Packard Forum Index » V-8 (1955-56)

Hello Guys.
i recently purchased a 1955 Patrician.
Can someone help me with the part numbers for the brake shoes from and back ? All listings I find are Clipper only.
In addition, I read on here several posts about bendix treadle-vac conversion / update, but did not see one that has a good parts list in regards to a brake booster and a Master cylinder.
Maybe someone who has actually done it can give me some info

thanks

On the power brake conversion, there are no complete drop in kits available for Packards probably because of the location Packard used for the Treadlevac which was space confined and at the very bottom of the pedal arm.

That location provides a pedal ratio of 1:1 which was adequate for the Treadlevac (BTV as it is usually referenced on this forum) due to the way the ram displaces fluid rather than pushes it ahead of a piston. Since modern systems all use a piston to push fluid, none will be able to use that location without pedal modifications to increase the ratio to somewhere in the range of 3.5 up to around 4.5:1. That makes an awkward pedal both in looks and function since it usually raises the pedal or drops more toward the floor -- either approach a distance away from the original location.

For that reason many have started mounting a booster in the area of the Left air vent. Removing the air tube and making a plate to cover the opening, then mounting the booster has been done but almost everyone has picked a unit out of a junkyard in order to also get a suspended pedal with the proper ratio for their particular booster. I know of one Ford Ranger setup and another who used a Chevrolet booster and pedal. Others have done fabrication of their own designs to mount universal boosters from MPB and whatever generic dual master that will bolt onto the booster they chose. Boosters have been 7" single, 7 1/2 dual and even an 8" Master piston diameter has been fairly consistent at 1" though. Pedal was in most cases a generic hanging pedal.

Guess the long and short is there are no consistent part numbers or tried and proven conversions to recommend. The late Craig Hendrickson did the first mod and had some numbers on his now defunct website. Since that is gone except for a few pages found in web archives about the best you can do a search for BTV related posts on this forum. There are many! Several of the threads have some photos and indications of what others have done.

yeah i knew about the pedal ratio and the need of modification. was just wondering what parts to use.. ie I seen references to 1" bore as well as 3/4" bore or the master . Also seen some info about a 7" diameter booster. but again, there are many versions available. just want to make sure i have the right combo, so the amount of fluid send in each circuit is sufficient to stop the car.

In regards to shoes, i hope someone has some part numbers. only source i seen an actual listing for shoes was through Kanter. but their pricing is a bit up there.
thanks again

Hi,
It's been about 10 years now but what I did was to have the shoes on my '55 Patrician relined. As I said, it's been 10 years but I haven't had any problems with the shoes or the BTV after I had the unit rebuilt. I think that the key thing to avoid BTV problems is to drive the car regularly. It's worked for me.

JimL in OR

I know the 3/4" master has been mentioned several times but don't remember anyone saying they have actually tried it or remember seeing any reports as to if or how well it works. As I recall, almost if not all of the installed conversions have been 1" diameter masters which seems to be a fairly standard size cylinder.

The reasoning behind the smaller diameter master discussion is the BTV ram is also relatively small but can do a long stroke to make up the volume. From an increasingly feeble memory, I think the BTV ram is just over 5/8" in diameter with a 4" max length stroke. It functions by the solid ram inserting inside a closed cylinder and displacing an equal volume of fluid out to the wheels. With the displacement method a considerable amount of force is generated hence getting away with the 1:1 ratio.

The theory behind trying a smaller diameter master is a belief it will require less force to move a smaller amount of fluid. If that is so perhaps a lower pedal ratio would work with a smaller cylinder as long as it still has an adequate size booster on a very heavy car. The vacuum section of a BTV is right at 6" in diameter with a single piston. The max size of a modern booster that will still fit the original space is 7". Craig used a 7" single diaphragm but for a bit of additional power a 7" dual diaphragm is available. Length is over an inch longer on the dual and will barely fit depending on the length of the master. Not sure if the 3/4" master is the same length as a 1" though and less would definitely be better.

On the reduced volume out, as long as the wheel cylinders and shoes are adjusted properly the BTV ram does not move more than about an inch so does not displace a large amount either. I do not think it would be a good idea if a disc conversion was also contemplated. I believe there is at least one disc conversion using the BTV but to me that volume capacity leaves very little margin for error. Almost as worrisome as those asking for trouble using the ElectroBoost setup with a 1"1 ratio with no margin for error if the power unit failed.

As to volume and force of a smaller master, In theory the smaller amount from a 3/4" piston might be sufficient but until someone tries it that force theory still remains to be proven.

I tried a 3/4" master out of Ford Courier with a 7" booster (also out of a Ford Courier IIRC), I put a post up with part #'s and pictures, you'd have to search back a while but it's there. I still have it stashed somewhere.

It DIDN'T WORK. The pedal force required was still too much. I had other people try it as well and they agreed. You are still off by a fair bit ( (5/8)^2/(3/4)^2 ) = 0.70, so you only had 70% of the standard braking force available. You would need a 1.25 or so pedal ratio to get back to where you were. Possible, maybe. But also the Ford Courier master cylinder was pretty small stroke, so that would be something to consider. In the case of brake fade might have to pump the brakes a lot.

At a 1" master you are at ((5/8)^2/1^2) = 0.40, or only 40% of the braking force available. You would need a 2.56 pedal ratio to get back to where you are.

Ross also points out that in some conversions of Studebakers that he's investigated the linkage, etc. was set up so the pedal could never travel far enough to actually "activate" the dual option, e.g. if one of the cylinder sections actually failed.

Recently I think the best way to go is to either move to DOT 5 or move to a low-vapor-absorption DOT 3 like Prestone MAX, and do things like in my earlier post about the "bladder cap", to keep moisture out when the car is sitting. That and frequent maintenance.

But I talked to some Packard people this weekend and they all said they used DOT 5, which I understand is what Kanter uses in their cars.

Kanter and Wilwood both sells Disc Brake conversions and I believe they are set up for the BTV, I would talk to them about it.

I bought my new brake shoes for the '56 Caribbean from Kanter, completely satisfactory. Likewise never a problem with the Bendix BTV on the Caribbean or on my '54 Patrician, both driven extensively and regularly.

G'day Dieselsubmariner,
to PackardInfo.

While you're resolving your brake shoe issues I invite you to include your '55 Patrician in the Packard Vehicle Registry.

The older Jeeps used the same 2" brake shoe. Thats what I used. Exactly the same

Phil_78: any chance you have and could add the part number for the Jeep shoes to the Parts X-Ref page?

https://packardinfo.com/xoops/html/modules/parts/index.php?cat=7&catname=BRAKES

thanks