Packard Forum Index » V-8 (1955-56)

Hi,

Does anybody know where I can obtain a replacement, NOS or overhauled power piston assembly for the BTV as fitted to a 1955 400 or maybe a replacement poppet valve and diaphragm kit.
I recently overhauled my BTV with a kit from Max due to loss of braking efficiency and discovered fluid had leaked into the power section and has contaminated the power piston diaphragm and the internal poppet valves are also worn. The overhaul kit did not include these parts for the power piston only the leather outer seal and cord which I have replaced.
The hydraulic section was fully overhauled and is now fine but the power section is not working properly, I am aware of the downfalls of the BTV system and would replace it with something more modern if a direct bolt in replacement kit were available, however I currently don't have the resources or time to try and adapt something else to fit so I am stuck with having to repair what I have for now.
Any help or links to a supplier for these parts would be appreciated.

Regards,

Dave.

QUOTE:
"I am aware of the downfalls of the BTV system and would replace it with something more modern if a direct bolt in replacement kit were available, however I currently don't have the resources or time to try and adapt something else to fit so I am stuck with having to repair what I have for now."

U mite want to ask the BTV experts how often the BTV should be completely rebuilt and how often the entire brake sytem should be purged and filled with new fluid. THEN consider how well that fits your resources and time.

Either way, best wishes on finding the parts u need.
Mite be better off just sending the entire unit to one of the Packard clubs' approved rebuilders. Ed Strain is often recommended.

Hi PackardV8,

I have purged and re-filled the entire braking system and fully overhauled the BTV apart from the power piston internals which unfortunately were not part of the kit. These parts are now letting me down, the hydraulics are fine it's just a vacuum power piston replacement or repair kit I need.

Regards,

Dave.

Joel Ray (packards1@aol.com) has a 52-4 booster side kit on his ebay store now. Might see if he has anything later. If not and the other vendors can't help either, might have to send the entire unit for repair.

PackardDaveUK;

U mite want to read the article in the following thread, Page 2, post #38.

packardinfo.com/xoops/html/modules/newbb ... orum=3&post_id=50325#forumpost50325


Pay close atention to the portion of the article titled "LEAKING".
About 1/2 way thru the "Leaking" paragragh it claims seal replacement is recommended every 3 to 5 years.

OR, let me put it another way:
U just mite find yourself expending the same 'resources and time' all over again 3 to 5 years from now.

The poppets are easily rebuilt by peeling off the old rubber and gluing on some new discs cut from sheet rubber. This will have a very good effect on the "feel" of the unit.

If your diaphragm is cut, then you will have to replace it--I bought one from Sandy Chirco (Tuscan Packard)last year. Otherwise just clean it up and "massage" the brake fluid out from between the two halves. There should be a small hole on the back of the metal center portion that will let it out. In fact, if that little hole is plugged the reaction diaphragm can't do its job and you will get a terrible harsh pedal.

Occasional bleeding and refilling is a good idea for any brake system running conventional fluid, especially in a moist climate. Done every two years it gives all the components a very long service life in my experience. Don't know where the 3-5 years life of the seals info came from. Just did it this morning on a 56 and a 52. Took about 45 minutes apiece.

Hi Ross,

Thanks for the info, I had already ''massaged'' the fluid out of the diaphragm and cleaned it up and the small hole is OK, the diaphragm seems expanded though I don't think there are any holes but I wanted to replace it anyway.
I think the main problem is the poppet valves or probably the atmospheric one not seating. When pressing the pedal I can hear a hissing sound and the engine idle changes as if it is drawing air in, also there is no power boost. The hydraulics are fine and I bled out all the old fluid and replaced it with DOT 5.1
I will try the poppet rubber replacement and still try and get a new diaphragm.

Regards,

Dave.