converting to dual master cylinder questions

[cometcougar]

Hi all. Has anyone here ever switched from a single bowl master cylinder to a dual master cylinder? (I tried the search feature above, but didn't find any previous threads with specific info.) I found a tech article at CJ Pony Parts on doing this switch on an early Mustang, but I still have a question I thought someone here might be able to help me with. It looks to me like the brake light circuit is attached directly to the "nose" (or front) of the master cylinder on my 60 Comet (manual drum brakes). A 67 dual master cylinder is not going to have a place for me to hook that up, is it? Therefore, wouldn't I need to fabricate a new stop light switch to attach to the pedal arm somehow? If anyone here has encountered this kind of situation already, I would be very grateful for your insight and experience.

[pbrown]

You can plumb the pressure switch to a brass T-fitting.

A better solution would be to buy a Ford truck brake light switch that mounts under the dash. It's an easy project. Look under your dash at the brake pedal pivot point. You'll see a rubber bumper that is used when you let up on the brake. Remove that bumper and attach the brake light switch to that location. Extend the two wires from the engine bay to under the dash and hook them to the switch.

http://www.partsamerica.com/productdetail.aspx?MfrCode=SMP&MfrPartNumber=SLS66&PartType=422&PTSet=A

This switch is a normaly closed unit.

As for the master cylinder - make sure you get a drum/drum version or a disk/drum depending on what brakes your car has. If you are keeping the drums, then get the drum/drum version.

[cometcougar]

Thanks for the help. I really appreciate it.

[redfalken]

Go for the switch on the pedal if you can. It's really easy and I hear they are way less prone to fail on you as the hydraulic switch is. I installed one. Plus there are 3 less places on the brake line for leaks to occur.

Thought I had photos of mine but can't find them.

[Jeff W]

I used the brass T-Fitting and it has worked well. The dual master cylinder is a great upgrade. One of the FCA newsletter last year had an article on the conversion. The whole job would cost much lass than $100 if you limit it to the bare necessities. I replaced all four wheel cylinders, shoes, two drums, hardware and made all new brake lines. It was probably around $300 and about 6 hours work. Let me know how I can help with pictures or advice. Jeff

[cometcougar]

I put in my dual resevoir master cylinder yesterday, and also switched over to the brake light switch under the dash, and everything seems to be working great. Thanks a bunch to ya'll for your help and expertise. It is great to have a forum like this to get ideas and suggestions before tackling a project.

[Jeff W]

Nice work on the best upgrade you can do to the old girl. Welcome to 1967 technology!

[redfalken]

And I'm betting it really wasn't that hard [thumb] Even kinda satisfying when you step back and check it out. At least now you know what condition the brake system is in.

Unless a car is a museum piece or a trailer queen, put in a dual. Not only is a single dangerous for the people in the car but also anyone in its way when something goes wrong.

[cometcougar]

Exactly as Redfalken said it wasn't all that hard, and satisfying. I actually think my favorite part was when it came to to bleed the lines, I had my daughter out there pushing the brake pedal for me while I opened and closed the bleeders. It is very satisfying sharing this hobby with the kids, just like my dad did with me since I was very young.

[redfalken]

This just was posted recently on the Comet East site. Looks to be almost exactly like you would do on a Falcon.

http://www.cometeastcarclub.org/PDFs/Conversion_of_SingleBowl_to_Duel_BowlMasterCylinde r.pdf

[cometcougar]

That's a well-done article. I really appreciated all the assistance and advice I got from this site when I tackled this job. It was not too hard, and not too expensive, and is much safer now.

[Jeff W]

This just was posted recently on the Comet East site. Looks to be almost exactly like you would do on a Falcon.

http://www.cometeastcarclub.org/PDFs/Conversion_of_SingleBowl_to_Duel_BowlMasterCylinde r.pdf


The article is well done but I think neglected to mention the trouble with finding the 8" lines with the 1/2-20 and 9/16-18 thread sizes found on the new Master Cylinder.

You can use adapters - like those found here:

http://www.tperformance.com/street_rod_store/4600/master_cylinder_-boss_bore-_adapter_fittings/

or use the correct size tube nut and just reflare the 8" tubes - found here:

http://www.ultrastang.com/Page.asp?PageID=4

If someone finds the 8" tubes with the proper size fittings for the master cylinder on one side and the little guys on the other, please post.

[cometcougar]

For the short brake lines needed for the conversion, I got this kit from CJ Pony Parts, which is actually designed to convert a 65-66 Mustang. I had to rebend the lines some, but otherwise they fit perfectly with the right size fittings on each end.

http://www.parts123.com/parts123/yb.dll?parta~partsort

They also have a brief but pretty good tech article for doing the swap (on a 65-66 Mustang) on the CJ Pony Parts website.

http://www.cjponyparts.com/NewTechDualMC.aspx

EDIT: For some reason that first link doesn't work, but if you click the second one, there is a link at the bottom of that page that will take you to the page where you can order the parts.
I got my master cylinder at Napa. They were out of the brake light switch that mounts on the brake pedal arm, so I went over to Autozone and got that.

[Jeff W]

Part#
MU14200O

This is great! The first link didn't work but the second took me to the right spot. It's worth the $17.00 to avoid the adapters. This makes for a cleaner look with less potential for leaks. Thank you.

[jeff0547]

The last post was exactly 6 years ago and none of the product links are still working. :doh:
Here's the latest link as of: 11-20-14.

http://www.cjponyparts.com/catalogsearch/result/?q=dual+master+cylinder+conversion+kits