Packard Forum Index » V-8 (1955-56)

The other concern is avaialability of replacment parts in the futire out say 10 years or more. With the way the aftermarket is now then maybe shorten that to 5 years. Replacement Electric pump and accumulator would be my biggest worrys forr replacement parts.

No doubt, this is a greaat conversion for those with factory air con.

No doubt, this is a greaat conversion for those with factory air con.

Keith, Fortunately (or not), those of us with that particular AC issue are a distinct minority but it is the challenge.

I agree the unit looks very viable and am considering scrapping my earlier efforts in favor of the package. Aside from your concern on future parts availability I still can't quite get comfortable with the worst case scenario of absolutely no reserve and no pedal ratio. That is what I would really like to understand better.

Granted, I always look at the empty glass and think of something that is never likely to appear so here is one that is off the wall. Without knowing exactly how it plumbs internally I wonder what would happen if there was a complete failure somewhere on the power side. If something happened between the accumulator and pump unit to master -- like maybe a line or component failed for example. In that case would we have a BTV moment and the brakes totally fail or would fluid on the wheel side of master still be intact and able to move to wheels but really need the pedal ratio in addition to a lot of foot pressure.

I expect many of us know what kind of pressure a BTV needs with no boost and it isn't fun. Believe I remember Craig writing his first attempt on his conversion using a 1" piston and 1:1 ratio was problematic and he needed to increase the ratio on his pedal. With the larger 1 3/16" piston this unit has, no boost and a 1:1 ratio, that sounds like a big problem. Even with no catastrophic failure I can't believe the unit will have enough oomph with just foot pressure and no mechanical advantage that a ton or two will do much more than a leisurely slow down.

So I have been looking on this site on the BTV conversion and I see people going to the vacuum booster that takes up the drivers side fresh air vent. In my case I would rather not use that method, the car in question is an A/C car.

I have seen people use vacuum boosters and a couple people use a hydro boost system, I think someone used it from a 71-72 Lincoln.

I was looking at the 56 Patrician this past weekend and it would appear if the booster/master cylinder assembly was moved outboard of the column there would be a decent amount of room ahead. This would require a bell crank that would connect the stock pedal to the back of the booster/master cylinder. With that bell crank a pedal ratio could be factored in. I am not to sure if it would be the optimal 4:1 ratio, but something is better than nothing. The car I was thinking of robbing these parts out of was a 96-98 or 03-04 SVT Mustang. Another benefit of this is that all the mount points/brackets would be on the frame rail, so the force gets transferred to the thicker metal there as opposed to the firewall.

I do understand if your power steering pump goes out, line bursts or the car stalls you loose your power assisted option. But if your car stalls you would still loose the power assist on a vacuum boosted car.

Thoughts?

As far as I know the only reasonably easy vacuum options to get a decent pedal ratio have been to use the air vent location or modifying the pedal as Craig developed in his original conversion when he used the standard location. There has been at least one conversion done with moving the vacuum setup to a space near the top of the firewall and completely relocating the pedal support. That required some special fabrication but apparently worked well. If you have a 55-6 AC car, that higher location is not an option any more than the vent.

Two or three people have used an ElectroBoost setup from ABS Power Brake in the original location with the pedal still at the 1:1 ratio and took advantage of the adjustable output pressure to provide adequate stopping. IMO, this is an accident waiting to happen because the same hydroboost failure you are concerned about could also happen to the ElectroBoost but the situation would be worse because of the low ratio. I would think a failure with a ratio of 1:1 would result in barely slowing the car. Even if a fix for the ratio is found, for 6v owners, the ElectroBoost is also only a 12v option.

I also have an AC car and did several experiments with relocating the unit. I did manage to get an approx 3.5:1 ratio by redesigning and made some extensions to relocate the pedal arm upward slightly. Made a bellcrank type linkage to fit in the vent opening in order to keep the AC blower return intact. Because of the booster size, that approach entailed moving the boost and master off to the side and mounting at a steep angle. The brakes work -- too well as it turns out because they are too sensitive for my liking. Not sure if that is because I used a power unit with too much boost or if it is due to the angle. As per my usual MO, got tired of the project and moved on to something else before all the bugs were worked out. At my age, am unlikely to pick it up again but IMO, that approach would work more satisfactorily with the ElectroBoost rather than vacuum. The master on the remote fill Electro unit is small and thin and could be positioned level and almost parallel to the firewall instead of needing to be at an angle. 3.5:1 would be in the realm of possibility for safety and space for the bellcrank could be obtained by making a small 2-3" wide tube like housing for the linkage and master mount. Slightly move the blower assy or modify if needed and maybe move the air flapper valve forward to accommodate the adapter requirements.

If you wanted to try something along those lines be my guest. I will share the photos of my setup. If all the negative comments about BTV reliability -- mostly in V8s -- are to be believed, if you can come up with a viable 55-6 easy to do replacement you would probably be remembered by a lot of people. An adapter and ElectroBoost would also work on non AC cars and if the master could be mounted parallel off to the side, the small size would be less seen or likely to scream modification.

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Listen up I had problems with the BTV for years and you know what I discovered, ITS NOT THE UNIT. Its the unqualified idiots that are rebuilding these units! I had Ross Miller of the Speedwell garage in Parkton Md rebuild my unit and you know what PROBLEM SOLVED and the car now stops on a dime. He also discovered three things wrong with the rebuild job done by White Post restoration yeah they snagged me with that "lifetime warranty" bs and like an idiot I fell for it. I had two return the unit twice because of problems with it. The second time I asked them well what was wrong with the BTV they couldn't tell me! If they don't know what was wrong how can they fix it! Remember these are your brakes that is a safety issue and Packards are typically very heavy cars; don't take a chance of ending up in an accident or CAUSING an accident.

If you want power brakes, what about using a remote booster you could mount along the frame somewhere?