what brake booster do I have?

[64stpside]

Here's what's up with this truck.....
The booster went bad on my 64 c10 (4 wheel drum brakes). I don't think this was the original booster and bracket setup. I ordered this one from rock auto :
https://www.rockauto.com/en/moreinfo...=1351&jsn=1351
It looks nothing like what was on it and it's about 2 in narrower than the old one as well.....but rockauto says this is what's supposed to be on it....The holes in the bracket on the new booster didn't line up ( neither did the top holes of the old booster) but I thought maybe just a different design, drilled some new holes and mounted it up. The pedal is really hard to push.

Things I've checked so far:
I had air hissing from the booster when pulling the the valve off the booster when the truck is off, no hissing when pushing the pedal when the truck is running. When the truck was off, I let it roll down the driveway and it's easier to push the pedal down than when the truck is running with the booster hooked up????? Weird right.....

Unless I'm missing something, I think I should get the same booster I had on it but I don't know what it came off of. It has delco moraine stamped on it. I think this originally came off a disc/drum set up as the master cyl that was on it had a bigger reservoir in the front than the rear (I put a 4 drum mast cyl on it). When the old booster worked, the truck stopped very very well. Is the old booster a dual diaphragm? The one I got from rockauto is a single. Here's some pics

[Captainfab]

Your old booster appears to be of the '67-'72 design minus the linkage assembly that was used. I'm not sure what the application is for the new booster you got. The original '63-'66 brake boosters had a bracket that angled them to the side and also used a linkage assembly for the ratio correction. Is the intermediate pushrod in the new booster correct for the particular master cylinder that you installed? If your booster and master assembly is not securely bolted to the pedal bracket, it really is not safe.

[64stpside]

Originally Posted by Captainfab

Your old booster appears to be of the '67-'72 design minus the linkage assembly that was used.

I think it's from a 3/4 ton. I swapped the linkage to the new booster.
See the 1st pic in this link:
http://outintheshop.com/faq/Brakes/brakeinfo.html

Originally Posted by Captainfab

I'm not sure what the application is for the new booster you got.

I looked up a booster for a 1964 c10 pickup. Sorry I had the wrong link before.....
https://www.rockauto.com/en/moreinfo...323504&jsn=446

Originally Posted by Captainfab

The original '63-'66 brake boosters had a bracket that angled them to the side and also used a linkage assembly for the ratio correction.

I don't have the original bracket. I had to drill 2 holes in the center of the bracket of the new booster to mount it as the holes in the 4 corners wouldn't line up. I made sure that the clevis rod coming from the pedal was as close to the proper angle as I could get it before drilling the holes. The old booster bracket only had the 2 bottom holes mounted as there were no holes to mount the top bolts.

Originally Posted by Captainfab

Is the intermediate pushrod in the new booster correct for the particular master cylinder that you installed?

Are you talking about the pushrod that comes out of the booster to the master cylinder? If so, it's adjustable.
----------------------------------------------------------------------------------------------
If I can make this new booster work I would like to. It's a single diaphragm which from what I understand works well with 4 wheel drum brakes, the 3/4 ton booster is a dual diaphragm. Last night I swapped my 5/16 fuel line hose I was using to 11/32 vac hose thinking that was my issue (super hard pedal and hard to stop).....no change. Then I checked the vacuum.....18-20 so that's good. Then I pumped up the brakes and started the truck and the pedal went down a little like it should. I'm out of ideas of things to check. I'm thinking I have a bad booster. Could the linkage have anything to do with it? As I stated earlier, the I swapped the lower linkage to the new booster and the truck had no issues with the old booster so I wouldn't think that would be the case. One other thing to point out is the new bracket is shorter than the old bracket.

[The Rocknrod]

I think it looked like this: