I will be converting my power drum brakes on the convertable to power disc brakes, can I use the same booster? It looks the same as the one on my SS, is there any difference I should be aware of?

Thks

Rich

I do not know of any difference between the two. You must match the master cylinder to the booster to get the right fit of the pushrod, though. One way to check this out online is to look up the part number for each part at Checker or Autozone web sites. I checked an interchange book which states that the 1970 Chevelle drum booster is a Moraine 5469396 (stamped 2505689) and the disk booster is a Moraine 5469400 (no stamp mentioned). All that being said, I do not really trust those books, so get a second opinion from the Autozone, etc sites.

Why not look at a Hollander interchange book.

Rich

The booster is the same, just get the disc master cylinder and the correct rod and you are good to go. The 69 style disc master is has an oval shaped lid and uses the long rod. The 70-72 style master has the square cap and uses the short rod. I just went all through this on my 70 about 2 months ago.

Tom,

Thks - I know I'll need the rod, just curious where you eneded up getting the correct rod is it sold after market?

Thks

Rich

Rich,

I bought a brand new GM booster and both rods came with it. I would pull the drum master cylider off and check it first. I think those ones have the long rod in it. If it does, just get a MC for a 69 and you're good to go smile.gif .

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I just went out and looked and I have a 69 MC that I am not using. I had it on my 70 then I got the correct one for it. I only had it on the car for a few months so just let me know when you are ready to do the swap, or if you come to Englishtown, I can bring it with me along with the extra rod I have.

Which rod are you talking about, the one that goes in the MC orthe one that goes to the pedal. I just put a new booster from NAPA on a 67 Chevelle with a new MC but when i hook up the rod to the pedal the pedal is only 3 inches from the floor and my stop switch is way to short now, there,s no way it will reach the pedal. Do i need to change one of the rods. Thanks Dirks SS

dirkey, you probably didn't adjust the rod that attaches to the brake pedal properly. That is threaded and it is what sets the pedal location.

When you change the front brakes from drum to disk don't forget to change the proportioning valve.

There is a fork on the end of the rod from the booster that hooks to the pedal. It is adjusted as far as it will go. When i got the carthere was no MC or anything,even the old drum MC was in a box in the car,the rod from it to the pedal was missing. Would that rod be the same lenght as the one in the new Power booster or maybe the fork that hooks to the pedal is different, i dont know it about 3/4 of a inch to short. I,m going to try and make a fork that is a little longer than the one i got with the disc brake setup which is off a 69 Camaro, the rod in that booster was even shorter. I just bought a new booster from Napa and is is for a 67 Chevelle so it might be the fork, What do you guys think Thanks Dirkey

I believe there is two holes in the brack pedal. Bottom hole for manuel, and top hole for booster........or is that reverse???

Pat

If I remember right the rod is 2.5" from the booster to the master cyl. Did you put that in? not the rod that hooks to the pedal, this is the one that sticks out when you remove the m/c

Hi everyone. This is Todd from The Right Stuff. I have a couple of notes about this thread. There are generally two holes in the brake pedal. Pat, you did have it reversed, the top hole is used for manual brakes. The brackets for the power brake booster tilt the booster up, therefore the rod coming out of the back of the booster naturally aims at the bottom hole in the pedal.

Second, when talking about the rod that comes out of the front of the booster and presses in the piston on the master cylinder, here is what you need to know. There is a lot of variation in rod length and/or master cylinder bore depth, you just need to make sure that this rod is whatever length it needs to be to "almost" be making contact with the master cylinder piston. About 1/8" play is good. If the rod is too long, it will cause your brakes to drag, and if it is too short you will have a low pedal. Make sure that the master cylinder will slide freely onto the booster studs until it makes contact with the booster!

Here is an article I wrote about boosters

http://www.getdiscbrakes.com/rightstuff/TechStuff/TipsTricks/Choosingthecorrectboosterbrackets/tabid/90/Default.aspx

E-mail questions to todd@getdiscbrakes.com