The Stovebolt Site Forums The Shop Area Driveline Dual Master Cylinder adapter

Hi
I am converting over to a dual master cylinder on a 1st series 1954, 1/2 ton truck. It will stay all drums. I purchased an adaptor fitting from Ecklers and made by Classic Performance (4756MCA). I have not installed it yet. The adaptor, which looks nothing at all like the one in Ecklers Catalog, mounts the new master cylinder back about 6 or 7" aft of the original location. It will be impossible to check and fill the new MC through the old access hole in the cab floor. It also looks like a real POA to get the retainer screw off the MC cap to check or fill. I called Classic Performance and only get a message that they are having a "high call volumes" and to leave a message. Eckler says the part should fit.

Questions:
Will this install really require another hole in the floor to get access? If so it gets returned.

Is there another fitting available which allows access through the original floor hole?

Does anyone know why the MC gets pushed this far aft? I have been an engineer for 30 years and I can't see an obvious reason. It looks like there should be plenty of room to mount it very close the original location.

Am I missing something obvious? The installation instructions from Classic seem pretty clear. The linkage looks like it will fit (eyeball). It just seems like a horrible design for access.

Anyway, If someone has been through this before I would like to hear from you.

Thanks
John

I think you purchased the wrong adapter from Ecklers. They offer two styles, early and late for '55 and later. This is the one you should have. It fits in the original location.

http://www.ecklerstrucks.com/chevy-...sssell=Homepage_Featured_Category_Brakes

Check out my bolt bucket so you can see how its supposed to be installed. Yes, Drew has it right, that is the adapter you need. If you have more questions, don't hesitate to ask!

DrewP:
I ordered that part numbered. It is a Classic Performance part. Eckler claims the part number is correct. Classic Perf does not answer their phone. The delivered adapter looks nothing like that. The instruction sheet looks like the delivered part and says it will fit 47 through 54. I will attach the sheet in my next post. It pretty clear.

Deve:
I saw your photo's. That is one absolutely fantastic looking truck and I am wallowing in sinful envy. I was wondering what mine looked like 59 years ago. Back to the adapter: Those adapter pics are good. I was expecting to get one that looks exactly like what is on your truck. Take a look at the installation sheet, you will see what I mean. Its funny even the install instructions say it will fit a 54. Where did you buy yours?

Thanks for help. I really do appreciate it. Check out the instructions that came with it in the next post.
John

The installation sheet from the Classic Perf 4756MCA.

photobucketinstructrions

Even though the directions pic of the adapter is different than the catalog pic it is usable. I think what is happening is that you are mounting the adapter exactly as pictured in instruction pic #4. What you just need to do is flip the bracket 180 degrees so the MC mounting plate is now closer to the brake pedal. Look at Deve's picture closely.
http://s160.photobucket.com/user/st...628_zpsd0e8c892.jpg.html?sort=3&o=60

That was the first thing I tried. First thing before looking at the instructions, that is. It did not fit. The brace arms hits the cylinder housing. Even if it fit, the bolt line on the adapter is not on the centerline of the cylinder. When you flip the adaptor over the cylinder is shifted too high and will not align with the pedal clevis.

Anyway, thanks for giving it some thought. Its hard when you don't have the part in your hands.

I think this one is going to be returned. Does anyone know of an adapter that actually fits??

I bought mine from a Stovebolter here on the forum that was making them for awhile. If I can find my links I'll let you know.

Latest Brothers Catalog page 109. If you want to go to the Brothers site to see it, its called 1947-59 Dual Master Cylinder Conversion. (Part No. DMC5900). Doesn't matter that its Brothers, its the same company that makes them all. Don't worry that the cylinders do not line up. The bracket will put your new MC 3/4" too far towards the passenger side, then the plunger rod has a fix for that. Look real close at the pics and if you need more clarification, let us know.

The swiveling end on the plunger rod has a long bolt and a spacer to make it end up in the right place.