Double Diaphram Brake Booster Question ...

[Fast79Chief]

I have the 79 Chief with the 360. It has a factory single booster and cast iron master cylinder. If I read the earlier posts correctly, the Cardone 54-71014 is the right double upgrade part # for my year and M.C.. If the Cardone's are not available, is there another manufacturer part number that will work without messing with the plunger length?

Thanks.

[Fast79Chief]

No members ever done this conversion?

[Stuka]

All the ones I have seen have switched to the 80+ master. I am sure there is a way to use the older cast iron master with one, I am just not sure of what vehicle to cross reference.

[dodgerammit]

What exactly is this mod? What are the benefits?

[Renodemona]

I used the one for a 1982 J20 it bolted right up to the firewall on my 76 Cherokee. I bought a new master with it but it was cast iron too. Just went to Rock Auto and used the 82 J20 from the drop down menus.

[Renodemona]

What exactly is this mod? What are the benefits?

Double Diaphragm puts out a little more boost for power brakes, useful for oversize tires and more precise braking on the trails. Hydro boost puts out even more, but the conversion is a lot more $$$ plus you have to have power steering. It's a good easy mod for low cost, especially if you have to replace the booster or master anyway.

[Fast79Chief]

I used the one for a 1982 J20 it bolted right up to the firewall on my 76 Cherokee. I bought a new master with it but it was cast iron too. Just went to Rock Auto and used the 82 J20 from the drop down menus.

Right, since you bought both late model units, they work together. I'm keeping my 79 M.C. and only want to replace the booster with a D.D.
Having trouble locating a 74 - 80 double diaphragm booster.

[Stuka]

I used the one for a 1982 J20 it bolted right up to the firewall on my 76 Cherokee. I bought a new master with it but it was cast iron too. Just went to Rock Auto and used the 82 J20 from the drop down menus.

Right, since you bought both late model units, they work together. I'm keeping my 79 M.C. and only want to replace the booster with a D.D.
Having trouble locating a 74 - 80 double diaphragm booster.

They didn't exist until the 80's as far as I know. That goes for all makes. Maybe a late 70's C30 or something had them. BUT, there are lots of after market DD boosters out there that fit a wide range of vehicles. If you are ok with not using an OEM product.

[Fast79Chief]

The J20 had them in the 70's. That would be a Cardone 54-71014. No longer available. Like you say, that same diaphragm may be known by another part number ... that is the nature of my original post.

[Fast79Chief]

I used the one for a 1982 J20 it bolted right up to the firewall on my 76 Cherokee. I bought a new master with it but it was cast iron too. Just went to Rock Auto and used the 82 J20 from the drop down menus.

Right, since you bought both late model units, they work together. I'm keeping my 79 M.C. and only want to replace the booster with a D.D.
Having trouble locating a 74 - 80 double diaphragm booster.

They didn't exist until the 80's as far as I know. That goes for all makes. Maybe a late 70's C30 or something had them. BUT, there are lots of after market DD boosters out there that fit a wide range of vehicles. If you are ok with not using an OEM product.

If you do a search for a 1977 J20 you will see that they had a factory double diaphragm with the cast iron master cylinder. That same diaphragm will fit 74-80 Wagoneer, Cherokee, J10 with cast iron master cylinder. It's very important to match the proper diaphragm to the proper master cylinder because of rod length and pressure setting.
Those of us who need the 74-80 double diaphragm were using the Cardone 54-71014. They stopped remanufacturing them.
My question from my original post has been, "Is this diaphragm available under another part number?"
As we all know, Cardone was not the Original manufacturer.
If we learn who made these, we may be able to source more of them from another parts house.
Maybe one of you guys that has
access to OEM part numbers can provide the # for a 77 J20 double diaphram?
My thinking is either Morain or Bendix, etc., made these back in the day. That's the info we need.
Thanks.