly empty. I'm sure you filled it and bled the system, but did you check the fluid level again after the incident?

I believe there was one or two mentions of problems in 51-4 maybe here or AACA but certainly not as many as later cars.

The heat may well have something to do with it but doubt the angle by itself since they were all the same since introduction. Do believe the angle would be a contributor though since any cooked fluid or debris would just float to the most vulnerable part of the unit, namely the compensator valve which is right at the top with it angled. On the cars with it mounted horizontal there may be enough difference in design where garbage could float & lodge somewhere else.

Regarding the low location and a modern unit, I would think the remote fill setup would go a long way toward eliminating moisture problems and perhaps a heat shield or insulating material would help the other.