Packard Forum Index » Modification Discussion

I'd also be curious to see what you did. I have one photo of a power brake booster installed on a late 30s model. Booster looks to be mounted on top of the frame rail adjacent to the starter but no photos of the pedal or actual mounting arrangement.

Since the 48 only had manual brakes with the pedal thru the floor did you use one of the all in one floor pedal actuated frame mounted underfloor units common in street rods or did you custom make a suspended pedal with a separate booster/cylinder or do something with the original pedal in order to mount where you did?

Underfloor options become limited on the 51-6 chassis because of space. Anything underfloor 51 or later gets a bit cramped because of the narrower frame rail depth. In 55-6 there is a farther limitation because the torsion bar cuts across the premium space where a brake booster assy could be installed. Frame depth again limits the size of the booster. Steering box location and pedal ratio limitations mess with a modern style booster mounting in the space where the original BTV unit was installed.

Herb Shriner, my favorite comedian, was killed (along with his wife) in 1970 when the brakes failed on his Avanti...which had a single chamber master cylinder. Tragic loss. So...for heaven's sake get a two chamber master cylinder for your car.

Certainly would fit...I'll see what I can do.

I used the original brake pedal and fabricated brackets for the booster assembly which fits between the frame rail and the oil pan. My installation is complicated because I'm running a GM 700R4 transmission so I've fabricated engine rear mounts in the same area as the brake booster. I had to lower the booster and user a 'stepped' pushrod from the pedal to the booster. This is why I had to lower the sheet metal splash between the frame and the oil pan.

I felt that rear engine mounts were necessary because of the elimination of the original mounts were on either side of the overdrive transmission. The automatic transmission only allowed for bell housing mounts and tail shaft mounts. I had a 1" thick adapter plate available to which I could bolt fabricated rear engine mounts.

How much narrower is the later model frame?

Here are some photos of the installation. I measure a little over 8" between the pan flange and the frame.

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  Looking Up and Aft.jpg (256.56 KB)

Here are some photos of the installation. I measure a little over 8" between the pan flange and the frame.

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  Aft Looking Up.jpg (0.00 KB)

Another photo.

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  Looking Up and Aft.jpg (256.56 KB)

P/N's from Pirate Jack:
PB7537 Dual Booster
MC1322H Master Cylinder (4 Port)
PV2K-1BM Proportional Valve

10 lb front and 2 lb rear residual valves installed in the respective lines. Used Eastman flaring tool...easy.

The 4 port Master Cylinder allows installation of a hydraulic brake light switch. Also...the folks at Pirate Jack are very helpful.

Packard didn't give a depth measurement on the 48-50 frames but 51-4 is 6" and 55-6 is 5". There is probably another inch between the top of frame and body on all years.

The 51 frame was apparently smaller or weaker than earlier models. Packard issued service bulletin 50T-41 advising mechanics that had been using a single floor jack positioned under the center X member to lift cars not to do so on 24th series models.

Using the dual 7" booster which IIRC has about a 7 1/2" diameter at the section joining flange would under best circumstances on a 55-6 leave almost 2" hanging down below the frame. I think that much unprotected could leave the booster vulnerable to road junk.

I think you're right. I'm only marginally happy with my location but at least I have some high-strength tinfoil to protect the installation. The original sheet metal splash will give some water protection.

The booster is 'out of sight' right now. I thought hanging it on the firewall would be very unsightly. Of course the AC compressor on top of the engine is sort of a red flag that the setup is not exactly original.